tag:theconversation.com,2011:/us/topics/prebiotics-14352/articlesPrebiotics – The Conversation2024-01-21T12:59:06Ztag:theconversation.com,2011:article/2213842024-01-21T12:59:06Z2024-01-21T12:59:06ZDietary fibre affects more than your colon: How the immune system, brain and overall health benefit too<figure><img src="https://images.theconversation.com/files/570412/original/file-20240119-19-bkynf2.jpg?ixlib=rb-1.1.0&rect=66%2C6%2C3923%2C2249&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Most people only consume about half of the recommended amount of dietary fibre, and it can negatively affect overall health.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/dietary-fibre-affects-more-than-your-colon-how-the-immune-system-brain-and-overall-health-benefit-too" width="100%" height="400"></iframe>
<p>There’s no shortage of advice about what to eat, including hype about the latest <a href="https://www.hsph.harvard.edu/nutritionsource/superfoods/">superfoods</a> that will help you <a href="https://www.npr.org/sections/thesalt/2015/04/11/398325030/eating-to-break-100-longevity-diet-tips-from-the-blue-zones">live to 100</a>, or about the newest <a href="https://food-guide.canada.ca/en/tips-for-healthy-eating/diets-food-trends/#section-2">restrictive diets</a> that claim to help you lose weight and look beautiful. As a researcher from the <a href="https://farncombe.mcmaster.ca/">Farncombe Family Digestive Health Research Institute</a>, I’m well aware that there is no universal “healthy diet” that will work for everyone. </p>
<p>However, most professionals would agree that a diet should be well balanced between the food groups, and it’s better to include more things like vegetables and <a href="https://doi.org/10.3390%2Fnu11081806">fermented foods</a> in your diet than restrict yourself unnecessarily. Eating foods that promote gut health improves your overall health too.</p>
<h2>Why is everyone so concerned about fibre?</h2>
<p>The importance of fibre has been known for decades. The late great surgeon and fibre researcher <a href="https://doi.org/10.1017/S0954422417000117">Denis Burkitt</a> once said, “If you pass small stools, you have to have large hospitals.” But dietary fibre does more than just help move your bowels. Fibre can be considered a <a href="https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/probiotics/faq-20058065">prebiotic nutrient</a>. </p>
<p>Prebiotics aren’t actively digested and absorbed, rather they are selectively used to promote the growth of a beneficial species of microbes in our gut. <a href="https://doi.org/10.3390%2Ffoods8030092">These microbes then help digest foods</a> for us so we can obtain more nutrients, promote gut barrier integrity and prevent the growth of harmful bacteria. </p>
<figure class="align-center ">
<img alt="High-fibre foods against the outline of intestines" src="https://images.theconversation.com/files/570413/original/file-20240119-17-wpd6x9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570413/original/file-20240119-17-wpd6x9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570413/original/file-20240119-17-wpd6x9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570413/original/file-20240119-17-wpd6x9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570413/original/file-20240119-17-wpd6x9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570413/original/file-20240119-17-wpd6x9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570413/original/file-20240119-17-wpd6x9.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">Prebiotics aren’t actively digested and absorbed, rather they are selectively used to promote the growth of a beneficial species of microbes in our gut.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Fibres can also have microbe-independent effects on our immune system when they <a href="https://doi.org/10.1111/bph.14871">interact directly with receptors expressed by our cells</a>. These beneficial effects may even help teach the immune system to be more tolerant and reduce inflammation.</p>
<h2>Getting enough dietary fibre?</h2>
<p>Probably not. The so-called <a href="https://doi.org/10.3390%2Fnu15122749">western diet</a> is low in fibre and filled with ultra-processed foods. The <a href="https://www.canada.ca/en/health-canada/services/nutrients/fibre.html">recommendation for daily fibre</a> is between <a href="https://doi.org/10.1038/s41575-020-00375-4">25-38 grams depending on factors like age, sex and activity level</a>. Most people consume about half of the recommendation, and it can negatively affect overall health. </p>
<p>Good sources of dietary fibre include whole grains, fruits and vegetables, beans and legumes, and nuts and seeds. There is a lot of emphasis on soluble fibres and less on insoluble fibres, but in reality, most foods will contain a mixture of both, and they each <a href="https://www.healthline.com/health/soluble-vs-insoluble-fiber%23risks">have their merits</a>. </p>
<p>High fibre snacks are also gaining popularity. With an estimated global value of US$7 billion in 2022, the <a href="https://www.precedenceresearch.com/prebiotic-ingredients-market#:%7E:text=The%2520global%2520prebiotic%2520ingredients%2520market,13.25%2525%2520from%25202022%2520to%25202030">value of the prebiotic ingredient market</a> is expected to triple by 2032.</p>
<h2>The benefits of dietary fibre</h2>
<figure class="align-right ">
<img alt="Diagram of a human with arrows linking brain and intestines" src="https://images.theconversation.com/files/570414/original/file-20240119-17-fwfmrl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/570414/original/file-20240119-17-fwfmrl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570414/original/file-20240119-17-fwfmrl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570414/original/file-20240119-17-fwfmrl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570414/original/file-20240119-17-fwfmrl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570414/original/file-20240119-17-fwfmrl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570414/original/file-20240119-17-fwfmrl.jpg?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">Fibre is associated with overall health and brain health through the gut-brain axis.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>There’s plenty of evidence supporting the benefits of dietary fibre. Fibre isn’t just associated with colon health; it’s associated with overall health and brain health through the <a href="https://my.clevelandclinic.org/health/body/the-gut-brain-connection">gut-brain axis</a>. Diets low in fibre have been associated with gastrointestinal disorders such as irritable bowel syndrome or inflammatory bowel disease. </p>
<p>On the other hand, consuming adequate fibre also <a href="https://doi.org/10.1038/s41575-020-00375-4">reduces the risk and mortality associated with cardiovascular diseases and obesity</a>. There are studies that show <a href="https://doi.org/10.3390/nu13072159">improvements of cognitive function with certain types of fibre</a>. </p>
<p>There are some gastrointestinal diseases, like Celiac disease, which are not typically associated with the benefits of dietary fibre. However, <a href="https://doi.org/10.1038/s41575-020-00375-4">there isn’t a consensus</a> to the specific type of fibre and dose that would be beneficial in treating most diseases.</p>
<h2>Not all fibre is good fibre</h2>
<p>Shockingly, not all fibre is good for you. Fibre is used as an umbrella term for indigestible plant polysaccharides, so there are many different types with varying fermentability, solubility and viscosity in the gut. </p>
<p>To make things more complex, <a href="https://doi.org/10.3389/fped.2020.620189">the source matters too</a>. Fibre from one plant isn’t the same as fibre from another plant. Additionally, the old proverb, “too much good is not good” rings true, where overconsumption of fibre supplements can cause symptoms such as constipation, bloating and gas. This is partly due to the differences in gut microbiomes that affect the ability to metabolize fibre to produce beneficial molecules like short-chain fatty acids. </p>
<p>In some cases, such as inflammatory bowel disease patients, lack of microbes with the capacity to digest fibre may allow intact fibres to <a href="https://doi.org/10.1053/j.gastro.2022.09.034">interact with intestinal cells directly and exert pro-inflammatory effects</a>. Recent evidence has even shown that excessively high consumption of soluble fibres, such as inulin, a common supplement, <a href="https://doi.org/10.1053/j.gastro.2023.10.012">can increase the risk of colon cancer development in an experimental animal model</a>.</p>
<h2>Part of a healthy diet</h2>
<p>Dietary fibre is an important part of a healthy diet that can promote both gut and overall health. Fibre helps you feel more satisfied after meals and helps to regulate your blood sugar and cholesterol. Do your best to consume fibre as part of your diet, and when needed, take only the dose of supplements as recommended. </p>
<p>Prebiotics promote the growth of gut microbes that can affect gut health and immunity in the context of many different diseases, although not all fibres are created equal. While fibre won’t cure illness, diet is a great addition to medicines and treatment strategies that can improve their efficacy.</p><img src="https://counter.theconversation.com/content/221384/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Wulczynski 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>Fibre isn’t just associated with colon health; it’s associated with overall health and brain health through the gut-brain axis. But not all fibres are created equal.Mark Wulczynski, Medical Sciences PhD Candidate, McMaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2163552024-01-16T19:15:14Z2024-01-16T19:15:14ZSpace travel taxes astronauts’ brains. But microbes on the menu could help in unexpected ways<figure><img src="https://images.theconversation.com/files/565638/original/file-20231213-27-4xr8mj.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5991%2C3000&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-vector/smiling-man-astronaut-presents-shawarma-kebab-1128088580">studiostoks/Shutterstock</a></span></figcaption></figure><p>Feeding astronauts on a long mission to Mars goes well beyond ensuring they have enough nutrients and calories to survive their multi-year journey.</p>
<p>Providing astronauts with the right diet is also paramount in supporting their <a href="https://www.frontiersin.org/articles/10.3389/fncir.2023.1170395/full?trk=public_post_comment-text">mental and cognitive health</a>, in a way unlike previous missions.</p>
<p>So we need to radically rethink how we feed astronauts not only on a challenging mission to Mars, which could be on the cards in the late 2030s or early 2040s, but to prepare for possible settlement on the red planet. </p>
<p>That includes acknowledging the role of microbes in mental health and wellbeing, and providing astronauts with the right foods and conditions for a variety of these beneficial microbes to grow. Our research aims to do just that.</p>
<p>Here’s why a healthy balance of microbes is important under such challenging conditions, and how we could put microbes on the menu.</p>
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<p>
<em>
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Read more:
<a href="https://theconversation.com/was-going-to-space-a-good-idea-218235">Was going to space a good idea?</a>
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</em>
</p>
<hr>
<h2>Why are missions to Mars so challenging?</h2>
<p>Deep space missions will expose humans to immense physical and psychological challenges. These include prolonged isolation from loved ones, extreme space and resource constraints, and the difficulties of microgravity. </p>
<p>Disruption to astronauts’ circadian rhythms, prolonged radiation exposure and dietary changes can also lower their cognitive performance and wellbeing. </p>
<p>The hazardous conditions, combined with the psychological toll of potential spacecraft failures, can all contribute to mental health problems.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-to-live-in-space-what-weve-learned-from-20-years-of-the-international-space-station-144851">How to live in space: what we've learned from 20 years of the International Space Station</a>
</strong>
</em>
</p>
<hr>
<h2>Why is diet important for mental health?</h2>
<p>We already know the quality of people’s diet not only influences their physical health, but also their mental and brain health. </p>
<p>Diet quality is <a href="https://www.nature.com/articles/s41380-018-0237-8">consistently and independently linked</a> to the risk of depression or anxiety. Clinical trials <a href="https://pubmed.ncbi.nlm.nih.gov/35441666/">show</a> improving diet quality <a href="https://www.ncbi.nlm.nih.gov/pubmed/30720698">can lead to</a> profound improvements in depression and anxiety symptoms. </p>
<p>Diet also affects the size and function of a specific brain region – the hippocampus – that is crucial to learning and memory, as well as for maintaining <a href="https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-015-0461-x?report=reader">mental health</a>. When even young healthy adults eat “junk” foods, aspects of cognition linked to the hippocampus quickly <a href="https://royalsocietypublishing.org/doi/abs/10.1098/rsos.191338">decline</a>.</p>
<p>On the other hand, research shows a diet containing more and varied plant foods and seafood (which are rich in components called long-chain omega-3 fatty acids and flavonoids) leads to <a href="https://www.nature.com/articles/s41598-022-21927-5">better cognitive performance</a>. This study was conducted in a closed chamber for 45 days, designed to mimic conditions in space.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Plate of salmon on bed of green salad, with lemon slices, on blue wood table" src="https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.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">A diet rich in plant food and seafood might help your brain, but how do you turn that into space food that will go the distance?</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/grilled-salmon-vegetables-366852431">Jacek Chabraszewski/Shutterstock</a></span>
</figcaption>
</figure>
<p>Diet can have such consequences by <a href="https://www.ncbi.nlm.nih.gov/pubmed/33144709">altering</a>:</p>
<ul>
<li>immune function</li>
<li>the size and functioning of the hippocampus </li>
<li>chemical messenger (neurotransmitter) systems</li>
<li>how our bodies respond to stress.</li>
</ul>
<p>Diet can also influence the many ways microbes in the gut affect the brain, a link known as the <a href="https://journals.physiology.org/doi/full/10.1152/physrev.00018.2018?rfr_dat=cr_pub">microbiota gut-brain axis</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/essays-on-health-microbes-arent-the-enemy-theyre-a-big-part-of-who-we-are-79116">Essays on health: microbes aren't the enemy, they're a big part of who we are</a>
</strong>
</em>
</p>
<hr>
<h2>Not all foods make the grade</h2>
<p>Space foods need to appeal to a diverse crew and stay nutritious for an extremely long time (likely a three- to five-year mission). They also need to be lightweight and compact enough to fit on the spacecraft.</p>
<p>Once on Mars, challenges include growing fresh food and culturing protein sources. Beyond providing nutrients, we also need to consider providing more recently identified factors including phytonutrients (such as polyphenols), fermentation products and microbes. These will likely be crucial to sustain health and, indeed, life on deep space missions.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/humans-are-going-back-to-the-moon-and-beyond-but-how-will-we-feed-them-189794">Humans are going back to the Moon, and beyond – but how will we feed them?</a>
</strong>
</em>
</p>
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<h2>Why are microbes so important?</h2>
<p>If you’ve seen the film <a href="https://theconversation.com/the-martian-review-science-fiction-that-respects-science-fact-48373">The Martian</a>, you’ll know microbes are a crucial aspect of growing food, and are essential for keeping humans alive and functioning. </p>
<p>We have co-evolved with, and are hosts to, trillions of different microbes that live on our skin and in all our niches and cavities. This includes our mouths, nose, vagina, lungs and – crucially – our gut.</p>
<p>Most of these microbes are bacteria. The largest number are in the gut, where they influence our digestion, metabolism, and immune, endocrine (hormone) and nervous systems.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/YB-8JEo_0bI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">What is the human microbiome?</span></figcaption>
</figure>
<p>The relationship between gut microbes and <a href="https://journals.physiology.org/doi/full/10.1152/physrev.00018.2018?rfr_dat=cr_pub">mental health and behaviour</a> goes both ways. Gut microbes influence our mental health and behaviour, and these, in turn, influence our gut microbes. </p>
<p>Other components of our microbiomes – viruses, fungi and even parasites – and the oral and lung microbiome are also linked to mental and <a href="https://journals.physiology.org/doi/full/10.1152/physrev.00018.2018?rfr_dat=cr_pub">brain health</a>. </p>
<p>Importantly, we <a href="https://www.nature.com/articles/s41586-022-05620-1">share microbes</a> with others, including via the exchange of air, which is highly relevant in closed-environment systems such as inside spacecrafts.</p>
<p>So ensuring all astronauts have the healthiest and most diverse of microbes for the whole of the mission is vital.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-do-some-farts-smell-and-some-dont-and-why-do-some-farts-feel-hot-215064">Curious Kids: why do some farts smell and some don’t? And why do some farts feel hot?</a>
</strong>
</em>
</p>
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<h2>How could we encourage healthy microbes?</h2>
<p>It’s not just the food itself we have to think about. We also need to think about how we grow the food if we are to support healthy microbiomes. </p>
<p>Indeed, microbes play an essential role in the nutrient and phytochemical content of plants, and the microbes in soil, plants and humans are interconnected. Research published in 2023 confirms bacteria on vegetables and other plant foods find a home in the <a href="https://www.tandfonline.com/doi/abs/10.1080/19490976.2023.2258565">human gut</a>, enhancing microbe diversity. </p>
<p>But current ways of growing foods on spacecraft don’t use natural soil. Standard “vertical farming” methods grow plants in an alternative growth medium – imagine a next-generation hydroponics system. So we may need to add an optimised microbial cocktail to these systems to enhance the health properties of the foods astronauts grow and eat.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Growing tending plants in a vertical farm" src="https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=421&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=421&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=421&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=529&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=529&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=529&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This closed chamber mimics how astronauts will grow fresh crops in space.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/technology/tech-transfer-spinoffs/nasa-research-launches-a-new-generation-of-indoor-farming/">NASA</a></span>
</figcaption>
</figure>
<p><a href="https://www.cell.com/cell/fulltext/S0092-8674(22)01515-X?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS009286742201515X%3Fshowall%3Dtrue">Fermented protein</a> from microbes can be quickly produced in a bioreactor on board the spacecraft, even from food waste. Some types have a meat-like flavour and texture, and can provide all the amino acids humans need as well as useful byproducts from the microbes themselves. </p>
<p>Fermentation itself creates thousands of different bioactive molecules, including some vitamins, that have diverse <a href="https://www.tandfonline.com/doi/abs/10.1080/1028415X.2018.1544332">beneficial effects on health</a>, including possible benefits to mental health.</p>
<p>While we don’t yet know what types of fermented foods are possible in space, we could include fermented foods, such as kimchi and sauerkraut, in astronauts’ diets on Earth.</p>
<p>Probiotics and prebiotics as supplements may also be essential. Probiotics are live microbes that have demonstrated health benefits and prebiotics are food for these healthy microbes.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-kombucha-and-how-do-the-health-claims-stack-up-87180">What is kombucha and how do the health claims stack up?</a>
</strong>
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<h2>Benefits on Earth too</h2>
<p>We’re only at the start of learning how to optimise microbes to keep space crews healthy, which is crucial for long space flights and for possible settlement on other planets. </p>
<p>However, this research could have many other applications. We can use what we learn to help create self-sustaining and <a href="https://www.nasa.gov/technology/tech-transfer-spinoffs/nasa-research-launches-a-new-generation-of-indoor-farming/">sustainable food systems</a> on Earth to improve the environment and human health.</p><img src="https://counter.theconversation.com/content/216355/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Felice N Jacka is supported by a National Health and Medical Research Council investigator grant (#1194982). She has received: (1) competitive grant/research support from the Brain and Behaviour Research Institute, the National Health and Medical Research Council, Australian Rotary Health, the Geelong Medical Research Foundation, the Ian Potter Foundation, The University of Melbourne; (2) industry support for research from Meat and Livestock Australia, Woolworths Limited, the A2 Milk Company, Be Fit Foods, Bega Cheese; (3) philanthropic support from the Fernwood Foundation, Wilson Foundation, the JTM Foundation, the Serp Hills Foundation, the Roberts Family Foundation, the Waterloo Foundation and; (4) travel support and speakers honoraria from Sanofi-Synthelabo, Janssen Cilag, Servier, Pfizer, Network Nutrition, Angelini Farmaceutica, Eli Lilly, Metagenics, and The Beauty Chef. She is on the Scientific Advisory Board of the Dauten Family Centre for Bipolar Treatment Innovation and Zoe Limited. Felice Jacka has written two books for commercial publication.</span></em></p><p class="fine-print"><em><span>Dorit Donoviel is Executive Director, NASA-Funded Translational (moving products from lab-bench to practice) Research Institute for Space Health at Baylor College of Medicine. Dorit receives funding from NASA through Cooperative Agreement NNX16AO69A and disburses this funding to research groups and companies performing work to safeguard the health of humans in deep space.</span></em></p>Here’s why a healthy balance of microbes is important for astronauts when they travel to Mars and beyond.Felice Jacka, Alfred Deakin Professor, Deakin UniversityDorit Donoviel, Executive Director/Associate Professor, Baylor College of Medicine Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2187442024-01-08T16:43:05Z2024-01-08T16:43:05ZHow to maintain a healthy gut microbiome in 2024<figure><img src="https://images.theconversation.com/files/567608/original/file-20240102-17-7n4kg4.jpg?ixlib=rb-1.1.0&rect=17%2C0%2C5973%2C3988&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/adult-child-hands-holding-intestine-shape-1935965023">SewCreamStudio/Shutterstock</a></span></figcaption></figure><p>We all know by now that the pillars of a healthy lifestyle are regular exercise, eating enough fruit and vegetables, a good night’s sleep and staying hydrated. All of these things also support the gut microbiome – all the microbes that live in your digestive system – but there are some extras to consider if you want to optimise your gut health.</p>
<p>It’s widely accepted among those of us who study the gut microbiome that a healthy gut is one that contains a <a href="https://theconversation.com/diverse-gut-microbiomes-give-better-protection-against-harmful-bugs-now-we-know-why-219734">diverse range of microbes</a> and has an effective gut barrier (the lining between your intestine and bloodstream).</p>
<p>Let’s look at diet first. It probably has the biggest influence on your gut health. Diets high in fibre, unsaturated fatty acids (found in fish and nuts), and polyphenols (chemicals found in plants) will <a href="https://www.annualreviews.org/doi/full/10.1146/annurev-physiol-031522-092054">promote a healthy gut</a>, while those high in saturated fats, additives (such as “E numbers”) and sugar can harm gut health. So avoid consuming a lot of ultra-processed foods.</p>
<p>Emulsifiers, a common additive in ultra-processed foods, have been found to cause <a href="https://www.mdpi.com/2072-6643/14/15/3049">intestinal inflammation and a leaky gut</a>. The most common ones to look out for on packaging are lecithin, polysorbates (such as E433) and carrageenan.</p>
<p>These additives are also common in protein supplements, whose popularity has steadily been increasing since the <a href="https://theconversation.com/decades-of-hype-turned-protein-into-a-superfood-and-spawned-a-multibillion-dollar-industry-163711#:%7E:text=Global%20retail%20sales%20of%20protein,around%20half%20of%20the%20market.">early 2000s</a>, especially among gym goers looking to bulk up. </p>
<h2>Prebiotics and probiotics</h2>
<p>It would be unreasonable and unrealistic to tell you to avoid foods with additives, but trying to limit consumption, while increasing your consumption of prebiotic and probiotic foods, could help protect your gut.</p>
<p>Dietary fibre is a good example of a prebiotic, which is defined as a non-digestible food ingredient that can stimulate the growth of good bacteria <a href="https://www.nature.com/articles/s41575-020-00375-4">in the colon</a>. As the main food source of your gut microbes, it is important to consume enough if you want your microbiome to flourish. Government guidelines suggest around 30g of fibre a day for adults and 15-25g for children. </p>
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<img alt="Foods that are rich in fibre." src="https://images.theconversation.com/files/567719/original/file-20240103-25-e1au68.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567719/original/file-20240103-25-e1au68.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567719/original/file-20240103-25-e1au68.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567719/original/file-20240103-25-e1au68.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567719/original/file-20240103-25-e1au68.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567719/original/file-20240103-25-e1au68.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567719/original/file-20240103-25-e1au68.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">
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<span class="caption">Adults should aim to consume 30g of fibre a day.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/high-fiber-foods-healthy-balanced-dieting-1916962526">Tatjana Baibakova/Shutterstock</a></span>
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<p>Most prebiotics come from plant foods, so getting a high diversity of plant products in your diet will keep your gut healthy. The latest recommendation is to include 30 plant species in your <a href="https://journals.asm.org/doi/10.1128/msystems.00031-18">diet per week</a>. This may sound hard to achieve but bear in mind that both good-quality coffee and dark chocolate count.</p>
<p>Probiotics, the live bacteria and yeasts themselves, can be easily consumed through fermented food products, drinks or supplements. Choosing a high-quality probiotic is important. While there is an increasing amount on the market in supplement, powder and tablet form, they can be expensive. Fermented foods can be just as effective, but a whole lot cheaper. </p>
<p>Yoghurts, cheese, sauerkraut, kimchi and fermented soy products, such as tempeh and miso, are examples of fermented foods that not only support the healthy balance of your gut bacteria but provide a good source of fibres, vitamins and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5425481/">other nutrients</a>. </p>
<p>To get the most benefit from these products, look for those in the fridge section labelled as containing “live cultures” or “live bacteria”, with minimal ingredients and no heating or pasteurisation processing. </p>
<p>Aside from what you eat, how often you eat could also affect your gut health. Fasting can allow repair of the gut lining and <a href="https://www.sciencedirect.com/science/article/pii/S0966842X23000574?via%3Dihub#s0085">reduce inflammation</a>.</p>
<h2>Medication and the microbiome</h2>
<p>Medications can directly and indirectly affect our gut health. You may have heard that antibiotics are bad for your gut microbiome, especially those which are “broad spectrum” and will kill off not only harmful bacteria but beneficial ones too. This can be associated with <a href="https://www.mdpi.com/1422-0067/24/4/3074">gastrointestinal problems and decreased immunity</a>, especially after prolonged use. </p>
<p>Of course, doctors do not prescribe antibiotics lightly, so it is important to take them as instructed. If you are concerned, discuss the potential effects on your gut health with your GP.</p>
<p>Although you may not have much say over which medications you take, there are a few strategies to support your gut during and after medication. </p>
<p>Staying healthy by prioritising good sleep and managing stress levels is also important, but increasing your intake of both <a href="https://www.nature.com/articles/s41467-023-40553-x">prebiotics</a> and <a href="https://journals.sagepub.com/doi/10.1177/20499361231154443">probiotics</a> at this time may <a href="https://www.mdpi.com/1422-0067/24/4/3074">lessen the blow</a> of medication on your microbiome. </p>
<p>It is always recommended you check with your doctor before introducing a probiotic supplement in the rare case that it may not be suitable alongside the treatment. </p>
<p>Microbiome research is continuously shedding new light on the intricate connections between the microbes that live in our gut and our wellbeing. So watch this space. In the meantime, follow the above advice – it will help you maintain a healthy gut microbiome in 2024 and beyond.</p>
<p><em>Correction: An earlier version of this article incorrectly stated that guar and xantham gum are emulsifiers.</em></p><img src="https://counter.theconversation.com/content/218744/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>Improve your gut microbiome health and you improve so many aspects of your overall health. Here’s how to do it.Rosie Young, PhD Candidate, Gut Microbes in Health and Disease, Quadram InstituteMariam Gamal El-Din, Visiting Postdoctoral Scientist, Food Microbiome Interactions, Quadram InstituteYang Yue, PhD Candidate in Plants, Food and Health, Quadram InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2038552023-04-21T14:53:28Z2023-04-21T14:53:28ZHay fever could be linked to our gut and nose bacteria – and probiotics may help symptoms<figure><img src="https://images.theconversation.com/files/522085/original/file-20230420-15-nvus1a.jpg?ixlib=rb-1.1.0&rect=17%2C0%2C5734%2C3837&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Many people suffer with hay fever.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/handsome-hipster-blowing-his-nose-on-287952305">wavebreakmedia/Shutterstock</a></span></figcaption></figure><p>For many people, spring has brought with it the dreaded symptoms of <a href="https://www.nhs.uk/conditions/hay-fever/">hay fever</a>, such as itchy eyes, sneezing and a stuffy nose. Hay fever is common, affecting <a href="https://europepmc.org/article/med/17153005">up to 42%</a> of people. It occurs when the immune system overreacts to allergens including pollen.</p>
<p>Research suggests there could be a link between <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5378446/">hay fever and the microbiome</a>, the collection of microorganisms that live in and on our bodies. Specifically, the composition of a person’s <a href="https://www.karger.com/Article/Abstract/510536">gut</a> and <a href="https://link.springer.com/article/10.1007/s00405-020-06311-1">nasal microbiomes</a> may play a role in the development of hay fever symptoms. </p>
<p>By exploring this connection, we can identify potential alternative treatments that may help reduce the effects of hay fever on people’s daily lives.</p>
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Read more:
<a href="https://theconversation.com/got-allergies-you-could-be-at-lower-risk-of-catching-covid-188486">Got allergies? You could be at lower risk of catching COVID</a>
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<h2>Hay fever and the microbiome</h2>
<p>Studies have shown that people with hay fever often have <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/all.13812">a less diverse gut microbiome</a> compared to those without the condition. Reduced diversity of gut bacteria can lead to an imbalance in the microbiome, and result in higher levels of inflammation (the body’s immune response to irritants, such as an allergens).</p>
<p>So the fact that reduced diversity of gut bacteria can lead to an increased risk of hay fever makes sense since the gut microbiome plays a key role in <a href="https://akjournals.com/view/journals/030/68/3/article-p135.xml">regulating the immune system</a>, and we know the immune system influences allergies. </p>
<p>The gut microbiome is thought to affect immune system function in several ways, including through the production of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9040132/">short-chain fatty acids</a>. These are produced by gut bacteria during the fermentation of dietary fibre (a part of normal digestion). </p>
<p>Short-chain fatty acids are known to have anti-inflammatory properties. Research has shown that lower levels of two bacterial strains which produce short-chain fatty acids – <em>Bifidobacterium</em> and <em>Lactobacillus</em> – are associated with <a href="https://pubmed.ncbi.nlm.nih.gov/21340202/">an increased risk of hay fever</a>.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/hay-fever-why-some-people-suffer-from-it-and-others-dont-202553">Hay fever: why some people suffer from it and others don't</a>
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<p>In addition to the gut microbiome, hay fever also seems to be linked to the <a href="https://www.frontiersin.org/articles/10.3389/fcimb.2022.841995/full">nasal microbiome</a>, the community of microorganisms that inhabit the nasal passages. </p>
<p>The nasal microbiome plays an important role in regulating the immune system and protecting against harmful pathogens that enter our bodies through the nose. Imbalance and reduced diversity of the nasal microbiome can lead to an <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8566799/">increased risk of respiratory infections</a> and <a href="https://www.nature.com/articles/s41564-022-01301-x">exacerbation of hay fever symptoms</a>. </p>
<p>Studies have shown that people with hay fever often have a different <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4101129/">composition of their nasal microbiome</a> compared to those without the condition, with more of certain bacteria such as <em><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2984262/">Staphylococcus aureus</a></em>. This imbalance in the nasal microbiome can lead to increased inflammation and a higher risk of certain hay fever symptoms.</p>
<h2>The potential role of probiotics and prebiotics</h2>
<p>Probiotics are <a href="https://academic.oup.com/ajcn/article/71/6/1682S/4729644?login=false">live microorganisms</a> which enhance the composition of “good” bacteria in the body. Prebiotics, meanwhile, are fibres that stimulate beneficial bacteria in the gut. Essentially, good bacteria <a href="https://www.healthline.com/nutrition/probiotics-and-prebiotics">feed on prebiotics</a>. Both are important for maintaining a healthy gut microbiome, which plays a crucial role in our overall health.</p>
<p>Several strains of <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/alr.21492">probiotic bacteria</a> have been studied in connection to hay fever.</p>
<p>One strain of interest is <em>Lactobacillus acidophilus</em>, which has been found to <a href="https://www.karger.com/Article/Abstract/515352">reduce hay fever symptoms</a> such as congestion, itching and sneezing. Another is <em>Lactobacillus rhamnosus GG</em>, which has shown potential in preventing hay fever development in infants.</p>
<p>Other <a href="https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1440-1711.2000.00886.x">strains</a> such as <em><a href="https://www.nature.com/articles/ejcn2012197">Bifidobacterium lactis</a></em>, <em>Bifidobacterium bifidum</em> and <em>Lactobacillus casei</em> have also shown some promise in reducing hay fever symptoms. But further research is needed.</p>
<h2>How does this work?</h2>
<p>Probiotics appear to modulate the immune response and in particular, decrease the production of inflammatory cytokines. These are signalling molecules produced by cells of the immune system that promote inflammation.</p>
<p>For example, <em>Lactobacillus acidophilus</em> can <a href="https://www.sciencedirect.com/science/article/pii/S0022030205727144">decrease the expression of</a> inflammatory cytokines associated with allergic inflammation in the mucous membranes in the nasal cavity. </p>
<p>Similarly, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8256161/"><em>Lactobacillus rhamnosus GG</em></a> has been shown to reduce airway hyperresponsiveness (where the airways narrow excessively in response to stimuli), decrease inflammatory cells in the lungs, and reduce inflammatory cytokines.</p>
<figure class="align-center ">
<img alt="Six different types of fermented food in jars." src="https://images.theconversation.com/files/522176/original/file-20230420-24-h28hpw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/522176/original/file-20230420-24-h28hpw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/522176/original/file-20230420-24-h28hpw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/522176/original/file-20230420-24-h28hpw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/522176/original/file-20230420-24-h28hpw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/522176/original/file-20230420-24-h28hpw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/522176/original/file-20230420-24-h28hpw.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">
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<span class="caption">Fermented foods contain probiotics.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/set-fermented-food-great-gut-health-485504767">marekuliasz/Shutterstock</a></span>
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<p>Prebiotics, such as fructo-oligosaccharides, have also been studied for their <a href="https://pubmed.ncbi.nlm.nih.gov/33376575/">potential in hay fever prevention</a>. They’ve been found to increase beneficial gut bacteria such as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6115998/"><em>Bifidobacterium</em> and <em>Lactobacillus</em></a>. One study showed that fructo-oligosaccharides supplementation in infants <a href="https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/specific-mixture-of-shortchain-galactooligosaccharides-and-longchain-fructooligosaccharides-induced-an-antiallergic-ig-profile-in-infants-at-risk-for-allergy/22B21443140E6A7F6956CC8F733492D0">decreased their risk</a> of developing hay fever. </p>
<h2>Incorporating probiotics and prebiotics</h2>
<p>If you suffer from hay fever, you may want to consider incorporating probiotics and prebiotics into your routine.</p>
<p>Probiotic supplements are widely available in various forms, including capsules, tablets, powders and drinks. It’s important to choose a supplement that contains the specific strains of probiotic bacteria that have been studied in relation to hay fever. These include <em>Lactobacillus acidophilus</em>, <em>Lactobacillus rhamnosus GG</em>, <em>Bifidobacterium lactis</em>, <em>Bifidobacterium bifidum</em> and <em>Lactobacillus casei</em>. </p>
<p>You can also incorporate <a href="https://www.webmd.com/digestive-disorders/ss/slideshow-probiotics">probiotic-rich foods</a> into your diet. These include fermented foods such as yogurt, kefir, sauerkraut, kimchi and kombucha.</p>
<p>As for prebiotics, fructo-oligosaccharides are <a href="https://www.webmd.com/diet/foods-high-in-prebiotic">commonly found in certain foods</a> such as bananas, onions, garlic, asparagus, artichokes and whole grains. Supplements are also available in various forms, including powders and capsules.</p>
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Read more:
<a href="https://theconversation.com/probiotics-regulate-our-immune-system-and-could-help-fight-off-covid-new-research-175470">Probiotics regulate our immune system and could help fight off COVID – new research</a>
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<p>Sometimes, taking probiotics and prebiotics may have <a href="https://www.tandfonline.com/doi/abs/10.1517/14740338.2014.872627">side effects</a>, including digestive discomfort such as gas, bloating and diarrhoea. To minimise these risks, it’s recommended you start with a low dose and gradually increase this over time. It’s also worth consulting a healthcare provider before taking these supplements, especially if you have a medical condition or are on medications.</p><img src="https://counter.theconversation.com/content/203855/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>Research suggests there could be a link between hay fever and the microbiome. Exploring this connection paves the way for potential treatments.Samuel J. White, Senior Lecturer in Genetic Immunology, Nottingham Trent UniversityPhilippe B. Wilson, Professor of One Health, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1928312023-01-24T13:22:49Z2023-01-24T13:22:49ZParsing which foods are healthy and which are less so isn’t always straightforward – a new rating system aims to demystify the process<figure><img src="https://images.theconversation.com/files/504494/original/file-20230113-22-lolqv7.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5615%2C3741&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The new system generally gives higher scores to fruits, vegetables and minimally processed foods.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/shopping-cart-speeding-down-supermarket-aisle-royalty-free-image/1147480854?phrase=packaged%20foods%20in%20grocery%20store&adppopup=true">RapidEye/iStock via Getty Images Plus</a></span></figcaption></figure><p>Many people aim to start the year off with healthier food choices. But how do you choose between seemingly similar foods, snacks or beverages? How does a bagel with cream cheese compare to toast topped with avocado, for instance? Or a protein-based shake compared to a smoothie packed with fruits? Or two chicken dishes, prepared in different ways?</p>
<p>As nutrition scientists who have spent our entire careers studying how different foods influence health, <a href="https://sites.tufts.edu/foodcompass/about/">our team at Tufts University</a> has created a new food rating system, <a href="https://sites.tufts.edu/foodcompass/">the Food Compass</a>, that could help consumers and others make informed choices about these kinds of questions. </p>
<h2>Food rating systems explained</h2>
<p>Many such systems <a href="https://doi.org/10.1007/s11883-020-00857-5">exist and are widely used</a> around the globe. Each one combines facts about different nutritional aspects of foods to provide an overall measure of healthfulness, which can be communicated to consumers through package labels or shelf tags. They can also be used to help guide product reformulations or socially conscious investment goals for investors.</p>
<p>Examples of common systems include <a href="https://www.iarc.who.int/wp-content/uploads/2021/09/IARC_Evidence_Summary_Brief_2.pdf">Nutri-Score</a> and <a href="http://www.healthstarrating.gov.au/internet/healthstarrating/publishing.nsf/content/home">Health Star Rating</a> – widely used in Europe, the U.K., Australia and New Zealand – and “<a href="https://www.npr.org/sections/thesalt/2016/08/12/486898630/chile-battles-obesity-with-stop-signs-on-packaged-foods">black box” warning label systems</a>, which are increasingly used throughout Latin America.</p>
<p>All such food rating systems have strengths and limitations. Most aim to be simple, using data on just a few nutrients or ingredients. While this is practical, it can omit other important determinants of healthfulness – like the degree of food processing and fermentation and the presence of diverse food ingredients or nutrients like <a href="https://ods.od.nih.gov/factsheets/Omega3FattyAcids-Consumer/">omega-3s</a> and <a href="https://www.webmd.com/diet/foods-high-in-flavonoids">flavonoids</a>, plant compounds that offer an array of health benefits.</p>
<p>Some systems also emphasize older nutrition science. For example, nearly all give negative points for total fat, regardless of fat type, and focus on saturated fat alone, rather than overall fat quality. Another common shortcoming is not assessing refined grains and starches, which have <a href="https://www.healthline.com/nutrition/why-refined-carbs-are-bad">similar metabolic harms as added sugars</a> and <a href="https://doi.org/10.1001/jama.2019.13771">represent about one-third of calories</a> in the U.S. food supply. And many give negative points for total calories, regardless of their source. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/XMcab1MFaLc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Millions of Americans are overweight yet undernourished.</span></figcaption>
</figure>
<h2>Enter the Food Compass</h2>
<p>To address each of these gaps, in 2021 our research team created the <a href="https://sites.tufts.edu/foodcompass/">Food Compass</a>. This system assesses 54 different attributes of foods, selected based on the strength of scientific evidence for their health effects. Food Compass maps and scores these attributes across nine distinct dimensions and then combines them into a single score, ranging from 1 (least healthy) to 100 (most healthy). It incorporates new science on multiple food ingredients and nutrients; does not penalize total fat or focus on saturated fat; and gives negative points for processing and refined carbs.</p>
<p>We have now evaluated 58,000 products using Food Compass and found that it generally <a href="https://doi.org/10.1038/s43016-021-00381-y">performs very well</a> in scoring foods. Minimally processed, bioactive-rich foods like fruits, veggies, beans, whole grains, nuts, yogurt and seafood score at the top. Other animal foods, like eggs, milk, cheese, poultry and meat, typically score in the middle. Processed foods rich in refined grains and sugars, like refined cereals, breads, crackers and energy bars, and processed meats fall at the bottom. </p>
<p>We found Food Compass to be especially useful <a href="https://doi.org/10.1038/s43016-021-00381-y">when comparing seemingly similar food items</a>, like different breads, different desserts or different mixed meals. Food Compass also appears to work better than existing rating systems for certain food groups. </p>
<p>For example, it gives lower scores to processed foods that are rich in refined grains and starch and to low-fat processed foods that are often marketed as healthy, like deli meats and hot dogs, fat-free salad dressings, pre-sweetened fruit drinks, energy drinks and coffees. It also gives higher scores to foods rich in unsaturated oils, like nuts and olive oil. Compared with older rating systems, these improvements are more aligned with the latest science on the health effects of these foods.</p>
<p>We also assessed how Food Compass <a href="https://doi.org/10.1038/s41467-022-34195-8">relates to major health outcomes</a> in people. In a national sample of 48,000 Americans, we calculated each person’s individual Food Compass score, ranging from 1 to 100, based on the different foods and beverages they reported eating.</p>
<p>We found that people whose diets scored higher according to Food Compass <a href="https://doi.org/10.1038/s41467-022-34195-8">had better overall health</a> than those with lower scores. This includes less obesity, better blood sugar control, lower blood pressure and better blood cholesterol levels. They also had a lower risk of metabolic syndrome or cancer and a lower risk of death from all causes. For every 10-point higher Food Compass score, a person had about a 7% lower risk of dying. These are important findings, showing that, on average, eating foods with higher Food Compass scores is linked to numerous improved health outcomes.</p>
<h2>Fine-tuning</h2>
<p>While we believe Food Compass represents a significant advance over existing systems, more work is needed before it can be rolled out to consumers.</p>
<p>As one step, we’re investigating how the scoring algorithm can be further improved. For example, we’re considering the most appropriate scoring for food items like certain cereals that are high in whole grains and fiber but are also processed and have added sugar. And we’re looking at the scoring of different egg, cheese, poultry and meat products, which have a wide range of scores but sometimes score a bit lower than may make intuitive sense.</p>
<p>Over the coming year we will be refining and improving the system based on our research, the latest evidence and feedback from the scientific community.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/sNCQJWIFvRw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Whole grains are much better for you than refined grains.</span></figcaption>
</figure>
<p>In addition, more research is needed on how a consumer might understand and use Food Compass in practice. For example, it could be added as a <a href="https://www.ncbi.nlm.nih.gov/books/NBK209847/">front-of-pack label</a> – but would that be helpful without more education and context?</p>
<p>Also, while the scoring system ranges from 1 to 100, could it be more accessible if scores were grouped into broader categories? For instance, might a green/yellow/red traffic light system be easier to understand? </p>
<p>And we’re hoping that future Food Compass versions might contain additional criteria to filter foods for people who follow special diets, such as low-carb, paleo, vegetarian, diabetic-friendly, low-sodium and others.</p>
<h2>The big picture</h2>
<p>Food Compass should not be used to replace food-based dietary guidelines and preferences. Raspberries and asparagus score really well – but a diet of only these foods would not be very healthy. People should seek a <a href="https://www.myplate.gov/">balanced diet</a> across different food groups. </p>
<p>To help, Food Compass may be most useful to compare similar products within a food group. For example, someone who prefers eggs for breakfast can look for higher-scoring egg dishes. Those preferring cereal can look for higher-scoring cereals. And even better, Food Compass can help people add other highest-scoring foods to their plate – like veggies and healthy oils to eggs, and fruit and nuts to cereal – to increase the overall health benefits of that meal.</p>
<p>To make use by others as easy as possible, <a href="https://sites.tufts.edu/foodcompass/publications/">we’ve published</a> all the details of the scoring algorithm, and the scores of the products evaluated, so that anyone can take what we’ve done and use it. </p>
<p>Stay tuned – as we complete <a href="https://sites.tufts.edu/foodcompass/research/our-work/">additional research</a>, we believe Food Compass will become an important tool to clear up confusion in the grocery store and help people make healthier choices.</p><img src="https://counter.theconversation.com/content/192831/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dariush Mozaffarian has received research funding from the National Institutes of Health, the Gates Foundation, The Rockefeller Foundation, Vail Innovative Global Research, and the Kaiser Permanente Fund at East Bay Community Foundation; personal fees from Acasti Pharma and Barilla; serves on the scientific advisory board of Beren Therapeutics, Brightseed, Calibrate, Elysium Health, Filtricine, HumanCo, Instacart, January Inc., Perfect Day, Tiny Organics, and (ended) Day Two, Discern Dx, and Season Health; owns stock in Calibrate and HumanCo; and receives chapter royalties from UpToDate. </span></em></p><p class="fine-print"><em><span>Jeffrey B. Blumberg has received research funding from Danone S.A. and USDA and serves on the scientific advisory boards of Advocare International, American Botanical Council, Blueshift Nutrition, Bragg Live Food Products LLC, California Prune Board, California Walnut Commission, Cranberry Institute, Good Pharma LLC, Everly Health, Guiding Stars Licensing Co, January.ai Inc, Segterra Inc, SmartyPants Vitamins, and Vital Technologies Ltd.</span></em></p><p class="fine-print"><em><span>Paul F. Jacques currently receives research funding from the US Department of Agriculture Agricultural Research Service, the National Institutes of Health, and the Institute for the Advancement of Food and Nutrition Science, and has previously received research funding from Danone Nutricia Research. Dr. Jacques is a member of the Danone North America Essential Dairy and Plant-Based Advisory Board, the Grains for Health Foundation Scientific Advisory Committee, and the Bay State Milling Nutrition and Science Advisory Council. </span></em></p><p class="fine-print"><em><span>Renata Micha has received research funding from the National Institute of Health, Gates Foundation and Danone S.A. Dr. Micha is the Chair of the Independent Expert Group for the Global Nutrition Report. </span></em></p>The Food Compass system scores foods based on variables like the amounts of refined grains and sugars, processing and healthful ingredients. People who ate better-scoring foods had better overall health.Dariush Mozaffarian, Dean of Friedman School of Nutrition Science and Policy, Tufts UniversityJeffrey B. Blumberg, Professor Emeritus in Nutrition Science and Policy, Tufts UniversityPaul F. Jacques, Professor of Nutrition Science and Policy, Tufts UniversityRenata Micha, Associate Professor in Human Nutrition, Tufts UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1932382022-10-27T15:28:22Z2022-10-27T15:28:22ZFermented foods and fibre may lower stress levels – new study<figure><img src="https://images.theconversation.com/files/492088/original/file-20221027-18659-el39uc.jpg?ixlib=rb-1.1.0&rect=0%2C9%2C6016%2C3998&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Foods such as kimchi are great to include in a psychobiotic diet.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/kimchi-cabbage-cucumber-radish-jar-korean-1543686266">Nungning20/ Shutterstock</a></span></figcaption></figure><p>When it comes to dealing with stress, we’re often told the best things we can do are exercise, make time for our favourite activities or try meditation or mindfulness. </p>
<p>But the kinds of foods we eat may also be an effective way of dealing with stress, according to research published by me and other members of <a href="https://www.ucc.ie/en/apc/">APC Microbiome Ireland</a>. Our latest study has shown that eating more fermented foods and fibre daily for just four weeks had a significant effect on lowering <a href="https://www.nature.com/articles/s41380-022-01817-y">perceived stress levels</a>. </p>
<p><a href="https://www.nature.com/articles/s41579-019-0256-8">Over the last decade</a>, a growing body of research has shown that diet can have a <a href="https://www.nature.com/articles/s41380-021-01360-2">huge impact on our mental health</a>. In fact, a healthy diet may even reduce the risk of <a href="https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-017-0791-y">many common mental illnesses</a>. </p>
<p>The mechanisms underpinning the effect of diet on mental health are still not fully understood. But one explanation for this link could be via the relationship between our brain and our microbiome (the trillions of bacteria that live in our gut). Known as the <a href="https://psychscenehub.com/psychinsights/the-simplified-guide-to-the-gut-brain-axis/">gut-brain axis</a>, this allows the brain and gut to be in constant communication with each other, allowing essential body functions such as digestion and appetite to happen. It also means that the emotional and cognitive centres in our brain are closely connected to our gut.</p>
<p>While previous research has shown stress and behaviour are also <a href="https://www.sciencedirect.com/science/article/pii/S2352289516300509">linked to our microbiome</a>, it has been unclear until now whether changing diet (and therefore our microbiome) could have a distinct effect on stress levels. </p>
<p>This is what our study set out to do. To test this, we recruited 45 healthy people with relatively low-fibre diets, aged 18–59 years. More than half were women. The participants were split into two groups and randomly assigned a diet to follow for the four-week duration of the study.</p>
<figure class="align-center ">
<img alt="A bowl of slices apples." src="https://images.theconversation.com/files/492089/original/file-20221027-20344-nhnm85.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492089/original/file-20221027-20344-nhnm85.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492089/original/file-20221027-20344-nhnm85.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492089/original/file-20221027-20344-nhnm85.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492089/original/file-20221027-20344-nhnm85.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492089/original/file-20221027-20344-nhnm85.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492089/original/file-20221027-20344-nhnm85.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">Participants were told to eat foods high in prebiotic fibres, such as apples.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/fresh-red-apples-sliced-bowl-on-1366904762">gowithstock/ Shutterstock</a></span>
</figcaption>
</figure>
<p>Around half were assigned a diet designed by nutritionist Dr Kirsten Berding, which would increase the amount of prebiotic and fermented foods they ate. This is known as a <a href="https://www.ucc.ie/en/research/spotlight/thepsychobioticrevolution/">“psychobiotic” diet</a>, as it included foods that have been linked to better mental health.</p>
<p>This group was given a one-on-one education session with a dietitian at both the start and halfway through the study. They were told they should aim to include 6-8 servings daily of fruits and vegetables high in prebiotic fibres (such as onions, leeks, cabbage, apples, bananas and oats), 5-8 servings of grains per day, and 3-4 servings of legumes per week. They were also told to include 2-3 servings of fermented foods daily (such as sauerkraut, kefir and kombucha). Participants on the control diet only received general dietary advice, based on the healthy eating <a href="https://www.hse.ie/eng/about/who/healthwellbeing/our-priority-programmes/heal/healthy-eating-guidelines/">food pyramid</a>. </p>
<h2>Less stress</h2>
<p>Intriguingly, those who followed the psychobiotic diet reported they felt less stressed compared with those who followed the control diet. There was also a direct correlation between how strictly participants followed the diet and their perceived stress levels, with those who ate more psychobiotic foods during the four-week period reporting the greatest reduction in perceived stress levels.</p>
<p>Interestingly, the quality of sleep improved in both groups – though those on the psychobiotic diet reported greater improvements in sleep. Other studies have also shown that gut microbes are implicated in <a href="https://www.sciencedirect.com/science/article/pii/S1471491421001854">sleep processes</a>, which may explain this link. </p>
<p>The psychobiotic diet only caused subtle changes in the composition and function of microbes in the gut. However, we observed significant changes in the level of certain key chemicals produced by these gut microbes. Some of these chemicals have been <a href="https://www.sciencedirect.com/science/article/pii/S0149763421001032">linked to mental health</a>, which could potentially explain why participants on the diet reported feeling less stressed.</p>
<p>Our results suggest specific diets can be used to reduce perceived stress levels. This kind of diet may also help to <a href="https://academic.oup.com/advances/article/12/4/1239/6164875?login=true">protect mental health</a> in the long run as it targets the microbes in the gut.</p>
<p>While these results are encouraging, our study is not without its limitations. First, the sample size is small due to the pandemic restricting recruitment. Second, the short duration of the study could have limited the changes we observed – and it’s unclear how long they would last. As such, long-term studies will be needed. </p>
<p>Third, while participants recorded their daily diet, this form of measurement can be susceptible to error and bias, especially when estimating food intake. And while we did our best to ensure participants didn’t know what group they’d been assigned to, they may have been able to guess based on the nutrition advice they were given. This may have affected the responses they gave at the end of the study. Finally, our study only looked at people who were already healthy. This means we don’t understand what effect this diet could have on someone who may not be as healthy. </p>
<p>Still, our study offers exciting evidence that an effective way to reduce stress may be through diet. It will be interesting to know if these results can also be replicated in people suffering from stress-related disorders, such as anxiety and depression. It also adds further evidence to this <a href="https://www.sciencedirect.com/science/article/pii/S0924977X19317237">field of research</a>, showing evidence of an association between diet, our microbiome and our mental health. </p>
<p>So the next time you’re feeling particularly stressed, perhaps you’ll want to think more carefully about what you plan on eating for lunch or dinner. Including more fibre and fermented foods for a few weeks may just help you feel a little less stressed out.</p><img src="https://counter.theconversation.com/content/193238/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Cryan receives funding from Science Foundation Ireland (SFI), Irish Research Council and the Health Research Board. He also receives funding from the Saks-Kavanaugh Foundation. The author receives research funding, has been a consultant and been on the Speakers Bureau of food and pharmaceutical companies in the microbiome, food and neuroscience arena.
</span></em></p>Our latest study adds further evidence that diet and mental health are closely connected.John Cryan, Vice President for Research & Innovation, University College CorkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1903482022-10-25T22:43:45Z2022-10-25T22:43:45ZWhat are postbiotics and how can they improve our gut health?<figure><img src="https://images.theconversation.com/files/490282/original/file-20221018-22859-g3xky2.jpg?ixlib=rb-1.1.0&rect=0%2C26%2C4493%2C2964&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/photograph-of-a-person-s-hand-picking-vegetables-7341749/">Photo by Alesia Kozik/Pixabay</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Many of us are familiar with probiotics, such as certain yogurts and fermented foods, full of “good” bacteria that can keep the gut healthy.</p>
<p>You might even have heard of prebiotics, foods rich in complex carbohydrates (dietary fibre) that help foster good bacteria in the large intestine. Popular prebiotic foods include oats, nuts and legumes.</p>
<p>But what about postbiotics? What are they and how do they affect our gut health?</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-should-you-eat-after-youve-been-on-antibiotics-and-can-probiotics-and-prebiotics-get-your-gut-back-to-normal-163363">What should you eat after you've been on antibiotics? And can probiotics and prebiotics get your gut back to normal?</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/489713/original/file-20221014-17-cmyp4e.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C1917%2C1267&q=45&auto=format&w=1000&fit=clip"><img alt="A colourful display of fruits and vegetables." src="https://images.theconversation.com/files/489713/original/file-20221014-17-cmyp4e.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C1917%2C1267&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/489713/original/file-20221014-17-cmyp4e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/489713/original/file-20221014-17-cmyp4e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/489713/original/file-20221014-17-cmyp4e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/489713/original/file-20221014-17-cmyp4e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/489713/original/file-20221014-17-cmyp4e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/489713/original/file-20221014-17-cmyp4e.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">A diet rich in vegetables and fruits increases the levels of prebiotics in your body.</span>
<span class="attribution"><a class="source" href="https://pixabay.com/photos/fruit-vegetables-market-stall-428057/">Image by Michal Jarmoluk from Pixabay</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>What is a postbiotic?</h2>
<p>Postbiotics are essentially the by-products of our gut microbiota. In other words, your body <a href="https://www.health.harvard.edu/nutrition/what-are-postbiotics#:%7E:text=So%2C%20what%20are%20postbiotics%3F,the%20growth%20of%20harmful%20bacteria">produces postbiotics</a> <em>after</em> digesting prebiotic and probiotic foods.</p>
<p>Examples of postbiotics include the short-chain fatty acids butyric acid (or butyrate), acetic acid (or acetate) and propionic acid (or propionate).</p>
<p>These molecules are produced when good probiotic bacteria break down dietary fibre from foods such as fruits and vegetables, grains and legumes.</p>
<p>These postbiotic molecules are important for your gut microbiota. Healthy probiotic bacteria thrive on these short-chain fatty acids in our gut. </p>
<p>And some postbiotics can help suppress “bad” bacteria. For example, probiotic bacteria (such as <em>Lactococcus lactis</em>) produce special chemicals called bacteriocins which can <a href="https://www.sciencedirect.com/science/article/pii/S1040842821002171">prevent</a> the colonisation of pathogens like <em>E. coli</em> in the gut. This process is known as “colonisation resistance”.</p>
<p>Microbial fermentation is where microbes in the gut break down complex carbohydrates. Microbial fermentation of <a href="https://pubs.acs.org/doi/pdf/10.1021/acs.jafc.8b04102">plant-based diets</a> (which are rich in polyphenols), in particular, leads to the production of the postbiotic phenylacetic acid. This postbiotic can reduce the growth of harmful <a href="https://academic.oup.com/pcp/article/60/2/243/5289543?login=true">pathogens</a> in the body.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/489716/original/file-20221014-20-oy88m9.jpg?ixlib=rb-1.1.0&rect=0%2C26%2C5991%2C3961&q=45&auto=format&w=1000&fit=clip"><img alt="A customers holds a shopping bag while looking at vegetables." src="https://images.theconversation.com/files/489716/original/file-20221014-20-oy88m9.jpg?ixlib=rb-1.1.0&rect=0%2C26%2C5991%2C3961&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/489716/original/file-20221014-20-oy88m9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/489716/original/file-20221014-20-oy88m9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/489716/original/file-20221014-20-oy88m9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/489716/original/file-20221014-20-oy88m9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/489716/original/file-20221014-20-oy88m9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/489716/original/file-20221014-20-oy88m9.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">A plant-rich diet is good for postbiotic production.</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/unrecognizable-customer-near-greens-in-supermarket-7129141/">Photo by Michael Burrows/Pexels</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Not all postbiotics are good</h2>
<p>Not all postbiotics are heroes, though.</p>
<p>One type of postbiotic is bile acids, which are produced when we eat too many <a href="https://journals.lww.com/co-gastroenterology/Fulltext/2014/05000/Bile_acids_and_the_gut_microbiome.18.aspx">high-fat foods</a>.</p>
<p>Bile acids have been linked to <a href="https://www.nature.com/articles/s41385-019-0162-4">inflammation</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7225675/">colon cancer</a>.</p>
<p>Staying on a high-protein, low-carbohydrate diet for the long term often means people don’t eat enough fibre, which is linked to a <a href="https://academic.oup.com/ajcn/article/93/5/1062/4597729">higher risk</a> of colon cancer.</p>
<p>This may be due to the production of <a href="https://academic.oup.com/ajcn/article/93/5/1062/4597729">hazardous postbiotics</a> like bile acids.</p>
<h2>What’s the link between postbiotics and cancer?</h2>
<p>Our recent <a href="https://www.tandfonline.com/doi/full/10.1080/19490976.2022.2038865">review</a> (led by my colleague Kayla Jaye at Western Sydney University) found short-chain fatty acids – particularly butyrate – have shown promising results against breast and colorectal cancer cells in previous laboratory studies.</p>
<p>One clinical <a href="https://iopscience.iop.org/article/10.1088/1742-6596/1146/1/012037/pdf">study</a> showed colorectal cancer patients produced significantly lower levels of short-chain fatty acids in their gut than healthy participants.</p>
<p>Another <a href="https://link.springer.com/article/10.1007/s10096-020-04036-x">study</a> found the numbers of bacteria that produce short-chain fatty acids were low in premenopausal breast cancer patients. </p>
<p>Some cellular and animal <a href="https://www.mdpi.com/1422-0067/23/16/9490/htm">studies</a> have also reported that the postbiotic butyrate can help chemotherapy work better against breast cancer and regulate the immune system.</p>
<p>As <a href="https://academic.oup.com/ajcn/article/93/5/1062/4597729">reported</a> in epidemiological studies, a fibre-rich diet, particularly whole grains, can lower the risk of colorectal cancer. This is mainly because fibre-rich diets lead to the production of short-chain fatty acids in the colon.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/490285/original/file-20221018-15124-ybay5v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two bags of legumes sit on a kitchen bench." src="https://images.theconversation.com/files/490285/original/file-20221018-15124-ybay5v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/490285/original/file-20221018-15124-ybay5v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490285/original/file-20221018-15124-ybay5v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490285/original/file-20221018-15124-ybay5v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490285/original/file-20221018-15124-ybay5v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490285/original/file-20221018-15124-ybay5v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490285/original/file-20221018-15124-ybay5v.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 best way to improve the levels of good postbiotics is to consume more vegetables, fruits, legumes, wholegrain bread, nuts and seeds.</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/high-angle-shot-of-cereal-and-beans-inside-of-white-plastic-5843562/">Photo by Karolina Grabowska/Pexels</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>OK great, so what do I eat to get more postbiotics in my gut?</h2>
<p>Dietary fibre is the key. </p>
<p>Women and men should consume at least <a href="https://www.monash.edu/medicine/ccs/gastroenterology/prebiotic/faq">25 and 30 grams</a> of fibre, respectively, every day. But few Australians meet this recommendation. </p>
<p>The best way to improve the levels of good postbiotics is to consume more vegetables, fruits, legumes, wholegrain bread, nuts and seeds.</p>
<p>Jerusalem artichokes, garlic, onion, leek and asparagus are fantastic prebiotic vegetables.</p>
<p>A diet rich in fruits and vegetables increases the levels of postbiotics like short-chain fatty acids in the gut. It also helps reduce <a href="https://journals.asm.org/doi/10.1128/msystems.01174-21">bile acids</a>.</p>
<p>Gut health is all about diversity, which means eating a variety of fruits, vegetables, legumes and whole grains to support healthy gut microbiota. </p>
<p>You can also include fermented foods like sauerkraut and kimchi in your diet. These fermented foods have both prebiotic fibre and live probiotic bacteria, which can help produce healthy postbiotics in the gut. </p>
<p>Of course, further research is needed. But to ensure good gut health, you should include plenty of fruits, vegetables and legumes in your diet.</p><img src="https://counter.theconversation.com/content/190348/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Deep Jyoti Bhuyan 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>Your body produces postbiotics after digesting prebiotic and probiotic foods – and many postbiotics are crucial to good gut health.Deep Jyoti Bhuyan, Research Fellow in Healthy Ageing, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1781902022-03-02T15:07:32Z2022-03-02T15:07:32ZWe’re recycling potato skins to make prebiotics: here’s why that’s good for your gut – and the planet<figure><img src="https://images.theconversation.com/files/449316/original/file-20220301-23-by30oc.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/hands-harvesting-fresh-organic-potatoes-soil-203943361">Mjaud/shutterstock</a></span></figcaption></figure><p>It’s an unbelievable tragedy that <a href="https://www.usda.gov/media/blog/2022/01/24/food-waste-and-its-links-greenhouse-gases-and-climate-change">a third</a> of the world’s <a href="https://www.fao.org/fileadmin/templates/nr/sustainability_pathways/docs/FWF_and_climate_change.pdf">food is wasted</a>. To put that in perspective, it would take an area the size of China to grow that much food – and if food waste were a country it would be the world’s third-largest greenhouse gas emitter. </p>
<p>Reducing the amount of food we discard is imperative – it’s a major threat to our climate, food security and the global economy. Everyone can play a role in addressing this problem by <a href="https://www.lovefoodhatewaste.com/">eliminating unnecessary food wastage</a>. But despite our best efforts there will always be some, and it’s really important that we make the best use of it. </p>
<p>One way to approach this goal is to use a food waste management <a href="https://publications.parliament.uk/pa/cm201617/cmselect/cmenvfru/429/42905.htm">hierarchy</a>. The first priority is to minimise waste (for example by using up leftovers or buying wonky fruit and veg) or to redistribute unavoidable waste to hungry people or animals. </p>
<p>But a large amount of food waste is inedible – either because it has gone off, become contaminated, or is an inedible co-product of the food industry such as onion skins or cocoa bean shells. These products are then either recycled for relatively low value purposes (such as to make fertiliser or generate energy) or disposed of as landfill.</p>
<p>But a new category is emerging in this hierarchy – recycling that retains the value of the food molecules so that they can still be used for their intended purpose of providing health and nutritional benefits. One example of this is the production of prebiotics.</p>
<h2>Food for the gut</h2>
<p>Prebiotics are a group of nutrients (mostly carbohydrates) that are resistant to the acidic conditions found in the human gut and boost the growth of beneficial bacteria. Various types of these non-digestible carbohydrates are found naturally in fruits and vegetables such as asparagus, chicory, jerusalem artichoke, beans, chickpeas, bananas and apples. Human milk is also known to be rich in prebiotic oligosaccharides (a simple sugar), which have been shown to promote a specific group of beneficial gut microorganisms called bifidobacteria. </p>
<p>It has been shown that consuming prebiotics <a href="https://www.sciencedirect.com/science/article/abs/pii/S0924224419303371?via%3Dihub%20%22%22">boosts overall digestive health</a> by improving the absorption of micronutrients such as calcium, changing the rate at which certain foods lead to spikes in blood sugar, and improving the barrier function of the gut.</p>
<p>Most importantly, prebiotics support the immune system by increasing the number of protective microorganisms in the gut and decreasing harmful bacteria. And the benefits don’t stop there – the growth of healthy bacteria that use prebiotics as their source of energy leads to the production of small molecules called short-chain fatty acids, which enter blood circulation <a href="https://www.nature.com/articles/nrgastro.2017.75">and benefit</a> the immune, cardiovascular and central nervous system.</p>
<figure class="align-center ">
<img alt="Variety of prebiotic foods for gut health" src="https://images.theconversation.com/files/449299/original/file-20220301-17-1ssq861.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/449299/original/file-20220301-17-1ssq861.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/449299/original/file-20220301-17-1ssq861.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/449299/original/file-20220301-17-1ssq861.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/449299/original/file-20220301-17-1ssq861.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/449299/original/file-20220301-17-1ssq861.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/449299/original/file-20220301-17-1ssq861.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 fruits, vegetables and wholegrains are sources of prebiotics.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/variety-prebiotic-foods-gut-health-keto-1115657315">SewCream/shutterstock</a></span>
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<p>Although prebiotics naturally exist in foods, they are usually found in low quantities. That’s why scientists are looking into alternative ways to make them on a large scale so that they can be used as supplements or to fortify existing food products. </p>
<h2>Making prebiotics from food waste</h2>
<p>Most prebiotic oligosaccharides for supplements are produced commercially using enzymes, which are biological catalysts that speed up the rate of chemical reactions. Enzymes may work in various ways, from breaking down large carbohydrates into prebiotic oligosaccharides, to synthesising oligosaccharides from simple sugars such as glucose and galactose. </p>
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Read more:
<a href="https://theconversation.com/we-throw-away-a-third-of-the-food-we-grow-heres-what-to-do-about-waste-165997">We throw away a third of the food we grow – here’s what to do about waste</a>
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<p>But nowadays several industries are shifting their focus to synthesise nutrients in a sustainable way by using microorganisms or enzymes that grow on food industry waste – or by developing technologies that are more environmentally friendly. </p>
<p>There is some evidence that pectin oligosaccharides, which have been produced from carbohydrates extracted from certain food waste such as potato peel, could be used to make a prebiotic – but so far it has only been done on a <a href="https://pubmed.ncbi.nlm.nih.gov/25641325/">small scale</a> within a lab setting. </p>
<p>These carbohydrates couldn’t be extracted from food waste using existing industrial-scale processes, meaning that until now it hasn’t been possible to produce large enough quantities of pectin oligosaccharides from food waste to test their prebiotic properties in human trials. This was a major stumbling block, so since 2016 we have been working to develop a new process to extract the target carbohydrates <a href="https://www.sciencedirect.com/science/article/pii/S1385894720310482">from potato waste</a> on a large scale. </p>
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<p>The process uses microwave technology – and as it is electrically powered it means that they can use renewable energy sources rather than relying on burning fossil fuels. Unlike similar industrial-scale extraction processes which use acids to extract target molecules, our process uses only water as the solvent. The water diffuses into the plant material, where the pectins are released from the plant cell wall and dissolve into the water. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/five-ways-to-cut-down-on-food-waste-and-why-it-matters-171347">Five ways to cut down on food waste – and why it matters</a>
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<p>So, we are now able to extract sufficient quantities of pectin oligosaccharides to test their prebiotic activity – and we’re using a number of different food waste materials in addition to potato waste, such as sugar beet pulp and apple pomace, which are significant co-products of the UK food industry. And the best part is that we only use electrical power and water – no fossil energy and no toxic chemicals. </p>
<p>With this new technology, we hope to produce a new range of novel prebiotic products. That will be good for our health, and help us to reduce the impact of food waste on the environment too.</p><img src="https://counter.theconversation.com/content/178190/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Eleanor Binner received funding from the Biotechnology and Biological Research Council and the Engineering and Physical Sciences Reserach Council to carry out the work reported here.</span></em></p><p class="fine-print"><em><span>Dr Afroditi Chatzifragkou has previously worked on BBSRC and Innovate UK funded projects on the valorisation of vegetable by-products for food ingredients.</span></em></p>Our new technology to recycle food waste into prebiotics uses no toxic chemicals and no fossil fuels.Eleanor Binner, Associate Professor in Chemical Engineering, University of NottinghamAfroditi Chatzifragkou, Associate Professor in Sustainable Bioprocessing, University of ReadingLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1633632021-07-19T01:13:10Z2021-07-19T01:13:10ZWhat should you eat after you’ve been on antibiotics? And can probiotics and prebiotics get your gut back to normal?<figure><img src="https://images.theconversation.com/files/411348/original/file-20210715-15-ogr7wi.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/probiotic-fermented-food-theme-bowl-greek-1317374771">Shutterstock</a></span></figcaption></figure><p>Antibiotics <a href="https://www.nps.org.au/consumers/antibiotics-explained">treat infections</a> caused by bacteria. But they can also destroy the good bacteria in your gut. For some people, this results in an upset stomach and diarrhoea. </p>
<p>One <a href="https://pubmed.ncbi.nlm.nih.gov/32958481/">UK review of the research</a> looked at changes in gut bacteria after antibiotics commonly prescribed for respiratory and urinary tract infections found that after treatment, the numbers and diversity in bacteria types rapidly declines. </p>
<p>It also found some types of “bad” microorganisms increased while some “good” ones decreased. </p>
<p>For most people, once antibiotic treatment was stopped, the <a href="https://pubmed.ncbi.nlm.nih.gov/32958481/">gut bacteria recover</a> to some degree. But <a href="https://pubmed.ncbi.nlm.nih.gov/31629863/">other studies suggest</a> some antibiotics can have long-lasting effects on the balance of microorganisms.</p>
<p>It’s important to use antibiotics only when needed, and definitely not for viral infections, because antibiotics can’t kill viruses such as the common cold or COVID-19.</p>
<p>So what should you eat after a course of antibiotics? You might have heard of probiotics and prebiotics, but what are they, and what evidence is there to show they’re beneficial?</p>
<h2>Probiotics contain ‘good gut bacteria’</h2>
<p><a href="https://en.wikipedia.org/wiki/Probiotic">Probiotics</a> are foods, typically yoghurts and yoghurt drinks, that contain “good gut bacteria”: live microorganisms that can recolonise the gut or improve your gut health. </p>
<p>To be called a probiotic, they <a href="https://pubmed.ncbi.nlm.nih.gov/26443321/">must be</a> able to resist stomach acid and digestive processes, and then be able adhere to the gut walls and grow, while not causing any issues for the gut wall. They must also be tested for safety and efficacy in controlled trials.</p>
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Read more:
<a href="https://theconversation.com/plain-greek-low-fat-how-to-choose-a-healthy-yoghurt-94295">Plain, Greek, low-fat? How to choose a healthy yoghurt</a>
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<p>To be called a probiotic, the dose of microorganisms needs to be sufficient to help restore the “good” bacteria, by elbowing out the “bad bacteria”. </p>
<p>Most yoghurts contain “good bacteria” but not all can survive the acidity of the stomach acid or the bacteria won’t grow in the bowel, so there is no probiotic benefit. </p>
<p>For probiotics to exert these beneficial effects, they not only have to make it to the large bowel, but once there they need the right fuel to help them grow well. That’s where prebiotics come into play – but more on them shortly. </p>
<h2>What does the science say about probiotics?</h2>
<p>Probiotics are widely promoted as being good for your overall health. The science on that <a href="https://pubmed.ncbi.nlm.nih.gov/32498430/">has been mixed</a>, but it does suggest people who are likely to get diarrhoea after antibiotics may benefit from consuming them. </p>
<p>One <a href="https://pubmed.ncbi.nlm.nih.gov/29257353/">review of the evidence</a> found probiotics may be useful for those at high risk of antibiotic-associated diarrhoea, such as the elderly and people in hospital. </p>
<figure class="align-center ">
<img alt="Woman in supermarket looks at the packaging of a yoghurt container." src="https://images.theconversation.com/files/411779/original/file-20210718-23-1wkz81t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/411779/original/file-20210718-23-1wkz81t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=383&fit=crop&dpr=1 600w, https://images.theconversation.com/files/411779/original/file-20210718-23-1wkz81t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=383&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/411779/original/file-20210718-23-1wkz81t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=383&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/411779/original/file-20210718-23-1wkz81t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=481&fit=crop&dpr=1 754w, https://images.theconversation.com/files/411779/original/file-20210718-23-1wkz81t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=481&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/411779/original/file-20210718-23-1wkz81t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=481&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Most yoghurts contain good bacteria but can’t survive the acidity of the stomach.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/portrait-interested-elderly-woman-shopping-supermarket-1979903105">Shutterstock</a></span>
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<p>The review found side effects were common when taking antibiotics and include taste disturbances, nausea, abdominal cramping, soft stools, fever and flatulence. </p>
<p>But people taking probiotics reported fewer side effects, suggesting they may be helpful in countering some of the side effects. </p>
<h2>So what are prebiotics?</h2>
<p><a href="https://en.wikipedia.org/wiki/Prebiotic_(nutrition)">Prebiotics are compounds that</a> help beneficial gut microorganisms grow and survive. </p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/26443321/">Prebiotic foods</a> contain complex carbohydrates that can’t be digested and dietary fibres that resist digestive processes in the stomach and small intestine. </p>
<p>They pass undigested into the large bowel where they are fermented by the healthy “good” bacteria. </p>
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Read more:
<a href="https://theconversation.com/gut-feeling-how-your-microbiota-affects-your-mood-sleep-and-stress-levels-65107">Gut feeling: how your microbiota affects your mood, sleep and stress levels</a>
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<p>To be called a prebiotic, they need to undergo the processes above, and be shown in clinical trials to <a href="https://pubmed.ncbi.nlm.nih.gov/26443321/">selectively improve</a> the microorganism composition in the gut.</p>
<p>Not all dietary fibres are prebiotic. <a href="https://pubmed.ncbi.nlm.nih.gov/33809763/">Common ones include</a> complex carbohydrates called fructo-oligosaccharides, inulin and resistant starch. </p>
<p>You can find foods at the supermarket with added prebiotics, but non-digestible carbohydrates occur naturally in many everyday foods, <a href="https://www.monash.edu/medicine/ccs/gastroenterology/prebiotic/faq">including</a>:</p>
<ul>
<li><p><strong>grains:</strong> barley, rye bread, rye crackers, pasta, gnocchi, couscous, wheat bran, wheat bread, oats</p></li>
<li><p><strong>legumes:</strong> chickpeas, lentils, red kidney beans, baked beans, soybeans </p></li>
<li><p><strong>vegetables:</strong> artichokes, asparagus, beetroot, chicory, fennel bulb, garlic, green peas, leek, onion, shallots, spring onion, snow peas, sweetcorn, savoy cabbage</p></li>
<li><p><strong>fruit:</strong> nectarines, white peaches, persimmon, tamarillo, watermelon, rambutan, grapefruit, pomegranate, dates, figs</p></li>
<li><p><strong>nuts:</strong> cashews, pistachios.</p></li>
</ul>
<figure class="align-center ">
<img alt="Large bowl of mixed bean salad." src="https://images.theconversation.com/files/411780/original/file-20210718-25-1idcnt7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/411780/original/file-20210718-25-1idcnt7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/411780/original/file-20210718-25-1idcnt7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/411780/original/file-20210718-25-1idcnt7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/411780/original/file-20210718-25-1idcnt7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/411780/original/file-20210718-25-1idcnt7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/411780/original/file-20210718-25-1idcnt7.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">
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<span class="caption">Prebiotics can be found in a range of foods, including legumes.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/five-bean-salad-226518142">Shutterstock</a></span>
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<p>Additional sources of resistant starch include under-ripe bananas, cooked and cooled rice, cornflour, cooked and cooled potatoes. </p>
<p>For babies, breast milk is naturally rich in oligosaccharides. </p>
<h2>So who should have them?</h2>
<p>Prebiotic foods are good for everyone, contain a range of nutrients and help promote a healthy bacterial gut environment. </p>
<p>The benefits of <em>probiotics</em> for a range of health conditions are unclear – they’re likely to be small, and depend on what is being taken and the underlying health issues. </p>
<p>But people at high risk of diarrhoea after antibiotics may benefit from consuming probiotic – as well as prebiotic – foods daily. </p>
<p>There is also emerging evidence that <a href="https://pubmed.ncbi.nlm.nih.gov/26443321/">combining specific probiotics and prebiotics</a> can increase the beneficial effects of both. Both the pro- and prebiotics could be added to the one food, termed a “synbiotic”, or they could be from separate sources but eaten together. </p>
<p>When it comes to antibiotics, the bottom line is only take them when prescribed for bacterial infections. Take them according to instructions from the manufacturer, your pharmacist and your doctor.</p>
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Read more:
<a href="https://theconversation.com/health-check-what-happens-when-you-hold-in-a-fart-98310">Health Check: what happens when you hold in a fart?</a>
</strong>
</em>
</p>
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<img src="https://counter.theconversation.com/content/163363/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 has received research grants from NHMRC, ARC, MRFF, Hunter Medical Research Institute, Diabetes Australia, Heart Foundation, Bill and Melinda Gates Foundation, nib foundation, Rijk Zwaan Australia, WA Dept. Health, Meat and Livestock 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>Antibiotics can destroy the good bacteria in your gut. But some foods can help get it back to normal.Clare Collins, Laureate Professor in Nutrition and Dietetics, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1390942020-06-21T05:34:02Z2020-06-21T05:34:02ZGut reaction: How the gut microbiome may influence the severity of COVID-19<figure><img src="https://images.theconversation.com/files/340491/original/file-20200609-165357-rmp03n.jpg?ixlib=rb-1.1.0&rect=41%2C83%2C6769%2C5396&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The gut microbiome is the community of micro-organisms living inside the gastrointestinal tract, which performs many beneficial functions, including educating the immune system. </span> <span class="attribution"><span class="source">(Shutterstock))</span></span></figcaption></figure><p>The risk of severe COVID-19 infection is more common in those with high blood pressure, diabetes and obesity, conditions that are all associated with <a href="https://dx.doi.org/10.3390%2Fmedsci6020032">changes to the composition of the gut microbiome — the community of bacteria, viruses and fungi that live in the intestines</a>. This raises the question of whether the gut microbiome has a role in dictating COVID-19 severity.</p>
<p>Let’s recap what we know about COVID-19. <a href="https://doi.org/10.1038/s41586-020-2012-7">COVID-19 is a new disease</a> caused by a very contagious virus called SARS-CoV-2. </p>
<p>In <a href="https://www.canada.ca/content/dam/phac-aspc/documents/services/publications/diseases-conditions/coronavirus/covid-19-know-the-facts/04-03-02-COVID-Know-The-Facts-EN-04.pdf">most infected individuals</a>, the virus does not cause serious illness. However, it causes a very serious respiratory disease — and even death — in a minority of patients. Through many studies of people with COVID-19 over the past few months, we have learned what <a href="https://www.the-scientist.com/news-opinion/why-some-covid-19-cases-are-worse-than-others-67160">characteristics are more likely to be linked</a> to mild versus severe forms of the disease. </p>
<h2>Who is predisposed to serious COVID-19?</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/341313/original/file-20200611-80789-1ez8z5x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/341313/original/file-20200611-80789-1ez8z5x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/341313/original/file-20200611-80789-1ez8z5x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/341313/original/file-20200611-80789-1ez8z5x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/341313/original/file-20200611-80789-1ez8z5x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/341313/original/file-20200611-80789-1ez8z5x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/341313/original/file-20200611-80789-1ez8z5x.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">
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<span class="caption">Coronavirus causes respiratory infections.</span>
<span class="attribution"><span class="source">(Piqsels)</span></span>
</figcaption>
</figure>
<p><a href="https://doi.org/10.1542/peds.2020-0702">Children</a> and <a href="https://doi.org/10.1016/j.jmii.2020.05.001">young adults</a> are less likely to develop symptomatic COVID-19, although <a href="https://doi.org/10.1056/NEJMc2005073">infection readily occurs in young people</a> with equally <a href="https://doi.org/10.1093/cid/ciaa201">high viral loads</a> in the airway, suggesting that they can certainly infect others. In contrast, people of older age and those with <a href="https://doi.org/10.1016/j.ijid.2020.03.017">pre-existing chronic conditions</a> are highly at risk and very likely develop symptomatic, severe disease. </p>
<p>If we consider the gradient of severity of the disease, children are at one end, and the elderly and patients with chronic conditions are at the other end. </p>
<h2>What conditions are linked to severe COVID-19?</h2>
<p>The information collected by researchers from many countries all points to similar characteristics and health conditions that are more commonly seen in patients with severe disease. These include older age, high blood pressure, diabetes and <a href="https://doi.org/10.1016/S2213-8587(20)30160-1">obesity</a>. </p>
<p>The strength of these associations is even more prominent among younger individuals, as younger patients with <a href="https://doi.org/10.1016/S0140-6736(20)31024-2">obesity</a> and <a href="https://doi.org/10.1016/j.dsx.2020.04.018">diabetes</a> are more likely to have serious disease. </p>
<p>In <a href="http://dx.doi.org/10.1136/bmj.m1966">New York City</a>, 5,279 patients tested positive for COVID-19 between March 1 and April 8, 2020. Of these, 22.6 per cent had diabetes and 35.3 per cent were obese. </p>
<p>Obesity was associated with an increased rate of hospital admission and critical illness. Similar findings were provided by <a href="https://doi.org/10.1101/2020.05.06.20092957">investigators in the United Kingdom</a> about the outbreak in Britain, where obese patients were twice as likely to develop severe disease.</p>
<p>Do these findings raise the possibility that the mechanisms underlying high blood pressure, diabetes and obesity may help explain why these conditions lead to severe COVID-19 disease? Before exploring this question, let’s zoom in on cellular and molecular mechanisms known to be involved in COVID-19 disease.</p>
<h2>How does the body fight COVID-19 infection?</h2>
<p>When the virus enters the body, it mostly goes to the <a href="https://doi.org/10.1038/s41591-020-0868-6">airways</a> and the <a href="https://www.doi.org/10.1126/science.abc1669">gastrointestinal tract</a>. The virus then binds to <a href="https://doi.org/10.1016/j.cell.2020.02.052">specific receptors present</a> on the surface of epithelial cells to enter these cells. Viral replication within the cells leads to cell damage and cell death. This results in the release of specific signalling molecules that alert the local <a href="https://doi.org/10.1038/s41418-020-0530-3">immune system</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/341349/original/file-20200611-80774-4u8yi6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/341349/original/file-20200611-80774-4u8yi6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/341349/original/file-20200611-80774-4u8yi6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/341349/original/file-20200611-80774-4u8yi6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/341349/original/file-20200611-80774-4u8yi6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/341349/original/file-20200611-80774-4u8yi6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/341349/original/file-20200611-80774-4u8yi6.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">Illustration of the initial stage of COVID-19 infection: SARS-CoV-2 virus particles binding to specific receptors on the surface of cells.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Armies of immune cells are then dispatched to initiate an antiviral response. Some of these cells are specialized to locate and identify the virus, while others mount a specific immune attack. The <a href="https://doi.org/10.1038/s41577-020-0311-8">immune response</a> results in the release of cytokines, chemokines and antibodies, which in many cases can defeat the virus, and the patient recovers. </p>
<p>Sometimes the immune system is dangerously at high alert and overreacts. In this case, the immune cells mount an especially strong inflammatory response — one that goes beyond what is required to kill the virus. This extra-strong attack releases cytokines and chemokines on a massive scale throughout the body, resulting in a <a href="https://doi.org/10.1016/j.cytogfr.2020.05.003">cytokine storm</a>, which causes widespread inflammation and tissue damage in patients with severe COVID-19. </p>
<p>One of the reasons for an abnormal, overreactive immune response lies in the gastrointestinal tract. Millions of interactions are constantly occurring between the immune system and trillions of non-dangerous microbes that live within the body. These interactions educate the immune system in how to function and, importantly, in how not to overreact to infectious microbes. Could this help explain why some people are more likely to develop uncontrolled inflammation upon COVID-19 infection?</p>
<h2>Trillions of micro-organisms that call your gastrointestinal tract home</h2>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/341316/original/file-20200611-80758-lnvb8u.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/341316/original/file-20200611-80758-lnvb8u.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=777&fit=crop&dpr=1 600w, https://images.theconversation.com/files/341316/original/file-20200611-80758-lnvb8u.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=777&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/341316/original/file-20200611-80758-lnvb8u.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=777&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/341316/original/file-20200611-80758-lnvb8u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=977&fit=crop&dpr=1 754w, https://images.theconversation.com/files/341316/original/file-20200611-80758-lnvb8u.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=977&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/341316/original/file-20200611-80758-lnvb8u.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=977&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">You’ve got a trillion friends in low places: bacteria in the gut may protect against viruses by signalling their presence to the immune system.</span>
<span class="attribution"><span class="source">(Piqsels)</span></span>
</figcaption>
</figure>
<p>The gut microbiome is the community of micro-organisms living inside the gastrointestinal tract, mostly in the large bowel. The microbiome contains bacteria, fungi (yeast), viruses and protozoa, all of which contribute to maintaining a balanced ecosystem and human health. These microbes collectively perform many beneficial functions, including educating the immune system. </p>
<p>When studying the microbiome, scientists examine the composition (what is there) and function (what are they doing) of this ecosystem. We have learned that both composition and function of the gut microbiome are important <a href="https://doi.org/10.1016/J.ENG.2017.01.008">features linked to human health</a>. In certain conditions, the balance of the gut microbiome composition and function is disrupted in a way that leads to disease, a phenomenon called microbiome dysbiosis. </p>
<p>There is accumulating evidence from animal and human studies that <a href="https://doi.org/10.1016/j.molcel.2020.03.005">gut microbiome dysbiosis has a causal role</a> in metabolism dysregulation manifested as diabetes and obesity — the risk factors of severe COVID-19 disease. </p>
<h2>Is gut microbiome predisposing patients to severe COVID-19?</h2>
<p>The gut microbiome regulates host defences against viral infections including respiratory viruses, such as <a href="https://doi.org/10.1073/pnas.1019378108">influenza virus</a>. This occurs through the activation of immune antiviral mechanisms and the prevention of excessive inflammation. </p>
<p>Different species of the gut microbiome have pro- or anti-inflammatory properties and play different roles in regulating the immune system. In the context of COVID-19, <a href="https://doi.org/10.1101/2020.04.22.20076091">a recent preprint study (not yet peer reviewed)</a> showed that specific members of the gut microbiome were associated with severe disease and with immune markers known to be elevated in severe disease. The association of these gut bacteria with the immune markers was even higher than that of the known risk factors of COVID-19 severity: age and obesity.</p>
<p>Further work is needed to confirm that pro-inflammatory microbial species can contribute to the immune responses that make severe COVID-19 more likely, but based on what we know about the microbiome, this is certainly a possibility. This also could mean that beneficial gut microbiome species, the type that promote low inflammation, have the potential to prevent or remediate the immune alterations that lead to severe COVID-19.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1258086047415754755"}"></div></p>
<h2>Potential for treatments and prevention</h2>
<p>The research community is working very hard to develop and test <a href="https://doi.org/10.1016/j.immuni.2020.03.007">safe and effective vaccines</a> and treatments against COVID-19. Tapping into the potential of the gut microbiome is another avenue that we can pursue to identify potential <a href="https://doi.org/10.1038/s41564-020-0721-1">safe and affordable probiotics</a> for prevention and treatment. This is not unprecedented in the context of viral respiratory diseases: probiotics and prebiotics can affect the immune response to the <a href="https://doi.org/10.3390/nu9111175">flu vaccine</a>, and may improve outcomes in <a href="https://doi.org/10.3389/fphar.2019.00980">flu-like illnesses</a>. </p>
<p>Until effective treatments are available, “mind your microbes” and maintain a healthy lifestyle.</p><img src="https://counter.theconversation.com/content/139094/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Shirin Moossavi receives funding from Canadian Institute of Health Research.</span></em></p><p class="fine-print"><em><span>Marie-Claire Arrieta receives funding from the Cumming School of Medicine, the Alberta Children Hospital Research Institute, the Snyder Institute of Chronic Diseases, the Canadian Institutes for Health Research, the Sick Kids Foundation, the W. Garfield Weston Foundation, and the Canadian Lung Association. She is affiliated with the University of Calgary. </span></em></p>The disease is more severe in people with obesity, diabetes and hypertension — all conditions linked to changes in the gut microbiome.Shirin Moossavi, Postdoctoral Fellow, International Microbiome Centre, University of CalgaryMarie-Claire Arrieta, Assistant Professor, Physiology, Pharmacology and Pediatrics, University of CalgaryLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/998752018-07-18T11:15:57Z2018-07-18T11:15:57ZProbiotics and prebiotics – is it safe to use them to treat disease?<figure><img src="https://images.theconversation.com/files/228178/original/file-20180718-142414-d62lyt.jpg?ixlib=rb-1.1.0&rect=1%2C0%2C997%2C667&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Bifidobacterium bacteria.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/bacteria-bifidobacterium-grampositive-anaerobic-rodshaped-which-1036394278?src=zqRmphGy9apVidYjjM3H2w-1-2">Kateryna Kon/Shutterstock.com</a></span></figcaption></figure><p>The link between gut microbes and health is now <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4290017/">well established</a>. As a result, researchers have been investigating the effects of probiotics, prebiotics and synbiotics on various diseases. Worryingly, though, they haven’t been reporting on the safety of these treatments – as one would for a drug trial. </p>
<p>A <a href="http://annals.org/aim/article-abstract/2687953/harms-reporting-randomized-controlled-trials-interventions-aimed-modifying-microbiota-systematic">new review</a> of 384 randomised controlled trials, published in Annals of Internal Medicine, found that information on the safety of these supplements is either lacking or not reported.</p>
<p>More than a quarter of the trials (28%) didn’t report any harms data, and safety results weren’t reported in 37% of the studies. Of the studies that did mention harms, 37% used only “generic statements” to describe adverse events, and 16% used “inadequate metrics”, according to the researchers.</p>
<h2>So what?</h2>
<p>But what’s all the fuss about, you might wonder? Aren’t these all natural products that are available in supermarkets and health food shops? Indeed, the two main families of probiotic bacteria, Lactobacillus and Bifidobacterium, are found in many fermented foods, such as sauerkraut, kimchi and yogurt. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/228182/original/file-20180718-142432-m8jd1j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/228182/original/file-20180718-142432-m8jd1j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/228182/original/file-20180718-142432-m8jd1j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/228182/original/file-20180718-142432-m8jd1j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/228182/original/file-20180718-142432-m8jd1j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/228182/original/file-20180718-142432-m8jd1j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/228182/original/file-20180718-142432-m8jd1j.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">Probiotic bacteria are found in fermented foods.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/486286906?src=zqRmphGy9apVidYjjM3H2w-1-40&size=medium_jpg">marekuliasz/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>Prebiotics don’t even contain bacteria, they are merely food on which probiotics feast. They are fibres that can’t be absorbed or broken down by the body, but they nourish friendly bacteria, particularly the Bifidobacteria genus. Bananas, onions, garlic and legumes are natural prebiotic sources. </p>
<p>Synbiotics are foods or supplements that combine probiotics and prebiotics. </p>
<p>Although these products all sound harmless, and may not do any harm to a healthy person, a good clinical trial should always report adverse events (harms). Trials involving these supplements are often in patients who are severely ill or physically vulnerable, such as preterm babies, so the effect of probiotics, prebiotics or synbiotics might be different in these patients.</p>
<p>Several case studies have reported an increased risk of <a href="https://www.ncbi.nlm.nih.gov/pubmed/21029521">fungaemia</a> – the presence of fungi or yeasts in the blood – in people treated with probiotics. This complication is rare and it tends to happen in people with suppressed immune systems, but it is serious. </p>
<p>Probiotics can have serious adverse effects in other vulnerable groups. For example, a 24-year-old woman, who was administered probiotics before aortic valve replacement surgery, developed <a href="https://www.sciencedirect.com/science/article/pii/S1198743X14618838">sepsis</a>.</p>
<p>In the past few years, probiotic use in hospitals has increased greatly. However, there is growing evidence that the use of probiotics in patients with organ failure, compromised immune systems and those whose intestinal barrier mechanisms are impaired increases the risk of infection. </p>
<p>A <a href="https://www.ncbi.nlm.nih.gov/pubmed/18279948">trial in the Netherlands</a>, designed to see whether probiotics could reduce the incidence of infectious complications in patients with severe acute pancreatitis, ended up being investigated after 15 patients died unexpectedly. </p>
<p>A few trials involving probiotics have reported on adverse events in vulnerable groups, such as the elderly, and found no serious harms. But these trials tend to have very <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0113456">low participant numbers</a>, reducing the significance of the claims.</p>
<p>It is clear that there is an urgent need for <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2234554/">standard</a> safety and administration protocols for probiotics in clinical trials.</p>
<p><em>An earlier version of this article stated that the 15 people with pancreatitis who died while taking part in a trial in The Netherlands were given Yakult. This was incorrect. The trial participants were administered a multispecies probiotic preparation, administered enterally (via a tube, directly to the gut). Yakult played no part in the study and none of their products were used in the study. The Conversation UK apologises for this error.</em></p><img src="https://counter.theconversation.com/content/99875/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Amreen Bashir 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>Clinical trials involving probiotics are failing to report on the safety and harms of these treatments.Amreen Bashir, Lecturer in Biomedical Science, Aston UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/990982018-07-10T06:59:47Z2018-07-10T06:59:47ZGut microbes are tiny sensors of your general health<figure><img src="https://images.theconversation.com/files/226709/original/file-20180709-122280-873yid.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Gut microbe composition is fairly similar across a range of diseases.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/709319197?src=EOpvIjrmRApNR067Ofu3eA-1-24&size=medium_jpg">Perception7/Shutterstock.com</a></span></figcaption></figure><p>The number of studies that have found a link between a disease and a specific gut microbiome composition seems to be ever increasing. Until recently, though, almost all these studies have looked at single diseases in isolation. But most people tend to have more than one health complaint at a time – “comorbidities”, in medical parlance. </p>
<p>For our <a href="https://rdcu.be/2Is3">latest study</a>, published in Nature Communications, we studied the gut microbe composition across a range of diseases. What we found surprised us. The kind of microbes (such as <em>Enterobacteriaceae</em>) that increased in one disease, increased in pretty much all 38 diseases studied. Also, some microbes that might be considered to be “healthy gut microbes”, were reduced in all 38 diseases studied. </p>
<p>We used data from the TwinsUK cohort, a unique group of older British twins who have shared their health history, and many biological samples, for over 25 years. They are volunteers who, like all of us who have lived a while, have gathered health problems over time – 96% of the 2,700 who have donated stool samples have one or more health problems.</p>
<p>The most striking finding from our analysis was that the microbes weren’t specific to individual diseases, but rather to the state of general health. From a biological perspective, this makes sense. The environment that each bug likes is quite specific; anything that alters it, even slightly, means some sensitive bugs won’t survive. </p>
<p>For example, the colon is a surprisingly low-oxygen (anaerobic) environment. Many illnesses lead to low level inflammation, which means that tiny blood vessels open and white cells creep out into tissues, including in the gut. White cells use oxygen as a weapon, so oxygen levels in the colon rise. This can be toxic to the normal gut bacteria, which evolved for strictly anaerobic conditions. An example is the friendly (yet frightening sounding) bug <em>Faecalibacteria Prausnitsii</em> which is wiped out in the presence of almost any disease.</p>
<p>The knock-on effect the loss of these friendly microbes has on a person’s health is not yet known. They may simply be markers of good health, or they may actively contribute to good health. If they do contribute to good health, doctors will need to intervene early in the disease process to keep the friendly bugs alive. This might involve taking prebiotics (food for the friendly bugs) and probiotics, side by side. </p>
<p>In the future, researchers may even find a way to isolate your healthy gut bacteria and grow them outside your gut. Once enough have been grown, they could be reintroduced to your gut to boost your health. A personalised combination of healthy gut bacteria may be more likely to survive in your gut than a random implant of any good bacteria.</p>
<h2>Care in the community</h2>
<p>A family of bacteria that increased in all the diseases we looked at was <em>Enterobacteriaceae</em>. These bacteria are adapted to survive in higher oxygen environments than the normal colon, and they include bacteria, such as <em>E. coli</em>, that can make you really ill. They also harbour high numbers of antibiotic-resistant genes. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/226708/original/file-20180709-122274-1ldtl27.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/226708/original/file-20180709-122274-1ldtl27.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=407&fit=crop&dpr=1 600w, https://images.theconversation.com/files/226708/original/file-20180709-122274-1ldtl27.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=407&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/226708/original/file-20180709-122274-1ldtl27.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=407&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/226708/original/file-20180709-122274-1ldtl27.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/226708/original/file-20180709-122274-1ldtl27.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/226708/original/file-20180709-122274-1ldtl27.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">E. coli can survive in higher oxygen environments than the normal colon.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/w/index.php?curid=57721205">CDC/Janice Haney Carr</a></span>
</figcaption>
</figure>
<p>Bacteria can pass special genes between each other (<a href="https://theconversation.com/new-gene-transfer-rules-could-help-prevent-spread-of-antibiotic-resistance-99071">horizontal gene transfer</a>) to survive an antibiotic onslaught. So if it turns out that bacteria that carry these genes are also found in people with multiple diseases, then that makes a difference to how we deliver safe, effective care for patients while maintaining infection control. For example, putting a bunch of vulnerable people together in a hospital is likely to create more opportunities for virulent strains of bacteria to evolve. We might need to invest more in treating people safely in their own homes. </p>
<h2>Bug sensors and bug census</h2>
<p>Our findings suggest that we could all benefit from being more aware of exactly what we are carrying inside us. Specifically, it suggests two things.</p>
<p>One, bugs are good sensors of our general health. So, in the future, we might want to consider over-the-counter poo tests to monitor our overall health. An early warning, such as a dip in anaerobic bugs, could help us to head things off at the pass. Subsequent tests could tell us if any of the action we have taken is working. If not, we can change tack.</p>
<p>Two, we should take a regular census of the bugs inside us, especially those associated with antibiotic resistant genes. The science is still in its infancy, but knowing where we are with these guys may help preserve antibiotics for when we really need them.</p><img src="https://counter.theconversation.com/content/99098/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Claire Steves receives funding from the MRC, Wellcome Trust and the Chronic Disease Research Foundation. </span></em></p>Certain gut microbes have been associated with certain diseases, but a new study finds that the pattern of microbes is consistent across a range of diseases.Claire Steves, Clinical Senior Lecturer, King's College LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/968612018-05-28T18:28:54Z2018-05-28T18:28:54ZPostbiotics and smart toilets: new era of harnessing our microbial chemicals to keep us slim and healthy<figure><img src="https://images.theconversation.com/files/220475/original/file-20180525-90281-4pzwu.jpg?ixlib=rb-1.1.0&rect=4%2C0%2C989%2C631&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> </figcaption></figure><p>Ever since Alexander Fleming discovered penicillin growing naturally on a petri dish, we have been aware of the power of chemicals produced by microbes. But we have only recently realised their vast potential. </p>
<p>Microbiome research has now become one of the hottest topics in science as multiple conditions, including <a href="https://theconversation.com/gut-microbes-may-affect-heart-disease-risk-new-research-94552">heart diseases</a>, <a href="https://theconversation.com/do-you-really-choose-what-you-eat-or-do-your-gut-microbes-decide-for-you-76337">obesity and appetite</a> and mood changes, appear to be linked to the microbes inside our gut. </p>
<p>The collection of microbes in our bodies is called our microbiota, and most of the 100 trillion of them (bacteria, viruses, fungi and parasites) are concentrated in the colon of our intestines. Although they are similar in number to our own human cells they have around 200 times more genes than we do. </p>
<p>Each set of these microbial genes acts like a chemical factory, pumping out thousands of chemicals that provide vitamins and many essential metabolites that control our immune system, metabolism and brain functions. As we can now modify an individual gut microbiome with diet (for instance, by eating lots of fibre or fish oil), this opens up many exciting opportunities to use food as medicine.</p>
<h2>Postbiotics</h2>
<p>Our latest research, published in <a href="https://www.nature.com/articles/s41588-018-0135-7">Nature Genetics</a>, sheds new light on the interplay between what we eat, the way it is processed by our gut microbes and how we accumulate fat in our bodies, particularly around our waistline. </p>
<p>We collected stool samples from 500 twin pairs and measured over 800 biochemical compounds that microbes produce – the faecal metabolites. We were able to identify key biochemical substances in the gut that predict the amount of belly fat of a given person. It’s well known that the more abdominal fat we have, the more likely we are to develop diseases, such as type 2 diabetes and heart disease.</p>
<p>Our results show that our gut’s bacterial chemical activity is only minimally controlled by our genes (less than 20%). The rest is influenced by environmental factors – mainly diet. This is exciting because, unlike our genes and our innate risk to develop fat around the belly, which doesn’t change throughout life, our gut microbes can be modified much more easily. </p>
<p>Although radical changes can be made through faecal transplants from healthy donors, the results in obesity are <a href="https://theconversation.com/why-poo-transplants-are-nothing-to-be-sniffed-at-49319">still unpredictable</a>. More conventional treatments are diet (such as high-fibre diets or fermented foods), prebiotics (foods or chemicals that “fertilise” your gut microbes) and probiotics (live microbes known to be beneficial, such as Lactobacillus). Now there is a new concept in gut health: postbiotics. These are the bacterial products or metabolic byproducts from gut microbes that have <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3575601/">biologic activity in our bodies</a>. </p>
<h2>One creature’s trash…</h2>
<p>If we want to take advantage of postbiotics, we need to give them the precise foods they need to maximise production, or we can make those compounds synthetically and add them to our diets or medication. </p>
<p>As part of our latest research, we built a “gut metabolome” database linking the various postbiotic compounds to the microbes, and this can help other scientists make ideal, bespoke gut environments.</p>
<p>For instance, many people take omega-3 supplements, but trials are disappointing. We <a href="https://theconversation.com/for-better-gut-bacteria-eat-more-oily-fish-83513">recently discovered</a> that omega-3 is beneficial because it makes gut bacteria produce other substances (a faecal metabolite called n-carbamyl glutamate that is anti-inflammatory and good for us). But not everyone can produce this chemical from their mix of microbes, explaining why these supplements don’t always work. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/220473/original/file-20180525-90281-4zk3av.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/220473/original/file-20180525-90281-4zk3av.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/220473/original/file-20180525-90281-4zk3av.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/220473/original/file-20180525-90281-4zk3av.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/220473/original/file-20180525-90281-4zk3av.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/220473/original/file-20180525-90281-4zk3av.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/220473/original/file-20180525-90281-4zk3av.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">Mum! We’ve run out of smart toilet paper again.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/214240336?src=Xg-qzjljMymOFrMHJh25rg-1-16&size=medium_jpg">Evan Lorne/Shutterstock.com</a></span>
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<p>The aim of scientists working in this field now is to identify the postbiotics produced by gut bacteria that help our body to efficiently distribute fat, so that we can use them to reduce obesity and diabetes. </p>
<p>In the not too distant future, smart toilets or smart toilet paper will give us a snapshot of the metabolites produced in our guts, and what foods to eat to redress any imbalance. This unique snapshot could be the key to manipulating our microbiota with personalised nutrition. In the new era of postbiotics, we can start to mine the huge hidden pharmacy that our trillions of microbes produce every day to keep us healthy.</p><img src="https://counter.theconversation.com/content/96861/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim Spector receives grants from the MRC, EU, NIH and is a co-founder of MapMyGut Ltd and consults for Zoe Global LTD. He is author of a book on microbes and diet "The Diet Myth" by Orion 2015. </span></em></p><p class="fine-print"><em><span>Cristina Menni 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>Gut microbe metabolites can tell us a lot about our health.Tim Spector, Professor of Genetic Epidemiology, King's College LondonCristina Menni, Research Fellow, King's College LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/879542018-01-11T12:16:10Z2018-01-11T12:16:10ZWhat supplements do scientists use, and why?<figure><img src="https://images.theconversation.com/files/200526/original/file-20180102-26139-g5uyja.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/586345679?src=EreHScEMckLIca_2KH3b_A-1-0&size=medium_jpg">RobsPhoto/Shutterstock</a></span></figcaption></figure><p>Supplements are a <a href="https://www.statista.com/statistics/521746/market-size-vitamins-minerals-and-supplements-worldwide-category/">multi-billion dollar industry</a>. But, unlike pharmaceutical companies, manufacturers of these products don’t have to prove that their products are effective, <a href="https://www.fda.gov/Food/DietarySupplements/UsingDietarySupplements/ucm109760.htm">only that they are safe</a> – and that’s for new supplements only. </p>
<p>We wanted to know which supplements are worth our attention (and money) so we asked six scientists – experts in everything from public health to exercise physiology – to name a supplement they take each day and why they take it. Here is what they said.</p>
<h2>Turmeric</h2>
<p><em>Simon Bishop, lecturer in public health and primary care, Bangor University</em></p>
<p>Turmeric is more familiar as an ingredient in South Asian cooking, adding an earthy warmth and fragrance to curried dishes, but, in recent years, it has also garnered attention for its potential health benefits. I have been taking ground turmeric root as a dietary supplement for around two years, but I have been interested in its use in Ayurvedic medicine for far longer. </p>
<p>Turmeric is used as a traditional remedy in many parts of Asia to <a href="http://www.ncbi.nlm.nih.gov/books/NBK92752/">reduce inflammation and help wounds heal</a>. Now, mounting evidence suggests that curcumin, a substance in turmeric, may also help to protect against a range of diseases, including <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5506636/">rheumatoid arthritis, cardiovascular disease, dementia and some cancers</a>.</p>
<p>The evidence underpinning these claims of health-giving properties is not conclusive, but it is compelling enough for me to continue to take turmeric each morning, along with my first cup of coffee – another habit that may help me <a href="http://annals.org/aim/article-abstract/2643435/coffee-drinking-mortality-10-european-countries-multinational-cohort-study">live a bit longer</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/200527/original/file-20180102-26172-sc3t4p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/200527/original/file-20180102-26172-sc3t4p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/200527/original/file-20180102-26172-sc3t4p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/200527/original/file-20180102-26172-sc3t4p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/200527/original/file-20180102-26172-sc3t4p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/200527/original/file-20180102-26172-sc3t4p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/200527/original/file-20180102-26172-sc3t4p.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">Turmeric may protect against arthritis, heart disease and some cancers.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/751324675?src=rMcdCgbqcs5itMRErUmmeA-1-4&size=medium_jpg">Trum Ronnarong/Shutterstock.com</a></span>
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<h2>Vitamin D</h2>
<p><em>Graeme Close, professor of human physiology, Liverpool John Moores University</em></p>
<p>Vitamin D is a peculiar vitamin in that it is synthesised in our bodies with the aid of sunlight, so people who live in cold countries, or who spend a lot of time indoors, are at risk of a deficiency. People with <a href="http://ajcn.nutrition.org/content/79/3/362.long">darker skin tone</a> are also more at risk of vitamin D deficiency as melanin slows down skin production of vitamin D. It is estimated that about <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4143492/">a billion people</a> are deficient in the vitamin. </p>
<p>Most people are aware that we need enough vitamin D to maintain healthy bones, but, over the past few years, scientists have become increasingly aware of other important roles of vitamin D. We now believe vitamin D deficiencies can result in a <a href="https://www.ncbi.nlm.nih.gov/pubmed/26853300">less efficient immune system</a>, <a href="https://www.ncbi.nlm.nih.gov/pubmed/26506852">impaired muscle function and regeneration</a>, and even <a href="https://www.ncbi.nlm.nih.gov/pubmed/23377209">depression</a>. </p>
<p>Vitamin D is one of the cheapest supplements and is a really simple deficiency to correct. I used to test myself for deficiencies, but now – because I live in the UK where sunlight is scarce between October and April, and it doesn’t contain enough UVB radiation during these cold months – I supplement with a dose of 50 micrograms, daily, throughout the winter. I also advise the elite athletes that I provide nutrition support to, to do the same. </p>
<h2>Probiotic</h2>
<p><em>Justin Roberts, senior lecturer in sport and exercise nutrition, Anglia Ruskin University</em></p>
<p>Having diverse beneficial gut bacteria is important for your physical and mental health. However, the balance of bacterial species can be <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4303825/">disrupted by poor diet</a>, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4757670/">being physically inactive</a> and <a href="http://jpp.krakow.pl/journal/archive/12_11/pdf/591_12_11_article.pdf">being under constant stress</a>. One way to support the health of the gut is to consume dietary probiotics (live bacteria and yeasts), such as yogurt, <a href="https://theconversation.com/do-humans-need-dairy-heres-the-science-70434">kefir</a> and kombucha. </p>
<p>I first came across probiotics after years of triathlon training, often experiencing gastrointestinal symptoms – such as nausea and stomach cramps – after training and races. I was also more susceptible to colds. After researching the area, I was surprised at how many people experience similar <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4008808/">gastrointestinal problems after exercise</a>. Now I have found that taking a probiotic regularly lessens my symptoms after training and benefits my general health. </p>
<p>A <a href="https://www.ncbi.nlm.nih.gov/pubmed/27869661">recent study</a> we conducted showed that taking a probiotic in the evening with food, over 12 weeks of exercise training, reduced gastrointestinal problems in novice triathletes. </p>
<p>There is also a wealth of research supporting the use of probiotics for general health benefits, including <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4045285/">improving intestinal health, enhancing the immune response and reducing serum cholesterol</a>.</p>
<h2>Prebiotic</h2>
<p><em>Neil Williams, lecturer in exercise physiology and nutrition, Nottingham Trent University</em></p>
<p>Prebiotics are non-digestible carbohydrates that act as a “fertiliser” to increase the growth and activity of beneficial bacteria in the gut. This is turn can have positive effects on <a href="https://www.ncbi.nlm.nih.gov/pubmed/18814803">inflammation and immune function</a>, <a href="https://www.ncbi.nlm.nih.gov/pubmed/23303873">metabolic syndrome</a>, increase <a href="https://www.ncbi.nlm.nih.gov/pubmed/23507173">mineral absorption</a>, reduce <a href="https://www.ncbi.nlm.nih.gov/pubmed/19756029">traveller’s diarrhoea</a> and improve <a href="https://www.ncbi.nlm.nih.gov/pubmed/21892075">gut health</a>. </p>
<p>I first came across prebiotics in my research to target the gut microbiota in athletes suffering from exercise-induced asthma. Previous research had shown asthma patients to have <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4739579/">altered gut microbiota</a>, and feeding prebiotics to mice had been shown to <a href="https://www.ncbi.nlm.nih.gov/m/pubmed/26003185/">improve their allergic asthma</a>. Taking this as our launching point, we showed that taking prebiotics for three weeks could reduce the severity of exercise-induced asthma in adults <a href="https://www.ncbi.nlm.nih.gov/pubmed/27523186">by 40%</a>. Participants in our study also noted improvements in eczema and allergic symptoms. </p>
<p>I add prebiotic powder to my coffee every morning. I have found that it reduces my hayfever symptoms in the summer and my likelihood of getting colds in the winter. </p>
<h2>Omega 3</h2>
<p><em>Haleh Moravej, senior lecturer in nutritional sciences, Manchester Metropolitan University</em></p>
<p>I started taking omega 3 after attending a Nutrition Society winter conference in 2016. The scientific evidence that omega 3 could improve my <a href="http://www.mdpi.com/journal/jcm/special_issues/omega-3-fatty-acids">brain function</a>, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2798585/">prevent mood disorders</a> and help to prevent <a href="http://www.fasebj.org/content/31/1/282">Alzheimer’s disease</a> was overwhelming. After analysing my diet it was obvious that I wasn’t getting enough omega 3 fatty acids. A healthy adult should get a minimum of <a href="http://www.who.int/nutrition/topics/FFA_summary_rec_conclusion.pdf?ua=1">250-500mg</a>, daily. </p>
<p>Omega 3 is a form of fatty acid. It comes in many forms, two of which are very important for brain development and mental health: EPA and DHA. These types are primarily found in fish. Another type of omega 3 – ALA (alpha-linolenic acid) – is found in plant-based foods, such as nuts and seeds, including walnuts and flax seeds. Due to my busy schedule as a lecturer, during term time my diet is not as varied and enriched with omega 3 fatty acids as I would like, forcing me to choose a supplement. I take one 1,200mg capsule, daily.</p>
<h2>Nothing but real food</h2>
<p><em>Tim Spector, professor of genetic epidemiology, King’s College London</em></p>
<p>I used to take supplements, but six years ago I changed my mind. After researching <a href="https://www.orionbooks.co.uk/books/detail.page?isbn=9781780229003">my book</a> I realised that the clinical studies, when properly carried out and independent of the manufacturers, clearly showed they didn’t work, and in many cases could be harmful. Studies of multivitamins show regular users are more likely to <a href="http://annals.org/aim/fullarticle/1789253/enough-enough-stop-wasting-money-vitamin-mineral-supplements">die of cancer or heart disease</a>, for example. The <a href="https://www.ncbi.nlm.nih.gov/pubmed/28756618link">only exception</a> is supplements for preventing blindness due to macular degeneration, where randomised trials have been generally positive for a minor effect with a mixture of antioxidants. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/200528/original/file-20180102-26169-1yqqnmb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/200528/original/file-20180102-26169-1yqqnmb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/200528/original/file-20180102-26169-1yqqnmb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/200528/original/file-20180102-26169-1yqqnmb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/200528/original/file-20180102-26169-1yqqnmb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/200528/original/file-20180102-26169-1yqqnmb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/200528/original/file-20180102-26169-1yqqnmb.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">
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<span class="caption">Why take supplements when you can get all you need from a healthy diet?</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/594621377?src=bGprpByhWOJskTP1K_QbsQ-1-4&size=medium_jpg">margouillat photo/Shutterstock.com</a></span>
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<p>In many cases, there is some experimental evidence these chemicals in supplements work naturally in the body or as foods, but no good evidence that when given in concentrated form as tablets they have any benefit. Recent evidence shows that high doses of some supplements can even be harmful – a case in point being calcium and <a href="https://theconversation.com/the-sun-goes-down-on-vitamin-d-why-i-changed-my-mind-about-this-celebrated-supplement-52725">vitamin D</a>. Rather than taking expensive and ineffective synthetic products, we should get all the nutrients, microbes and vitamins we need from eating a range of real foods, as evolution and nature intended.</p><img src="https://counter.theconversation.com/content/87954/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Graeme Close consults to Gatorade Sport Science Institute (GSSI) and Healthspan Elite. He has received funding from The MRC, BBSRC, Aliment Nutrition, GSK and GSSI.</span></em></p><p class="fine-print"><em><span>Tim Spector receives funding from The MRC, Wellcome Trust, CDRF, NIHR, EU Horizon Grants, and is author of "The Diet Myth : the real science behind what we eat - Orion 2016" </span></em></p><p class="fine-print"><em><span>Haleh Moravej, Justin Roberts, Neil Williams, and Simon Bishop 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>Six scientists on the supplements they take every day and why they take them.Simon Bishop, Lecturer in Public Health and Primary Care, Bangor UniversityGraeme Close, Professor of Human Physiology, Liverpool John Moores UniversityHaleh Moravej, Senior Lecturer in Nutritional Sciences, Manchester Metropolitan UniversityJustin Roberts, Senior Lecturer, Anglia Ruskin UniversityNeil Williams, Lecturer in Exercise Physiology and Nutrition, Nottingham Trent UniversityTim Spector, Professor of Genetic Epidemiology, King's College LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/691262016-11-22T12:32:52Z2016-11-22T12:32:52ZEat your fibre or face the flesh-eating microbe cannibals<figure><img src="https://images.theconversation.com/files/146677/original/image-20161120-19356-ck9i2j.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/371849248?src=MYEnBWBcO7yNXNjCpvEbsg-1-14&id=371849248&size=medium_jpg">Moving Moment/Shutterstock.com</a></span></figcaption></figure><p>“Eat your bran even if it tastes horrible – its good for you!” Many of us remember this advice from decades ago. While fibre has been a good cure as a bulking agent for exciting disorders like constipation, it has a dull image and has faded into the background behind trendier (and more commercial) food messages like gluten, cholesterol, saturated fat and sugar. Often it can be the hardest item to find on the food label. </p>
<p>But fibre’s fortunes may now be on the turn. New research in the journal <a href="http://www.cell.com/cell/abstract/S0092-8674(16)31464-7?_returnURL=http%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867416314647%3Fshowall%3Dtrue">Cell</a> sheds light on how fibre works to protect the gut.</p>
<p>An international team used special mice born and raised in sterile conditions with no gut microbes of their own. Normally, all animals from birth have a massive microbe community living mainly in the lower intestine (colon). In humans, this reaches 100 trillion microbes – outnumbering our own cells. </p>
<p>These microbes (mainly bacteria but also viruses and fungi) have co-evolved with us and produce many of our vitamins, hormones and chemicals. They are also key to regulating our immune systems, weight and mood. Abnormalities have been linked to many disorders. Humans have around 17 digestive enzymes and microbes have thousands – the primary role of microbes is digesting high fibre foods (that we can’t) to extract the key nutrients.</p>
<p>In the experiment, the sterile mice received a transplant of 14 well-known bacteria that normally grow in the human gut. They were then starved of fibre, which led the microbes to change their normal eating habits and instead feed on the natural layer of mucus (made up of tasty carbs) that lines the gut. This would be fine for short periods of time, when the body has time to regenerate the layer, but when it is prolonged – as in people on long-term junk food diets – the mucus layer becomes dangerously thin.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/146957/original/image-20161122-24543-edhvfn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/146957/original/image-20161122-24543-edhvfn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=392&fit=crop&dpr=1 600w, https://images.theconversation.com/files/146957/original/image-20161122-24543-edhvfn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=392&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/146957/original/image-20161122-24543-edhvfn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=392&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/146957/original/image-20161122-24543-edhvfn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/146957/original/image-20161122-24543-edhvfn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/146957/original/image-20161122-24543-edhvfn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">A permanent junk-food diet can be extremely harmful.</span>
<span class="attribution"><span class="source">Dmitri Ma</span></span>
</figcaption>
</figure>
<p>The new study showed that when the mucus layer is thinner because of a lack of fibre the gut is much more susceptible to infections. Microbes more easily cross the gut wall into the blood stream. As well as infections this also causes irritation and inflammation of the colon – called colitis. This is believed to be the basis of many common modern gut problems. The team tried to rectify the problem by feeding the mice with prebiotics. They found that while real unprocessed fibre did the trick, when the mice were fed processed, supplement fibre, like <a href="http://health.usnews.com/health-news/blogs/eat-run/2015/05/05/what-is-inulin-chicory-root-fiber">inulin powder</a>, it didn’t work nearly as well.</p>
<h2>What about humans?</h2>
<p>What are the lessons we can learn for our own diets? It underlines first how crucial fibre is to our health. Our own TwinsUK study has recently shown that low fibre eaters gain weight more quickly and have less microbial diversity. Most of us are eating far below the <a href="https://theconversation.com/health-check-are-you-eating-the-right-sorts-of-fibre-20089">minimum recommendation of 25-30g per day</a> causing a deficiency which could <a href="https://theconversation.com/explainer-what-is-irritable-bowel-syndrome-34039">explain modern epidemics like food allergies and irritable bowel syndrome</a>, which have been related to the ill defined and hard to measure problem of “leaky gut”. </p>
<p>If we ate more fibre and increased the diversity and health of our microbes this could prevent many diseases. It also suggests that real plant food as a source of fibre is better than processed or refined fibre produced industrially. This has implications for the food industry – and as with vitamin supplements reinforces the view that (although we don’t yet know why) natural is best.</p>
<p>The new study also helps us understand why people on permanent junk food diets do so badly. As I reported previously, ten days of an intensive burger and fries diet can decimate the number (and diversity) of healthy microbes by <a href="https://theconversation.com/your-gut-bacteria-dont-like-junk-food-even-if-you-do-41564">up to 40%</a>. </p>
<p>This new work confirms that fibre starvation is the major factor affecting the microbes – not just fat and sugar overload. The clear message is that we need to eat regular real plant fibre to keep our microbes happy and prevent them devouring our guts from the inside. Food for thought indeed.</p><img src="https://counter.theconversation.com/content/69126/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim Spector is a co-founder of British Gut and MapmyGut Ltd and receives funding from many sources including NIHR, EU, Wellcome Trust and MRC. He is author of "The Diet Myth"- the real science behind what we eat - Orion 2016 </span></em></p>Low fibre eaters gain weight more quickly and may be more susceptible to certain illnesses.Tim Spector, Professor of Genetic Epidemiology, King's College LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/338402015-01-12T19:28:14Z2015-01-12T19:28:14ZWe know too little about probiotics to proclaim their virtues<figure><img src="https://images.theconversation.com/files/68637/original/image-20150112-23804-1s1c2gx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">We don't actually know whether probiotics have a measurable impact on digestive health.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/brownpau/8708427874">brownpau/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>The terms probiotics and prebiotics are appearing on more items in supermarket aisles all the time. Both words, their placement and the products they adorn, imply they’re good for you, that more of these bacteria will help you in some way. But there’s actually scant evidence for such claims.</p>
<p>Let’s start at the beginning: a probiotic is something full of bacteria expected to take up residence in your gut, while a prebiotic promotes the growth of already-present gut bacteria. </p>
<p>Before you buy probiotics, you need to know whether they survive the perilous journey through the stomach and into the lower gut. And whether the bacteria have a measurable impact on your health once they reach their destination. </p>
<p>Sadly, this information is not available because we haven’t done the research to find out. But new European food regulations are starting to push manufacturers to provide evidence for probiotics’ advertised health benefits.</p>
<h2>What they’re supposed to do</h2>
<p>When you consume a probiotic, you’re eating a particular strain of bacteria that you – and the product’s manufacturer – consider helpful. Many bacteria are killed by the acidic conditions in the stomach but a small number survive and may make it to the lower gut – the colon or large intestine. </p>
<p>Once at their destination, these bacteria need to establish themselves. But it’s a jungle down there, with many competing species of bacteria and scarce resources. In order to survive, new arrivals need food and this is where the prebiotics come in.</p>
<p>Prebiotics feed gut bacteria and are not usually digestible. One example of a prebiotic is a sugar contained in many beans called raffinose, which the gut is not equipped to use. It’s the basis for the well-known – and entirely true – story that beans make you fart. Specifically, the bacteria in your gut that like raffinose also like to <a href="http://vimeo.com/103721959">produce gas</a> when they eat it.</p>
<p>Prebiotics nurture specific types of bacteria already present in your lower gut. As with the probiotics, the idea is that nurturing these bacteria and increasing their numbers will provide a health benefit. </p>
<h2>Regulatory hurdles</h2>
<p>Both probiotics and prebiotics are generally sold as food products. To put a health claim on a food label in Europe requires strict scientific evidence. </p>
<p>In 2006, the European Union adopted a <a href="http://ec.europa.eu/food/food/labellingnutrition/claims/index_en.htm">new set of regulations</a> that defined the terms probiotic and prebiotic as making specific health claims. The directive effectively acted as a ban on using these words on packaging because none of the products using the words has the evidence to back up their health claims.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/68638/original/image-20150112-23795-djgyon.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/68638/original/image-20150112-23795-djgyon.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/68638/original/image-20150112-23795-djgyon.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/68638/original/image-20150112-23795-djgyon.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/68638/original/image-20150112-23795-djgyon.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/68638/original/image-20150112-23795-djgyon.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/68638/original/image-20150112-23795-djgyon.jpg?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">
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<span class="caption">Labelling a food as a probiotic without evidence is banned in Europe.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/mag3737/5153943708">Tom Magliery/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>To have these words on the labels of their products, manufacturers need to provide evidence that the bacteria survive the long journey through the stomach and into the lower gut. Importantly, they also need to show that once there, the bacteria have a specific action to enhance health. </p>
<p>The ban on using probiotic on packaging has been phased in over the last few years and has been upheld by <a href="http://www.nutraingredients.com/Regulation/Loophole-free-EU-s-highest-court-backs-health-claim-regulation-in-disease-ruling">EU courts</a>. Products such as yogurt and cheese can still be sold, but the regulations <a href="http://www.fsai.ie/faqs/probiotic_health_claims.html">limit the health claims</a> manufacturers can make on their labels. </p>
<p>What the European Food Safety Authority (EFSA) is looking for is a direct cause-and-effect relationship. To gather this type of evidence, you generally need well-funded, multi-centre clinical trials – and these haven’t yet been done for many probiotics or prebiotics.</p>
<h2>So many doubts</h2>
<p>There are good reasons for the European ban. Consider a recent probiotic cheese that claimed to lower blood pressure. The EFSA found <a href="http://www.efsa.europa.eu/en/efsajournal/pub/3842.htm">little evidence</a> that edam-style cheese loaded with Lactobacillus plantarum helped maintain normal blood pressure, as it claimed. </p>
<p>In another recent case, the EFSA looked at the consumption of a combination of Lactobacillus rhamnosus and Lactobacillus paracasei. This mixture was supposed to improve intestinal regularity and fecal volume. Once again, the <a href="http://www.efsa.europa.eu/en/scdocs/doc/1773.pdf">opinion</a> of the EFSA was that a cause-and-effect relationship had not been established.</p>
<p>The ban has caused many manufacturers to <a href="http://www.dairyreporter.com/Big-Brands/Danone/Yoghurt-group-lobbies-EC-over-probiotic-labelling-ban">cry foul</a>, arguing that banning the terms probiotics and prebiotics hurts business and confuses consumers. Nonetheless, no products labelled as probiotics or prebiotics have yet been <a href="http://ec.europa.eu/nuhclaims/">approved</a> by the EFSA for sale in Europe, though several are still under consideration. </p>
<p>In Australia, probiotics and prebiotics are regulated by Food Standards Australia New Zealand (<a href="http://www.foodstandards.gov.au/Pages/default.aspx">FSANZ</a>). In answer to the increasing regulation in Europe, this body has recently <a href="http://www.foodstandards.gov.au/consumer/labelling/nutrition/Pages/default.aspx">adopted a framework</a> for regulating health claims. </p>
<p>The framework is now similar to how the Therapeutics Goods Administration (<a href="http://www.tga.gov.au/">TGA</a>) regulates drugs. Despite this recent change, manufacturers are still allowed to use the terms probiotic and prebiotic on their packaging – though this may change. </p>
<p>That your gut bacteria are critical in maintaining your health is well established. But we don’t know which bacteria are helpful and how they act. Until these questions are answered, probiotics and by extension prebiotics will struggle to fulfil their claimed promises. And manufacturers may need to learn to temper their language.</p><img src="https://counter.theconversation.com/content/33840/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Bertrand receives funding from National Health and Medical Research Council for projects relating to gastrointestinal health and disease</span></em></p><p class="fine-print"><em><span>Andrew Ball receives funding from the Australian Research Council.</span></em></p><p class="fine-print"><em><span>Kate Polglaze 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>The terms probiotics and prebiotics are appearing on more items in supermarket aisles all the time. Both words, their placement and the products they adorn, imply they’re good for you, that more of these…Paul Bertrand, Senior Lecturer in School of Medical Sciences, RMIT UniversityAndrew Ball, Professor of Environmental Microbiology, RMIT UniversityKate Polglaze, Associate Lecturer in Pharmaceutical Science, RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.