tag:theconversation.com,2011:/fr/topics/vitamin-d-3191/articlesVitamin D – The Conversation2024-03-25T19:05:37Ztag:theconversation.com,2011:article/2241442024-03-25T19:05:37Z2024-03-25T19:05:37ZSummer’s over, so how much sun can (and should) I get?<figure><img src="https://images.theconversation.com/files/583381/original/file-20240321-22-89ys3l.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6016%2C3998&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/woman-sitting-on-beach-shore-during-daytime-f9HmXiFNKXM">Tamara Bellis/Unsplash</a></span></figcaption></figure><p>As we slide of out summer, you might be wondering how careful you need to be about sun exposure. Excessive exposure causes <a href="https://www.cancer.org.au/about-us/policy-and-advocacy/prevention-policy/national-cancer-prevention-policy/skin-cancer-statistics-and-issues/uv-radiation">skin cancer</a>, but sun exposure also has <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9976694/">benefits</a>. How do you balance the two? </p>
<p>A new <a href="https://www.sciencedirect.com/science/article/pii/S1326020023052949?via%3Dihub">position statement</a> from cancer, bone health and other experts <a href="https://www.assc.org.au/wp-content/uploads/2023/01/Sun-Exposure-Summit-PositionStatement_V1.9.pdf">aims to help</a> Australians balance the good and bad effects of sun exposure by taking into account their skin colour, risk of skin cancer, and where they live.</p>
<h2>What are the benefits of sunlight?</h2>
<p>Ultraviolet (UV) radiation (the wavelengths in sunlight that cause skin cancer) also leads to vitamin D production. <a href="https://dermnetnz.org/topics/vitamin-d">Vitamin D</a> is very important for maintaining strong bones, and is likely to have <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9976694/">multiple other health benefits</a>. </p>
<p>But vitamin D probably isn’t the whole story. Sunshine, including UV radiation, is thought to affect health in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9976694/">other ways</a> such as improving our mood and reducing the risk of autoimmune diseases and infections. So for many people, avoiding the sun and taking a vitamin D supplement may not be the best approach.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/vitamin-d-supplements-can-keep-bones-strong-but-they-may-also-have-other-benefits-to-your-health-219521">Vitamin D supplements can keep bones strong – but they may also have other benefits to your health</a>
</strong>
</em>
</p>
<hr>
<h2>How much time does it take to make vitamin D?</h2>
<p>It’s complicated, but for most people and most of the year across most of Australia, it’s a lot less than you think.</p>
<p>The <a href="https://onlinelibrary.wiley.com/doi/10.1111/php.13854">amount of time needed</a> depends on the amount of skin covered by clothing and the intensity of UV radiation (indicated by the UV index). More skin exposed and higher UV index equate to less time needed. </p>
<p>Both the UV index and the amount of the year that UV radiation is high increase as you get closer to the equator. In summer, all of Australia is bathed in sunshine. But in winter, opposite ends of the country have <a href="https://onlinelibrary.wiley.com/doi/10.1111/php.13854">very different exposures</a>. </p>
<p>In summer, everybody except those with deeply pigmented skin can make enough vitamin D in <a href="https://www.sciencedirect.com/science/article/pii/S1326020023052949?via%3Dihub">just five minutes</a> between 9am and 3pm, anywhere in Australia, provided they are wearing shorts and a T-shirt. </p>
<p>In winter it’s a different story. In <a href="https://www.sciencedirect.com/science/article/pii/S1326020023052949?via%3Dihub">Darwin and Brisbane</a>, 5–10 minutes between 10am and 3pm will do the trick, but in <a href="https://www.sciencedirect.com/science/article/pii/S1326020023052949?via%3Dihub">Hobart</a>, factoring in winter clothing, it will take nearly an hour in the middle of the day.</p>
<p>Hover your mouse over the lines below to see the length of exposure needed at specific times of day.</p>
<p><iframe id="X5szQ" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/X5szQ/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Staying out for longer than needed doesn’t necessarily make more vitamin D, but it <a href="https://www.sciencedirect.com/science/article/pii/S1326020023052949?via%3Dihub#bib25">does cause skin damage</a>. </p>
<h2>Hang on, what about those with darker skin?</h2>
<p>People with deeply pigmented, brown to black skin accumulate both vitamin D and DNA damage at a much slower rate than people with lighter skin tones. </p>
<p>When UV radiation hits a DNA strand, it causes the DNA to become distorted. If the distortion isn’t fixed, it will cause a mistake when the DNA is copied for a new cell, causing a permanent mutation that sometimes leads to cancer. </p>
<p>Melanin, the brown pigment in the skin, absorbs UV photons before that can happen, and the high melanin content in the darkest skin tones provides <a href="https://faseb.onlinelibrary.wiley.com/doi/full/10.1096/fj.201701472R">60 times</a> as much UV protection as the small amount in very fair skin. </p>
<p>The flip side is the risk of vitamin D deficiency is much higher than the risk of skin cancer. </p>
<p>The new statement accounts for this by putting people into <a href="https://www.sciencedirect.com/science/article/pii/S1326020023052949?via%3Dihub">three groups</a> based on their risk of skin cancer, with specialised advice for each group.</p>
<h2>Highest skin cancer risk</h2>
<figure class="align-center ">
<img alt="Red-headed woman" src="https://images.theconversation.com/files/583354/original/file-20240321-22-qfrbj0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583354/original/file-20240321-22-qfrbj0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583354/original/file-20240321-22-qfrbj0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583354/original/file-20240321-22-qfrbj0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583354/original/file-20240321-22-qfrbj0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583354/original/file-20240321-22-qfrbj0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583354/original/file-20240321-22-qfrbj0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">People with pale skin that burns easily are in the high-risk group.</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/close-up-photo-of-person-with-nose-ring-2146042/">Luriko Yamaguchi/Pexels</a></span>
</figcaption>
</figure>
<p>This includes people with very pale skin that burns easily and tans minimally, but also people with darker white or olive skin who can tan easily but have extra skin cancer risk factors because they: </p>
<ul>
<li>have had <strong>skin cancer</strong> before</li>
<li>have a <strong>family history</strong> of melanomas</li>
<li>have many <strong>moles</strong></li>
<li>are taking <strong>immunosuppressant</strong> medications.</li>
</ul>
<p>For these people, the harms of sun exposure almost certainly <a href="https://www.sciencedirect.com/science/article/pii/S1326020023052949?via%3Dihub">outweigh the benefits</a>.</p>
<p>These people should wear sunscreen every day the <a href="https://www.arpansa.gov.au/our-services/monitoring/ultraviolet-radiation-monitoring/ultraviolet-radiation-index">UV index</a> is forecast to get to <a href="https://www.assc.org.au/peak-health-bodies-recommend-new-approach-to-sunscreen-use/">three or more</a>, and use the <a href="https://www.cancer.org.au/cancer-information/causes-and-prevention/sun-safety/be-sunsmart">five sunsmart steps</a> whenever the UV index is above three: </p>
<ul>
<li><strong>slip</strong> on clothing covering as much of the body as possible</li>
<li><strong>slop</strong> on SPF30+ sunscreen on areas that can’t be covered up</li>
<li><strong>slap</strong> on a hat</li>
<li><strong>seek</strong> shade</li>
<li><strong>slide</strong> on sunglasses.</li>
</ul>
<p>They shouldn’t spend time outdoors deliberately to make vitamin D, but should discuss vitamin D supplements with their doctor. </p>
<h2>Intermediate skin cancer risk</h2>
<figure class="align-center ">
<img alt="Man drinks soda from a cup" src="https://images.theconversation.com/files/583358/original/file-20240321-20-42mfoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583358/original/file-20240321-20-42mfoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583358/original/file-20240321-20-42mfoy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583358/original/file-20240321-20-42mfoy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583358/original/file-20240321-20-42mfoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583358/original/file-20240321-20-42mfoy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583358/original/file-20240321-20-42mfoy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">People with skin that tans easily are at intermediate risk.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/man-in-gray-shirt-drinking-from-white-ceramic-mug-TfqM6Kg2Rh4">Jarritos/Unsplash</a></span>
</figcaption>
</figure>
<p>This means people with dark white/olive skin that sometimes burns but tans easily, and who don’t have other skin cancer risk factors. </p>
<p>These people should still apply sunscreen as part of their usual routine on all days when the UV index is forecast to get to <a href="https://www.assc.org.au/peak-health-bodies-recommend-new-approach-to-sunscreen-use/">three or more</a>, but they can spend enough time outdoors to get a “dose” of vitamin D on most days of the week. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-how-does-the-sun-help-your-body-make-vitamin-d-139670">Curious Kids: how does the Sun help your body make vitamin D?</a>
</strong>
</em>
</p>
<hr>
<p>Once the time needed for their vitamin D dose is up, they should also use the <a href="https://www.cancer.org.au/cancer-information/causes-and-prevention/sun-safety/be-sunsmart">slip-slop-slap-seek-slide</a> steps to avoid accumulating DNA damage. </p>
<p>If they’re unable to do this because of health or lifestyle factors, like being housebound, working night shifts, or always covering up with clothing, they should see their doctor about whether they need vitamin D supplements.</p>
<h2>Lowest skin cancer risk</h2>
<figure class="align-center ">
<img alt="Family members sit outside, laughing" src="https://images.theconversation.com/files/583359/original/file-20240321-16-fk5ehb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583359/original/file-20240321-16-fk5ehb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583359/original/file-20240321-16-fk5ehb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583359/original/file-20240321-16-fk5ehb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583359/original/file-20240321-16-fk5ehb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583359/original/file-20240321-16-fk5ehb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583359/original/file-20240321-16-fk5ehb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">People with skin that rarely burns have the lowest risk of cancer.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/two-persons-staring-at-each-other-jg_t3PBq5Jo">Eye for Ebony/Unsplash</a></span>
</figcaption>
</figure>
<p>This covers people with deeply pigmented brown to black skin that rarely or never burns. </p>
<p>These people can <a href="https://www.sciencedirect.com/science/article/pii/S1326020023052949?via%3Dihub#bib14">safely spend enough time outdoors</a> to make vitamin D and get the other benefits of sunshine. But because more time is needed, it can be difficult, particularly when the weather is cold. Vitamin D supplements might be needed. </p>
<p>They don’t need to routinely protect their skin, but might need to <a href="https://www.cancer.org.au/cancer-information/causes-and-prevention/sun-safety/be-sunsmart">slip-slop-slap-seek-slide</a> if they are outdoors for more than two hours.</p>
<h2>How do I get the feel-good effects of sunshine?</h2>
<p>Spending time outdoors in the early morning is the best way to get the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9976694/">feel-good effects</a> of sunshine. An early morning walk is a great idea for all of us, but it won’t make vitamin D.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/should-i-be-getting-my-vitamin-d-levels-checked-211268">Should I be getting my vitamin D levels checked?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/224144/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Katie Lee receives funding from the National Health and Medical Research Council for a student stipend. </span></em></p><p class="fine-print"><em><span>Rachel Neale receives funding from the National Health and Medical Research Council for grants related to vitamin D and sunscreen. She was the lead author of the manuscript describing the revised position statement and chaired the Summit that led to the revised recommendations.</span></em></p>Excessive exposure causes skin cancer, but sun exposure also has benefits. How do you balance the two?Katie Lee, PhD Candidate, Dermatology Research Centre, The University of QueenslandRachel Neale, Principal research fellow, QIMR Berghofer Medical Research InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2183442023-12-21T23:19:57Z2023-12-21T23:19:57ZGot period pain or cramps? What to eat and avoid, according to science<figure><img src="https://images.theconversation.com/files/566750/original/file-20231219-27-7x7oaq.jpg?ixlib=rb-1.1.0&rect=1%2C1%2C1276%2C848&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.pexels.com/photo/woman-suffering-from-a-stomach-pain-5938362/">Sora Shimazaki/Pexels</a></span></figcaption></figure><p>Painful periods are common. More than half of people who menstruate have some pain for up to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8943241/">three days a month</a>, typically throbbing or cramping in the lower abdomen. </p>
<p>Digestive changes – such as vomiting, gas, bloating, diarrhoea and a “bubbling gut” – are also <a href="https://bmcwomenshealth.biomedcentral.com/articles/10.1186/s12905-018-0538-8">common</a> around the time of menstruation. </p>
<p>There are many <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8943241/">treatments</a> for period pain (known medically as dysmenorrhoea). Not all these treatments are well-tolerated or work for everyone.</p>
<p>We’re learning more about food’s role in influencing <a href="https://theconversation.com/9-signs-you-have-inflammation-in-your-body-could-an-anti-inflammatory-diet-help-210468">inflammation</a> in our body. So, could eating or avoiding certain foods <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5963185/">help</a> with painful periods? Here’s what we know based on high-quality research.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/from-sharp-butt-pains-to-period-poos-5-lesser-known-menstrual-cycle-symptoms-191352">From sharp butt pains to period poos: 5 lesser-known menstrual cycle symptoms</a>
</strong>
</em>
</p>
<hr>
<h2>Foods that may relieve period pain or cramps</h2>
<p><strong>Foods containing omega-3 fatty acids</strong></p>
<p>Foods rich in omega-3 fatty acids include chia seeds, walnuts, flaxseeds, salmon, herring, sardines, mackerel, oysters and edamame beans. Omega-3 fatty acids are naturally present in oils including fish, cod liver, algal, krill, flaxseed (linseed), soybean and canola oils.</p>
<p>Omega-3 fatty acids <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3257651/">affect</a> how our cells function and the signalling pathways associated with inflammation and pain. </p>
<p>Earlier this year, researchers published a <a href="https://pubmed.ncbi.nlm.nih.gov/37545015/#:%7E:text=Meta%2Danalysis%20(n%20%3D%208,0.51)%20at%20reducing%20dysmenorrhoea%20pain.">meta-analysis</a> where they combined and analysed all data available on the impact of omega-3 fatty acids on period pain. They found diets high in omega-3 fatty acids (including supplements of 300-1,800 milligrams a day) over two to three months may reduce pain, and pain medication use, in people with painful periods.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/566754/original/file-20231219-15-vu9xne.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Open sardine can, parsley, cut lemon on wooden table." src="https://images.theconversation.com/files/566754/original/file-20231219-15-vu9xne.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566754/original/file-20231219-15-vu9xne.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566754/original/file-20231219-15-vu9xne.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566754/original/file-20231219-15-vu9xne.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566754/original/file-20231219-15-vu9xne.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566754/original/file-20231219-15-vu9xne.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566754/original/file-20231219-15-vu9xne.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sardines and other oily fish are rich in omega-3 fatty acids.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/open-can-sardines-preserves-oil-on-1636046179">BearFotos/Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/are-fish-oil-supplements-as-healthy-as-we-think-and-is-eating-fish-better-212250">Are fish oil supplements as healthy as we think? And is eating fish better?</a>
</strong>
</em>
</p>
<hr>
<p><strong>Foods high in vitamin D</strong></p>
<p>Foods high in vitamin D include trout, salmon, tuna and mackerel, as well as fish liver oils. Small amounts are also found in beef liver, egg yolk and cheese. Mushrooms contain varying levels of vitamin D, and you can <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6213178/">boost</a> this by exposing them to direct midday sunlight for 15-120 minutes. </p>
<p>The body can make vitamin D when it gets sunlight exposure and you can also get vitamin D from supplements.</p>
<p>Vitamin D <a href="https://pubmed.ncbi.nlm.nih.gov/24262718/">may help</a> reduce the factors that cause inflammation in the uterus. This includes levels of hormone-like molecules called prostaglandins. </p>
<p>A 2023 <a href="https://www.mdpi.com/2072-6643/15/13/2830#B11-nutrients-15-02830">meta-analysis</a> showed women who received weekly doses of vitamin D greater than 50,000 IU (or international units) had relief from period pain, regardless of how long and how often women took the vitamin.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/should-i-be-getting-my-vitamin-d-levels-checked-211268">Should I be getting my vitamin D levels checked?</a>
</strong>
</em>
</p>
<hr>
<p><strong>Foods high in vitamin E</strong></p>
<p>Foods rich in vitamin E include seeds (particularly sunflower seeds), nuts (particularly almonds, hazelnuts and peanuts) and spinach, broccoli, kiwifruit, mango and tomato. </p>
<p>There is some evidence vitamin E supplements reduce period pain. In a well-conducted <a href="https://pubmed.ncbi.nlm.nih.gov/15777446/">trial</a> run over the course of four periods, women took vitamin E supplements (90 milligrams, twice a day) for five days, beginning two days before the expected start of the period. This significantly reduced the severity and duration of period pain. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/566756/original/file-20231220-17-d2da5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Woman tipping out nut mix into palm of hand" src="https://images.theconversation.com/files/566756/original/file-20231220-17-d2da5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566756/original/file-20231220-17-d2da5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566756/original/file-20231220-17-d2da5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566756/original/file-20231220-17-d2da5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566756/original/file-20231220-17-d2da5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566756/original/file-20231220-17-d2da5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566756/original/file-20231220-17-d2da5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Seeds and nuts are rich in vitamin E.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/hands-holding-jar-nuts-dried-fruits-1112521214">NazarBazar/Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/i-have-painful-periods-could-it-be-endometriosis-101026">I have painful periods, could it be endometriosis?</a>
</strong>
</em>
</p>
<hr>
<h2>Foods that may worsen period pain or cramps</h2>
<p><strong>Highly processed foods</strong></p>
<p>Highly processed foods include energy-dense, nutrient-poor foods such as takeaways, chips, biscuits, doughnuts, processed meats and soft drinks. </p>
<p>Research findings on the impact of a diet high in processed foods on period pain vary. A 2019 <a href="https://karger.com/goi/article/84/3/209/153726/Nutrition-as-a-Potential-Factor-of-Primary">review</a> found sugar consumption had little association with painful periods. </p>
<p>However, some observational studies (which do not involve an intervention) suggest women who eat more processed foods may have more intense period pain. For example, a <a href="https://pubmed.ncbi.nlm.nih.gov/19468949/">2009 study</a> found adolescent females who ate fast or processed foods for two days or more a week reported more period pain compared with those who did not. Therefore, eating less processed food may be something to consider. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/8-everyday-foods-you-might-not-realise-are-ultra-processed-and-how-to-spot-them-197993">8 everyday foods you might not realise are ultra processed – and how to spot them</a>
</strong>
</em>
</p>
<hr>
<p><strong>Caffeine</strong></p>
<p>Foods high in caffeine include coffee, energy drinks and some processed energy bars. Caffeine intake is <a href="https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwij7LmPxfSCAxV5d_UHHRnyDyUQFnoECBIQAQ&url=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC4222008%2F&usg=AOvVaw2mEjyMadOB1D6geQgAwckc&opi=89978449">associated with</a> menstrual pain. </p>
<p>Although we don’t know the precise underlying mechanism, researchers think caffeine may narrow blood vessels, which limits blood flow, leading to stronger cramps.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/566757/original/file-20231220-23-u1d2j2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Tired woman staring at bowl of breakfast, cereal and cup on kitchen table" src="https://images.theconversation.com/files/566757/original/file-20231220-23-u1d2j2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566757/original/file-20231220-23-u1d2j2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566757/original/file-20231220-23-u1d2j2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566757/original/file-20231220-23-u1d2j2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566757/original/file-20231220-23-u1d2j2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566757/original/file-20231220-23-u1d2j2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566757/original/file-20231220-23-u1d2j2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Avoiding coffee may help your period pain.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/woman-does-not-want-eat-her-151886987">Lolostock/Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/nope-coffee-wont-give-you-extra-energy-itll-just-borrow-a-bit-that-youll-pay-for-later-197897">Nope, coffee won't give you extra energy. It'll just borrow a bit that you'll pay for later</a>
</strong>
</em>
</p>
<hr>
<p><strong>Alcohol</strong></p>
<p>Drinking alcohol is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4859868/">not</a> a recognised risk factor for painful periods. However, chronic heavy alcohol use reduces levels of <a href="https://academic.oup.com/alcalc/article/55/2/164/5734241">magnesium</a> in the blood. Magnesium is an important factor in relaxing muscles and supporting blood flow.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/adele-called-herself-a-borderline-alcoholic-but-is-that-a-real-thing-215987">Adele called herself a 'borderline alcoholic'. But is that a real thing?</a>
</strong>
</em>
</p>
<hr>
<h2>A healthy, balanced diet is your best best</h2>
<p>Having a healthy, balanced diet is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7071223/">one of the best ways</a> we can support our own health and prevent future chronic conditions. This can help reduce inflammation in our bodies, thought to be the main way diet can help people with painful periods.</p>
<p>If you are looking for tailored dietary advice or a menstrual health meal plan, speak with an <a href="https://member.dietitiansaustralia.org.au/Portal/Portal/Search-Directories/Find-a-Dietitian.aspx">accredited practising dietitian</a>.</p>
<p>It’s important to stress, however, that diet alone cannot treat all forms of menstrual pain. So if you are concerned about your painful periods, check in with your GP who can discuss your options.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/9-signs-you-have-inflammation-in-your-body-could-an-anti-inflammatory-diet-help-210468">9 signs you have inflammation in your body. Could an anti-inflammatory diet help?</a>
</strong>
</em>
</p>
<hr>
<p><em>This article has been updated to reflect the correct date of a review that found sugar consumption had little association with painful periods.</em></p><img src="https://counter.theconversation.com/content/218344/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lauren Ball works for The University of Queensland and receives funding from the National Health and Medical Research Council, Queensland Health and Mater Misericordia. She is a Director of Dietitians Australia, a Director of the Darling Downs and West Moreton Primary Health Network and an Associate Member of the Australian Academy of Health and Medical Sciences.</span></em></p><p class="fine-print"><em><span>Emily Burch is an Accredited Practising Dietitian and member of Dietitians Australia. She works for Southern Cross University. </span></em></p><p class="fine-print"><em><span>Pui Ting Wong is a PhD Candidate at The University Queensland (UQ) Centre for Community Health and Wellbeing, and receives the UQ Tuition Fee Offset and Stipend Scholarship. She is also an Accredited Practising Dietitian and a member of Dietitians Australia.</span></em></p>A cup of coffee might help you kick-start your day, but it may actually make painful periods worse. Here’s what else to avoid (and eat) if you have period pain.Lauren Ball, Professor of Community Health and Wellbeing, The University of QueenslandEmily Burch, Lecturer, Southern Cross UniversityPui Ting Wong, PhD Candidate, culinary education and adolescent mental health, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2195212023-12-14T13:19:18Z2023-12-14T13:19:18ZVitamin D supplements can keep bones strong – but they may also have other benefits to your health<figure><img src="https://images.theconversation.com/files/565312/original/file-20231212-21-3lnqwf.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4165%2C2774&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Our ability to make vitamin D declines in the winter.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/leisure-spending-free-time-outside-healthy-538729522">Anetlanda/ Shutterstock</a></span></figcaption></figure><p>Most of us don’t worry about getting vitamin D when the weather’s warm and the sun is shining. But as winter approaches, accompanied by overcast days and long nights, you may be wondering if it could be useful to take a vitamin D supplement – and what benefit it might have.</p>
<p>During the summer, the best way to get vitamin D is by getting a bit of sunshine. Ultraviolet rays (specifically UVB, which have a shorter wavelength) interact with a form of cholesterol called <a href="https://www.ncbi.nlm.nih.gov/books/NBK278935/">7-dehydrocholesterol</a> in the skin, which is then converted into vitamin D. </p>
<p>Because vitamin D production is dependent on UVB, this means our ability to make it <a href="https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/#:%7E:text=From%20about%20late%20March%2Fearly,enough%20vitamin%20D%20from%20sunlight.">declines in the winter months</a>. Vitamin D production also <a href="https://pubmed.ncbi.nlm.nih.gov/24494042/">depends on where you live</a>, with people living nearer to the equator making more vitamin D than those living nearer the poles.</p>
<p>Vitamin D deficiency is a <a href="https://assets.publishing.service.gov.uk/media/5a804e36ed915d74e622dafa/SACN_Vitamin_D_and_Health_report.pdf">problem in the UK</a> during the winter months. This is due to its northerly position and cloudy weather, and lack of time spent outdoors.</p>
<p>One study of over 440,000 people in the UK found that <a href="https://pubmed.ncbi.nlm.nih.gov/33309415/">18% were vitamin D deficient</a> during the winter months. Vitamin D deficiency was even higher in certain ethnic groups – with the data showing 57% of Asian participants and 38% of black participants were vitamin D deficient. This is because the melanin content of skin determines a person’s ability to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5946242/#:%7E:text=Skin%20pigmentation%2C%20i.e.%2C%20melanin%2C,%5B7%5D%20and%20more%20generally.">make UVB into vitamin D</a>. </p>
<p>Given the prevalence of vitamin D deficiency in the UK, and the importance it has for our health, in 2016 the UK’s Science Advisory Council on Nutrition outlined recommendations for the <a href="https://www.gov.uk/government/publications/sacn-vitamin-d-and-health-report#:%7E:text=In%20a%20change%20to%20previous,aged%204%20years%20and%20older">amount of vitamin D</a> people should aim to get in the winter.</p>
<p>They recommend people aim to get ten micrograms (or 400 IU – international units) of vitamin D per day. This would help people avoid severe deficiency. This can be achieved either by taking a supplement, or eating <a href="https://www.bhf.org.uk/informationsupport/heart-matters-magazine/nutrition/ask-the-expert/foods-high-in-vitamin-d">certain foods</a> that are rich in vitamin D – including fatty fish such as herring, mackerel and wild salmon. A 100 gram serving of fresh herring, for example, would have approximately five micrograms of vitamin D. </p>
<p>The clearest benefit of taking a vitamin D supplement is for <a href="https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/">bone health</a>. In fact, vitamin D was <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3899558/">first discovered</a> 100 years ago because of its ability to prevent the disease rickets, which causes weak bones that bend. </p>
<figure class="align-center ">
<img alt="A person's hand holds a vitamin D supplement up towards a sunny sky." src="https://images.theconversation.com/files/565313/original/file-20231212-29-aipxfy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565313/original/file-20231212-29-aipxfy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=387&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565313/original/file-20231212-29-aipxfy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=387&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565313/original/file-20231212-29-aipxfy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=387&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565313/original/file-20231212-29-aipxfy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=486&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565313/original/file-20231212-29-aipxfy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=486&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565313/original/file-20231212-29-aipxfy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=486&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Vitamin D supplements may help prevent vitamin D deficiency.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/vitamin-d-keeps-you-healthy-while-1148454926">FotoHelin/ Shutterstock</a></span>
</figcaption>
</figure>
<p>Although rickets <a href="https://www.nhs.uk/conditions/rickets-and-osteomalacia/#:%7E:text=The%20number%20of%20rickets%20cases,from%20sunlight%2C%20can%20develop%20rickets.">isn’t very common</a> in the UK today, it can still occur in children if they lack vitamin D. In adults, vitamin D deficiency can cause bone pain, tenderness and muscles weakness, as well as increased risk of osteomalacia – often called “soft bone disease” – which leads to weakening or softening bones.</p>
<p>The reason a lack of vitamin D can have such an effect on bone health is due to the vitamin’s relationship with <a href="https://pubmed.ncbi.nlm.nih.gov/18844850/">calcium and phosphate</a>. Both of these minerals help keep our bones strong – but they require vitamin D in order to be able to reinforce and strengthen bones.</p>
<h2>Other health benefits</h2>
<p>In addition to its effects on the skeleton, a growing body of research is beginning to indicate that vitamin D supplements may have additional benefits to our health.</p>
<p>For example, <a href="https://ar.iiarjournals.org/content/42/10/5009.long">research shows</a> there’s a link between vitamin D deficiency and increased risk of catching certain viral illnesses, including the <a href="https://pubmed.ncbi.nlm.nih.gov/19237723/">common cold</a>, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7231123/">flu</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7385774/">COVID</a>.</p>
<p>Similarly, several studies – <a href="https://pubmed.ncbi.nlm.nih.gov/32904944/">including my own</a> – have demonstrated in cell models that vitamin D promotes immunity against microbes, such as the bacteria which causes tuberculosis. This means vitamin D may potentially prevent some types of infections.</p>
<p>Vitamin D may also dampen inflammatory immune responses, which could potentially protect against autoimmune diseases, such as <a href="https://pubmed.ncbi.nlm.nih.gov/29243029/">multiple sclerosis</a> and <a href="https://www.frontiersin.org/articles/10.3389/fmed.2020.596007/full">rheumatoid arthritis</a>.</p>
<p>One 2022 trial, which looked at over 25,000 people over the age of 50, found taking a 2,000 IU (50 micrograms) vitamin D supplement each day was associated with an <a href="https://www.bmj.com/content/376/bmj-2021-066452">18% lower risk</a> of autoimmune disease – notably rheumatoid arthritis. </p>
<p>Vitamin D supplements may also be linked with lower risk of cardiovascular disease. A <a href="https://www.bmj.com/content/381/bmj-2023-075230">major Australian study</a>, which looked at over 21,000 people aged 60-84, found that participants who took a 2,000 IU vitamin D supplement a day for five years had a lower risk of suffering a major cardiovascular event (such as stroke or heart attack) compared to those who didn’t take a supplement. </p>
<p>It’s currently not known why vitamin D may have these benefits on these other areas of our health. It’s also worth noting that in many of these trials, very few of the participants were actually vitamin D deficient. While we might speculate the observed health benefits may be even greater in people with vitamin D deficiency, it will be important for future research to study these factors. </p>
<p>While it’s too early to say whether vitamin D supplements have broad health benefits, it’s clear it’s beneficial for bone health. It may be worthwhile to take a supplement in the winter months, especially if you’re over 65, have darker skin or spent a lot of time indoors as these factors can put you at <a href="https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/vitamin-d-deficiency/faq-20058397#:%7E:text=However%2C%20some%20groups%20%E2%80%94%20particularly%20people,sun%20exposure%20or%20other%20factors.">increased risk of vitamin D deficiency</a>.</p>
<p>The research also shows us that we should be rethinking vitamin D supplementation advice. While in the UK it’s recommended people get 400 IU of vitamin D a day, many trials have shown 2,000 IU a day is associated with health benefits.</p><img src="https://counter.theconversation.com/content/219521/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Martin Hewison has received funding from Medical Research Council, Biotechnology and Biological Sciences Research Council, National Institutes of Health (USA), Royal Society, Wellcome Trust, Diabetes UK, March of Dimes (USA), WK Kellogg Foundation. </span></em></p>In the UK, it’s recommended people aim to get at least 400IU of vitamin D a day.Martin Hewison, Professor of Molecular Endocrinology, University of BirminghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2112682023-10-02T01:25:59Z2023-10-02T01:25:59ZShould I be getting my vitamin D levels checked?<figure><img src="https://images.theconversation.com/files/547920/original/file-20230913-23-limj5h.jpg?ixlib=rb-1.1.0&rect=1014%2C476%2C4958%2C3485&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.pexels.com/photo/a-beautiful-woman-sitting-on-a-wooden-bench-looking-sideways-9032708/">Pexels/Kevin Malik</a></span></figcaption></figure><p>Australia has seen a <a href="https://insightplus.mja.com.au/2023/29/gps-urged-not-to-routinely-test-children-for-vitamin-d/">surge in vitamin D testing</a> of children, with similar trends reported for adults around the <a href="https://pubmed.ncbi.nlm.nih.gov/29659534/">world</a>. GPs are now <a href="https://insightplus.mja.com.au/2023/29/gps-urged-not-to-routinely-test-children-for-vitamin-d/">being urged</a> not to test for vitamin D unnecessarily.</p>
<p>So when is low vitamin D a potential concern? And when might you need to get your levels tested?</p>
<h2>How much vitamin D do we need?</h2>
<p>Vitamin D is not only a nutrient – when metabolised in the body it acts as a <a href="https://pubmed.ncbi.nlm.nih.gov/29080638/">hormone</a>. We have receptors for this hormone all around our body and it helps regulate the metabolism of calcium and phosphorus. </p>
<p>Vitamin D also has many other roles, including helping our immune defences and contributing to <a href="https://pubmed.ncbi.nlm.nih.gov/11295155/">DNA repair</a> and cell differentiation. </p>
<p>We can thank the sun for most of our vitamin D. A chemical in our skin called 7-dehydrocholesterol is converted to vitamin D after contact with UVB radiation from the sun. </p>
<p>While we get some vitamin D also <a href="https://pubmed.ncbi.nlm.nih.gov/35253289/">through our diet</a>, this makes a relatively small contribution. It’s difficult to get much more than one-third of our daily vitamin D requirement from diet without supplementation. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-how-does-the-sun-help-your-body-make-vitamin-d-139670">Curious Kids: how does the Sun help your body make vitamin D?</a>
</strong>
</em>
</p>
<hr>
<p>Nutritional vitamin D status is <a href="https://en.wikipedia.org/wiki/Calcifediol">typically measured</a> via a blood test. This checks the calcidiol (calcifediol, 25-hydroxyvitamin D) concentrations, which reflect the average intakes from the sun and diet over the past three to four weeks. </p>
<p>The <a href="https://pubmed.ncbi.nlm.nih.gov/22708765/">current recommendation</a> is that we should all aim to have at least 50nmol/L (20ng/mL) at the end of winter.</p>
<p>However, one problem with vitamin D tests is that there is <a href="https://pubmed.ncbi.nlm.nih.gov/37182753/">variation</a> in measured concentrations between the laboratories and between the assays, and whether you’re deemed to have a deficiency can depend on the testing method used. </p>
<figure class="align-center ">
<img alt="Man wearing glasses looks into the distance" src="https://images.theconversation.com/files/547934/original/file-20230913-29-2kgkhk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/547934/original/file-20230913-29-2kgkhk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/547934/original/file-20230913-29-2kgkhk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/547934/original/file-20230913-29-2kgkhk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/547934/original/file-20230913-29-2kgkhk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/547934/original/file-20230913-29-2kgkhk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/547934/original/file-20230913-29-2kgkhk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">We get most of our vitamin D from sunshine.</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/man-wearing-black-sunglasses-343717/">Pexels/Asim Alnamat</a></span>
</figcaption>
</figure>
<p>Doctors do not always agree with what is deficiency. While very low concentrations are likely to prompt doctors to recommend a supplement (and, potentially, follow-up testing), some may consider even relatively high concentrations as inadequate. </p>
<p>This is all understandable as research in this space is still evolving, and we know low concentrations do not always cause any symptoms. </p>
<h2>Why avoid vitamin D deficiency?</h2>
<p>Prolonged, severe vitamin D deficiency will lead to softening of bone tissue and cause diseases such as rickets (children) and osteomalacia (adults). </p>
<p>However, avoiding low concentrations is likely to be good for <a href="https://pubmed.ncbi.nlm.nih.gov/37483080/">many aspects of health</a>, with consistent evidence suggesting benefits for <a href="https://www.bmj.com/content/356/bmj.i6583">infectious diseases</a> and autoimmune conditions such as multiple sclerosis. </p>
<p>Randomised trials have also provided evidence for lower <a href="https://pubmed.ncbi.nlm.nih.gov/35676320/">cancer</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/24414552/">all cause mortality</a> by daily supplementation, although any benefit is likely to be restricted to those who otherwise have insufficient intakes. </p>
<h2>Who is at risk of deficiency?</h2>
<p>Most of us do not need tests to have a relatively good idea whether we might be at risk of a clinically important deficiency. </p>
<p>If it’s not late winter, we spend regularly at least some time outside with skin exposed to the sun, and we do not belong to a specific high-risk group, it is unlikely that our <a href="https://pubmed.ncbi.nlm.nih.gov/22168576/">levels would be very low</a>. </p>
<p>The two main reasons for vitamin D deficiency typically relate to:</p>
<p><strong>1. not getting (enough) vitamin D through sun exposure.</strong> Deficiency risk <a href="https://www.healthdirect.gov.au/vitamin-d-deficiency">can be high</a> for anyone who is housebound, such as older or disabled people in residential care. The risk of deficiency increases if we always cover our skin carefully by <a href="https://pubmed.ncbi.nlm.nih.gov/19211395/">modest cultural dress,</a> and also <a href="https://pubmed.ncbi.nlm.nih.gov/6119494/">dark skin pigmentation</a> is known to reduce vitamin D synthesis. </p>
<p><strong>2. having a chronic disease that alters your requirement.</strong> Medications such as anticonvulsants used to treat epilepsy, and conditions such as <a href="https://my.clevelandclinic.org/health/diseases/15050-vitamin-d-vitamin-d-deficiency">liver and kidney diseases</a> can interfere with vitamin D metabolism. Some <a href="https://my.clevelandclinic.org/health/diseases/15050-vitamin-d-vitamin-d-deficiency">digestive diseases</a> can reduce vitamin D absorption from your diet, while <a href="https://pubmed.ncbi.nlm.nih.gov/30020507">obesity</a> will increase your vitamin D requirement and make it more difficult to raise your blood levels.</p>
<h2>Am I getting enough sun exposure?</h2>
<p>In Australia, it is possible to get enough vitamin D from the sun <a href="https://healthybonesaustralia.org.au/your-bone-health/vitamin-d-bone-health">throughout the year</a>. This isn’t so for many people living in the northern hemisphere. </p>
<p>For those who live in the top half of Australia – and for all of us during summer – we <a href="https://healthybonesaustralia.org.au/your-bone-health/vitamin-d-bone-health">only need</a> to have skin exposed to the sun a few minutes on most days. </p>
<p>The body can only produce a certain amount of vitamin D at the time, so staying in the sun any longer than needed is not going to help increase your vitamin D levels, while it will increase your risk of skin cancer. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-you-need-more-vitamin-d-in-the-winter-128898">Why you need more Vitamin D in the winter</a>
</strong>
</em>
</p>
<hr>
<p>During winter, catching enough sun can be difficult, especially if you spend your days confined indoors. Typically, the required exposure increases to two to three hours per week in winter. This is because sunlight exposure can only help produce vitamin D if the UVB rays reach us at the correct angle. So in winter we should regularly spend time outside in the middle of the day to get our dose of vitamin D. </p>
<p>If you are concerned, you have very dark skin, or are otherwise in a high-risk group, you may want to talk to your GP. </p>
<p>In any case, taking a modest daily dose of vitamin D (1,000-2,000 IU) during the darker winter months is unlikely to cause harm and it <a href="https://pubmed.ncbi.nlm.nih.gov/37483080/">may be beneficial</a>.</p>
<h2>Why does excess vitamin D testing matter?</h2>
<p>When not indicated, testing can cause unnecessary worry and promote a cascade of <a href="https://pubmed.ncbi.nlm.nih.gov/32675268/">laboratory, prescription and imaging services</a> that are of low value. </p>
<p>Excessive testing is also a waste of health-care resources, with one <a href="https://onlinelibrary.wiley.com/doi/full/10.5694/mja2.50619">single test</a> costing about the same as a years’ worth of vitamin D supplementation.</p>
<p>Very often, we can make relatively small changes to our lifestyles to reduce the risks of vitamin D deficiency. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/theres-no-such-thing-as-a-safe-tan-heres-whats-happening-underneath-your-summer-glow-109439">There's no such thing as a safe tan. Here's what's happening underneath your summer glow</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/211268/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Elina Hypponen receives funding from the National Health and Medical Research Council, Australian Research Council, Medical Research Future Fund Australia, and Arthritis Australia. She is affiliated with Multicultural Communities Council South Australia. </span></em></p>Here’s when low vitamin D is a potential concern and when you might need to get your levels tested.Elina Hypponen, Professor of Nutritional and Genetic Epidemiology, University of South AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2026442023-04-03T15:38:49Z2023-04-03T15:38:49ZA professor is going to live in an underwater hotel for 100 days – here’s what it might do to his body<p>As nightmares go, being trapped in a small box deep underwater is probably high on many peoples’ lists. But one US professor is <a href="https://www.usf.edu/news/2023/usf-researcher-attempts-to-set-world-record-by-living-underwater-for-100-days-hopes-to-emerge-super-human.aspx">doing this on purpose</a>. Joe Dituri, a former US navy diver and expert in biomedical engineering has been living in a 55 square meter space 30 feet below the surface of the Florida Keys since March 1, and plans to stay for 100 days. If he manages this, he will break a record for most time spent in a habitat beneath the surface of the ocean. </p>
<p>Dituri conducts research into the effects of hyperbaric pressure – when air pressure is greater than it would be at sea level – on the human body. He is hoping to use his time spent below the surface to examine what impact living in this high-pressure environment has on his health.</p>
<p>Interestingly, Dituri’s endeavour will be very different from living on a submarine. Submarines are sealed when submerged and maintained at sea level pressure. This means there’s no significant difference in pressure, even when a submarine is at depths of hundreds of meters.</p>
<p>But Dituri’s underwater habitat won’t have any solid hatches or air locks between the ocean and the dry living space, as a submarine does. Think of it like when a glass of water is turned upside down and pushed into a sink full of water. A pocket of air will still exist at the top of Dituri’s living space, with a pool of water in the floor of one room that comes from the ocean outside. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/u5GhJKBB5P8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A tour of the underwater habitat Dituri will be using.</span></figcaption>
</figure>
<p>This means that the air inside his habitat is squeezed by the ocean’s weight, increasing the air pressure around him. At a depth of 30 feet, the air pressure inside this habitat is about twice as much as what he’d be used to on land. </p>
<h2>Under pressure</h2>
<p>Little research has investigated what effect long-term exposure to hyperbaric pressure has on the body.</p>
<p>As every certified diver is well aware, though, hyperbaric pressure can pose a very real threat to us. Our bodies have been adapted by generations of evolution for sea level conditions, where the two major gases involved in breathing (oxygen and carbon dioxide) are the only two that freely cross between our lungs and our blood. </p>
<p>But as pressure increases, nitrogen in the air is forced across the delicate walls of our lungs and into our blood. This can cause a range of adverse effects. At depths of ten to 30 meters, this <a href="https://pubmed.ncbi.nlm.nih.gov/33510647/">may cause mild euphoria</a> and positive moods. After about 30 meters below sea level and beyond, it can lead to intoxicated-like behaviour – hence the name “narcosis”. </p>
<p>Scientists don’t fully understand <a href="https://pubmed.ncbi.nlm.nih.gov/27347903/">why this happens</a>, but it could be due to changes in the way neurotransmitters signal between neurons in our brain. Fortunately, this won’t be a risk to Dituri, as he’s only at a depth of ten meters.</p>
<h2>Health changes</h2>
<p>But Dituri can expect to experience other physical changes while living in his underwater habitat.</p>
<p>Although the habitat has large windows, Dituri will still only be exposed to half the amount of sunlight as on land. This could cause issues with his circadian rhythm – the internal “clock” that controls many body functions, including our sleep-wake cycle – which relies on daylight. This may mean disrupted sleeping.</p>
<p>Another challenge for Dituri will be getting enough vitamin D. The skin must receive UV exposure to make this vitamin, and this typically comes from the sun. It’s likely that Dituri will not be exposed to enough vitamin D while living in his underwater environment.</p>
<p>Vitamin D plays key roles in maintaining <a href="https://efsa.onlinelibrary.wiley.com/doi/abs/10.2903/j.efsa.2010.1468">bone density, muscle function and immunity</a>. Research on people who lived at an underwater habitat run by NASA as a spaceflight analogue found they had <a href="https://pubmed.ncbi.nlm.nih.gov/26116982/">reduced immune function</a> after only a 14-day stay. </p>
<p>Dituri will need to get vitamin D from other sources – such as foods high in vitamin D, supplements or from <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2846322/">UV lamps</a> – to minimise reductions in his immune function. Even though Dituri will be living alone, astronauts living in similar environments <a href="https://humanresearchroadmap.nasa.gov/Evidence/reports/IMMUNE%20EB%20Update%202021%20v02%20FINAL_6-15-22.pdf">report latent infections occuring</a>. These are viruses that many of us carry which our immune system normally keeps under control. This could also cause Dituri to fall ill if his immune function wavers.</p>
<p>Besides a minimal amount of walking around a very small habitat, the only exercise Dituri will get is from swimming. As swimming is non-weight bearing, losses in bone and muscle mass are likely – and may be similar to what astronauts see during <a href="https://pubmed.ncbi.nlm.nih.gov/27779600/">long missions on the International Space Station</a> (but not as exteme). Adding some resistance exercises such as squats and lunges may help Dituri offset muscle and bone mass losses. </p>
<h2>Long-term effects</h2>
<p>While Dituri’s underwater habitat will be different from a submarine, the amount of time he’s spending there is not altogether different from what many submarine crews endure. We know from research on submariners that even just a few months below the surface can have long-term effects, despite measures to prevent this from happening. </p>
<p>For instance, even after two months below the sea, submariners still had disturbed sleep patterns and problems with the levels of <a href="https://pubmed.ncbi.nlm.nih.gov/35142558/">certain hormones</a> linked to sleep. Crew also showed <a href="https://pubmed.ncbi.nlm.nih.gov/19882096/">losses in bone and muscle mass</a>. This reinforces how important it will be for Dituri to get enough vitamin D exposure and exercise.</p>
<p>Of course, the biggest question that remains is what effect long-term hyperbaric pressure will have on Dituri. What studies we do have on the effects of hyperbaric pressure have only looked at <a href="https://pubmed.ncbi.nlm.nih.gov/27984436/">short-term exposures</a>, which may have shown <a href="https://pubmed.ncbi.nlm.nih.gov/34376365/">positive effects on wound healing</a>. This will be both a physiologically and possibly psychologically challenging feat so, although Dituri is only one person, data from his experiment will still be useful to the field.</p><img src="https://counter.theconversation.com/content/202644/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bradley Elliott receives funding from The Endocrine Society, The Physiological Society, the Quintin Hogg Charitable Trust and private philanthropic donors. He has consulted with industry partners on atmospheric physiology. He is affiliated with The Physiological Society, and is a Trustee of the British Society for Research on Ageing.</span></em></p>Dr Joe Dituri is hoping to set a world record during his experiment.Bradley Elliott, Senior Lecturer in Physiology, University of WestminsterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1982002023-02-06T12:19:56Z2023-02-06T12:19:56ZCurious Kids: why do I feel happier when the sun is out?<figure><img src="https://images.theconversation.com/files/507644/original/file-20230201-10491-cnbcpu.jpg?ixlib=rb-1.1.0&rect=19%2C13%2C4341%2C2890&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/happy-child-outdoors-spring-sunflower-field-173333366">Sunny studio/Shutterstock</a></span></figcaption></figure><p><strong>Why do I feel happier when the sun is out? – Mabli, aged 13, Barry, Wales</strong></p>
<p>That is exactly the same question I asked many years ago when I was sitting on a nice sunny beach, far away on a lovely warm island. I remember thinking, “Oh gosh, tomorrow I need to fly back to rainy London where the weather is horrible. I don’t want to go; the weather will make me unhappy.”</p>
<p>I actually <a href="https://onlinelibrary.wiley.com/doi/10.1111/manc.12126">did some research</a> into whether sunshine does make us happier. I’m a professor of economics, and I wanted to look at whether higher temperatures, more sunshine and less rainfall on a given day makes people happier. Happiness matters to economists because it is an important way of measuring quality of life. Did you know that the Office of National Statistics has been collecting <a href="https://www.ons.gov.uk/peoplepopulationandcommunity/wellbeing/articles/measuresofnationalwellbeingdashboardqualityoflifeintheuk/2022-08-12">happiness data</a> for more than 10 years?</p>
<p>My own <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/manc.12126">research</a> has shown that while sunshine matters as a seasonal factor, it doesn’t matter much whether it’s sunny on any given day here in the UK. The sunlight you get over the course of a season is what’s important. You may generally feel a bit unhappier in the winter, but it won’t matter much whether it’s a sunny or a cloudy winter’s day. </p>
<p>Medically, exposure to sunlight causes your brain to produce the hormone <a href="https://my.clevelandclinic.org/health/articles/22572-serotonin">serotonin</a> inside your body. Hormones are complex chemicals that play an important role in regulating many of your body functions. </p>
<hr>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/282267/original/file-20190702-126345-1np1y7m.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em><a href="https://theconversation.com/au/topics/curious-kids-36782">Curious Kids</a> is a series by <a href="https://theconversation.com/uk">The Conversation</a> that gives children the chance to have their questions about the world answered by experts. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskids@theconversation.com">curiouskids@theconversation.com</a> and make sure you include the asker’s first name, age and town or city. We won’t be able to answer every question, but we’ll do our very best.</em></p>
<hr>
<p>Two functions that are affected by serotonin are your mood and your sleep quality. When you’re exposed to sunlight your body will make more serotonin, which can boost your mood and make you feel better. High levels of serotonin will make you a feeling positive and full of energy.</p>
<p>At night, when it is dark, your body produces another hormone called <a href="https://www.nhs.uk/medicines/melatonin/">melatonin</a>. Melatonin helps your body relax and will make you feel tired. It’s a chemical produced by your body to prepare you for a good night’s sleep. A good balance between these two chemicals is very important in regulating your energy levels, giving you a good night’s rest and making you feel well during the day.</p>
<h2>Not enough sunshine</h2>
<p>However, for many people it is hard to balance sunlight with darkness. People who work indoors a lot, or live in parts of the world where it gets dark for a long time – like countries near the North Pole in the winter – may not get enough sunlight. </p>
<p>There is <a href="https://www.sciencedirect.com/science/article/pii/S0140673698010150?casa_token=s-i479aPLeAAAAAA:n3sPnD68j0wxaXpKJSHxqW3ltORsZ6Bc70CGdkmiu-bDgq6FF_5hYVY6kF8Imrg8cryFIbpR">typically 100 times less light</a> in a house and 25 times less light in an office when compared to a nice sunny day outside. This is why getting outside in the sun is a great way to get some exercise, enjoy the fresh air, and boost your mood all at the same time. </p>
<figure class="align-center ">
<img alt="Three girls outside in warm clothes" src="https://images.theconversation.com/files/507659/original/file-20230201-13415-orsgzp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/507659/original/file-20230201-13415-orsgzp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/507659/original/file-20230201-13415-orsgzp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/507659/original/file-20230201-13415-orsgzp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/507659/original/file-20230201-13415-orsgzp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/507659/original/file-20230201-13415-orsgzp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/507659/original/file-20230201-13415-orsgzp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">It’s important to spend time outside, all year round.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/trio-pretty-multiethnic-cheerful-teen-girls-1828137389">Prostock-studio/Shutterstock</a></span>
</figcaption>
</figure>
<p>People who live in places where there is less daylight are more likely to suffer from <a href="https://www.nhs.uk/mental-health/conditions/seasonal-affective-disorder-sad/overview/">seasonal affective disorder</a> (Sad). Sad is a type of depression that often occurs in the autumn and winter. </p>
<p>People with Sad may experience symptoms such as low energy, sadness, sleep problems, and a decreased interest in activities they normally enjoy. The most common treatment for Sad is light therapy where you sit underneath bright artificial lights for some time. This mimics sunshine and will trick your body into creating serotonin. </p>
<h2>We need the light</h2>
<p>However, there is more to sunlight than just hormones. Your skin produces Vitamin D from sunlight and this is important for strong bones and being healthy. From April to September most people in the UK make <a href="https://www.britishskinfoundation.org.uk/sunlight-and-vitamin-d">enough Vitamin D from sunshine alone</a>. In the winter, though, you won’t get enough from sunshine, which is why <a href="https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/">the UK government recommends</a> that everyone should consider taking vitamin D supplements in the autumn and winter. </p>
<p>There is also an evolutionary component. Human eyesight is designed for daylight. We don’t have good night vision like cats. A long time ago in the past, when we didn’t have streetlamps, long periods of darkness might have made our ancestors nervous, fearful, and therefore unhappy. And while you don’t have to worry about being eaten by a lion at night any more, you may still have some of that fear from <a href="https://www.tandfonline.com/doi/full/10.1080/02699931.2022.2029358?needAccess=true">your ancestors 5,000 years ago</a>.</p>
<p>Please remember that while sunlight can have many positive effects on your mood and health, it’s also important to be safe in the sun. This means wearing sunscreen, wearing a hat and sunglasses, and avoiding being in direct sunlight for too long. And never look at the sun directly. That’s super dangerous.</p>
<p><em>This article has been updated to better represent government advice on taking Vitamin D.</em></p><img src="https://counter.theconversation.com/content/198200/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Franz Buscha does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Day to day, sunshine might not affect our mood – but light and dark seasons do.Franz Buscha, Professor of Economics, University of WestminsterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1983452023-02-02T12:23:35Z2023-02-02T12:23:35ZVitamins and supplements: what you need to know before taking them<figure><img src="https://images.theconversation.com/files/507046/original/file-20230130-20-x1ljxi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Supitcha McAdam/Shutterstock </span></span></figcaption></figure><p>If you were to open your medicine cabinet right now, there’s a fair chance that you’d find at least one bottle of vitamins alongside the painkillers, plasters and cough syrup.</p>
<p>After all, people are definitely buying vitamins: in 2020, the global market for complementary and alternative medicines, which includes multivitamin supplements, had an estimated value of <a href="https://www.grandviewresearch.com/industry-analysis/complementary-alternative-medicine-market">US$82.27 billion</a>. The use of natural health products such as minerals and amino acids has <a href="https://journals.lww.com/nutritiontodayonline/Abstract/2007/03000/Why_People_Use_Vitamin_and_Mineral_Supplements.4.aspx">increased</a> – and continues to rise, partly driven by consumers’ buying habits during the COVID-19 pandemic.</p>
<p>People <a href="https://www.businesslive.co.za/bd/companies/healthcare/2021-02-08-native-sales-of-sas-vitamins-and-nutritional-supplements-boom/">sought out</a> vitamins C and D, as well as zinc supplements, as potential preventive measures against the virus – even though the <a href="https://www.health.harvard.edu/blog/do-vitamin-d-zinc-and-other-supplements-help-prevent-covid-19-or-hasten-healing-2021040522310">evidence</a> for their efficacy was, and <a href="https://pubmed.ncbi.nlm.nih.gov/35888660/#:%7E:text=Concluding%2C%20available%20data%20on%20the,trials%20(RCTs)%20are%20inconsistent">remains</a>, inconclusive. </p>
<p>Multivitamins and mineral supplements are easily accessible to consumers. They are often marketed for their health claims and benefits – sometimes unsubstantiated. But their potential adverse effects are not always stated on the packaging.</p>
<p>Collectively, vitamins and minerals are known as micronutrients. They are essential elements needed for our bodies to function properly. Our bodies can only produce micronutrients in small amounts or not at all. We get the bulk of these nutrients <a href="https://www.iprjb.org/journals/index.php/IJF/article/view/1024">from our diets</a>. </p>
<p>People usually buy micronutrients to protect against disease or as dietary “insurance”, in case they are not getting sufficient quantities from their diets. </p>
<p>There’s a common perception that these supplements are harmless. But they can be dangerous at incorrect dosages. They provide a false sense of hope, pose a risk of drug interactions – and can delay more effective treatment. </p>
<h2>Benefits</h2>
<p>Vitamins are beneficial if taken for the correct reasons and as prescribed by your doctor. For example, folic acid supplementation in pregnant women has been shown to prevent neural tube defects. And individuals who reduce their intake of red meat without increasing legume consumption require a vitamin B6 supplement. </p>
<p>But a worrying trend is increasing among consumers: intravenous vitamin therapy, which is often punted by celebrities and social media marketing. Intravenous vitamins, nutrients and fluids are administered at pharmacies as well as beauty spas, and more recently “<a href="https://www.health.harvard.edu/blog/drip-bar-should-you-get-an-iv-on-demand-2018092814899">IV bars</a>”. Users believe these treatments can quell a cold, slow the effects of ageing, brighten skin, fix a hangover or just make them feel well. </p>
<p>Intravenous vitamin therapy was previously only used in medical settings to help patients who could not swallow, needed fluid replacements or had an electrolyte imbalance. </p>
<p>However, the evidence to support other benefits of intravenous vitamin therapy is limited. No matter how you choose to get additional vitamins, there are risks. </p>
<h2>Warning bells</h2>
<p>Most consumers use multivitamins. But others take large doses of single nutrients, especially vitamin C, iron and calcium. </p>
<p>As lecturers in pharmacy practice, we think it’s important to highlight the potential adverse effects of commonly used vitamins and minerals: </p>
<ul>
<li><p><a href="https://www.hsph.harvard.edu/nutritionsource/vitamin-a/">Vitamin A/retinol</a> is beneficial in maintaining good eye health. But it can cause toxicity if more than 300,000IU (units) is ingested. Chronic toxicity (hypervitaminosis) has been <a href="https://www.ncbi.nlm.nih.gov/books/NBK532916/">associated</a> with doses higher than 10,000IU a day. Symptoms include liver impairment, loss of vision and intracranial hypertension. It can cause birth defects in pregnant women.</p></li>
<li><p><a href="https://www.hsph.harvard.edu/nutritionsource/niacin-vitamin-b3/">Vitamin B3</a> is beneficial for nervous and digestive system health. At moderate to high doses it can cause peripheral vasodilation (widening or dilating of the blood vessels at the extremities, such as the legs and arms), resulting in skin flushing, burning sensation, pruritis (itchiness of the skin) and hypotension (low blood pressure). </p></li>
<li><p><a href="https://www.hsph.harvard.edu/nutritionsource/vitamin-b6/">Vitamin B6</a> is essential for brain development and in ensuring that the immune system remains healthy. But it can result in damage to the peripheral nerves, such as those in the hands and feet (causing a sensation of numbness and often referred to as pins and needles) at doses over 200mg/daily.</p></li>
<li><p><a href="https://www.hsph.harvard.edu/nutritionsource/vitamin-c/">Vitamin C</a> is an antioxidant and assists in the repair of body tissue. Taken in high doses it can cause kidney stones and interactions with drugs, such as the oncology drugs doxorubicin, methotrexate, cisplatin and vincristine. </p></li>
<li><p><a href="https://www.hsph.harvard.edu/nutritionsource/vitamin-d/">Vitamin D</a> is essential for bone and teeth development. At high doses it can cause hypercalcaemia (calcium level in the blood is above normal) that results in thirst, excessive urination, seizures, coma and death.</p></li>
<li><p><a href="https://www.hsph.harvard.edu/nutritionsource/calcium/#:%7E:text=Calcium%20is%20a%20mineral%20most,heart%20rhythms%20and%20nerve%20functions">Calcium</a> is essential for bone health, but can cause constipation and gastric reflux. High doses can cause hypercalciuria (increased calcium in the urine), kidney stones and secondary hypoparathyroidism (underactive parathyroid gland). It can have drug interactions with zinc, magnesium and iron. </p></li>
<li><p><a href="https://www.hsph.harvard.edu/nutritionsource/magnesium/">Magnesium</a> is important for muscle and nerve functioning. At high doses it can cause diarrhoea, nausea and abdominal cramping, and can interact with tetracyclines (antibiotics).</p></li>
<li><p>Zinc <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7781367/">can impair</a> taste and smell, and doses over 80mg daily have been <a href="https://link.springer.com/article/10.1007/s10654-022-00922-0#:%7E:text=Zinc%20supplementation%20of%20more%20than,zinc%20supplements%20among%20adult%20men.">shown</a> to have adverse prostate effects.</p></li>
<li><p><a href="https://www.hsph.harvard.edu/nutritionsource/selenium/">Selenium</a> can cause hair and nail loss or brittleness, lesions of the skin and nervous system, skin rashes, fatigue and mood irritability at high doses.</p></li>
<li><p><a href="https://www.sciencedirect.com/science/article/pii/S0098299720300364#:%7E:text=Expert%20guidelines%20for%20oral%20iron%20supplementation&text=Traditionally%2C%20the%20recommended%20daily%20dose,iron%20(Brittenham%2C%202018).">Iron</a> at 100-200mg/day can cause constipation, black faeces, black discoloration of teeth and abdominal pain.</p></li>
</ul>
<h2>Recommendations</h2>
<p>People need to make <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8377299/">informed decisions</a> based on evidence before consuming health products. </p>
<p>Regular exercise and a well-balanced diet are more likely to do us good, as well as being lighter on the pocket.</p>
<p>Seeking advice from a healthcare professional before consuming supplements can reduce the risk of adverse effects.</p>
<p>Be aware of the potential adverse effects of vitamins and seek a healthcare professional’s guidance if you have symptoms.</p><img src="https://counter.theconversation.com/content/198345/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>There’s a common perception that supplements are harmless. But they can be dangerous at incorrect dosages.Neelaveni Padayachee, Senior Lecturer, Department of Pharmacy and Pharmacology, University of the WitwatersrandVarsha Bangalee, Associate Professor, Pharmaceutical Sciences, University of KwaZulu-NatalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1835612022-05-27T12:50:25Z2022-05-27T12:50:25ZVegan and vegetarian diets may lack certain nutrients – here’s how to get more of them<figure><img src="https://images.theconversation.com/files/465720/original/file-20220527-11-h3yqf7.jpg?ixlib=rb-1.1.0&rect=9%2C0%2C6312%2C4217&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Vitamin supplements may help you avoid deficiencies. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/smiling-girl-bottle-vitamins-sitting-kitchen-1572303289">YAKOBCHUK VIACHESLAV/ Shutterstock</a></span></figcaption></figure><p>Vegan and vegetarian diets are certainly trendy, with more people than ever before <a href="https://www.vegansociety.com/news/media/statistics">making the switch</a>. While some people are choosing to go plant-based for environmental reasons, others are adopting these diets because of their health benefits. It’s hardly surprising, given studies have linked vegetarian and vegan diets to a lower body mass index (BMI) and a lower risk of certain diseases – including <a href="https://theconversation.com/vegetarian-pescatarian-or-low-meat-diets-may-reduce-cancer-risk-new-research-177787">cancer</a>, <a href="https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002039">type 2 diabetes</a>, and <a href="https://www.sciencedirect.com/science/article/pii/S0735109717375216?via%253Dihub">heart disease</a>.</p>
<hr>
<iframe id="noa-web-audio-player" style="border: none" src="https://embed-player.newsoveraudio.com/v4?key=x84olp&id=https://theconversation.com/vegan-and-vegetarian-diets-may-lack-certain-nutrients-heres-how-to-get-more-of-them-183561&bgColor=F5F5F5&color=D8352A&playColor=D8352A" width="100%" height="110px"></iframe>
<p><em>You can listen to more articles from The Conversation, narrated by Noa, <a href="https://theconversation.com/us/topics/audio-narrated-99682">here</a>.</em></p>
<hr>
<p>But while plant-based diets may have many health benefits, they can, without some planning, also result in nutrient deficiencies. In fact, <a href="https://www.hsis.org/vegetarian-and-vegan-trends-pushing-more-people-into-deficiency-risk/">one survey</a> suggests around 28% of vegans and 13% of vegetarians show one or more nutrient deficiencies. This is because many plant-based diets don’t contain high levels of <a href="https://www.sciencedirect.com/science/article/pii/S0261561420306567#bib5">certain nutrients</a>, such as vitamin B12, omega-3 fatty acids, iodine, calcium, selenium, <a href="https://www.gov.uk/government/statistics/ndns-results-from-years-9-to-11-2016-to-2017-and-2018-to-2019/ndns-results-from-years-9-to-11-combined-statistical-summary">iron</a> and zinc. </p>
<p>Research shows that veganism in particular is linked with <a href="https://www.clinicalnutritionjournal.com/article/S0261-5614(20)30656-7/fulltext">significantly low intakes</a> of vitamin B12 and calcium – especially in people who aren’t taking any vitamin supplements. Intakes of <a href="https://www.sciencedirect.com/science/article/pii/S0261561420306567?via%3Dihub">selenium, zinc</a>, vitamin D and iodine are <a href="https://pubmed.ncbi.nlm.nih.gov/35010904/">also low</a> in this group.</p>
<hr>
<figure class="align-right ">
<img alt="Quarter life, a series by The Conversation" src="https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/451343/original/file-20220310-13-1bj6csd.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em><strong><a href="https://theconversation.com/uk/topics/quarter-life-117947?utm_source=TCUK&utm_medium=linkback&utm_campaign=UK+YP2022&utm_content=InArticleTop">This article is part of Quarter Life</a></strong>, a series about issues affecting those of us in our twenties and thirties. From the challenges of beginning a career and taking care of our mental health, to the excitement of starting a family, adopting a pet or just making friends as an adult. The articles in this series explore the questions and bring answers as we navigate this turbulent period of life.</em></p>
<p><em>You may be interested in:</em></p>
<p><em><a href="https://theconversation.com/do-these-three-popular-anti-ageing-skincare-ingredients-work-heres-what-the-evidence-says-182200?utm_source=TCUK&utm_medium=linkback&utm_campaign=UK+YP2022&utm_content=InArticleTop">Do these three popular anti-ageing skincare ingredients work? Here’s what the evidence says</a></em></p>
<p><em><a href="https://theconversation.com/barbell-exercises-arent-essential-for-getting-fit-heres-what-you-can-do-instead-181743?utm_source=TCUK&utm_medium=linkback&utm_campaign=UK+YP2022&utm_content=InArticleTop">Barbell exercises aren’t essential for getting fit – here’s what you can do instead</a></em></p>
<p><em><a href="https://theconversation.com/five-tips-for-young-people-dealing-with-long-covid-from-a-gp-180464?utm_source=TCUK&utm_medium=linkback&utm_campaign=UK+YP2022&utm_content=InArticleTop">Five tips for young people dealing with long COVID – from a GP</a></em></p>
<hr>
<p>While <a href="https://www.clinicalnutritionjournal.com/article/S0261-5614(20)30101-1/fulltext">vegetarian diets</a> may contain slightly higher levels of amino acids, B12, calcium and protein compared to vegan diets, intake may still be lower than when following an omnivorous diet. </p>
<h2>Proper planning</h2>
<p>Vitamins and minerals are important for good health. For example, vitamin B12 is important for brain function and producing red blood cells. But our body doesn’t naturally produce many important vitamins and minerals (including vitamin B12, iron, selenium, and iodine) which is why it’s essential to get them from the foods we eat.</p>
<figure class="align-center ">
<img alt="A person's hands. One hand is open with two tablets held in the palm, while the other holds a medicine bottle." src="https://images.theconversation.com/files/465721/original/file-20220527-23-bhvjss.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/465721/original/file-20220527-23-bhvjss.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/465721/original/file-20220527-23-bhvjss.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/465721/original/file-20220527-23-bhvjss.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/465721/original/file-20220527-23-bhvjss.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/465721/original/file-20220527-23-bhvjss.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/465721/original/file-20220527-23-bhvjss.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Be sure to consult your GP before taking any supplements.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/hands-young-women-holding-medicine-herbs-1989054578">Gumbariya/ Shutterstock</a></span>
</figcaption>
</figure>
<p>But not getting enough of these important vitamins and minerals can lead to deficiencies. These can have a range of side effects, including excessive tiredness and brain fog. If left untreated, over time, this can lead to serious <a href="https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/plantbased-diets-and-longterm-health-findings-from-the-epicoxford-study/771ED5439481A68AD92BF40E8B1EF7E6">nervous, skeletal and blood disorders</a>.</p>
<p>If you’re someone who’s thinking of making the switch to a vegetarian or vegan diet, here are a few things to consider to avoid vitamin deficiencies: </p>
<ol>
<li><strong>Seek expert advice</strong> to help you plan your diet to ensure that it contains all the essential nutrients you need, especially if you’re transitioning from a vegetarian diet to a vegan diet, if you are or may become pregnant, or if you’re older than 60 years of age. </li>
<li><strong>Focus on your nutrients.</strong> Aim to pick plant-based food products that have been fortified with important vitamins and minerals, or foods that naturally contain high amounts of important nutrients. For example, Brazil nuts are rich in selenium, while seaweed is a good source of vitamin B12 and iodine. </li>
<li><strong>Eat a varied diet.</strong> This is especially important when it comes to the plant-based proteins you eat to ensure you get all the essential amino acids from your diet. Some foods that contain these include lentils, pulses, beans, soy, tofu, nuts and seeds.</li>
<li><strong>Pair certain nutrients.</strong> Certain nutrients can help others be better absorbed into the body. For example, vitamin C can increase iron absorption. Vitamin B12 supplements should also be taken with food to help the body absorb it more easily.</li>
<li><strong>Keep an eye on your health.</strong> If you start experiencing fatigue, memory problems, or even low mood, it might be a sign of a vitamin deficiency. Be sure to consult a doctor before taking any supplements to be sure you’re taking the right ones. </li>
</ol>
<p>If you need to use a vitamin supplement, be sure to look for supplements that are labelled <a href="https://ispe.org/initiatives/regulatory-resources/gmp">GMP certified</a>, as these will contain proper nutrition. But long-term supplement use <a href="https://theconversation.com/vitamins-and-minerals-arent-risk-free-here-are-6-ways-they-can-cause-harm-165399">may have its downsides</a>, such as being costly or interacting with certain drugs. There is also a danger of over-supplementation, which can lead to an accumulation of certain unmetabolised nutrients in our body. It’s currently unknown how common this is and what the long-term effects might be. For all of these reasons, it’s important to consult a GP before taking any supplements. </p>
<p>A well-planned, plant-based diet can be good for both your health and the planet. But it’s important to keep an eye on what foods and nutrients you might be eating to avoid deficiencies of essential nutrients.</p><img src="https://counter.theconversation.com/content/183561/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Martin Warren receives funding from the BBSRC and the Royal Society. </span></em></p><p class="fine-print"><em><span>Kourosh Ahmadi has received funding from BBSRC, MRC, Welcome Trust, Chronic Diseases Research Foundation and the Royal Society. </span></em></p><p class="fine-print"><em><span>Liangzi Zhang works for Quadram Institute.</span></em></p><p class="fine-print"><em><span>Maria Traka receives funding currently from BBSRC, Horizon2020 and EITfood, and previously from Prostate Cancer Foundation.</span></em></p>Plant-based diets may lack a number of important nutrients, such as vitamin B12 and iodine.Martin Warren, Chief Scientific Officer and Group Leader, Synthetic Biology and Biosynthetic Pathways, Quadram InstituteKourosh Ahmadi, Reader in Precision Nutrition, University of SurreyLiangzi Zhang, Research scientist, Food Composition and Dietary Assessment, Quadram InstituteMaria Traka, Research Leader, Personalised Nutrition and Gut Microbiome, Quadram InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1822202022-05-09T20:00:05Z2022-05-09T20:00:05ZCan taking vitamins and supplements help you recover from COVID?<figure><img src="https://images.theconversation.com/files/461709/original/file-20220506-12965-zm9rtl.jpg?ixlib=rb-1.1.0&rect=19%2C9%2C6410%2C3711&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://image.shutterstock.com/image-photo/supporting-immune-system-season-flu-600w-1835540941.jpg">Shutterstock</a></span></figcaption></figure><p>Australia’s <a href="https://www.abc.net.au/news/2020-03-17/coronavirus-cases-data-reveals-how-covid-19-spreads-in-australia/12060704">surge in COVID cases</a> this year has seen many people looking for ways to protect themselves or boost their immunity and recovery. An upswing in sales of dietary supplements has followed.</p>
<p>In Australia, the Therapeutic Goods Administration includes vitamins, minerals, amino acids, enzymes, plant extracts and microbiome supplements under the term “<a href="https://www.tga.gov.au/node/4233">complementary medicine</a>”.</p>
<p>The supplement industry’s <a href="https://www.globenewswire.com/news-release/2020/07/29/2069678/0/en/Global-Dietary-Supplements-Industry.html">global estimated worth</a> was about US $170 billion (A$239 billion) in 2020. Australian complementary medicines revenue was estimated at A$5.69 billion in 2021 – <a href="https://www.cmaustralia.org.au/page-1859595">doubling in size</a> over the past decade. The latest data shows 73% of Australians <a href="https://www.statista.com/statistics/1285506/australia-leading-complementary-medicines-purchased/">bought complementary medicines</a> in the previous year, with vitamins featuring in more than half of purchases.</p>
<p>But how likely are these purchases to be effective in preventing COVID or treating it?</p>
<h2>Fear, avoidance and laboratory studies</h2>
<p>Historically, the public has purchased supplements from sources that also provide health-care advice. Lockdowns and blanket health messages about social distancing and personal hygiene have created a new normal. So people are doing more shopping online for supplements and turning to the internet, friends or social media for vitamin recommendations. For some, this has led to an unhealthy fear of COVID (<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7474809/">coronaphobia</a>) and negative impacts on daily life.</p>
<p>As with any medicine, consumers should seek information from reliable sources (doctors, pharmacists or evidence-based peer-reviewed articles) about the potential benefits and harms of supplements before purchase. Strong evidence <a href="https://www.nejm.org/doi/full/10.1056/NEJMoa2119451">supports</a> vaccination as effective against the acute respiratory symptoms of COVID. <a href="https://pubmed.ncbi.nlm.nih.gov/32334392/">Researchers</a> have also looked at whether supplements may prevent or reduce the duration and severity of this viral infection by boosting the immune response.</p>
<p>Deficiencies in essential nutrients that support immune function (vitamin C, vitamin D, zinc and selenium) <a href="https://pubmed.ncbi.nlm.nih.gov/35063248/">have been shown</a> to increase susceptibility to infection, including COVID. But there is <a href="https://pubmed.ncbi.nlm.nih.gov/34626488/">little evidence</a> supplementation in a healthy person prevents respiratory infections such as COVID. An evidence gap <a href="https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2776299">exists</a> between a supplement’s action in laboratory or animal studies and findings from well designed and conducted clinical trials. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/461710/original/file-20220506-23-ez6sya.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="couple browse vitamin aisle in supermarket" src="https://images.theconversation.com/files/461710/original/file-20220506-23-ez6sya.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/461710/original/file-20220506-23-ez6sya.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/461710/original/file-20220506-23-ez6sya.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/461710/original/file-20220506-23-ez6sya.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/461710/original/file-20220506-23-ez6sya.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/461710/original/file-20220506-23-ez6sya.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/461710/original/file-20220506-23-ez6sya.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The dietary supplementary industry has doubled in size over the last decade.</span>
<span class="attribution"><a class="source" href="https://image.shutterstock.com/image-photo/couple-doing-their-groceries-supermarket-600w-573335551.jpg">Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/no-cbd-is-not-a-miracle-molecule-that-can-cure-coronavirus-just-as-it-wont-cure-many-other-maladies-its-proponents-claim-132492">No, CBD is not a miracle molecule that can cure coronavirus, just as it won't cure many other maladies its proponents claim</a>
</strong>
</em>
</p>
<hr>
<h2>A pandemic ‘infodemic’</h2>
<p>Ready access to supplements without a prescription from a myriad of online and shopfront sources and the <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0266705">uncontrolled spread of claims</a> that supplements can prevent or treat COVID symptoms, has created an “<a href="https://www.who.int/health-topics/infodemic#tab=tab_1">infodemic</a>”. </p>
<p>These claims are fuelled by supplement manufacturers being able to <a href="https://www.tga.gov.au/node/4233">“list” their products</a> on the Australian Register of Therapeutic Goods, with limited evidence of safety or effectiveness. This appearance of official approval tallies with the common <a href="https://www.tandfonline.com/doi/abs/10.3109/13697139909025568">misperception</a> that “natural” means “safe”. </p>
<p>Supplements can cause <a href="https://www.tandfonline.com/doi/abs/10.3109/13697139909025568">harm</a> in the form of adverse effects, drug interactions and expense. They also add to a patient’s <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6165107/#:%7E:text=The%20concept%20of%20%E2%80%9Cmedication%2Drelated,19%2C20%2C21%5D.">medication burden</a>, may delay more effective therapy, or give false hope to the vulnerable.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/lemon-water-wont-detox-or-energise-you-but-it-may-affect-your-body-in-other-ways-180035">Lemon water won't detox or energise you. But it may affect your body in other ways</a>
</strong>
</em>
</p>
<hr>
<h2>Vitamins A to zinc</h2>
<p>The recent <a href="https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2776305">COVID A to Z Study</a> illustrates some of the challenges involved. </p>
<p>It was designed to test the effectiveness of high-dose zinc, vitamin C, and a combination of both, to shorten the duration of COVID-related symptoms compared with usual care in adult outpatients with confirmed infection. </p>
<p>These nutrients <a href="https://pubmed.ncbi.nlm.nih.gov/32334392/">were chosen</a> because:</p>
<ul>
<li>vitamin C studies in mice showed this antioxidant to be essential for antiviral immune responses against the influenza A virus, especially in the early stages of the infection</li>
<li>deficiency of zinc, an essential trace element, has been associated with increased susceptibility to viral infections.</li>
</ul>
<p>The authors planned to include 520 patients but the safety monitoring committee recommended the study be stopped early, due to low likelihood of detecting significant outcome differences between the groups. There were also more adverse effects (nausea, diarrhoea, and stomach cramps) reported in the supplement groups than those receiving usual care.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1519613353286590464"}"></div></p>
<h2>Little evidence of benefits</h2>
<p>Despite the large variety of complementary medicines marketed, most clinical trials to date have studied the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8873042/">impact of vitamin D</a>, <a href="https://clinicalnutritionespen.com/article/S2405-4577(22)00002-X/fulltext">vitamin C or zinc</a> to reduce the risk of contracting COVID, improve rates of hospitalisation or death. </p>
<p>Even with high treatment doses, results have been <a href="https://ods.od.nih.gov/factsheets/COVID19-HealthProfessional/#h2">generally disappointing</a>. Vitamin D, zinc and some probiotics <em>may</em> be beneficial to <em>prevent</em> viral infections. Vitamins D, C, A, zinc, calcium and some probiotics <em>may</em> be beneficial to <em>treat</em> viral infections. But other supplements studied (including copper, magnesium, selenium and echinacea) are unlikely to be beneficial or are not supported by sufficient data. </p>
<p>However, supplements may be beneficial when individuals are <a href="https://pubmed.ncbi.nlm.nih.gov/32334392/">unable to achieve</a> a balanced and varied diet.</p>
<hr>
<iframe src="https://flo.uri.sh/visualisation/9883728/embed" title="Interactive or visual content" class="flourish-embed-iframe" frameborder="0" scrolling="no" style="width:100%;height:600px;" sandbox="allow-same-origin allow-forms allow-scripts allow-downloads allow-popups allow-popups-to-escape-sandbox allow-top-navigation-by-user-activation" width="100%" height="400"></iframe>
<div style="width:100%!;margin-top:4px!important;text-align:right!important;"><a class="flourish-credit" href="https://public.flourish.studio/visualisation/9883728/?utm_source=embed&utm_campaign=visualisation/9883728" target="_top"><img alt="Made with Flourish" src="https://public.flourish.studio/resources/made_with_flourish.svg"> </a></div>
<hr>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sugar-detox-cutting-carbs-a-doctor-explains-why-you-should-keep-fruit-on-the-menu-173992">Sugar detox? Cutting carbs? A doctor explains why you should keep fruit on the menu</a>
</strong>
</em>
</p>
<hr>
<h2>Potentially harmful</h2>
<p>High doses or chronic use of COVID supplements have also been linked with <a href="https://pubmed.ncbi.nlm.nih.gov/20040703/">adverse effects</a>: vitamin D with muscle pain and loss of bone mass; vitamin A with elevated liver function tests and blurred vision; vitamin E with bleeding risk; plant extracts, magnesium with gastrointestinal effects; and selenium with hair loss and brittle nails.</p>
<p>So, the evidence is not convincing that taking vitamins and supplements will prevent you catching COVID or help you recover from the infection, unless you have a known nutrient deficiency or a poor diet.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/vitamins-and-minerals-arent-risk-free-here-are-6-ways-they-can-cause-harm-165399">Vitamins and minerals aren't risk-free. Here are 6 ways they can cause harm</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/182220/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Treasure McGuire does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Sales of vitamins are booming in pandemic times. But is there any evidence that vitamin and mineral supplements can protect you from COVID or help you recover from infection?Treasure McGuire, Assistant Director of Pharmacy, Mater Health SEQ in conjoint appointment as Associate Professor of Pharmacology, Bond University and Associate Professor (Clinical), The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1782102022-03-07T11:30:41Z2022-03-07T11:30:41ZVitamin D2 and D3: what’s the difference and which should you take?<figure><img src="https://images.theconversation.com/files/450062/original/file-20220304-13-1qxevmm.jpg?ixlib=rb-1.1.0&rect=508%2C316%2C4078%2C2262&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Vitamin D3 is found in fish, cheese, and eggs.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/black-table-ingredients-food-rich-vitamin-721103494">Cegli/Shutterstock</a></span></figcaption></figure><p>Vitamin D is important for maintaining health, as it has many roles in the human body. But there is more than one form of vitamin D, and recent research suggests that these forms may have <a href="https://www.frontiersin.org/articles/10.3389/fimmu.2022.790444/full">different effects</a>. So what are the different types of vitamin D, and is one really more beneficial than the other?</p>
<p>Although medical conditions later associated with vitamin D deficiency, such as the bone disease rickets, have been known about since the 17th century, vitamin D itself wasn’t identified until the early 20th century. This discovery led to <a href="https://academic.oup.com/jn/article/134/6/1299/4688802">Adolf Windaus</a> winning the Nobel prize for chemistry in 1928. </p>
<p>The vitamin D family actually includes five molecules, with the two most important being vitamin D2 and D3. These molecules are also known as ergocalciferol and cholecalciferol, respectively. While both of these types of vitamin D contribute to our health, they differ in how we get them. </p>
<p>Dietary vitamin D2 generally comes from plants, <a href="https://www.sciencedirect.com/science/article/pii/S1074552114000246">particularly mushrooms and yeast</a>, whereas we get vitamin D3 from animal sources, such as <a href="https://www.hsph.harvard.edu/nutritionsource/vitamin-d/">oily fish, liver and eggs</a>. Both forms of vitamin D are also available in dietary supplements. </p>
<p>What most people probably don’t know is that most of our vitamin D comes from <a href="https://www.bda.uk.com/resource/vitamin-d.html">exposing our skin to sunlight</a>. When our skin is exposed to the sun, ultraviolet rays convert a precursor molecule called 7-dehydrocholesterol into vitamin D3. This important effect of exposure to the sun explains why people living at more extreme latitudes, or people who have darker skin, are more prone to <a href="https://pubmed.ncbi.nlm.nih.gov/28662556/#:%7E:text=Conclusion%3A%20Latitude%20was%20found%20to,risk%20for%20vitamin%20D%20deficiency.">vitamin D deficiency</a>. Melanin, a pigment in the skin, blocks ultraviolet rays from activating 7-dehydrocholesterol, thus limiting D3 production. Wearing clothing or sunscreen has a similar effect. </p>
<figure class="align-center ">
<img alt="Man getting some sun rays." src="https://images.theconversation.com/files/450077/original/file-20220304-17-61rrpd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/450077/original/file-20220304-17-61rrpd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/450077/original/file-20220304-17-61rrpd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/450077/original/file-20220304-17-61rrpd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/450077/original/file-20220304-17-61rrpd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/450077/original/file-20220304-17-61rrpd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/450077/original/file-20220304-17-61rrpd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Most of our vitamin D comes from exposing our skin to sunlight.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/happy-asian-senior-male-wear-glasses-642155260">Eggeegg/Shutterstock</a></span>
</figcaption>
</figure>
<p>Both vitamins D2 and D3 are essentially inactive until they go through two processes in the body. First, the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3968073/">liver changes their chemical structure</a> to form a molecule known as calcidiol. This is the form in which vitamin D is stored in the body. Calcidiol is then further altered in the kidneys <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4303849/">to form calcitriol</a>, the active form of the hormone. It is calcitriol that is responsible for the biological actions of vitamin D, including helping bones to form, metabolising calcium and supporting how our <a href="https://www.ncbi.nlm.nih.gov/books/NBK526025/">immune system works</a>. </p>
<p>Technically, vitamin D isn’t a vitamin at all, but a pro-hormone. This means the body converts it into an active hormone. All hormones have receptors (on bone cells, muscle cells, white blood cells) that they <a href="https://www.sciencedirect.com/science/article/pii/B9780128096338900876">bind to and activate</a>, like a key unlocking a lock. Vitamin D2 has the same <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3968073/">affinity for the vitamin D receptor as vitamin D3</a>, meaning neither form is better at binding to its receptor.</p>
<h2>Different effects on the immune system</h2>
<p>A <a href="https://www.frontiersin.org/articles/10.3389/fimmu.2022.790444/full">recent study</a> found that vitamin D2 and D3 supplementation had different effects on genes important for immune function. These findings are significant, as most previous research has failed to find much difference in the effect of supplementation with either vitamin D2 or D3. </p>
<p>Most of the research published to date has suggested that the main difference between vitamin D2 and D3 supplementation is the effect on circulating vitamin D levels in the bloodstream. Studies have repeatedly shown that vitamin D3 is <a href="https://www.nutritionadvance.com/vitamin-d2-vs-d3/#:%7E:text=Vitamin%20D2%20and%20D3%20both%20significantly%20raise%20serum%20vitamin%20D,for%20longer%20periods%20of%20time">superior</a> at raising levels of vitamin D in the body. These findings were supported by a recent review of the evidence which found that vitamin D3 supplementation increased vitamin D levels in the body <a href="https://www.mdpi.com/2072-6643/13/10/3328">better than vitamin D2</a>. But not all studies <a href="https://academic.oup.com/jcem/article/93/3/677/2598025?login=true">agree</a>.</p>
<p>Very few studies support vitamin D2 supplementation being superior to vitamin D3. One trial showed that vitamin D2 was better at treating immune issues in patients who were on <a href="https://www.hindawi.com/journals/jos/2015/729451/">steroid therapy</a>. However, other than increasing vitamin D levels in the body, there is not much evidence that vitamin D3 supplements are better than vitamin D2 supplements. One study found that vitamin D3 <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4971338/">improved calcium levels</a> more than vitamin D2. But we need more research to provide definitive answers.</p>
<h2>So which should I take?</h2>
<p>Vitamin D deficiency is now <a href="https://www.ncbi.nlm.nih.gov/books/NBK532266/">more prevalent than ever</a>, with around <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356951/">a billion people</a> worldwide being vitamin D deficient. It is important that people at risk of vitamin D deficiency – older adults, people living in less sunny climates and people with darker skin – take vitamin D supplements. </p>
<p>Health professionals recommend that most people take <a href="https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/">10 micrograms of vitamin D a day</a>, especially <a href="https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/longterm-vitamin-d3-supplementation-is-more-effective-than-vitamin-d2-in-maintaining-serum-25hydroxyvitamin-d-status-over-the-winter-months/A6CD4FE5C649E0FAC9BCBAFB23538707">in winter</a>. It would appear that vitamin D3 supplements are the superior option for maintaining vitamin D levels, but short exposure of the skin to the sun, even on a cloudy day, will also help you keep healthy vitamin D levels.</p><img src="https://counter.theconversation.com/content/178210/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James Brown has previously received funding from the EU Horizon 2020 scheme to study personalised approaches to food choices.</span></em></p>Very few studies support vitamin D2 supplementation being superior to vitamin D3.James Brown, Associate Professor in Biology and Biomedical Science, Aston UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1724332021-12-17T14:29:10Z2021-12-17T14:29:10ZVitamin D supplements may reduce the duration of the common cold<p>After a couple of years of mask-wearing, social distancing and hand sanitising, the common cold is back. And – according to some people – back with a vengeance. Some are calling it a “<a href="https://www.bbc.co.uk/news/newsbeat-58624295">super cold</a>” – others, “the worst cold ever”. Fortunately, there may be a way to reduce the duration of a cold: vitamin D supplements. </p>
<p>We may suffer more common colds during the winter because we spend more time close to each other indoors. But vitamin D levels might also influence the risk of getting a cold. There are more colds during winter when vitamin D levels are lowest, and fewer colds during summer when vitamin D levels are highest.</p>
<p>We get most of our vitamin D from the sun’s rays (80%–100%) and only a small amount from our diet. For people living at latitudes above 30 degrees, such as in the UK, there is a higher risk of having low vitamin D levels (vitamin D insufficiency) in the winter. People who spend most of their time indoors, or with their skin covered, are also at a higher risk of vitamin D insufficiency. More than half of the UK population is considered to have <a href="https://pubmed.ncbi.nlm.nih.gov/26853300/">insufficient vitamin D levels in winter</a>. </p>
<p>In the UK, the sun’s rays are too weak to provide enough vitamin D between October and March. This means that from October until March, people’s vitamin D levels are likely to fall.</p>
<figure class="align-center ">
<img alt="Man outdoors in shorts and T-shirt." src="https://images.theconversation.com/files/438183/original/file-20211217-19-1cabaoh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/438183/original/file-20211217-19-1cabaoh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/438183/original/file-20211217-19-1cabaoh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/438183/original/file-20211217-19-1cabaoh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/438183/original/file-20211217-19-1cabaoh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/438183/original/file-20211217-19-1cabaoh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/438183/original/file-20211217-19-1cabaoh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Try and spend 15 minutes a day in the sun during spring and summer to top up your vitamin D.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/african-american-man-white-tee-beach-1939023259">Rawpixel/Shutterstock</a></span>
</figcaption>
</figure>
<p>Research shows that vitamin D influences the risk of catching common colds and other respiratory infections. People with lower vitamin D levels are <a href="https://pubmed.ncbi.nlm.nih.gov/19237723/">more likely</a> to have a common cold, and people supplemented with vitamin D are <a href="https://pubmed.ncbi.nlm.nih.gov/28202713/">less likely</a> to get a common cold. </p>
<p>As well as reducing the chance of getting a common cold, our recent <a href="https://pubmed.ncbi.nlm.nih.gov/33481482/">research</a> shows that vitamin D supplementation reduces the severity and duration of common colds.</p>
<p>First, we found that vitamin D-sufficient military recruits were less likely to have a common cold than vitamin D-insufficient recruits during 12 weeks of basic military training. Then we examined the effect of vitamin D supplementation during winter on common colds. We supplemented recruits with either simulated sunlight (UV radiation by a whole-body irradiation cabinet) or oral vitamin D₃ tablets (1,000 IU per day for four weeks to restore vitamin D to normal levels and then 400 IU per day for eight weeks to maintain healthy vitamin D levels). Both supplements similarly achieved vitamin D sufficiency in almost all recruits.</p>
<p>We found that vitamin D supplementation did not reduce the likelihood of getting a common cold, but it did reduce the number of days a participant had a common cold by 36%. It also reduced the peak severity of common cold symptoms by 15%.</p>
<h2>How to get your vitamin D topped up</h2>
<p>Our findings support the <a href="https://www.gov.uk/government/publications/vitamin-d-supplements-how-to-take-them-safely/vitamin-d-supplements-how-to-take-them-safely">UK government’s recommendation</a> to maintain vitamin D sufficiency all year round, and they show a potentially beneficial role of wintertime vitamin D supplementation.</p>
<p>It is not possible to get enough sunlight in the UK between October and March, so it’s advisable to take a 10 microgram vitamin D supplement daily during this period (this value is sometimes shown as 400 IU on the label). If you can’t get any sunlight at all, or you have not supplemented with vitamin D from October onwards, you may need to take 25 micrograms (1,000 IU) of vitamin D for four weeks to restore your vitamin D to a healthy level.</p>
<p>To ensure that you get enough vitamin D during the summer, make sure you get short periods of regular sunlight exposure. Safe sunlight exposure for people living at latitudes between 30 and 60 degrees north involves being in the <a href="https://pubmed.ncbi.nlm.nih.gov/26853300/">sun for 15 minutes</a> between 10am and 3pm while wearing a T-shirt and shorts.</p><img src="https://counter.theconversation.com/content/172433/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Neil Walsh receives funding from MOD UK. </span></em></p><p class="fine-print"><em><span>Sam Oliver receives funding from MOD UK. </span></em></p><p class="fine-print"><em><span>Sophie E Harrison does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Winter vitamin D supplementation may reduce the burden of common coldSophie E Harrison, Research Development and Innovation Officer, Bangor UniversityNeil Walsh, Professor, Director Extremes Research Group, Liverpool John Moores UniversitySam Oliver, Reader in Sport & Exercise Science, Bangor UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1700592021-10-20T14:05:05Z2021-10-20T14:05:05ZSix popular beliefs about colds: experts explain the facts<figure><img src="https://images.theconversation.com/files/427491/original/file-20211020-15-1wg9107.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sticking garlic up your nose will not help you recover from a cold.</span> <span class="attribution"><span class="source">Fizkes/Shutterstock</span></span></figcaption></figure><p><em>As we return to pre-lockdown levels of social mixing, colds are starting to become all too common. A TikTok video has <a href="https://www.tiktok.com/tag/garlicinnose">gone viral</a> involving putting garlic up your nose as a cold cure, just one in a long line of claimed treatments or cures.</em></p>
<p><em>We asked two experts to examine some commonly held beliefs around colds.</em></p>
<p><strong>1. Can you get a cold by getting cold?</strong></p>
<p>Colds become more common in winter. Like other upper respiratory tract infections (in the nose, throat and windpipe) they are normally caused by a virus. There might be a little truth in the idea that getting cold can give you a cold, because as the temperature changes this can alter the lining of our throat and windpipe, <a href="http://www.giargianese.it/wp-content/uploads/2018/04/Exposure-to-cold-and-acute-upper-respiratory-tract-infection.pdf">which can possibly</a> make it easier for viruses to infect cells. However, the main reason we get more colds in winter is spending more time inside, closer to other people – the perfect environment to transmit viruses. </p>
<p><strong>2. Does sticking garlic up your nose help?</strong></p>
<p>The TikTok trend involves putting cloves of garlic up your nose because it claims to act as a decongestant. Sticking something up your nose blocks the flow of mucus, so when it is removed, the flow starts and the mucus drips or even runs out of your nose. Mucus not only helps trap and remove pathogens including viruses, but also contains antibodies and can <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4752725/">reduce how</a> infectious and spreadable viruses are. So this is not a good idea.</p>
<p>Garlic contains a range of compounds which might irritate the nose, and remember sticking anything up your nose isn’t a great idea. It could damage the lining and lead to bleeding or even get stuck. So it doesn’t really help and could be harmful. </p>
<p><strong>3. Can herbal remedies prevent colds?</strong></p>
<p>Various herbal remedies claim to either prevent or speed up recovery from a cold. People often <a href="https://www.nccih.nih.gov/health/echinacea">mention echinacea</a>, a family of plants that grow in North America. Some trials have suggested a small preventative effect, but <a href="https://www.cochrane.org/CD000530/ARI_echinacea-for-preventing-and-treating-the-common-cold">the evidence</a> does not show statistically significant reductions in illness levels. Turmeric is also touted as a preventative medicine, but there is no robust evidence for its effectiveness either.</p>
<figure class="align-center ">
<img alt="A man and a woman with a cold." src="https://images.theconversation.com/files/427490/original/file-20211020-22-8ydkp2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/427490/original/file-20211020-22-8ydkp2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/427490/original/file-20211020-22-8ydkp2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/427490/original/file-20211020-22-8ydkp2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/427490/original/file-20211020-22-8ydkp2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/427490/original/file-20211020-22-8ydkp2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/427490/original/file-20211020-22-8ydkp2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Hot drinks can help soothe your sinuses, but they can’t cure a cold.</span>
<span class="attribution"><span class="source">Studio Romantic/Shutterstock</span></span>
</figcaption>
</figure>
<p><strong>4. Can vitamin C help?</strong></p>
<p>Nobel prize-winning scientist <a href="https://pubmed.ncbi.nlm.nih.gov/9350474/#:%7E:text=In%201970%20Linus%20Pauling%20claimed,regards%20the%20size%20of%20benefit.">Linus Pauling</a> suggested that vitamin C in high doses could be an effective treatment for many viral infections. But a <a href="https://www.cochrane.org/">Cochrane review</a>, a very robust system in which researchers assess evidence, found that vitamin C did not <a href="https://pubmed.ncbi.nlm.nih.gov/23440782/">prevent colds</a>, but may reduce their duration, in some people. As vitamin C supplements of around 200mg per day are considered low risk, some suggest this is a reasonable strategy to shorten the effects of a cold.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/pure-fruit-juice-healthy-or-not-122962">Pure fruit juice: healthy, or not?</a>
</strong>
</em>
</p>
<hr>
<p><strong>5. Does vitamin D prevent colds?</strong></p>
<p>Vitamin D has moved from being the sunshine vitamin associated with healthy bones, to being linked to reducing the risks around everything from heart disease and diabetes to viruses. This has included a lot of interest in vitamin D as a way of helping us fight off flu and more recently COVID-19. </p>
<p><a href="https://www.mdpi.com/2072-6643/12/5/1248/htm">Laboratory experiments</a> show that vitamin D is important in supporting immunity and this is critical in fighting off viruses. The problem may be that some people have inadequate vitamin D levels. Sunshine allows us to make our own vitamin D - but that happens less in winter. So it is likely that taking vitamin D supplements as advised by the <a href="https://www.gov.uk/government/publications/vitamin-d-for-vulnerable-groups/vitamin-d-and-clinically-extremely-vulnerable-cev-guidance">UK government</a> over winter is sensible so that you get enough, and this <a href="https://www.bmj.com/content/356/bmj.i6583">may help</a> prevent you from getting a cold.</p>
<p><strong>6. What about chicken soup?</strong></p>
<p>Chicken soup has been used through the ages to treat colds, and <a href="https://ebm.bmj.com/content/26/2/57">like honey</a> it might have some benefits in managing symptoms. But it is unlikely to make a big impact on driving out the infection. The water in the soup will help with hydration, which is a <a href="https://mrmjournal.biomedcentral.com/articles/10.1186/s40248-019-0200-9">often a problem</a> when we have a cold. Like most hot drinks it can help to relieve painful sinuses. There are studies looking at the effect on our <a href="https://www.sciencedirect.com/science/article/abs/pii/S0012369215377217">immune system cells</a>, but the evidence from these is far from conclusive. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/kKNqyE3OvZU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">How to make homemade chicken soup.</span></figcaption>
</figure>
<p>Sadly, there are no miracle cures for the common cold. Some suggestions may be helpful, and are generally not harmful, such as getting enough vitamin C and D. But others are definitely not worth trying and could be risky, such as putting garlic up your nose. The best thing to do is get plenty of rest and drink plenty of fluids to stay hydrated.</p><img src="https://counter.theconversation.com/content/170059/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Duane Mellor has acted in a consultancy role with Kinerva and is a member of the British Dietetic Association.</span></em></p><p class="fine-print"><em><span>James Brown has previously received funding from Seven Seas Ltd (UK).</span></em></p>As winter approaches, every family has a favourite cold remedy, but experts say few work.Duane Mellor, Lead for Evidence-Based Medicine and Nutrition, Aston Medical School, Aston UniversityJames Brown, Associate Professor in Biology and Biomedical Science, Aston UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1647762021-08-26T01:48:57Z2021-08-26T01:48:57ZRates of COVID might increase in winter, but it’s not necessarily because the virus thrives in the cold<figure><img src="https://images.theconversation.com/files/416755/original/file-20210818-15-d5s5wl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/woman-wearing-medical-protective-mask-dusk-1850607568">Shutterstock</a></span></figcaption></figure><p>Colder weather has long been associated with coughs, colds and other respiratory illnesses. Seasonal influenza and common colds peak throughout the winter months in both hemispheres – usually <a href="https://www.immunisationcoalition.org.au/wp-content/uploads/2018/03/17Dec-Aust-Flu-Stats-2019.pdf">around August</a> in Australia. </p>
<p>Given many common colds are caused by coronaviruses, it seems logical that cases of SARS-CoV-2, the virus that causes COVID-19, would be driven upward as temperatures decline. </p>
<p>But while there are plausible biological explanations for why this occurs, we can’t be certain of the effect of temperature on SARS-CoV-2. There is too little data to make solid conclusions. </p>
<p>Behavioural factors, such as spending more time indoors where viruses are more easily transmitted, are also at play.</p>
<h2>What does the data say?</h2>
<p>COVID case numbers in Australia are at their highest now and were at their second-highest levels 12 months ago, in winter:</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/417546/original/file-20210824-23-1s151w5.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/417546/original/file-20210824-23-1s151w5.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/417546/original/file-20210824-23-1s151w5.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/417546/original/file-20210824-23-1s151w5.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/417546/original/file-20210824-23-1s151w5.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/417546/original/file-20210824-23-1s151w5.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=494&fit=crop&dpr=1 754w, https://images.theconversation.com/files/417546/original/file-20210824-23-1s151w5.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=494&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/417546/original/file-20210824-23-1s151w5.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=494&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Australia’s COVID-19 daily case numbers have been highest in August.</span>
<span class="attribution"><a class="source" href="https://ourworldindata.org/coronavirus/country/australia">Our World In Data</a></span>
</figcaption>
</figure>
<p>But this is not true for other countries, especially those in the Northern Hemisphere. In the United Kingdom, for instance, cases peaked last winter, and then again in summer with the Delta variant:</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/417934/original/file-20210825-18784-1muu8fy.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/417934/original/file-20210825-18784-1muu8fy.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/417934/original/file-20210825-18784-1muu8fy.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/417934/original/file-20210825-18784-1muu8fy.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/417934/original/file-20210825-18784-1muu8fy.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/417934/original/file-20210825-18784-1muu8fy.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/417934/original/file-20210825-18784-1muu8fy.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/417934/original/file-20210825-18784-1muu8fy.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Cases in the UK peaked in January 2021 and again last month.</span>
<span class="attribution"><a class="source" href="https://ourworldindata.org/coronavirus/country/united-kingdom">Our World In Data</a></span>
</figcaption>
</figure>
<h2>Why do cases often rise in winter? Biological explanations</h2>
<p>Coronaviruses <a href="https://www.tandfonline.com/doi/full/10.1080/02786826.2020.1829536?casa_token=g0kUhMfPDQsAAAAA%3ASsHz6mweEa5jVNVnsAfvPc2fEoFYU0eX6_667ymtb6LqWLC0ThMA5T5lS4O3pSCNrfZdipXrqfTn57U">survive longer</a> in environments of decreased sunlight, lower temperatures and lower relative humidity. </p>
<p>So the amount of active virus in the environment might be greater during the winter months, and in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7361302/">cold, dry climates</a>. </p>
<p>In environments with low humidity, there is less water vapour in the air (in other words, the air is dry), and when a COVID-19 positive person coughs, aerosolised particles stay suspended for <a href="https://www1.racgp.org.au/newsgp/clinical/new-research-finds-link-between-covid-19-and-lower">much longer in the air</a>. This increases the potential exposure and transmission to other people.</p>
<p>One study from 2020 reported a link between <a href="https://onlinelibrary.wiley.com/doi/pdf/10.1111/tbed.13631">COVID-19 and lower humidity</a>. The researchers noted a 1% decrease in humidity could increase the number of COVID-19 cases by 6%. </p>
<p>Another recent <a href="https://bmjopen.bmj.com/content/11/2/e043863">study from the United States and China</a> found higher temperatures and higher relative humidity potentially suppressed COVID-19 transmission. </p>
<p><a href="https://theconversation.com/research-shows-coronavirus-thrives-in-dry-air-and-august-is-coastal-australias-least-humid-month-144508">In Sydney</a>, humidity is lowest in winter, particularly in August, and highest in summer. The same is true for most coastal areas in Australia.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/research-shows-coronavirus-thrives-in-dry-air-and-august-is-coastal-australias-least-humid-month-144508">Research shows coronavirus thrives in dry air (and August is coastal Australia's least humid month)</a>
</strong>
</em>
</p>
<hr>
<h2>It’s in the air</h2>
<p>On April 30 this year, the <a href="https://www.who.int/news-room/q-a-detail/coronavirus-disease-covid-19-how-is-it-transmitted">World Health Organization updated its guidance</a> on how COVID-19 was transmitted:</p>
<blockquote>
<p>The virus can spread from an infected person’s mouth or nose in small liquid particles when they cough, sneeze, speak, sing or breathe. These particles range from larger respiratory droplets to smaller aerosols.</p>
</blockquote>
<p>These aerosols can remain suspended in the air for up to <a href="https://pubmed.ncbi.nlm.nih.gov/32568661/">16 hours</a>. </p>
<p>So, it’s the shared air that spreads the virus, and that’s why <a href="https://theconversation.com/are-you-wearing-gloves-or-a-mask-to-the-shops-you-might-be-doing-it-wrong-137393">face masks</a> are important.</p>
<h2>Behavioural explanations</h2>
<p>A range of other factors which coincide with winter are likely to have a greater impact on transmission than how the virus behaves in cold climates. </p>
<p>As the colder winter months arrive, we flee the outdoors, instead opting for indoor activities. Some indoor spaces – including shops, restaurants, homes – are poorly ventilated, allowing colds, flus and other <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/ina.12766?casa_token=Zr_RRUxir7cAAAAA%3Az6iMhCXLI9fFqlQceF1kdnP6Nv2V_JrPsR_oGoIA5tPyOtD8QwQgO9r73U0QqW6UpJz3jt1UqzU68HFA">respiratory illness</a> such as COVID to spread more easily.</p>
<figure class="align-center ">
<img alt="A man sits on a couch, coughing into a tissue." src="https://images.theconversation.com/files/416761/original/file-20210818-25-qjx5ii.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/416761/original/file-20210818-25-qjx5ii.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/416761/original/file-20210818-25-qjx5ii.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/416761/original/file-20210818-25-qjx5ii.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/416761/original/file-20210818-25-qjx5ii.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/416761/original/file-20210818-25-qjx5ii.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/416761/original/file-20210818-25-qjx5ii.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Respiratory illnesses spread more easily indoors.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/asian-man-getting-cold-flu-sitting-1355494856">Shutterstock</a></span>
</figcaption>
</figure>
<p>In the northern hemisphere, winter also coincides with the holiday season, which sees significant amounts of travel, both international and domestic, and a significant uptick in large social gatherings. In the United Kingdom in January this year, <a href="https://www.bbc.com/news/health-55587491">this caused a significant increase</a> in COVID-19 transmission. </p>
<h2>It’s unlikely due to vitamin D</h2>
<p>Another potential factor in COVID-19 transmission centres on the seasonal change in population-wide vitamin D levels. But so far, this isn’t backed up by evidence. </p>
<p>Vitamin D has received significant attention throughout the pandemic for a potentially protective effect against COVID-19. This was after a number of observational studies identified <a href="https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3561958">poorer outcomes in geographical areas</a> with high levels of vitamin D deficiency. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/does-vitamin-d-ward-off-coronavirus-dont-reach-for-the-supplements-yet-139063">Does vitamin D ward off coronavirus? Don't reach for the supplements yet</a>
</strong>
</em>
</p>
<hr>
<p>Other initial studies also showed <a href="https://www.mdpi.com/2072-6643/12/5/1359">lower levels of vitamin D</a> in those diagnosed with COVID-19. This was theorised to be due to the effect of vitamin D on the immune system, preventing some of the severe inflammatory impacts of the disease, and potentially improving the ability of the <a href="https://www.sciencedirect.com/science/article/pii/S0378512220303467#bib0105">individual to combat the infection</a>. </p>
<p>However, larger studies where one group was given vitamin D supplements and another weren’t have thrown doubt on these relationships, particularly in those <a href="https://www.thelancet.com/journals/landia/article/PIIS2213-8587(21)00003-6/fulltext">who were not deficient</a>.</p>
<h2>Social distance and masks matter most</h2>
<p>While there does seem to be an increase in COVID-19 cases in the winter months, the cause of this is multi-factorial. </p>
<p>While certainly something for health care and policymakers to be aware of, the effect of weather and climate on COVID-19 is unlikely to have significant impact overall, and is readily countered by control measures. </p>
<p>Importantly, social distancing and mask use help to limit other winter viral infections such as the seasonal influenza, which was <a href="https://www.cdc.gov/mmwr/volumes/69/wr/mm6937a6.htm">drastically reduced in winter 2020</a>. </p>
<p>Paying close attention to the public health advice, particularly when indoors, should counteract any increase in COVID-19 activity in the colder months. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/is-delta-defeating-us-heres-why-the-variant-makes-contact-tracing-so-much-harder-164780">Is Delta defeating us? Here's why the variant makes contact tracing so much harder</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/164776/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vasso Apostolopoulos' COVID-19 research has received internal funding from a Victoria University research grant and from philanthropic donations</span></em></p><p class="fine-print"><em><span>Jack Feehan does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>While there are plausible explanations for why this occurs, we can’t be certain of the effect of temperature on SARS-CoV-2. Being indoors in poorly ventilated spaces plays a big role.Vasso Apostolopoulos, Professor of Immunology and Associate Provost, Research Partnerships, Victoria UniversityJack Feehan, Research Officer - Immunology and Translational Research, Victoria UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1519102020-12-15T20:16:45Z2020-12-15T20:16:45ZWill going out in the cold give you a cold?<figure><img src="https://images.theconversation.com/files/374912/original/file-20201214-13-t6d99c.jpg?ixlib=rb-1.1.0&rect=33%2C0%2C5573%2C3732&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Viruses spread easier during the winter than other times of the year, but being outside isn't the main cause of transmission.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/man-shovels-the-sidewalk-outside-of-his-suburban-royalty-free-image/564190027?adppopup=true">Christopher Kimmel via Getty Images</a></span></figcaption></figure><p>Many of us have heard: “Don’t go outside without a coat; you’ll catch a cold.” </p>
<p>That’s not exactly true. As with many things, the reality is more complicated. Here’s the distinction: Being cold isn’t why you get a cold. But it is true that cold weather makes it easier to get the cold or flu. It is still too early to tell how weather impacts the COVID-19 virus, but scientists are starting to think it behaves differently than cold and flu viruses.</p>
<p>As an <a href="https://www.purdue.edu/aging/faculty/?id=256">associate professor of nursing</a> with a background in public health, I’m asked about this all the time. So here’s a look at what actually happens. </p>
<p>Many viruses, including <a href="https://doi.org/10.1073/pnas.1411030112">rhinovirus</a> – the usual culprit in the common cold – and influenza, remain infectious longer and replicate faster in colder temperatures. That’s why these viruses spread more easily in winter. Wearing a heavy coat won’t necessarily make a difference. </p>
<figure class="align-center ">
<img alt="Two women outside during the winter." src="https://images.theconversation.com/files/374894/original/file-20201214-24-1f7enxs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/374894/original/file-20201214-24-1f7enxs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/374894/original/file-20201214-24-1f7enxs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/374894/original/file-20201214-24-1f7enxs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/374894/original/file-20201214-24-1f7enxs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/374894/original/file-20201214-24-1f7enxs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/374894/original/file-20201214-24-1f7enxs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The cold weather does have an impact on whether or not you catch a cold.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/two-women-take-a-selfie-photo-in-front-of-a-frozen-fountain-news-photo/899344332?adppopup=true">Spencer Platt via Getty Images</a></span>
</figcaption>
</figure>
<h2>Virus transmission is easier when it’s cold</h2>
<p>More specifically, cold weather can <a href="https://www.nih.gov/news-events/nih-research-matters/flu-virus-fortified-colder-weather">change the outer membrane</a> of the influenza virus; it makes the membrane more solid and rubbery. Scientists believe that the rubbery coating makes person-to-person transmission of the virus easier. </p>
<p>It’s not just cold winter air that causes a problem. Air that is dry in addition to cold has been linked to flu outbreaks. A National Institutes of Health study suggests that <a href="https://www.nih.gov/news-events/nih-research-matters/dry-air-may-spur-flu-outbreaks">dry winter air</a> further helps the influenza virus to remain infectious longer. </p>
<p>How your immune system responds during cold weather also matters a great deal. <a href="https://doi.org/10.1038/nature.2013.13025">Inhaling cold air</a> may adversely affect the immune response in your respiratory tract, which makes it easier for viruses to take hold. That’s why wearing a scarf over your nose and mouth may help. </p>
<p>Also, most people get less sunlight in the winter. That is a problem because the <a href="https://theconversation.com/why-you-need-more-vitamin-d-in-the-winter-128898">Sun is a major source of vitamin D</a>, which is essential <a href="https://doi.org/10.1016/j.mayocp.2013.05.011">for immune system health</a>. Physical activity, another factor, also tends to drop <a href="https://doi.org/10.1007/s10238-020-00650-3">during the winter</a>. People are <a href="https://doi.org/10.1016/j.jshs.2016.07.007">three times more likely</a> to delay exercise in snowy or icy conditions.</p>
<p>Instead, people spend more time indoors. That usually means more close contact with others, which leads to disease spread. Respiratory viruses generally spread within a six-foot radius of an infected person. When you are indoors, it is very likely that you are closer together than six feet. </p>
<p>In addition, cold weather <a href="https://www.texashealthflowermound.com/how-cold-weather-affects-your-ear-nose-throat/">dries out</a> your eyes and the mucous membranes in your nose and throat. Because viruses that cause colds and flu are typically inhaled, the virus can attach more easily to these impaired, dried-out passages.</p>
<figure class="align-center ">
<img alt="A child in bed with a cold." src="https://images.theconversation.com/files/374909/original/file-20201214-19-eqxul0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/374909/original/file-20201214-19-eqxul0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/374909/original/file-20201214-19-eqxul0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/374909/original/file-20201214-19-eqxul0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/374909/original/file-20201214-19-eqxul0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/374909/original/file-20201214-19-eqxul0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/374909/original/file-20201214-19-eqxul0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Spending more time indoors can increase the chances of catching a cold.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/girl-sleeping-with-sickness-on-the-bed-royalty-free-image/926062370?adppopup=true">Rawpixel via Getty Images</a></span>
</figcaption>
</figure>
<h2>What you can do</h2>
<p>While the bottom line is that being wet and cold doesn’t make you sick, there are strategies to help prevent illness all year long. </p>
<ul>
<li><p>Wash your hands often. </p></li>
<li><p>Avoid touching your face, something people do <a href="https://theconversation.com/how-to-stop-touching-your-face-to-minimize-spread-of-coronavirus-and-other-germs-133683">between nine and 23 times an hour</a>. </p></li>
<li><p>Stay hydrated; <a href="https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/water/art-20044256">eight glasses a day</a> of water is a good goal, but that could be more or less depending on lifestyle and the size of the person. </p></li>
<li><p>Eat a well-balanced diet. Dark green, leafy vegetables are rich in immune system-supporting vitamins; eggs, fortified milk, salmon and tuna have vitamin D. </p></li>
<li><p>Stay physically active, even during the winter. </p></li>
<li><p>Clean the hard, high-touch surfaces in your home often. </p></li>
<li><p>If your nose or throat gets dry in the winter, consider using a humidifier.</p></li>
<li><p>Get the flu vaccine. </p></li>
</ul>
<p>And one more important thing this year: When it’s your turn, make sure you get the COVID-19 vaccine.</p>
<p>[<em><a href="https://theconversation.com/us/newsletters/science-editors-picks-71/?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=science-corona-important">The Conversation’s most important coronavirus headlines, weekly in a new science newsletter</a>.</em>]</p><img src="https://counter.theconversation.com/content/151910/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Libby Richards does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Going out in the cold won’t necessarily lead to you getting a cold. But cold weather in general is more hospitable to viruses, so it’s wise to take steps to keep your immune system strong.Libby Richards, Associate Professor of Nursing, Purdue UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1499442020-11-13T11:49:35Z2020-11-13T11:49:35ZTime to add some sunshine (vitamin D) to milk and bread<figure><img src="https://images.theconversation.com/files/368894/original/file-20201111-13-1ok81jq.jpg?ixlib=rb-1.1.0&rect=11%2C0%2C7337%2C4504&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-african-american-woman-over-grey-1167944866">Krakenimages/Shutterstock</a></span></figcaption></figure><p>Free vitamin D supplements will be sent to over two million clinically vulnerable people in England <a href="https://www.dailymail.co.uk/news/article-8925321/Millions-elderly-vulnerable-free-Vitamin-D-government.html">this winter</a>. Over 80% of patients hospitalised with COVID-19 are vitamin D deficient compared with the general population. In a small study, a <a href="https://www.sciencedirect.com/science/article/pii/S0960076020302764?via%3Dihub#bibl0005">high dose of vitamin D appeared to reduce the severity</a> of COVID-19. While some <a href="https://app.box.com/s/g0ldpth1upfd7fw763ew3aqa3c0pyvky">scientists disagree</a> about whether vitamin D should be used more widely, a <a href="https://www.gov.uk/government/publications/sacn-vitamin-d-and-health-report">consensus is emerging</a> that we should all take vitamin D supplements.</p>
<p>But the UK should go further and fortify basic food such as flour and milk with vitamin D, which is common practice in Canada, Sweden, Finland and Australia. After all, research shows that a third of people <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3068890/">don’t take the pills they are given</a>. And many of the vulnerable people being sent the pills take <a href="https://www.kingsfund.org.uk/sites/default/files/field/field_publication_file/polypharmacy-and-medicines-optimisation-kingsfund-nov13.pdf">several other medications</a> and suffer from ailments that <a href="https://www.alzheimers.org.uk/about-us/policy-and-influencing/dementia-uk-report">increase memory loss</a> so may be confused. Many of the people who need it most won’t be taking the free pills.</p>
<p>A century ago, <a href="https://publichealthreviews.biomedcentral.com/articles/10.1007/BF03391602">over 80% of children</a> in industrialised Europe and the northern hemisphere had bone damage caused by rickets. Growing up in Canada in the 1910s, my grandfather had rickets and lived out his life with bow legs. Rickets is caused by vitamin D deficiency. Vitamin D is the “sunshine vitamin” because the body creates it when skin is exposed to sunlight. In Canada’s long, cold winters, not much skin gets exposed to the sun. </p>
<p>In the 1930s a number of countries, including Canada, mandated the fortification of essential food with vitamin D. Overnight, cases of vitamin D deficiency (and rickets) almost vanished. Sadly, this trend may be reversing slightly with some evidence that <a href="https://pubmed.ncbi.nlm.nih.gov/28612338/">rates of rickets is now rising</a>.</p>
<figure class="align-center ">
<img alt="X-rays of the legs of people with rickets." src="https://images.theconversation.com/files/368895/original/file-20201111-23-jexc28.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/368895/original/file-20201111-23-jexc28.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=389&fit=crop&dpr=1 600w, https://images.theconversation.com/files/368895/original/file-20201111-23-jexc28.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=389&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/368895/original/file-20201111-23-jexc28.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=389&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/368895/original/file-20201111-23-jexc28.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=489&fit=crop&dpr=1 754w, https://images.theconversation.com/files/368895/original/file-20201111-23-jexc28.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=489&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/368895/original/file-20201111-23-jexc28.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=489&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Rickets causes bone deformation.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/xray-rickets-disease-hypophosphate-shown-varus-1470250262">Bunsinth-Nan-Pua/Shutterstock</a></span>
</figcaption>
</figure>
<p>In the UK, people need vitamin D even more than in Canada. Most of the inhabited parts of Canada are south of the UK. In the UK, days are shorter in the winter and there is even less time to expose skin to sun. Most people go to school or work before the sun comes up and leave their school or office after it goes down. Their skin is never exposed to the sun. These conditions are ripe for vitamin D deficiency.</p>
<p>Vitamin D deficiency seems common, affecting about <a href="https://www.ncbi.nlm.nih.gov/books/NBK532266/">a billion people in the world</a>, a <a href="https://www.gov.uk/guidance/vitamin-d-deficiency-migrant-health-guide">quarter of the adults</a>, and <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/594361/NDNS_Y1_to_4_UK_report_full_text_revised_February_2017.pdf">a tenth of the children</a> in the UK. Severe vitamin D deficiency (less than 12 nanograms/millilitres in the blood) is rare because diets have improved since my grandfather’s time. Oily fish, red meat, eggs, some mushrooms and fortified breakfast cereals contain vitamin D. But milder deficiency (less than 20 nanograms/millilitre in the blood) is common and increases the risk of a number of ailments ranging from bone, blood, problems to breathing issues.</p>
<p>Taking vitamin D reduces <a href="https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/#h5">the risk of fractures, improves muscle function, and may even reduce the risk of death from some cancers</a>. A large study with 7,000 patients found that women who take <a href="https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD008873.pub4/full">vitamin D during pregnancy have a lower risk of pre‐eclampsia, gestational diabetes</a>, low birth weight and possibly postpartum haemorrhage. One study with almost 100,000 people found that <a href="https://www.cochrane.org/CD007470/ENDOC_vitamin-d-supplementation-for-prevention-of-mortality-in-adults">taking vitamin D supplements reduces premature death</a> by a small amount. With all these benefits, why oppose fortifying essential foods with vitamin D?</p>
<p>Libertarians might say that people should choose whether or not they take vitamin D. Force-feeding people with vitamin D could violate their freedom and increase taxes. Also, too much vitamin D can cause harm. It <a href="https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/#en46">increases the risk of a number of things</a> including passing too much urine, feeling thirsty, dizziness, headaches, bone pain, kidney stones and even liver failure. It can also interact with some prescription drugs, such as statins. Some studies also suggest that fortified milk tastes different.</p>
<h2>Finding the middle ground</h2>
<p>There are easy ways to benefit from fortification while avoiding its pitfalls. Some of the objections are not based on evidence. For example, it barely costs anything to fortify staple foods with vitamin D. And an economic analysis in the journal Nature found that the economic benefits (saving money because of fewer people sick with vitamin D deficiency) <a href="https://www.nature.com/articles/s41430-019-0486-x">outweigh the costs</a>. </p>
<p>To avoid forcing vitamin D on the population, the solution is for the government to recommend and subsidise fortification. Companies that added vitamin D to their milk and bread could advertise it following Public Health England guidance.</p>
<p>To avoid overdosing, food should not be over-fortified. The World Health Organization has <a href="https://www.who.int/nutrition/publications/guide_food_fortification_micronutrients.pdf">guidelines for safe dosages of vitamin D</a> fortification. In Canada and the US, milk is fortified at a rate of about 1mcg/100mL. Drinking a cup of milk provides about 3mcg of vitamin D, which is just under a <a href="https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/">third of what is currently recommended</a> in the UK. You’d have to drink <a href="https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/#h8">100 cups of fortified milk</a> to be harmed by vitamin D. Giving people the choice also addresses the objection that fortified food tastes different. </p>
<p>Finally, anyone taking medication that might interact with vitamin D should tell their doctors if they are taking a lot of fortified food. Although, again, this is not a problem in countries that mandate the fortification of food.</p>
<p>Fortifying essential food with sensible amounts of vitamin D is a cheap intervention that would have a small but important health benefit. It could be achieved in advance of the next flu season – or another COVID-19 wave.</p><img src="https://counter.theconversation.com/content/149944/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jeremy Howick does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Fortifying essential food with sensible amounts of vitamin D is a cheap intervention that will have a small but important benefit.Jeremy Howick, Director of the Oxford Empathy Programme, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1488632020-11-03T12:16:11Z2020-11-03T12:16:11ZWhy COVID makes it more important than ever that pregnant (and breastfeeding) women take vitamin D<figure><img src="https://images.theconversation.com/files/367003/original/file-20201102-13-div8pn.jpg?ixlib=rb-1.1.0&rect=44%2C31%2C4187%2C2937&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/portrait-beautiful-pregnant-woman-field-283151243">Rawpixel.com/Shutterstock</a></span></figcaption></figure><p>Vitamin D, often known as the “sunshine vitamin”, is normally obtained through exposure of our <a href="https://www.health.harvard.edu/staying-healthy/time-for-more-vitamin-d">skin to the sun</a>. The Department of Health recommends that everyone in the UK should take a supplement of vitamin D during the winter months (October to March), as there is insufficient UV light for our bodies to manufacture vitamin D. </p>
<p>This advice was also recently extended during the COVID pandemic, for people who were self-isolating during the summer months – who were advised to take <a href="https://www.gov.uk/government/news/phe-publishes-new-advice-on-vitamin-d">vitamin D supplements daily</a>. </p>
<p>Vitamin D is also an essential supplement for pregnant women as it helps to aid calcium and phosphorous metabolism, which are necessary for fetal skeletal growth. Adequate vitamin D and calcium status during pregnancy are also associated with <a href="https://www.gov.uk/government/publications/sacn-vitamin-d-and-health-report">decreased risk</a> of pre-eclampsia, low birthweight, poor postnatal growth, bone fragility, an increased incidence of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4436962/">autoimmune diseases</a> and gestational diabetes. This is a condition where high blood sugar (glucose) develops during pregnancy. BAME women and those with a BMI greater than 30 are at an <a href="https://www.diabetes.org.uk/diabetes-the-basics/gestational-diabetes">increased risk</a>. </p>
<p>People from some ethnic minority groups are particularly at risk of vitamin D deficiency, due to increased levels of melanin in the skin – as this reduces absorption of <a href="https://www.thelancet.com/journals/langlo/article/PIIS2214-109X(19)30492-9/fulltext">vitamin D from sunlight</a>. People with a BMI of more than 30 are also at increased risk of the deficiency. And emerging research also indicates that supplementing with the recommended daily dose (10 ug) may <a href="https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/">not be enough for both these groups</a> .</p>
<p>So as we are now approaching a long, dark, socially-isolated winter in the UK, adequate vitamin D supplementation has never been more important. This is particularly the case for pregnant women. Especially those with darker skin or a BMI over 30. This is not only for fetal and maternal health but also to reduce the risk of compromised immunity.</p>
<h2>Importance of vitamin D</h2>
<p>Vitamin D deficiency is very common – with about one billion people around the world thought to be <a href="https://www.ncbi.nlm.nih.gov/books/NBK532266/">deficient</a>. The signs and symptoms of vitamin D deficiency can include muscle weakness and fatigue along with <a href="https://www.medicalnewstoday.com/articles/318060">bone pain and weakness</a>. Some <a href="https://www.jneuropsychiatry.org/peer-review/depression-and-vitamin-d-deficiency-causality-assessment-and-clinical-practice-implications-12051.html">further studies</a> have also linked vitamin D deficiency with <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6970300/#:%7E:text=All%20the%20studies%20found%20that,CI%5D%201.00%E2%80%931.71">depression</a>.</p>
<p>Vitamin D also has an essential role in supporting the <a href="https://www.hsph.harvard.edu/nutritionsource/nutrition-and-immunity/">immune system</a> – triggering the immune cells to produce <a href="https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/">antibodies</a>. So people who are deficient in vitamin D may be <a href="https://www.jneuropsychiatry.org/peer-review/depression-and-vitamin-d-deficiency-causality-assessment-and-clinical-practice-implications-12051.html">immunocompromised</a> and more <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6723551/">prone to infections</a>. </p>
<figure class="align-center ">
<img alt="Happy pregnant woman eating yogurt in bed at home." src="https://images.theconversation.com/files/366985/original/file-20201102-21-1auqxpb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/366985/original/file-20201102-21-1auqxpb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/366985/original/file-20201102-21-1auqxpb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/366985/original/file-20201102-21-1auqxpb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/366985/original/file-20201102-21-1auqxpb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/366985/original/file-20201102-21-1auqxpb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/366985/original/file-20201102-21-1auqxpb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Diet in pregnancy should include the recommended food groups identified by the UK government’s Eat Well Guide.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pregnancy-people-food-concept-happy-pregnant-754179556">Syda Productions/Shutterstock</a></span>
</figcaption>
</figure>
<p>This is of course particularly relevant during the COVID-19 pandemic, as research has indicated that people who have <a href="https://www.birmingham.ac.uk/news/latest/2020/10/vitamin-d-deficiency-increased-risk-of-covid-in-healthcare-workers-new-uk-study-shows.aspx">sub-optimal vitamin D</a> may be more <a href="https://www.endocrine.org/news-and-advocacy/news-room/2020/study-finds-over-80-percent-of-covid19-patients-have-vitamin-d-deficiency">susceptible to the virus</a>. </p>
<p>There has also been some <a href="https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(20)30228-9/fulltext">speculation</a> that the higher proportion of deaths among <a href="https://www.cdc.gov/obesity/data/obesity-and-covid-19.html">overweight</a> and BAME people in the UK may be related to low <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7276229/">vitamin D</a> levels. </p>
<p>This is why the Department of Health has increased its public health messaging around the importance of <a href="https://inews.co.uk/news/politics/vitamin-d-supplements-recommended-matt-hancock-covid-19-725284">vitamin D supplementation</a>. Indeed, scientists have also recently suggested that vitamin D should be <a href="https://www.theguardian.com/world/2020/oct/31/add-vitamin-d-bread-milk-help-fight-covid-urge-scientists-deficiency-supplements">added to bread and milk</a> to help fight COVID-19.</p>
<h2>Nutritional support</h2>
<p>For many women, pregnancy is a time of increased nutritional awareness and the motivation to do what’s right for <a href="https://theconversation.com/weight-monitoring-during-pregnancy-could-help-save-lives-105311%5D(https://theconversation.com/weight-monitoring-during-pregnancy-could-help-save-lives-105311">themselves and their baby</a>. So this means, from a public health perspective, it’s also a window of opportunity to impart nutritional messages to a mother and the family.</p>
<figure class="align-center ">
<img alt="Young pregnant woman taking supplements with water." src="https://images.theconversation.com/files/366983/original/file-20201102-19-jwdkq2.jpg?ixlib=rb-1.1.0&rect=22%2C44%2C7326%2C4858&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/366983/original/file-20201102-19-jwdkq2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/366983/original/file-20201102-19-jwdkq2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/366983/original/file-20201102-19-jwdkq2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/366983/original/file-20201102-19-jwdkq2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/366983/original/file-20201102-19-jwdkq2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/366983/original/file-20201102-19-jwdkq2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Pregnant women should take 400 ug Folic Acid (5000 ug if you have a BMI of more than 30) and 10 ug of Vitamin D.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-pregnant-woman-taking-medicine-1099964198">gpointstudio/Shutterstock</a></span>
</figcaption>
</figure>
<p>Midwives can have an effective role in helping to educate women on the benefits of healthy eating and appropriate <a href="https://www.nice.org.uk/Guidance/CG62">nutritional supplements during pregnancy</a>. But research shows that many midwives feel they lack adequate knowledge or confidence to <a href="https://pubmed.ncbi.nlm.nih.gov/28751991/">fulfil this role</a>. And <a href="https://www.magonlinelibrary.com/doi/10.12968/bjom.2017.25.11.742">time constraints and conflicting information</a> can also make this difficult. My research into this area has also found this to be true – 68% of the midwives I spoke with said they lacked in <a href="https://www.researchgate.net/publication/261762206_Nutrition_Advice_During_Pregnancy_Do_Women_Receive_it_and_Can_Health_Professionals_Provide_it">time, confidence and knowledge</a>. </p>
<p>Maybe then a more <a href="https://www.hindawi.com/journals/nrp/2017/7698510/">collaborative approach</a> between midwives, nutritionists and education experts is needed. This is important because a well-balanced diet is crucial for optimum health throughout life. </p>
<p>Indeed, <a href="https://www.who.int/maternal-health/publications/pregnancy/en/">the World Health Organization</a> has identified that the first 1,000 days – from conception until a child’s second birthday – are the most influential in terms of long-term health – making good nutrition and correct supplementation during pregnancy vital. So this winter, if you are pregnant or breastfeeding, make sure you take the correct dose of vitamin D – for both you and your baby.</p><img src="https://counter.theconversation.com/content/148863/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julie Abayomi receives funding from Liverpool CCG and The British Dietetic Association. </span></em></p><p class="fine-print"><em><span>Hazel Flight does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>As we are now approaching a long, dark, socially-isolated winter in the UK, adequate vitamin D supplementation has never been more important.Hazel Flight, Programme Lead Nutrition and Health, Edge Hill UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1396702020-07-28T03:37:53Z2020-07-28T03:37:53ZCurious Kids: how does the Sun help your body make vitamin D?<figure><img src="https://images.theconversation.com/files/345729/original/file-20200706-33926-14yysqc.jpg?ixlib=rb-1.1.0&rect=137%2C77%2C5613%2C3742&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Shutterstock</span> </figcaption></figure><blockquote>
<p><strong>How does the Sun help your body make vitamin D? Wesley, aged 7</strong></p>
</blockquote>
<p><a href="https://theconversation.com/au/topics/curious-kids-36782"><img src="https://images.theconversation.com/files/291898/original/file-20190911-190031-enlxbk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=90&fit=crop&dpr=1" width="100%"></a></p>
<p>Thanks for this great question, Wesley.</p>
<p>Vitamin D is created when the chemicals in our skin react to an invisible type of light from the Sun. </p>
<p>In Australia, most of our vitamin D is made in our skin, but we can can also get a little bit of vitamin D from some of the food we eat like fish, eggs and mushrooms.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-what-does-the-suns-core-look-like-141785">Curious Kids: what does the Sun's core look like?</a>
</strong>
</em>
</p>
<hr>
<p>It’s important we have vitamin D in our body as it helps to strengthen our bones and make our muscles work properly. </p>
<p>It’s especially important in young people when their bones are growing. </p>
<h2>Invisible and visible light</h2>
<p>Let’s first talk a little bit about sunlight. </p>
<p>Sunlight isn’t just the golden light that wakes you up in the morning or shines on your skin on a summer’s day. Sunlight actually exists in many colours, some we can see and some we can’t see.</p>
<p>A rainbow is an example of visible light, or sunlight you can see. Droplets of water in the sky split the light into all of its different colours. </p>
<p>But not all light is visible like the many colours of the rainbow.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/345731/original/file-20200706-33926-ff6han.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A rainbow in a blue sky." src="https://images.theconversation.com/files/345731/original/file-20200706-33926-ff6han.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/345731/original/file-20200706-33926-ff6han.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=279&fit=crop&dpr=1 600w, https://images.theconversation.com/files/345731/original/file-20200706-33926-ff6han.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=279&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/345731/original/file-20200706-33926-ff6han.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=279&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/345731/original/file-20200706-33926-ff6han.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=351&fit=crop&dpr=1 754w, https://images.theconversation.com/files/345731/original/file-20200706-33926-ff6han.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=351&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/345731/original/file-20200706-33926-ff6han.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=351&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Rainbows are an example of visible light, but not all light is visible.</span>
<span class="attribution"><span class="source">Nikki Zalewski/ Shutterstock</span></span>
</figcaption>
</figure>
<p>Some types of sunlight are invisible. Infrared sunlight is one of these. If you could see infrared sunlight it would sit just above the red in the rainbow. </p>
<p>Infrared light makes us warm as it produces heat. You might have felt it heat up your skin on a warm sunny day.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-does-the-sun-spin-as-well-as-the-planets-119877">Curious Kids: does the Sun spin as well as the planets?</a>
</strong>
</em>
</p>
<hr>
<p>Another type of invisible light is ultraviolet. If you could see ultraviolet light it would be below the violet colour in the rainbow.</p>
<p>Ultraviolet light is also called UV light, or UV radiation. </p>
<p>You might be interested to know that while we can’t see infrared or ultraviolet light, most animals can. In fact, <a href="https://sciencing.com/animals-can-see-infrared-light-6910261.html">goldfish can see both infrared and ultraviolet light</a>. Imagine what that might be like!</p>
<h2>Which light is important in making vitamin D?</h2>
<p>We often use something called the UV index to tell us how much UV light is outside. The UV index is sometimes reported with the weather forecast, and tells us how strong the UV radiation will be that day.</p>
<p>There are two types of UV light that reach us from the Sun, called UV-A and UV-B. But it’s only the UV-B light hitting our skin that causes vitamin D to be made. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/345937/original/file-20200707-18-9el3s4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A simplified UV index ranging from low to high." src="https://images.theconversation.com/files/345937/original/file-20200707-18-9el3s4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/345937/original/file-20200707-18-9el3s4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=385&fit=crop&dpr=1 600w, https://images.theconversation.com/files/345937/original/file-20200707-18-9el3s4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=385&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/345937/original/file-20200707-18-9el3s4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=385&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/345937/original/file-20200707-18-9el3s4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=484&fit=crop&dpr=1 754w, https://images.theconversation.com/files/345937/original/file-20200707-18-9el3s4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=484&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/345937/original/file-20200707-18-9el3s4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=484&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The UV index can tell you how careful you need to be about protecting yourself from the sun.</span>
<span class="attribution"><span class="source">Sudowoodo/ shutterstock</span></span>
</figcaption>
</figure>
<p>UV-B light is full of energy, a bit like a child who can’t sit still. It has more energy than UV-A and that extra energy is needed to make vitamin D. </p>
<h2>So how exactly is it made?</h2>
<p>When the UV-B light hits your skin, the energy in the light combines with chemicals in the very top layer of your skin. </p>
<p>Sometimes this results in your body making vitamin D. Other times the combination makes bad chemicals that lead to sunburn, and maybe later to skin cancers. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-dont-burns-bleed-130792">Curious Kids: why don't burns bleed?</a>
</strong>
</em>
</p>
<hr>
<p>When the UV-B energy is taken into a chemical, it gives the chemical more energy – scientists describe this as the chemical being “excited”.</p>
<p>When the heat from the infrared light is added, it gives the excited chemical even more energy – so much that the links holding the chemical together break apart and it changes into a totally different chemical.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/345954/original/file-20200707-27852-1oxub7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A paper chain of people in a circle." src="https://images.theconversation.com/files/345954/original/file-20200707-27852-1oxub7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/345954/original/file-20200707-27852-1oxub7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=474&fit=crop&dpr=1 600w, https://images.theconversation.com/files/345954/original/file-20200707-27852-1oxub7g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=474&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/345954/original/file-20200707-27852-1oxub7g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=474&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/345954/original/file-20200707-27852-1oxub7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=596&fit=crop&dpr=1 754w, https://images.theconversation.com/files/345954/original/file-20200707-27852-1oxub7g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=596&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/345954/original/file-20200707-27852-1oxub7g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=596&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A chain like this is a bit like the structure of the chemicals in your skin before UV-B energy makes them excited and they change shape.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/345956/original/file-20200707-27833-z87mb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A paper chain of people in a line formation." src="https://images.theconversation.com/files/345956/original/file-20200707-27833-z87mb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/345956/original/file-20200707-27833-z87mb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/345956/original/file-20200707-27833-z87mb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/345956/original/file-20200707-27833-z87mb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/345956/original/file-20200707-27833-z87mb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=540&fit=crop&dpr=1 754w, https://images.theconversation.com/files/345956/original/file-20200707-27833-z87mb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=540&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/345956/original/file-20200707-27833-z87mb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=540&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">When the chemicals become excited the chain changes shape and becomes vitamin D.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Imagine joining hands with all your friends and making a big circle, then running madly around. Some people lose their grip and their hands come apart. Suddenly it’s not a circle anymore, but a different shape. </p>
<p>This is what happens in the skin. The chemical that takes in the UV-B changes, because the links between atoms in the circle break, to become vitamin D. </p>
<p>The vitamin D is then picked up by the blood that flows through the skin. </p>
<p>But before it works properly in the body it has to go to the liver and then to the kidneys where it turns into the form that can help our bones and muscles.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-is-the-sun-orange-when-white-stars-are-the-hottest-120216">Curious Kids: why is the Sun orange when white stars are the hottest?</a>
</strong>
</em>
</p>
<hr>
<h2>But be careful not to get sunburned</h2>
<p>So getting some sun on your skin is really important, but you don’t want to get too much or you’ll get sunburned.</p>
<p>In summer in Australia, the sun is so strong that you only need to be outside for a few minutes every day to keep your vitamin D up. </p>
<p>But it’s still good to get plenty of time outside, especially in the morning and afternoon. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/349496/original/file-20200727-33-1uir4zp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Young girl rubbing sunscreen on her face, wearing a bucket hat and sunglasses." src="https://images.theconversation.com/files/349496/original/file-20200727-33-1uir4zp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/349496/original/file-20200727-33-1uir4zp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/349496/original/file-20200727-33-1uir4zp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/349496/original/file-20200727-33-1uir4zp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/349496/original/file-20200727-33-1uir4zp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/349496/original/file-20200727-33-1uir4zp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/349496/original/file-20200727-33-1uir4zp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">If the UV index is 3 or higher it’s very important to consider sun safety. Seek shade if possible and make sure you have a hat and sunscreen on.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Make sure you use sun protection like a hat, clothing, and sunscreen if the UV index is 3 or higher. </p>
<p>In summer it’s best to stay indoors or in the shade in the middle hours of the day because the Sun is very strong. But in winter the Sun’s not as strong, so the middle of the day is a good time to get outside in the sun to get your vitamin D.</p>
<hr>
<p><em>Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskids@theconversation.edu.au">curiouskids@theconversation.edu.au</a></em></p>
<hr><img src="https://counter.theconversation.com/content/139670/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Robyn Lucas receives funding from the National Health and Medical Research Council and Multiple Sclerosis Research Australia.</span></em></p>A light invisible to humans makes chemicals in our skin very excited. In fact, the chemicals become so excited they change shape and become vitamin D.Robyn Lucas, Professor of Epidemiology, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1390632020-06-25T10:44:17Z2020-06-25T10:44:17ZDoes vitamin D ward off coronavirus? Don’t reach for the supplements yet<figure><img src="https://images.theconversation.com/files/341957/original/file-20200615-65925-mh31qi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/blue-sky-sun-679749943">Iakov Kalinin/Shutterstock</a></span></figcaption></figure><p>It has been <a href="https://www.nytimes.com/2020/06/10/well/live/coronavirus-vitamin-d-immunity.html">suggested</a> that taking vitamin D may protect people from getting COVID-19. But should we be using supplements to ward off the virus? We need to separate fact from fiction.</p>
<p><a href="https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/">Vitamin D</a> is essential for maintaining overall health, especially for bones, teeth and muscle. It regulates the body’s stores of calcium and phosphate and helps us maintain a healthy immune system. While we can get vitamin D from oily fish, egg yolks, red meat and supplemented foods in our diet, the vast majority of vitamin D in the body is produced in the skin due to sunlight exposure.</p>
<p>Vitamin D concentrations are lower in people with obesity, those with high blood pressure or diabetes and in those who smoke. It can be stored in fat cells, thus reducing the circulating concentration in the blood. Poor diet in those with heart disease and a sedentary lifestyle away from sunlight contribute to lower blood concentrations of the vitamin, while smoking affects vitamin D and calcium regulation. </p>
<p>These conditions are <a href="https://www.nhs.uk/conditions/coronavirus-covid-19/people-at-higher-risk-from-coronavirus/whos-at-higher-risk-from-coronavirus/">associated with increased risk of COVID-19</a> and the more severe forms of the disease. It has therefore been proposed that people with <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7231123">low vitamin D are at higher risk of infection</a> or have worse outcomes with COVID-19. </p>
<h2>Northern hemisphere</h2>
<p>Between October and April, most of Western Europe and the northern states of North America <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5946282/">lie too far north</a> to have enough sunlight to provide adequate production of vitamin D in the skin. Many people in these places are at risk of becoming deficient during these six-months unless they get increased levels of the vitamin from their diet or supplements.</p>
<p>At the start of the pandemic, the northern hemisphere was emerging from the winter months of 2019-20. Also, with the lockdown, many people were isolating or shielding inside with very little exposure to natural sunlight. This will have had a negative effect on vitamin D concentration, making some people <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/537616/SACN_Vitamin_D_and_Health_report.pdf">deficient</a> and thus compromising immune system function.</p>
<p>Italy, Spain, the UK, China and some parts of North America all have a high proportion of the population with <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4018438/pdf/nihms541186.pdf">vitamin D deficiency</a>. These countries also have significantly higher numbers of COVID-19 deaths. Other countries in the same region such as Norway, Denmark and Finland have <a href="https://covid19.who.int/">lower COVID-19 mortality rates</a>, but higher levels of vitamin D in the population as supplementation and fortification of food in these countries is common.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/342158/original/file-20200616-23276-11yr4qn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/342158/original/file-20200616-23276-11yr4qn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/342158/original/file-20200616-23276-11yr4qn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/342158/original/file-20200616-23276-11yr4qn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/342158/original/file-20200616-23276-11yr4qn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/342158/original/file-20200616-23276-11yr4qn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/342158/original/file-20200616-23276-11yr4qn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Many northern European countries have high levels of vitamin D in their national diets.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/natural-sources-vitamin-d-healthy-food-520086745">Ekaterina Markelova/Shutterstock</a></span>
</figcaption>
</figure>
<p>It has also been highlighted that people from Black, Asian and minority ethnic (BAME) backgrounds make up a <a href="https://theconversation.com/why-are-black-and-asian-people-at-greater-risk-of-coronavirus-heres-what-we-found-140584">large proportion of patients</a> with severe COVID-19 requiring intensive care in the UK. Low concentration of vitamin D in BAME people in the northern hemisphere may contribute to a greater risk, however, <a href="https://digital.nhs.uk/coronavirus/shielded-patient-list">infants and children</a> of all ethnic backgrounds who are often vitamin D deficient don’t have a greater risk of COVID-19. </p>
<p>Further data analysis, specifically looking at ethnicity and vitamin D in COVID-19, would be needed to draw firm conclusions, and the discrimination faced by these populations <a href="https://theconversation.com/coronavirus-its-impact-cannot-be-explained-away-through-the-prism-of-race-138046">cannot be overlooked</a>.</p>
<h2>Treating COVID-19?</h2>
<p>Researchers have combined literature searches with statistical cross-sectional studies to assess the effect of vitamin D level on COVID-19. </p>
<p>Some suggest there is <a href="https://www.cebm.net/covid-19/vitamin-d-a-rapid-review-of-the-evidence-for-treatment-or-prevention-in-covid-19/">no evidence</a> to support vitamin D dosing in preventing COVID-19 while others have produced evidence for <a href="http://imj.ie/vitamin-d-and-inflammation-potential-implications-for-severity-of-covid-19/">supporting the use of supplements</a>. What is apparent is that we need more <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7202265">dedicated studies</a> to assess any relationship between vitamin D and COVID-19.</p>
<p>Currently, 28 trials have been <a href="https://clinicaltrials.gov/ct2/results?cond=Covid-19&term=vitamin+d&cntry=&state=&city=&dist=">registered</a> relating to vitamin D and COVID-19. The reporting of these findings will better guide the management of patients presenting with low concentrations of vitamin D.</p>
<p>Although vitamin D is beneficial to health, it should be noted that too much can be <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6158375/">toxic</a> and can cause dehydration, increased thirst, vomiting, abdominal cramps and mental confusion. </p>
<p>There have been reports that taking very large doses (so-called “megadoses”) of vitamin D supplements will prevent COVID-19 infection. This is simply not true. There is <a href="https://nutrition.bmj.com/content/early/2020/05/15/bmjnph-2020-000089">no scientific evidence</a> to support large doses of vitamin D being protective enough to outweigh the toxic effects.</p>
<p>We do not yet have a full clear picture of the relationship between vitamin D and COVID-19, but if your blood concentrations are found to be low, or you are shielding out of direct sunlight, it’s never a bad idea to see your doctor about taking supplements – just don’t take too many.</p><img src="https://counter.theconversation.com/content/139063/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr David C. Gaze is affiliated with The Association for Clinical Biochemistry and Laboratory Medicine; The American Association of Clinical Chemistry; Royal Society of Medicine; Pathological Society of Great Britain & Ireland; European Society of Pathology. </span></em></p>There is a relationship between vitamin D and COVID-19, but taking too many supplements can be toxic.David C. Gaze, Lecturer in Clinical Biochemistry, University of WestminsterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1380012020-05-21T02:26:01Z2020-05-21T02:26:01ZDoes vitamin D protect against coronavirus?<figure><img src="https://images.theconversation.com/files/335583/original/file-20200518-138665-p61xx5.jpg?ixlib=rb-1.1.0&rect=10%2C0%2C6716%2C4477&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Recent headlines have suggested vitamin D deficiency could increase the <a href="https://www.news.com.au/world/coronavirus/health/experts-claim-those-with-low-vitamin-d-levels/news-story/8207fd86200fd4902b25d47990464f6a">risk of dying</a> from COVID-19, and in turn, that we should consider taking <a href="https://www.bbc.com/news/health-52371688">vitamin D supplements</a> to protect ourselves. </p>
<p>Is this all just hype, or could vitamin D really help in the fight against COVID-19? </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/5-ways-nutrition-could-help-your-immune-system-fight-off-the-coronavirus-133356">5 ways nutrition could help your immune system fight off the coronavirus</a>
</strong>
</em>
</p>
<hr>
<h2>Vitamin D and the immune system</h2>
<p>At least in theory, there may be something to these claims. </p>
<p>Nearly all immune cells have <a href="https://www.ncbi.nlm.nih.gov/pubmed/22503810">vitamin D receptors</a>, showing vitamin D interacts with the immune system.</p>
<p>The active vitamin D hormone, calcitriol, helps regulate both the <a href="https://www.ncbi.nlm.nih.gov/books/NBK279396/">innate and adaptive immune systems</a>, our first and second lines of defence against pathogens.</p>
<p>And vitamin D deficiency is associated with <a href="https://www.mdpi.com/2072-6643/12/5/1248/htm">immune dysregulation</a>, a breakdown or change in the control of immune system processes.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/six-things-you-need-to-know-about-your-vitamin-d-levels-15814">Six things you need to know about your vitamin D levels</a>
</strong>
</em>
</p>
<hr>
<p>Many of the ways calcitriol affects the immune system are directly relevant to our ability to defend against viruses. </p>
<p>For example, calcitriol triggers the production of cathelicidin and other defensins – natural antivirals capable of <a href="https://www.ncbi.nlm.nih.gov/pubmed/30614127">preventing the virus</a> from replicating and entering a cell.</p>
<p>Calcitriol can also increase the number of a particular type of immune cell (CD8+ T cells), which play a critical role in <a href="https://www.ncbi.nlm.nih.gov/pubmed/30614127">clearing acute viral infections</a> (such as influenza) in the lungs.</p>
<p>Calcitriol also suppresses pro-inflammatory cytokines, molecules secreted from immune cells which, as their name suggests, promote inflammation. Some scientists have suggested vitamin D might help to alleviate the “<a href="https://www.ncbi.nlm.nih.gov/pubmed/32353742">cytokine storm</a>” described in the most severe COVID-19 cases.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/335585/original/file-20200518-138639-q0v5e0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/335585/original/file-20200518-138639-q0v5e0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/335585/original/file-20200518-138639-q0v5e0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/335585/original/file-20200518-138639-q0v5e0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/335585/original/file-20200518-138639-q0v5e0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/335585/original/file-20200518-138639-q0v5e0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/335585/original/file-20200518-138639-q0v5e0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Is there a link between vitamin D and coronavirus? We’re not sure yet.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Evidence from randomised controlled trials suggests regular vitamin D supplementation may help protect against acute respiratory infections.</p>
<p>A recent <a href="https://www.ncbi.nlm.nih.gov/pubmed/30675873">meta-analysis</a> brought together results from 25 trials with more than 10,000 participants who were randomised to receive vitamin D or a placebo.</p>
<p>It found vitamin D supplementation reduced the risk of acute respiratory infections, but only when it was given daily or weekly, rather than in a large single dose. </p>
<p>The benefits of regular supplementation were greatest among participants who were severely vitamin D deficient to begin with, for whom the risk of respiratory infection went down by 70%. In others the risk decreased by 25%. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/my-vitamin-d-levels-are-low-should-i-take-a-supplement-21738">My vitamin D levels are low, should I take a supplement?</a>
</strong>
</em>
</p>
<hr>
<p>Large one-off (or “bolus”) doses are often used as a quick way to achieve vitamin D repletion. But in the context of respiratory infections, there were no benefits if participants received high single doses. </p>
<p>In fact, <a href="https://pubmed.ncbi.nlm.nih.gov/26747333/">monthly</a> or <a href="https://www.ncbi.nlm.nih.gov/pubmed/20460620">annual</a> vitamin D supplementation has sometimes had unexpected side effects, such as increased risk of falls and fractures, where vitamin D was administered to <em>protect</em> against these outcomes. </p>
<p>It’s possible intermittent administration of large doses may <a href="https://www.ncbi.nlm.nih.gov/pubmed/19667164">interfere</a> with the synthesis and breakdown of the enzymes regulating vitamin D activity within the body.</p>
<h2>Vitamin D and COVID-19</h2>
<p>We still have relatively little direct evidence about the role of vitamin D in COVID-19. And while early research is interesting, much of it may be circumstantial.</p>
<p>For example, <a href="https://www.medrxiv.org/content/10.1101/2020.04.24.20075838v1">one small study</a> from the United States and <a href="https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3571484">another study</a> from Asia found a strong correlation between low vitamin D status and severe infection with COVID-19.</p>
<p>But neither study considered any confounders. </p>
<p>In addition to the elderly, COVID-19 generally has the greatest consequences for people with <a href="https://www.medrxiv.org/content/10.1101/2020.05.06.20092999v1">pre-existing conditions</a>. </p>
<p>Importantly, people with existing medical conditions are also often vitamin D deficient. Studies assessing <a href="https://www.ncbi.nlm.nih.gov/pubmed/30682545">ICU patients</a> have reported high rates of deficiency even before COVID-19. </p>
<p>So we would expect to see relatively high rates of vitamin D deficiency in seriously ill COVID-19 patients – whether vitamin D has a role or not. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/335586/original/file-20200518-138639-1akqdzu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/335586/original/file-20200518-138639-1akqdzu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/335586/original/file-20200518-138639-1akqdzu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/335586/original/file-20200518-138639-1akqdzu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/335586/original/file-20200518-138639-1akqdzu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/335586/original/file-20200518-138639-1akqdzu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/335586/original/file-20200518-138639-1akqdzu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Vitamin D affects our immune function.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Some researchers have noted high rates of COVID-19 infections in <a href="https://www.bmj.com/content/369/bmj.m1548/rr-6">ethnic minority groups</a> in the UK and US to suggest a role for vitamin D, as ethnic minority groups tend to have lower levels of vitamin D.</p>
<p>However, analyses from the <a href="https://www.ncbi.nlm.nih.gov/pubmed/32413819">UK Biobank</a> did not support a link between vitamin D concentrations and risk of COVID-19 infection, nor that vitamin D concentration might explain ethnic differences in getting a COVID-19 infection.</p>
<p>Although this research adjusted for confounders, vitamin D levels were measured ten years earlier, which is a drawback.</p>
<p>Researchers have also suggested vitamin D <a href="https://www.researchsquare.com/article/rs-21211/v1">plays a role</a> by looking at the average vitamin D levels of different countries alongside their COVID-19 infections. But in the hierarchy of <a href="https://www.healthknowledge.org.uk/public-health-textbook/research-methods/1a-epidemiology/descriptive-studies-ecological-studies">scientific evidence</a> these types of studies are weak.</p>
<h2>Should we be trying to get more vitamin D?</h2>
<p>There are several registered <a href="https://clinicaltrials.gov/ct2/results?cond=Covid-19&term=vitamin+D&cntry=&state=&city=&dist=">trials</a> on vitamin D and COVID-19 in their early stages. So hopefully in time we’ll get some more clarity about the potential effects of vitamin D on COVID-19 infection, particularly from studies using stronger designs.</p>
<p>In the meantime, even if we don’t know whether vitamin D can help mitigate the risk of or outcomes from COVID-19, we do know being vitamin D deficient won’t help.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/can-you-get-the-covid-19-coronavirus-twice-137309">Can you get the COVID-19 coronavirus twice?</a>
</strong>
</em>
</p>
<hr>
<p>It’s difficult to get enough vitamin D from food alone. A generous portion of oily fish can cover much of our need, but it’s neither healthy nor palatable to eat this every day.</p>
<p>In Australia we get most of our vitamin D from the sun, but about 70% of us have <a href="https://pubmed.ncbi.nlm.nih.gov/30674358/?from_term=vitamin+D+status+australia+winter&from_sort=date&from_pos=5">insufficient levels</a> during winter. The <a href="https://www.osteoporosis.org.au/vitamin-d">amount of exposure</a> we need to get enough vitamin D is generally low, only a few minutes during summer, while during the winter it might take a couple of hours of exposure in the middle of the day. </p>
<p>If you don’t think you’re getting enough vitamin D, speak to your GP. They may recommend incorporating <a href="https://www.healthline.com/nutrition/how-much-vitamin-d-to-take">daily supplements</a> into your routine this winter.</p><img src="https://counter.theconversation.com/content/138001/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Elina Hypponen has received funding for scientific research on vitamin D from the National Health and Medical Research Council (Australia), Medical Research Council (UK), Department of Health (UK), British Heart Foundation, Biotechnology and Biological Sciences Research Council (UK), Academy of Finland, The Judith Jane Mason & Harold Stannett Williams Memorial Foundation, and the BUPA Foundation.
</span></em></p>Early research has pointed to a link between severe illness with COVID-19 and vitamin D deficiency. But there’s more to the story.Elina Hypponen, Professor of Nutritional and Genetic Epidemiology, University of South AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1368902020-05-11T14:13:30Z2020-05-11T14:13:30ZWe found high UV doses at high-altitude hiking trails in Reunion and Cape Town<figure><img src="https://images.theconversation.com/files/332715/original/file-20200505-83725-1pq0shf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A couple taking in the view from Table Mountain, Cape Town.</span> <span class="attribution"><span class="source">Getty Images</span></span></figcaption></figure><p>Ultraviolet (UV) radiation from the sun is important for life on earth and especially for humans. </p>
<p>In <a href="http://www.scielo.org.mx/pdf/rmcp/v10n2/2448-6698-rmcp-10-02-416-en.pdf">animals</a> UV radiation is essential for biological functions like calcium metabolism. In <a href="https://books.google.com/books?id=Rq3SBAAAQBAJ&lpg=PA131&ots=BpvaX092Oa&dq=Caldwell%2C%20M.%20M.%20%3A%20Solar%20UV%20irradiation%20and%20the%20growth%20and%20development%20of%20higher%20plants%2CPhotophysiology%2C%206%2C%20131%E2%80%93177%2C%201971.&lr&hl=fr&pg=PA131#v=onepage&q&f=false">vegetation</a> it’s necessary for photosynthesis. And in humans, UV plays an <a href="https://www.mdpi.com/52688">important</a> role in synthesis of <a href="https://www.who.int/uv/resources/FAQ/uvhealtfac/en/index1.html">vitamin D</a>, which makes for strong bones, joints and muscles. </p>
<p>But too much UV radiation is also very dangerous for human health. Excessive exposure can cause skin ageing and sunburn and can induce skin cancer such as <a href="https://www.ncbi.nlm.nih.gov/books/NBK481848/">melanoma</a>, cataracts, ocular melanoma, and immunodeficiency. </p>
<p>The sun is the main natural source of <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-4632.2010.04474.x">ultraviolet radiation</a>. The risk for human health also depends on <a href="https://www.who.int/uv/publications/en/UVIGuide.pdf">UV intensity</a>. The UV level is affected by several atmospheric factors, such as ozone, aerosol, cloud cover or altitude. This is one reason why changes to the <a href="https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/91GL02786">ozone layer</a> as a result of global pollutant emissions make a difference to human health. The UV intensity is higher at <a href="https://www.who.int/uv/publications/en/UVIGuide.pdf">high altitudes</a> because there is less atmosphere to absorb it. Tropical regions also experience high UV exposure because the sun shines there a lot of the time.</p>
<p>We tested the <a href="https://www.mdpi.com/2073-4433/10/10/589">UV exposure</a> in high-altitude sites in Cape Town and Reunion Island. We assessed human exposure for hiking activities at two popular high-altitude hiking trails on the Maïdo–Grand Bénare (Reunion) and Table Mountain (Cape Town) with a handheld radiometer. We recorded extreme exposure doses. </p>
<p>These high exposure doses highlight the importance of raising public awareness on the risk related to excess UVR exposure at tourist sites, especially those at high altitude. Our findings suggest a need for strong public awareness campaigns among visitors to sites like these to prevent skin diseases and cancers that could result from overexposure to UV radiation.</p>
<h2>Our study</h2>
<p>We chose our testing sites – Table Mountain (altitude of 1,035 metres) in Cape Town and Maïdo-Grand Bénare (2,898 metres) on Reunion Island – because they are popular tourist destinations for outdoor activities for most of the year. Yet their high risk for UV is not necessarily well known. Tourists, hikers and employees of the local national parks may be exposed to high UV levels. Every year, <a href="https://www.tablemountain.net/annual_report_2019/">1,000,000 people</a> visit Table Mountain and <a href="http://www.ipreunion.com/photo-du-jour/reportage/2016/05/21/observatoire-regional-du-tourisme-le-tourisme-a-la-reunion-grimpe-de-1-pour-le-premier-trimestre-2016,44240.html">180,000 hike</a> on Réunion Island mountain.</p>
<p>Two markers were used to quantify the UV exposure. One was the UV index, <a href="https://www.who.int/uv/intersunprogramme/activities/uv_index/en/">defined</a> by the World Health Organisation (WHO) as a simple number for public awareness. UV index categories are low (1-2), moderate (3-5), high (6-7), very high (9-10), and extreme (11+). </p>
<p>The maximum UV index numbers recorded were 14 at Table Mountain and 20 at Maïdo-Grand Bénare, which is close to double the extreme UV index threshold <a href="https://www.who.int/uv/intersunprogramme/activities/en/uvcodes.jpg">defined</a> by the WHO. </p>
<p>The study also measured cumulative standard erythemal dose (SED), a measure of UV exposure in terms of joules per square metre.</p>
<p>The field measurement indicated that people were exposed to 40 SED when hiking Table Mountain and 64 when hiking Maïdo-Grand Bénare. These doses correspond to 3 to 25 times the minimal dose required to elicit a sunburn response depending on skin type (lighter skin requires a smaller dose while darker skin requires a larger dose).</p>
<p>Information about the <a href="https://www.mdpi.com/545770">climate</a> of the two sites shows that the total daily dose is extremely high during summer in Cape Town, and all year around in Reunion Island. Total daily dose is above the level where all skin types will experience sunburn, although people with deeply pigmented skin are less affected. These extreme exposures increase <a href="https://www.sciencedirect.com/science/article/pii/S0079610706000137">the risk</a> of cataracts, immunodeficiency and melanoma – at least for people with white skin. The link between sunburn and these health risks is not known for people with dark skin.</p>
<p>Melanoma is a type of skin cancer. The mean melanoma rate worldwide in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5575560/">2015</a> (male and female mixed) was five per 100,000. In South Africa, <a href="http://www.samj.org.za/index.php/samj/article/view/12576">the melanoma rate</a> for the total population, regardless of skin type, is five per 100,000 people for men and three per 100,000 for women. Among white South Africans, the melanoma rate is about 20 per 100,000 for men and 16 per 100,000 for women, which is similar to some of the rates recorded in Australia. </p>
<p><a href="https://www.em-consulte.com/es/article/1095782/donnees-epidemiologiques-des-melanomes-cutanes-a-l">From 2006 to 2015</a>, the male population of Reunion Island saw an increase in skin diseases from 2.7 to 7.1 cases per 100,000 people while cases in the female population surged from 3.0 to 6.1 per 100,000. These increasing rates may be due to an <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2697050/">atmospheric change</a> and a human behaviour change (such as the popularity of <a href="https://www.sciencedirect.com/science/article/abs/pii/S0190962203000215">suntanning</a> for aesthetic reasons). </p>
<h2>Cover up</h2>
<p>The results of our tests highlight the importance of public awareness and prevention of the <a href="https://www.who.int/uv/publications/en/UVIGuide.pdf">risks related to UV</a>, especially at exposed sites like Table Mountain and Maïdo-Grand Bénare. The <a href="https://www.who.int/uv/intersunprogramme/activities/uv_index/en/index1.html">WHO</a> recommends that people avoid being outside in the middle of the day and wear long-sleeved shirts, hats, sunglasses and sunscreen.</p>
<p>This is particularly important in <a href="https://www.atmos-chem-phys.net/19/10087/2019/">tropical regions</a>, where there are several factors that can increase UV radiation: being relatively close to the Equator, low ozone, low aerosols, low solar zenith angle and clouds.</p><img src="https://counter.theconversation.com/content/136890/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This research was funded jointly by the CNRS (Centre National de la Recherche Scientifique) and the NRF (National Research Foundation) in the framework of the International Research Project ARSAIO and by the South Africa - France PHC-Protea Program (project No 42470VA).</span></em></p><p class="fine-print"><em><span>Caradee Yael Wright receives funding from the South African Medical Research Council and the National Research Foundation of South Africa. </span></em></p><p class="fine-print"><em><span>This research was funded jointly by the CNRS (Centre National de la Recherche Scientifique) and the NRF (National Research Foundation) in the framework of the International Research Project ARSAIO and by the South Africa - France PHC-Protea Program (project No 42470VA)</span></em></p>Too much ultraviolet radiation is dangerous for human health. Excessive exposure can cause skin ageing and sunburn and can induce melanoma, cataracts, ocular melanoma, and immunodeficiency.Jean-Maurice Cadet, PhD Candidate, Université de la RéunionCaradee Yael Wright, Specialist Scientist (Public Health), South African Medical Research CouncilHassan Bencherif, Professor, Université de la RéunionLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1333562020-03-16T19:01:05Z2020-03-16T19:01:05Z5 ways nutrition could help your immune system fight off the coronavirus<figure><img src="https://images.theconversation.com/files/320678/original/file-20200316-18043-1rg6ra8.jpg?ixlib=rb-1.1.0&rect=0%2C6%2C4500%2C2977&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>The coronavirus presents many uncertainties, and none of us can completely eliminate our risk of getting COVID-19. But one thing we can do is eat as healthily as possible.</p>
<p>If we do catch COVID-19, our immune system is responsible for fighting it. Research shows improving nutrition helps <a href="https://www.ncbi.nlm.nih.gov/pubmed/15337163">support optimal immune function</a>. </p>
<p>Micronutrients essential to fight infection include vitamins A, B, C, D, and E, and the minerals iron, selenium, and zinc. </p>
<p>Here’s what we know about <a href="https://www.ncbi.nlm.nih.gov/pubmed/30336639">how these nutrients support our immune system</a> and the foods we can eat to get them. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-a-balanced-diet-anyway-72432">What is a balanced diet anyway?</a>
</strong>
</em>
</p>
<hr>
<h2>1. Vitamin A</h2>
<p><a href="https://www.healthdirect.gov.au/vitamin-a">Vitamin A</a> maintains the structure of the cells in the skin, respiratory tract and gut. This forms a barrier and is your body’s first line of defence. If fighting infection was like a football game, vitamin A would be your forward line. </p>
<p>We also need vitamin A to help make <a href="https://en.wikipedia.org/wiki/Antibody">antibodies</a> which neutralise the pathogens that cause infection. This is like assigning more of your team to target an opposition player who has the ball, to prevent them scoring. </p>
<p>Vitamin A is found in oily fish, egg yolks, cheese, tofu, nuts, seeds, whole grains and legumes. </p>
<p>Further, vegetables contain <a href="https://en.wikipedia.org/wiki/Beta-Carotene">beta-carotene</a>, which your body can convert into vitamin A. Beta-carotene is found in leafy green vegetables and yellow and orange vegetables like pumpkin and carrots.</p>
<h2>2. B vitamins</h2>
<p><a href="https://www.betterhealth.vic.gov.au/health/HealthyLiving/vitamin-b">B vitamins</a>, particularly B6, B9 and B12, contribute to your body’s first response once it has recognised a pathogen. </p>
<p>They do this by influencing the production and activity of “<a href="https://en.wikipedia.org/wiki/Natural_killer_cell">natural killer</a>” cells. Natural killer cells work by causing infected cells to “implode”, a process called <a href="https://en.wikipedia.org/wiki/Apoptosis">apoptosis</a>. </p>
<p>At a football match, this role would be like security guards intercepting wayward spectators trying to run onto the field and disrupt play.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/320685/original/file-20200316-18086-1i9edys.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/320685/original/file-20200316-18086-1i9edys.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/320685/original/file-20200316-18086-1i9edys.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/320685/original/file-20200316-18086-1i9edys.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/320685/original/file-20200316-18086-1i9edys.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/320685/original/file-20200316-18086-1i9edys.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/320685/original/file-20200316-18086-1i9edys.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Fish is a good source of vitamin B6.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>B6 is found in cereals, legumes, green leafy vegetables, fruit, nuts, fish, chicken and meat. </p>
<p>B9 (<a href="https://en.wikipedia.org/wiki/Folate">folate</a>) is abundant in green leafy vegetables, legumes, nuts and seeds and is added to commercial bread-making flour.</p>
<p><a href="https://theconversation.com/have-you-gone-vegan-keep-an-eye-on-these-4-nutrients-107708">B12</a> (cyanocobalamin) is found in animal products, including eggs, meat and dairy, and also in fortified soy milk (check the nutrition information panel). </p>
<h2>3. Vitamins C and E</h2>
<p>When your body is fighting an infection, it experiences what’s called oxidative stress. Oxidative stress leads to the production of <a href="https://en.wikipedia.org/wiki/Reactive_oxygen_species">free radicals</a> which can pierce cell walls, causing the contents to leak into tissues and exacerbating inflammation.</p>
<p><a href="https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/">Vitamin C</a> and <a href="https://www.healthdirect.gov.au/vitamin-e">vitamin E</a> help protect cells from oxidative stress. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/coronavirus-its-time-to-debunk-claims-that-vitamin-c-could-cure-it-132803">Coronavirus: it's time to debunk claims that vitamin C could cure it</a>
</strong>
</em>
</p>
<hr>
<p>Vitamin C also helps clean up this cellular mess by producing specialised cells to mount an immune response, including <a href="https://en.wikipedia.org/wiki/Neutrophil">neutrophils</a>, lymphocytes and <a href="https://en.wikipedia.org/wiki/Phagocyte">phagocytes</a>. </p>
<p>So the role of vitamin C here is a bit like cleaning up the football ground after the game.</p>
<p>Good sources of vitamin C include oranges, lemons, limes, berries, kiwifruit, broccoli, tomatoes and capsicum. </p>
<p>Vitamin E is found in nuts, green leafy vegetables and vegetables oils.</p>
<h2>4. Vitamin D</h2>
<p>Some immune cells need <a href="https://www.betterhealth.vic.gov.au/health/HealthyLiving/vitamin-d">vitamin D</a> to help destroy pathogens that cause infection. </p>
<p>Although sun exposure allows the body to produce vitamin D, food sources including eggs, fish and some milks and margarine brands may be fortified with Vitamin D (meaning extra has been added).</p>
<p>Most people need just <a href="https://www.cancer.org.au/preventing-cancer/sun-protection/vitamin-d/">a few minutes outdoors</a> most days.</p>
<p>People with vitamin D deficiency may need supplements. A <a href="https://www.ncbi.nlm.nih.gov/pubmed/30675873">review of 25 studies</a> found vitamin D supplements can help protect against <a href="https://www.healthline.com/health/acute-respiratory-disease">acute respiratory infections</a>, particularly among people who are deficient.</p>
<h2>5. Iron, zinc, selenium</h2>
<p>We need iron, zinc and selenium for immune cell growth, among other functions.</p>
<p><a href="https://www.betterhealth.vic.gov.au/health/ConditionsAndTreatments/iron">Iron</a> helps kill pathogens by <a href="https://www.ncbi.nlm.nih.gov/pubmed/30336639">increasing the number of free radicals</a> that can destroy them. It also regulates enzyme reactions essential for immune cells to recognise and target pathogens. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/320686/original/file-20200316-18079-my91st.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/320686/original/file-20200316-18079-my91st.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/320686/original/file-20200316-18079-my91st.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/320686/original/file-20200316-18079-my91st.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/320686/original/file-20200316-18079-my91st.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/320686/original/file-20200316-18079-my91st.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/320686/original/file-20200316-18079-my91st.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Whole grain foods contain a variety of important nutrients.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p><a href="https://www.healthdirect.gov.au/zinc">Zinc</a> helps maintain the integrity of the skin and mucous membranes. Zinc and <a href="https://en.wikipedia.org/wiki/Selenium">selenium</a> also act as an antioxidant, helping mop up some of the damage caused by oxidative stress. </p>
<p>Iron is found in meat, chicken and fish. Vegetarian sources include legumes, whole grains and iron-fortified breakfast cereals. </p>
<p>Zinc is found in oysters and other seafood, meat, chicken, dried beans and nuts. </p>
<p>Nuts (especially Brazil nuts), meat, cereals and mushrooms are good food sources of selenium.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-should-i-take-vitamin-c-or-other-supplements-for-my-cold-98309">Health Check: should I take vitamin C or other supplements for my cold?</a>
</strong>
</em>
</p>
<hr>
<h2>Putting it all together</h2>
<p>It’s true some supermarkets are out of certain products at the moment. But as much as possible, focus on eating a variety of foods <a href="https://www.eatforhealth.gov.au/guidelines/australian-guide-healthy-eating">within each of the basic food groups</a> to <a href="https://www.ncbi.nlm.nih.gov/pubmed/25625814">boost your intake</a> of vitamins and minerals.</p>
<p>While vitamin and mineral supplements are <a href="https://theconversation.com/mondays-medical-myth-take-a-vitamin-a-day-for-better-health-8482">not recommended for the general population</a>, there are some exceptions. </p>
<p>Pregnant women, some people with chronic health conditions, and people with conditions that mean they can’t eat properly or are on very restrictive diets, may need specific supplements. Talk to your doctor, Accredited Practising Dietitian or pharmacist.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/social-distancing-what-it-is-and-why-its-the-best-tool-we-have-to-fight-the-coronavirus-133581">Social distancing: What it is and why it's the best tool we have to fight the coronavirus</a>
</strong>
</em>
</p>
<hr>
<p>And beyond diet, there are other measures you can take to stay as healthy as possible in the face of coronavirus.</p>
<p><a href="https://www.ncbi.nlm.nih.gov/pubmed/30789425">Stop smoking</a> to improve your lung’s ability to fight infection, perform <a href="https://www.ncbi.nlm.nih.gov/pubmed/32139352">moderate intensity exercise</a> like brisk walking, <a href="https://www.ncbi.nlm.nih.gov/pubmed/31941836">get enough sleep</a>, practise social distancing and wash your hands with soap regularly.</p><img src="https://counter.theconversation.com/content/133356/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Clare Collins is affiliated with the Priority Research Centre for Physical Activity and Nutrition, the University of Newcastle, NSW. She is an NHMRC Senior Research and Gladys M Brawn Research Fellow. She has received research grants from NHMRC, ARC, Hunter Medical Research Institute, Meat and Livestock Australia, Diabetes Australia, Heart Foundation, Bill and Melinda Gates Foundation, nib foundation, Rijk Zwaan Australia and Greater Charitable Foundation. She has consulted to SHINE Australia, Novo Nordisk, Quality Bakers, the Sax Institute and the ABC. She was a team member conducting systematic reviews to inform the Australian Dietary Guidelines update and the Heart Foundation evidence reviews on meat and dietary patterns.</span></em></p>The food we eat influences our bodies’ immune responses to infection. So focusing on nutrition is one thing we can do to help protect ourselves in the face of the coronavirus threat.Clare Collins, Professor in Nutrition and Dietetics, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1288982020-01-16T14:00:02Z2020-01-16T14:00:02ZWhy you need more Vitamin D in the winter<figure><img src="https://images.theconversation.com/files/308468/original/file-20200103-11904-v09oed.jpg?ixlib=rb-1.1.0&rect=13%2C0%2C4448%2C3064&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Vitamin D is sometimes called the sunshine vitamin. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/vitamin-d-keeps-you-healthy-while-1148457554">FotoHelin/Shutterstock.com</a></span></figcaption></figure><p>Winter is upon us and so is the risk of vitamin D deficiency and infections. Vitamin D, which is made in our skin following sunlight exposure and also found in <a href="https://health.gov/dietaryguidelines/2015/guidelines/appendix-12/">oily fish (mackerel, tuna and sardines), mushrooms and fortified dairy and nondairy substitutes</a>, is essential for good health. Humans need vitamin D to <a href="https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/#h7">keep healthy and to fight infections</a>. The irony is that in winter, when people need vitamin D the most, most of us are not getting enough. So how much should we take? Should we take supplements? How do we get more? And, who needs it most?</p>
<p><a href="https://vbs.psu.edu/research/labs/cantorna">I am a medical microbiologist and immunologist</a> who studies the functions of vitamin D in immune cells. My laboratory has been interested in figuring out why the immune system has vitamin D receptors that determine which cells can use vitamin D. In the immune system, vitamin D acts to improve your ability to <a href="https://doi.org/10.1016/j.tem.2019.04.005">fight infections</a> and to <a href="https://doi.org/10.1080/10409238.2019.1611734">reduce inflammation</a>.</p>
<h2>Where to get your vitamin D</h2>
<p>Vitamin D is called the sunshine vitamin since it is made in the skin after exposure to sun. The same UVB rays that cause a sunburn also make vitamin D. Sunscreen, darker skin pigmentation, clothing and reduced daylight in winter diminish the skin’s ability to make vitamin D. The people who experience the biggest seasonal swings in vitamin D levels are fair-skinned individuals <a href="https://doi.org/10.3390/nu10040457">living in the northern regions</a> of the U.S. and at <a href="https://doi.org/10.3945/an.117.015578">higher latitudes around the globe</a> where there is very little daylight in winter. </p>
<p>But those most at risk for low vitamin D levels are people of color and people living at higher latitudes. Dark-skinned individuals are more likely than fair-skinned individuals to be low for vitamin D year-round because the darker skin blocks the UVB rays from producing vitamin D. However, even in dark skinned individuals, vitamin D is lowest in the winter. </p>
<p>In the winter, in addition to high vitamin D food, adults should take additional vitamin D from foods and/or supplements to <a href="https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/#en1">get at least 600 IU per day of vitamin D.</a> People who have dark skin or avoid sunshine should eat more vitamin D year-round. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/309314/original/file-20200109-80111-jn47z5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/309314/original/file-20200109-80111-jn47z5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=501&fit=crop&dpr=1 600w, https://images.theconversation.com/files/309314/original/file-20200109-80111-jn47z5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=501&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/309314/original/file-20200109-80111-jn47z5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=501&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/309314/original/file-20200109-80111-jn47z5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=630&fit=crop&dpr=1 754w, https://images.theconversation.com/files/309314/original/file-20200109-80111-jn47z5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=630&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/309314/original/file-20200109-80111-jn47z5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=630&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Food rich in vitamin D.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/vitamin-d-containing-foods-376614841">photka/Shutterstock.com</a></span>
</figcaption>
</figure>
<h2>Vitamin D is important for bones and your microbes</h2>
<p>Originally, doctors thought that vitamin D was only important for bone health. This was because the vitamin D deficiency caused bone diseases like <a href="http://doi.org/10.1172/JCI29449">rickets in children and osteoporosis in adults.</a>. However, in the 1980s scientists discovered that <a href="https://www.jci.org/articles/view/111557">immune cells</a> <a href="https://science.sciencemag.org/content/224/4656/1438">had receptors for vitamin D</a>. </p>
<p>My group’s research has shown that vitamin D plays an important role in <a href="https://doi.org/10.1080/10409238.2019.1611734">maintaining health in the gastrointestinal tract</a>. <a href="https://iai.asm.org/content/84/11/3094">Higher levels of vitamin D</a> reduce <a href="https://doi.org/10.1016/j.tem.2019.04.005">susceptibility to inflammatory bowel disease</a> and <a href="http://doi.org/10.1038/ajg.2016.53">Crohn’s disease</a>, <a href="https://doi.org/10.3389/fimmu.2019.00001">gut</a> and <a href="http://doi.org/10.1128/IAI.00679-16">lung infections</a> in animals and people. </p>
<p>My colleagues and I have discovered that one of the ways vitamin D functions is by keeping the microbes in the gut healthy and happy. Vitamin D <a href="https://doi.org/10.1177/1535370214523890">increases the number and diversity of microbes</a> living in the gut, which together reduce inflammation throughout the body. </p>
<p>Low vitamin D levels are <a href="https://doi.org/10.1038/nrgastro.2015.34">associated with inflammatory bowel disease</a> in humans. Researchers have found that <a href="https://doi.org/10.1007%2Fs00535-017-1313-6">inflammatory bowel disease patients in Japan</a> have more symptoms in winter than during other seasons. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/309317/original/file-20200109-80122-1r4bify.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/309317/original/file-20200109-80122-1r4bify.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/309317/original/file-20200109-80122-1r4bify.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/309317/original/file-20200109-80122-1r4bify.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/309317/original/file-20200109-80122-1r4bify.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/309317/original/file-20200109-80122-1r4bify.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/309317/original/file-20200109-80122-1r4bify.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/309317/original/file-20200109-80122-1r4bify.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">People with darker skin are most likely to have low vitamin D levels year-round.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pile-hands-isolated-on-white-caucasian-8316760">Lucian Coman/Shutterstock.com</a></span>
</figcaption>
</figure>
<h2>Why is vitamin D more important in winter?</h2>
<p>In the winter, humans are exposed to more infections and spend less time outside. Exactly how much vitamin D healthy adults should have is debated. Some authorities recommend from <a href="https://www.nature.com/articles/nrendo.2017.31">200 IU per day to 2,000 IU per day</a>. In the U.S., the <a href="https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/">Institutes of Medicine</a> recommends 600-800 IU per day for adults, while the <a href="https://doi.org/10.1210/jcem.96.12.zeg3908">Endocrine Society states that optimal vitamin D status</a> may require 1500-2,000 IU per day. In the winter, people have a reduced ability to make vitamin D when they go outside, so amounts of at least 600 IU per day of vitamin D from food or supplements would help maintain vitamin D status at summer levels. </p>
<p>But, just like many things, <a href="https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/">too much vitamin D can be harmful</a>. Vitamin D toxicity does not result from too much sun or food. Because of the risk of skin cancer, dermatologists and other health professionals do not recommend unprotected sun exposure to boost your vitamin D. Instead they suggest supplements. But vitamin D toxicity can occur if an individual takes too many.</p>
<p>The experts that set the national intakes of vitamin D for the U.S. recommend that adult individuals take <a href="https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/">no more than 4,000 IU per day of vitamin D</a> to avoid toxic side effects. Vitamin D helps you absorb calcium from your diet, but when vitamin D is too high, calcium levels in the blood go up and that can lead to kidney disease. </p>
<p>By consuming more vitamin D during the winter your gut microbes will be healthier and you’ll be more resistant to infection and inflammation year-round. </p>
<p>[ <em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters?utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/128898/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Margherita T. Cantorna receives funding from the National Institutes of Health.</span></em></p>Vitamin D is essential for good health and particularly for fighting infections and keeping the microbes in the human gut healthy. But in winter it can be difficult to get enough.Margherita T. Cantorna, Distinguished Professor of Molecular Immunology, Penn StateLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1095962019-01-11T13:34:22Z2019-01-11T13:34:22ZTreat vitamin D deficiency to prevent attacks of chronic obstructive pulmonary disease<figure><img src="https://images.theconversation.com/files/253068/original/file-20190109-32121-1is2m59.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/129311027?src=YROHv3J8TOqmH2DONmrqHQ-1-14&size=medium_jpg">R_Szatkowski/Shutterstock</a></span></figcaption></figure><p>Correcting vitamin D deficiency nearly halves the risk of potentially fatal lung attacks in patients with chronic obstructive pulmonary disease (COPD), our <a href="https://thorax.bmj.com/content/early/2019/01/10/thoraxjnl-2018-212092">latest study</a> has found.</p>
<p><a href="https://www.nhs.uk/conditions/chronic-obstructive-pulmonary-disease-copd/">COPD</a> describes several lung conditions, including emphysema and chronic bronchitis, where a person’s airways become inflamed, making it harder to breathe. Almost all COPD deaths are due to lung attacks (termed “exacerbations”) in which symptoms worsen sharply. These are often triggered by viral upper respiratory infections – the type that cause the common cold. </p>
<p>Vitamin D – “the sunshine vitamin” – is best known for its effects on bone, but it also boosts immunity to viral infections. Our previous research at Queen Mary, University of London, has shown that vitamin D supplements <a href="https://www.ncbi.nlm.nih.gov/pubmed/28986128">protect against</a> <a href="https://www.ncbi.nlm.nih.gov/pubmed/27595415">asthma attacks</a> and <a href="https://www.ncbi.nlm.nih.gov/pubmed/28202713">acute respiratory infections</a>, such as colds and flu, in people who have low vitamin D levels to start with.</p>
<p>A number of clinical trials have tested whether vitamin D supplementation might have a role in reducing the risk of COPD attacks, but they have yielded conflicting results. Some show a benefit, others do not. </p>
<p>One way to get a handle on the reason for their different findings is to pool the data from the various studies into a single database and then run analyses to determine whether vitamin D might have stronger protective effects against lung attacks in certain groups of COPD patients compared with others. This approach is known as “individual participant data meta-analysis”.</p>
<p>Our latest study, published in the journal Thorax, reports the findings of such an analysis. We pooled data from 469 patients who took part in one of three clinical trials of vitamin D that were conducted in the UK, Belgium and the Netherlands.</p>
<h2>Cheap, safe solution</h2>
<p>We found that giving vitamin D supplements led to a 45% reduction in the rate of lung attacks in COPD patients with low vitamin D levels (less than 25 nanomoles per litre of blood or 10 nanograms per millilitre of blood, which is the standard cut-off used by the UK Department of Health to define vitamin D deficiency). We didn’t observe any benefit in patients with higher vitamin D levels.</p>
<p>Doses of vitamin D investigated in the original trials ranged from 30 micrograms daily to 2,500 micrograms, monthly. For comparison, Public Health England and the Scientific Advisory Committee on Nutrition advise a daily intake of 10 micrograms of vitamin D. Supplementation at the higher doses given in the clinical trials did not influence the proportion of participants experiencing serious side effects, indicating that they were safe.</p>
<p>Given this excellent safety profile, and the fact that vitamin D supplements cost just a few pence per year, offering them to patients with COPD is a potentially highly cost-effective treatment that could be targeted at those who have low vitamin D levels following routine testing.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/253385/original/file-20190111-43532-1j77ahr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/253385/original/file-20190111-43532-1j77ahr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=442&fit=crop&dpr=1 600w, https://images.theconversation.com/files/253385/original/file-20190111-43532-1j77ahr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=442&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/253385/original/file-20190111-43532-1j77ahr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=442&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/253385/original/file-20190111-43532-1j77ahr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=556&fit=crop&dpr=1 754w, https://images.theconversation.com/files/253385/original/file-20190111-43532-1j77ahr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=556&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/253385/original/file-20190111-43532-1j77ahr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=556&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">COPD is a common condition that includes emphysema and chronic bronchitis.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/588313340?src=hSpyzyCANGQXAtiDBJXwZQ-1-8&size=medium_jpg">pathdoc/Shutterstock</a></span>
</figcaption>
</figure>
<p>Around one-fifth of COPD patients in the UK – about 240,000 people – have low levels of vitamin D. Reducing risk of attacks in such a large group would have major benefits for patients and for health services, since many attacks require costly hospital admission. (COPD costs the NHS <a href="https://www.nice.org.uk/guidance/ng115/documents/draft-scope">£800m</a> per year.)</p>
<p>Our study provides the strongest evidence yet of a benefit of giving vitamin D supplements to patients with COPD who have low vitamin D levels. But it is important to recognise that the data contributing to this analysis come from a relatively small number of trials, so our findings should be interpreted with caution. </p>
<p>Another clinical trial of vitamin D, focused just on COPD patients with low baseline vitamin D levels, is underway in the Netherlands. Results are expected in 2020.</p><img src="https://counter.theconversation.com/content/109596/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This research was supported by a grant from National Institute for Health Research (NIHR) under its Health Technology Assessment (HTA) Program (Reference Number 13/03/25, to Adrian Martineau). The views expressed are those of Professor Martineau and not necessarily those of the National Health Service, the NIHR or the Department of Health.</span></em></p>Vitamin D shows promise in treating COPD in people who are deficient in the vitamin.Adrian Martineau, Professor of Respiratory Infection and Immunity, Queen Mary University of LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1094392019-01-10T18:24:49Z2019-01-10T18:24:49ZThere’s no such thing as a safe tan. Here’s what’s happening underneath your summer glow<figure><img src="https://images.theconversation.com/files/253167/original/file-20190110-32130-1iudwn8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">You might prefer the way you look with a tan (most Aussies do), but you won't when your skin is prematurely aged. </span> <span class="attribution"><span class="source">from www.shutterstock.com</span></span></figcaption></figure><p>There’s a lot to be said for sunshine – both <a href="https://wiki.cancer.org.au/policy/Position_statement_-_Risks_and_benefits_of_sun_exposure">good and bad</a>. It’s our main source of vitamin D, which is essential for bone and muscle health. Populations with higher levels of sun exposure also have better blood pressure and mood levels, and fewer autoimmune diseases such as multiple sclerosis. </p>
<p>On the other hand, excess UV exposure is estimated to contribute to <a href="https://www.cancer.org.au/about-cancer/types-of-cancer/skin-cancer.html">95% of melanomas</a> and 99% of non-melanoma skin cancers. These skin cancers account for a whopping <a href="https://www.cancer.org.au/about-cancer/types-of-cancer/skin-cancer.html">80% of all new cancers</a> each year in Australia. </p>
<p>Like any medicine, <a href="https://theconversation.com/columns/ian-musgrave-1808">the dose counts</a>. And in Australia, particularly in the summer, our dose of UV is so high that even short incidental exposures – like while you hang out the washing or walk from your carpark into the shops – adds up to huge lifetime doses.</p>
<p>Fortunately, when it comes to tanning, the advice is clear: don’t. A UV dose that’s <a href="https://www.ncbi.nlm.nih.gov/pubmed/23749111">high enough to induce a tan</a> is already much higher than the dose needed for vitamin D production. A <a href="https://www.ncbi.nlm.nih.gov/pubmed/22634425">four-year-long study</a> of 1,113 people in Nambour, Queensland, found no difference in vitamin D levels between sunscreen users and sunscreen avoiders. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/mondays-medical-myth-were-not-getting-enough-sun-10205">Monday's medical myth: we’re not getting enough sun</a>
</strong>
</em>
</p>
<hr>
<h2>What’s happening in the skin when I get a tan?</h2>
<p>A tan forms when ultraviolet (UV) rays from the sun discharge too much energy into our skin, causing damage to membranes, proteins, and most importantly, DNA. The excess energy of UVB rays (part of the UV ray that penetrates the upper layers of our skin) prevents the DNA from copying correctly when the cells multiply which can cause mutations.</p>
<p>UVA rays which penetrate deeper into the skin can trigger a reactive and harmful process (known as oxidative free radical damage) which can damage not just DNA but also many of the skin’s structural components. It’s been estimated a single day’s sun exposure can cause <a href="https://www.ncbi.nlm.nih.gov/pubmed/23749111">up to a million DNA defects</a> in each skin cell. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/253157/original/file-20190110-32142-3dgzzc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/253157/original/file-20190110-32142-3dgzzc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=462&fit=crop&dpr=1 600w, https://images.theconversation.com/files/253157/original/file-20190110-32142-3dgzzc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=462&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/253157/original/file-20190110-32142-3dgzzc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=462&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/253157/original/file-20190110-32142-3dgzzc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=581&fit=crop&dpr=1 754w, https://images.theconversation.com/files/253157/original/file-20190110-32142-3dgzzc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=581&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/253157/original/file-20190110-32142-3dgzzc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=581&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Excess energy from UVB rays causes DNA bases to link up incorrectly, making it difficult to copy accurately and leading to mutations that can cause cancer.</span>
<span class="attribution"><span class="source">NASA/David Herring</span></span>
</figcaption>
</figure>
<p>Once their DNA repair mechanisms detect large amounts of damage, skin cells signal pigment-producing cells (melanocytes) to start producing extra melanin, the pigment that gives our skin, hair and eyes their colour. </p>
<p>The extra melanin is parcelled up and transported into other skin cells to settle over and protect the part of the cell containing the DNA. This filters some UV rays and gives tanned skin its brown colour. But this tan doesn’t provide much help – it’s only as protective as <a href="https://www.ncbi.nlm.nih.gov/pubmed/24891049">SPF 2 sunscreen</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-what-happens-to-your-skin-when-you-get-sunburnt-53865">Explainer: what happens to your skin when you get sunburnt?</a>
</strong>
</em>
</p>
<hr>
<h2>Wrinkles, blotches and broken capillaries</h2>
<p><a href="https://www.cancer.org.au/about-cancer/types-of-cancer/skin-cancer.html">Two in three Australians</a> will develop a skin cancer in their lifetime, mostly thanks to the DNA damage caused by UVB rays. But premature ageing is a less well-known effect of too much sun exposure.</p>
<p>UVA rays penetrate deep into the dermis, the lower layer of the skin, and generate reactive oxygen that damages the skin’s structures. Over time this causes <a href="https://www.dermnetnz.org/topics/solar-elastosis">solar elastosis</a>, where irregularly thickened clumps of elastic fibres form, then degrade into disorganised, tangled structures.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/253153/original/file-20190110-32139-1vt2olq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/253153/original/file-20190110-32139-1vt2olq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/253153/original/file-20190110-32139-1vt2olq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/253153/original/file-20190110-32139-1vt2olq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/253153/original/file-20190110-32139-1vt2olq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/253153/original/file-20190110-32139-1vt2olq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/253153/original/file-20190110-32139-1vt2olq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">This 70-year-old has deep wrinkling and skin darkening caused by long-term sun exposure on her neck and part of her chest exposed by her shirt, while the rest of her skin has stayed relatively clear and unwrinkled.</span>
<span class="attribution"><span class="source">Author provided</span></span>
</figcaption>
</figure>
<p>Eventually this can take the form of roughening or leathery appearance, deep wrinkling, dark blotches and star-shaped white patches, and an overall yellowish tone. Prematurely-aged skin is often more easily-bruised or has broken capillaries. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/253162/original/file-20190110-32139-xfwi6c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/253162/original/file-20190110-32139-xfwi6c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=225&fit=crop&dpr=1 600w, https://images.theconversation.com/files/253162/original/file-20190110-32139-xfwi6c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=225&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/253162/original/file-20190110-32139-xfwi6c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=225&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/253162/original/file-20190110-32139-xfwi6c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=283&fit=crop&dpr=1 754w, https://images.theconversation.com/files/253162/original/file-20190110-32139-xfwi6c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=283&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/253162/original/file-20190110-32139-xfwi6c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=283&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dark blotches and white scar-like patches are common signs of ageing caused by too much sun.</span>
<span class="attribution"><span class="source">DermNetNZ.org</span></span>
</figcaption>
</figure>
<h2>But I like the way a tan looks. What now?</h2>
<p>It’s well known that a tanned look seems healthy and attractive to many Australians. Recent research shows Australians who feel <a href="https://onlinelibrary.wiley.com/doi/10.1111/ajd.12974">particularly self-conscious</a> about their body are more likely to intentionally tan to increase their sense of attractiveness. </p>
<p>Fortunately, there’s a safe way to indulge in the aesthetics of golden-brown skin: any tan that comes out of a bottle with the active ingredient <a href="https://www.dermnetnz.org/topics/dihydroxyacetone">dihydroxyacetone</a>. This is a colourless sugar molecule that turns brown when it reacts with amino acids in the skin. It’s safe to use because it doesn’t penetrate deeper than the very top layer of skin, where the cells are already dead. </p>
<p>Don’t be tempted by solariums and sunbeds, because they emit <a href="http://www.sunsmart.com.au/uv-sun-protection/solariums">up to six times as much UV</a> as the midday summer sun. Commercial solariums are illegal in Australia for this reason, but there are still privately-owned sunbeds in use. Avoid them at all costs. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-do-the-chemicals-in-sunscreen-protect-our-skin-from-damage-74355">How do the chemicals in sunscreen protect our skin from damage?</a>
</strong>
</em>
</p>
<hr>
<h2>So how do I stay sun safe without living in a cave?</h2>
<p>There are two parts to sunsafe behaviour in Australia that lets you get the health benefits of sunshine and prevents you from being one of the <a href="https://www.cancer.org.au/news/media-releases/new-research-shows-almost-2.4-million-aussie-adults-sunburnt-on-summer-weekends.html">2.4 million Aussies</a> getting sunburnt each weekend.</p>
<p>First, you should wear 30+ SPF sunscreen every day when the UV index in your area is three or higher. By putting it on everywhere that isn’t covered by that day’s outfit, you protect yourself from the damage accumulated by short exposures, day in and day out, in Australia’s intense UV environment. </p>
<p>You should make sunscreen part of your morning routine, like brushing your teeth. Use the Cancer Council’s free <a href="https://www.cancer.org.au/preventing-cancer/sun-protection/uv-alert/sunsmart-app.html">Sun Smart app</a> or check your local weather report to find out the UV index where you are today. </p>
<p>During the cooler months in southern parts of Australia, when the UV index is often below three, it’s good to spend some time on most days, in the middle of the day, with skin exposed to the sun to <a href="https://wiki.cancer.org.au/policy/Position_statement_-_Risks_and_benefits_of_sun_exposure">maintain healthy vitamin D levels</a>. </p>
<p>So, a lunchtime stroll with your sleeves rolled up is a good idea in July in Hobart, where the UV index only gets up to one. In Brisbane at the same time, with an average July UV index of four, you don’t need to take special steps to get enough vitamin D.</p>
<p>Second, if you’re <a href="http://www.assc.org.au/eventssunscreen-summit-19-20-march-2018/">planning to be outside for a prolonged time</a>, you should follow the Slip Slop Slap Seek Slide advice. Slip on a long-sleeved shirt, slop on sunscreen, slap on a hat, seek shade and slide on some sunglasses. Reapply your sunscreen every two hours, and be sure to use plenty: you want about a teaspoon each for your back, chest, head/neck, and each arm and leg.</p><img src="https://counter.theconversation.com/content/109439/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>H. Peter Soyer is a consultant for Canfield Scientific Inc, MoleMap NZ Limited, e-derm consult GmbH, and First Derm, and is a shareholder in MoleMap NZ and e-derm GmbH. He receives funding from the National Health and Medical Research Council. </span></em></p><p class="fine-print"><em><span>Katie Lee does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>You need far less sun than you think you do.H. Peter Soyer, Professor of Dermatology, The University of QueenslandKatie Lee, Research assistant, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1061282018-11-22T23:05:04Z2018-11-22T23:05:04ZChildren with arthritis lack vitamin D<figure><img src="https://images.theconversation.com/files/246741/original/file-20181121-161621-u3s105.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Children play soccer in the small town of Baker Lake, Nunavut in 2009. Research among children with arthritis globally shows that those residing in northern latitudes have abnormally low vitamin D levels. </span> <span class="attribution"><span class="source">(THE CANADIAN PRESS/Nathan Denette)</span></span></figcaption></figure><p>In an analysis of global research, we recently found that children with the most frequent type of arthritis, juvenile idiopathic arthritis (JIA), have <a href="https://ped-rheum.biomedcentral.com/articles/10.1186/s12969-018-0250-0">abnormally low vitamin D blood levels</a>. We also found that those living in northern countries, such as Canada and northern European regions, are more likely to have low vitamin D levels and associated active disease.</p>
<p>In Canada, arthritis is among the most common chronic diseases of childhood. An estimated <a href="https://www.arthritis.ca/about-arthritis/arthritis-types-(a-z)/types/childhood-arthritis">three in 1,000 Canadian children</a> (more than 20,000 in total) have arthritis. The <a href="http://www.jrheum.org/content/29/7/1520">prevalence of childhood arthritis varies throughout the world</a>. </p>
<p>Geographical differences in the frequency of childhood arthritis might relate to genetic, ethnic, environmental and lifestyle influences. The cause of arthritis in children is unknown, but the <a href="https://doi.org/10.1093/rheumatology/kep383">interaction of genetic and environmental factors is believed to be important</a>.</p>
<p>Vitamin D is vital for bone health and is essential for regulating the body’s immune and inflammatory functions. The body’s level of vitamin D is also influenced by genetic factors, skin tone and clothing that affect the skin’s exposure to sunlight, and dietary intake of vitamin D. </p>
<p>Environmental variations in exposure to ultraviolet B radiation (UVB) from sunlight, which is necessary for activating vitamin D in the body, is affected by the latitude and season.</p>
<h2>Kids in northern countries fare worst</h2>
<p>Our team reviewed 38 studies from around the world. We found that in 84 per cent of them, vitamin D levels in children with JIA were <a href="https://endocrinenews.endocrine.org/nov-2014-just-right-how-much-vitamin-d-is-enough/">lower than recommended</a>.</p>
<p>Vitamin D status also followed a north-south geographical gradient — with those residing in northern latitudes having abnormally low vitamin D levels. </p>
<p>The analysis also showed a correlation between vitamin D status and arthritis activity as those children with lower vitamin D levels had more active arthritis.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/vuvXhVa2gzY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Information from the existing literature indicates that determining vitamin D status in children with arthritis is important. Children with arthritis who live in northern regions, in Canada and globally, may be vulnerable to vitamin D deficiency especially during the winter months. </p>
<p>We can ensure that children have proper levels of vitamin D through careful sun exposure, eating foods rich in vitamin D (such as fatty fish like salmon and tuna, eggs, beef, liver and fortified dairy products and cereals) and taking supplements when necessary.</p>
<h2>Indigenous children at risk</h2>
<p>The primary source of vitamin D is that produced in the skin after exposure to sunlight. Above 33 degrees north (the latitude of San Diego in the United States), UVB radiation is not intense enough for skin synthesis of vitamin D all year long. </p>
<p>At latitudes between 42 degrees (the latitude of the Oregon/California border) and 53 degrees north (the latitude of Fort McMurray in Canada), between October to April, UVB radiation is not intense enough for vitamin D synthesis.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/246739/original/file-20181121-161644-59krz7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/246739/original/file-20181121-161644-59krz7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=459&fit=crop&dpr=1 600w, https://images.theconversation.com/files/246739/original/file-20181121-161644-59krz7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=459&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/246739/original/file-20181121-161644-59krz7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=459&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/246739/original/file-20181121-161644-59krz7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=577&fit=crop&dpr=1 754w, https://images.theconversation.com/files/246739/original/file-20181121-161644-59krz7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=577&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/246739/original/file-20181121-161644-59krz7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=577&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Students board a school bus at the Nakasuk Elementary School in Iqaluit, Nunavut, in 2009.</span>
<span class="attribution"><span class="source">(THE CANADIAN PRESS/Nathan Denette)</span></span>
</figcaption>
</figure>
<p>Indigenous populations in northern Canada are especially at risk for vitamin D deficiency because of <a href="https://doi.org/10.1371/journal.pone.0049872">limited sun exposure due to geography and limited access to foods rich in vitamin D</a>. </p>
<p>Low vitamin D levels might partly explain the prevalence and severity of childhood arthritis in certain Canadian northern communities.</p>
<p>This research suggest that a comprehensive management plan for children with JIA should include ensuring optimal levels of vitamin D, through some combination of sensible sunshine exposure, diet and supplements when required.</p><img src="https://counter.theconversation.com/content/106128/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alan Rosenberg receives funding from: The Arthritis Society, The Jim Pattison Children's Hospital Foundation, The College of Medicine (University of Saskatchewan), The Royal University Hospital Foundation, The Canadian Institutes of Health Research.</span></em></p><p class="fine-print"><em><span>Hassan Vatanparast and Sarah Finch do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A new study points to a clear link between childhood arthritis and abnormally low levels of vitamin D, especially ion northern countries.Alan Rosenberg, Professor, University of SaskatchewanHassan Vatanparast, Professor Public Health, University of SaskatchewanSarah Finch, PhD Candidate in Nutrition and Registered Dietician, University of SaskatchewanLicensed as Creative Commons – attribution, no derivatives.