tag:theconversation.com,2011:/global/topics/lactose-intolerance-4700/articlesLactose intolerance – The Conversation2024-03-03T22:28:29Ztag:theconversation.com,2011:article/2236482024-03-03T22:28:29Z2024-03-03T22:28:29ZWhy is gluten-free bread so expensive? A food supply chain expert explains<figure><img src="https://images.theconversation.com/files/576432/original/file-20240219-26-3ck4ru.jpg?ixlib=rb-1.1.0&rect=40%2C10%2C6599%2C4436&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-girl-holding-sliced-white-bread-1891015522">CGN089/Shutterstock</a></span></figcaption></figure><p>Before the cost of living hit Australian families hard, a group of consumers were already paying top dollar for their staples. Whether it be gluten free, dairy free or lactose free, people with special dietary requirements are used to spending more at the supermarket checkout. </p>
<p>A 2016 study from the University of Wollongong found that Australians were <a href="https://onlinelibrary.wiley.com/doi/10.1111/1747-0080.12171">paying up to 17% more for a gluten-free diet</a>.</p>
<p>Current examples are easy to find. A <a href="https://www.coles.com.au/product/coles-white-bread-650g-4901345">white sandwich loaf at Coles</a> costs A$2.40 (or A$0.37 per 100g), whereas <a href="https://www.coles.com.au/product/coles-i'm-free-from-white-loaf-500g-3216673">the cheapest gluten-free option</a> costs $5.70 (or $1.14 per 100g). That’s over three times as much. Prices are closer comparing Coles Full Cream Milk at A$1.50 per litre with Coles Lactose Free Lite Milk at A$1.60, the exception that confirms the rule.</p>
<p>So why are allergen-free products more expensive?</p>
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Read more:
<a href="https://theconversation.com/why-does-everyone-seem-to-have-food-intolerances-these-days-183224">Why does everyone seem to have food intolerances these days?</a>
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<h2>Is it the ingredients?</h2>
<p>If manufacturers pay more for ingredients, this is usually reflected in the price of the final product. Regular and gluten-free bread share many common ingredients, but there is a substantial change where wheat flour is replaced by gluten-free flour. This ingredient may cost manufacturers around two times as much given the uniqueness of gluten-free grains, seeds, and nuts. These special ingredients are not as abundant or easy to process as wheat, and are also a bit more difficult to buy in very large scale.</p>
<p>For a simple reference, compare <a href="https://www.coles.com.au/product/coles-white-plain-flour-1kg-5881232">regular</a> and <a href="https://www.coles.com.au/product/coles-i'm-free-from-plain-flour-gluten-free-500g-2478197">gluten-free flour</a> at Coles.</p>
<p>Gluten, <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/jgh.13703">a complex mixture of hundreds of related but distinct proteins</a>, has unique properties. It is a binding agent that improves texture in recipes. Gluten-free bread therefore needs extra help to, literally, hold it together. Additional items such as thickeners, tapioca and maize starches are added to gluten-free recipes to improve viscosity and keep baked items in shape. That means a longer ingredient list and a slightly more complex manufacturing process.</p>
<p>So, from an ingredient perspective, gluten-free bread costs more than regular bread. This applies for other allergen-free products as well. But with so many common ingredients, it is reasonable to say that this is not the main explanation.</p>
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<img alt="Row of price tags on a supermarket shelf" src="https://images.theconversation.com/files/576442/original/file-20240219-28-2svnqh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576442/original/file-20240219-28-2svnqh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576442/original/file-20240219-28-2svnqh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576442/original/file-20240219-28-2svnqh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576442/original/file-20240219-28-2svnqh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576442/original/file-20240219-28-2svnqh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576442/original/file-20240219-28-2svnqh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">People with dietary restrictions face higher costs for everyday staples.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/city-melbourne-vicaustraliamay-11th-2019-price-1427246867">doublelee/Shutterstock</a></span>
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<h2>Is it manufacturing and transporting?</h2>
<p>A substantial part of price differences between regular and allergen-free foods comes from <a href="https://www.investopedia.com/terms/e/economiesofscale.asp">economies of scale</a>. Regular products are manufactured in very large quantities, while allergen-free products involve much smaller volumes. </p>
<p>Bulk buying from large suppliers gets you bigger discounts. The more machines in a factory, the cheaper it is to run them. Larger outputs coming from the same place mean smaller costs for each individual product. Given that you have fixed costs to pay anyway, size is king. </p>
<p>You pay the same amount for a grain mill regardless of whether you grind one kilo or one tonne of grains a day. Sure, you spend more on electricity or gas, but those are <a href="https://corporatefinanceinstitute.com/resources/accounting/fixed-and-variable-costs/">variable costs</a>.</p>
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Read more:
<a href="https://theconversation.com/were-in-a-food-price-crisis-what-is-the-government-doing-to-ease-the-pressure-222368">We're in a food price crisis. What is the government doing to ease the pressure?</a>
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<p>Then, there is the need for rigorous quality control. The United Nations Food and Agriculture Organization has a detailed <a href="https://www.fao.org/fao-who-codexalimentarius/sh-proxy/en/?lnk=1&url=https%253A%252F%252Fworkspace.fao.org%252Fsites%252Fcodex%252FStandards%252FCXC%2B80-2020%252FCXC_080e.pdf">code of practice on food allergen management for food business operators</a>, covering harvesting, handling, storage, transportation, packaging, and more. The <a href="https://www.foodstandards.gov.au/food-standards-code">Australia New Zealand Food Standards Code</a> also sets specific standards. </p>
<p>Deep cleaning machines, thoroughly checking that standards are met, and scrapping whole batches when they are not makes manufacturing allergen-free products more complex and expensive. The <a href="https://www.health.wa.gov.au/-/media/Files/Corporate/general-documents/food/PDF/DOHComplianceandEnforcementPolicyVersion3.pdf">implications for non-compliance</a> vary in severity, from a simple recall to a costly infringement notice, plus <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10574315/">reputational damage to consumer trust</a>.</p>
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<a href="https://images.theconversation.com/files/576916/original/file-20240221-16-jyuewt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A batch of bread in a manufacturing facility" src="https://images.theconversation.com/files/576916/original/file-20240221-16-jyuewt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576916/original/file-20240221-16-jyuewt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=340&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576916/original/file-20240221-16-jyuewt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=340&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576916/original/file-20240221-16-jyuewt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=340&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576916/original/file-20240221-16-jyuewt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=427&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576916/original/file-20240221-16-jyuewt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=427&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576916/original/file-20240221-16-jyuewt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=427&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Producing allergen-free products requires rigorous quality control.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/johannesburg-south-africa-9-march-2015-1136105552">Rich T Photo/Shutterstock</a></span>
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<p>It is hard to exactly measure the impact of economies of scale and quality costs on the price of allergen-free products. Each manufacturer will have its own challenges and solutions. But it is reasonable to say a considerable chunk of the difference we see when comparing gluten-free bread with its regular counterpart comes from these factors.</p>
<p>Transportation costs follow a similar rule. If it is easier and quicker to fill your trucks with regular products, while allergen-free products have a hard time making a full load, there are disadvantages in the latter.</p>
<h2>Is it the marketing strategy?</h2>
<p>The final consideration on allergen-free food prices has to do with competition and willingness to pay. </p>
<p>A quick search on Coles’ website shows 276 results for “bread” once you remove the 42 items that are gluten-free. That means that there are many more brands and products competing for bread consumers than for gluten-free bread consumers.
That’s over six to one! This means customers with dietary restrictions are at a disadvantage as they are beholden to the limited options on offer. As noted by the Australian Competition & Consumer Commission, “<a href="https://www.accc.gov.au/business/competition-and-exemptions/competition-and-anti-competitive-behaviour">competition leads to lower prices and more choice for consumers</a>”. </p>
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<img alt="Supermarket aisle" src="https://images.theconversation.com/files/576445/original/file-20240219-18-pwv50z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576445/original/file-20240219-18-pwv50z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576445/original/file-20240219-18-pwv50z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576445/original/file-20240219-18-pwv50z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576445/original/file-20240219-18-pwv50z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576445/original/file-20240219-18-pwv50z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576445/original/file-20240219-18-pwv50z.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">Fewer allergen-free options means less competition and higher prices.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/perth-australia-june-11-2018-interior-1193187478">TY Lim/Shutterstock</a></span>
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<p>Also, fewer allergen-free products make it to the “own brand” list. Australians are <a href="https://www.news.com.au/finance/money/costs/coles-woolworths-ownbrand-products-booming-on-back-of-costofliving-crisis/news-story/d0be8b8d6e98c0a6477959cd83da17ad">relying more on these when facing the cost-of-living crisis</a>.</p>
<p>There is also the <a href="https://online.hbs.edu/blog/post/willingness-to-pay">willingness to pay</a>, where consumers pay more for products deemed as having higher value. <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/obr.13525">Research</a> shows that on average consumers are willing to pay 30% more for food products that they perceive to be healthier.</p>
<p>Manufacturers and retailers more often than not will capitalise on that, increasing their profit margins for allergen-free products.</p>
<h2>4 tips for saving money if you have allergies</h2>
<p>People with dietary requirements looking to ease the cost of their weekly grocery shop should use the same strategies as every savvy consumer: </p>
<ul>
<li>research prices</li>
<li>buy larger quantities where possible</li>
<li>keep a keen eye on price reduction and items on sale</li>
<li>consider replacing products tagged “allergen-free” with alternatives from other categories, such as going for rice instead of gluten-free pasta in a dish. </li>
</ul>
<p>In the long run, if more customers choose allergen-free products it could lead to more volume and competition, bringing prices down. </p>
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<p>
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<strong>
Read more:
<a href="https://theconversation.com/trying-to-spend-less-on-food-following-the-dietary-guidelines-might-save-you-160-a-fortnight-216749">Trying to spend less on food? Following the dietary guidelines might save you $160 a fortnight</a>
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<img src="https://counter.theconversation.com/content/223648/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Flavio Macau is affiliated with the Australasian Supply Chain Institute (ASCI).</span></em></p>Ingredients, manufacturing, transportation and marketing factor into higher prices for allergen-free products.Flavio Macau, Associate Dean - School of Business and Law, Edith Cowan UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2073832023-06-22T13:38:35Z2023-06-22T13:38:35ZFull-fat or low-fat cheese and milk? A dietitian on which is better<figure><img src="https://images.theconversation.com/files/532750/original/file-20230619-1823-uf7sp3.jpg?ixlib=rb-1.1.0&rect=16%2C114%2C5447%2C3522&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Are low-fat dairy products really better for us?</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-woman-slice-cheese-her-hand-2056001120">Bernardo Emanuelle/Shutterstock</a></span></figcaption></figure><hr>
<iframe id="noa-web-audio-player" style="border: none" src="https://embed-player.newsoveraudio.com/v4?key=x84olp&id=https://theconversation.com/full-fat-or-low-fat-cheese-and-milk-a-dietitian-on-which-is-better-207383&bgColor=F5F5F5&color=D8352A&playColor=D8352A" width="100%" height="110px"></iframe>
<p><em>You can listen to more articles from The Conversation, narrated by Noa, <a href="https://theconversation.com/us/topics/audio-narrated-99682">here</a>.</em></p>
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<p>When it comes to dairy products do you tend to buy full-fat or low-fat products? For many people, going for low-fat options can seem like the “healthier” choice. </p>
<p>Indeed, a <a href="https://foodinsight.org/consumer-survey-purchasing-behaviors-eating-decisions-and-health-perceptions-of-dietary-fats-and-oils/">2020 survey</a> in the US found that out of 1,000 people questioned, one in three sought out “low fat” or “reduced fat” foods or drinks, with dairy being the most common food category for low–fat options. But is low-fat milk, cheese, yoghurt and butter really any better for us?</p>
<p>Many governments and public health bodies recommend dairy as a <a href="https://journals.lww.com/nutritiontodayonline/fulltext/2008/11000/Role_of_Dairy_Foods_in_the_Dietary_Guidelines.3.aspx?casa_token=y8APLahFjikAAAAA:fDX-SfWQ2mxKll7omZN0CYiSEwE04-DmCt43jks8deC_VCsPXRoRWiKDTyR_xK43yM9T2aVeW7f_djSoG0xkvu-MH1w">key part</a> of a healthy diet (although it’s perfectly possible to be healthy without it, as many people around the world are). And many people opt for low-fat options as part of this. </p>
<p>Low-fat milk is made by removing or skimming the cream off the milk. So you can get whole or full-fat milk (3.5% fat), semi-skimmed or half-fat milk (1.8% fat) or fully skimmed milk (0.1%-0.3% fat). </p>
<p>The same process can be used to make lower-fat cheeses and yoghurts. However, removing fat can affect how cheese dries and how flavours develop during maturing.</p>
<p>Most relevant dietary guidelines encourage the consumption of low-fat dairy foods, except for in very young children. But a recent <a href="https://academic.oup.com/advances/article/11/4/928/5760740?login=false">review</a> of the available research found that children who consumed full-fat dairy foods were healthier and leaner than those who consumed reduced-fat versions. </p>
<p>It could be that families who tend to have a history of living with health issues relating to diet or higher body weight may be more likely to eat low-fat products. An alternative view is that full-fat dairy products might be more filling and help with the regulation of appetite, meaning people eat less overall. </p>
<p>Either way, these observations in children have also been seen in <a href="https://academic.oup.com/advances/article/10/5/917S/5569504?login=false">adults</a>. </p>
<h2>Explaining the science</h2>
<p>It’s not just that low-fat dairy foods may not be better for our health. There is increasing evidence that some of the fatty acids found in dairy fats might actually reduce our risk of developing <a href="https://link.springer.com/article/10.1007/s11883-018-0724-z">heart disease</a> and <a href="https://www.sciencedirect.com/science/article/pii/S0261561421002934">type 2 diabetes</a>. </p>
<p>Indeed, it seems that higher intakes of <a href="https://link.springer.com/article/10.1007/s00394-017-1556-2">fermented dairy products</a> like unsweetened full-fat yoghurt and some cheeses might be associated with lower risks of heart disease and type 2 diabetes.</p>
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<img alt="Low-fat milk pile in supermarket" src="https://images.theconversation.com/files/532753/original/file-20230619-23-ztdomo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/532753/original/file-20230619-23-ztdomo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532753/original/file-20230619-23-ztdomo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532753/original/file-20230619-23-ztdomo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532753/original/file-20230619-23-ztdomo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532753/original/file-20230619-23-ztdomo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532753/original/file-20230619-23-ztdomo.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">Could low-fat be worse for you than whole milk?</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/los-angeles-california-united-states-09012020-1814166020"> The Image Party/Shutterstock</a></span>
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<p>When it comes to the recommendation to eat reduced-fat dairy foods, the Australian guidelines seem to be based on a <a href="https://www.health.gov.au/sites/default/files/australian-dietary-guidelines.pdf">mathematical decision</a> around how calories add up to meet the recommended calorie intake for an average adult. </p>
<p>It’s unclear if this is the same for the guidelines in other countries, as elsewhere the detailed evidence has not been published in the same way. But it may well be that other recommendations to use lower-fat dairy products are based more on maths than science. </p>
<p>It’s also worth noting that the potential health benefits linked to dairy foods do not extend to butter and possibly not milk either, but are largely linked to intakes of <a href="https://link.springer.com/article/10.1007/s00394-017-1556-2">yoghurt and some types of cheese</a>.</p>
<p>There’s also <a href="https://twitter.com/KenDBerryMD/status/1086679359719698433">a myth</a> that low-fat milk and cheese can lead to weight gain, but this is false. It appears to be based on historical farming practices that used leftover <a href="https://library.dpird.wa.gov.au/cgi/viewcontent.cgi?article=3923&context=journal_agriculture4">skimmed milk from making cream to fatten piglets</a>.</p>
<h2>Low-fat v full-fat</h2>
<p>So, given the minimal evidence, why do so many healthy eating guidelines – including in the <a href="https://www.nhs.uk/live-well/eat-well/food-guidelines-and-food-labels/the-eatwell-guide/">UK</a>, <a href="https://www.dietaryguidelines.gov/sites/default/files/2020-12/Dietary_Guidelines_for_Americans_2020-2025.pdf">US</a> and <a href="https://www.eatforhealth.gov.au/guidelines/australian-guide-healthy-eating">Australia</a> – recommend that we choose low-fat or reduced-fat versions of dairy products? </p>
<p>Research has found that higher intakes of saturated fatty acids are linked to an increased risk of <a href="https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/saturated-fats#:%7E:text=The%20American%20Heart%20Association%20recommends,of%20saturated%20fat%20per%20day.">heart disease</a>, type 2 diabetes and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1140705/#:%7E:text=The%20Chicago%20study%20reported%20the,by%202%20to%203%20times.">dementia</a>. </p>
<p>But this research looks at saturated fatty acids in general and not specifically saturated fatty acids found in dairy products, which have been shown in both <a href="https://academic.oup.com/advances/article/11/4/928/5760740?login=false">children</a> and <a href="https://academic.oup.com/advances/article/11/3/533/5697079?login=false">adults</a> to be potentially beneficial for our health. This is thought to be to do with the way these foods are fermented. </p>
<p>So these recommendations may come as part of suggestions to limit overall fat intake more broadly, rather than because full-fat dairy is “bad” for us.</p>
<p>Switching from full-fat milk to semi-skimmed milk in tea (up to five cups a day) is likely to save the average person less than 50kcal per day. This means, even when considering calories and energy, the effect of <a href="https://theconversation.com/dietary-guidelines-dont-work-heres-how-to-fix-them-68803">reducing fat is minimal</a>. </p>
<p>So if you consume dairy products, it’s likely that there’s no need to worry too much about the fat content. This is especially the case when it comes to unsweetened yoghurt and cheese, which when consumed in their full-fat form do seem to come with potential health benefits.</p><img src="https://counter.theconversation.com/content/207383/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Duane Mellor is a member of the British Dietetic Association</span></em></p>A recent evidence review found children who ate full-fat dairy were healthier and leaner.Duane Mellor, Lead for Evidence-Based Medicine and Nutrition, Aston Medical School, Aston UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2028482023-04-06T06:11:50Z2023-04-06T06:11:50ZHere’s why having chocolate can make you feel great or a bit sick – plus 4 tips for better eating<figure><img src="https://images.theconversation.com/files/518983/original/file-20230403-20-jmdrkw.jpg?ixlib=rb-1.1.0&rect=17%2C17%2C5879%2C3907&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/delicious-easter-holiday-chocolate-bunny-eggs-1661076946">Shutterstock</a></span></figcaption></figure><p>Australians are <a href="https://www.retail.org.au/media/sweet-spending-boon-predicted-for-easter-retail">predicted</a> to spend around A$1.7 billion on chocolates, hot cross buns and other special foods this Easter season. </p>
<p>Chocolate has a long history of production and consumption. It is made from cacao beans that go through processes including fermentation, drying, roasting and grounding. What is left is a rich and fatty liquor that is pressed to remove the fat (cocoa butter) and the cacao (or “cocoa”) powder which will then be mixed with different ingredients to produce dark, milk, white and other types of chocolates. </p>
<p>There are several health benefits and potential problems that come in these sweet chocolatey packages. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/at-chocolate-time-weve-discovered-what-the-brands-that-score-best-on-child-labour-and-the-environment-have-in-common-201682">At chocolate time, we've discovered what the brands that score best on child labour and the environment have in common</a>
</strong>
</em>
</p>
<hr>
<h2>The good news</h2>
<p>Cacao beans contain <a href="https://foodstruct.com/food/cocoa-bean">minerals</a> like iron, potassium, magnesium, zinc and phosphorus and some vitamins. They are also rich in beneficial chemicals called <a href="https://pubmed.ncbi.nlm.nih.gov/23150750/">polyphenols</a>. </p>
<p>These are great antioxidants, with the potential to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5465250/">improve heart health</a>, increase <a href="https://pubmed.ncbi.nlm.nih.gov/25164923/">nitric oxide</a> (which dilates blood vessels) and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3488419/">reduce blood pressure</a>, provide food for gut microbiota and <a href="https://www.mdpi.com/2072-6643/12/7/1908">promote gut health</a>, boost the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5465250/">immune system</a> and reduce inflammation. </p>
<p>However, the concentration of polyphenols in the chocolate we eat depends largely on the cocoa solid amounts used in the final product. </p>
<p>In general terms, the darker the chocolate, the more cocoa solids, minerals and polyphenols it has. For example, dark chocolates may have around <a href="https://www.tandfonline.com/doi/full/10.1080/10942912.2011.614984">seven times more polyphenols</a> compared to white chocolates and <a href="https://www.tandfonline.com/doi/full/10.1080/10942912.2011.614984">three times more polyphenols</a> compared to milk chocolates. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/518984/original/file-20230403-18-cku8bq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="selection of dark chocolate squares" src="https://images.theconversation.com/files/518984/original/file-20230403-18-cku8bq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/518984/original/file-20230403-18-cku8bq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/518984/original/file-20230403-18-cku8bq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/518984/original/file-20230403-18-cku8bq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/518984/original/file-20230403-18-cku8bq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/518984/original/file-20230403-18-cku8bq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/518984/original/file-20230403-18-cku8bq.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">Dark chocolate is less likely to give you problems.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/broken-slices-chocolate-close-564089023">Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-the-good-and-bad-of-easter-eggs-chocolate-and-hot-cross-buns-37920">Health Check: the good and bad of Easter eggs, chocolate and hot cross buns</a>
</strong>
</em>
</p>
<hr>
<h2>But also some bad news</h2>
<p>Unfortunately, the <a href="https://theconversation.com/treat-or-treatment-chocolate-is-good-but-cocoa-is-better-for-your-heart-3084">health benefits of cocoa solids</a> are easily offset by the high sugar and fat content of modern-day chocolates. For example, milk and white chocolate eggs are on average 50% sugar, 40% fat (mostly saturated fats) – which means a lot of added kilojoules (calories). </p>
<p>Also, there may be some side effects that come with ingesting chocolate. </p>
<p>Cocoa beans include a compound called theobromine. While it has the anti-inflammatory properties responsible for some of the health benefits of chocolate, it is also a mild brain stimulant that acts in a similar way to caffeine. The mood boost it offers may also be partly responsible for how much we <a href="https://www.frontiersin.org/articles/10.3389/fphar.2015.00030/full?crsi=662496658&cicada_org_src=healthwebmagazine.com&cicada_org_mdm=direct">like chocolate</a>. Dark chocolate has higher theobromine compared to milk and white chocolate. </p>
<p>But accordingly, overindulging in chocolate (and therefore theobromine) may lead to feeling restless, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3672386/">headaches</a> and nausea. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/whats-the-white-stuff-on-my-easter-chocolate-and-can-i-still-eat-it-181274">What's the white stuff on my Easter chocolate, and can I still eat it?</a>
</strong>
</em>
</p>
<hr>
<h2>What else is in your chocolate?</h2>
<p>Milk and dairy-based chocolates may also cause stomach upset, abdominal pain and bloating in people with <a href="https://dietitiansaustralia.org.au/health-advice/lactose-intolerance">lactose intolerance</a>. This happens when we don’t produce enough lactase enzymes to digest milk sugar (lactose). </p>
<p>People with lactose intolerance can usually tolerate up to 6 grams of lactose without showing symptoms. Milk chocolate can have around <a href="https://www.ncbi.nlm.nih.gov/books/NBK310258/">3 grams of lactose</a> per 40 grams (the size of a standard chocolate bar). So two chocolate bars (or the equivalent in milk chocolate eggs or bunnies) may be enough to cause symptoms. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/518981/original/file-20230403-24-w2xk2p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="little girl with bunny ears on and chocolate on face" src="https://images.theconversation.com/files/518981/original/file-20230403-24-w2xk2p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/518981/original/file-20230403-24-w2xk2p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/518981/original/file-20230403-24-w2xk2p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/518981/original/file-20230403-24-w2xk2p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/518981/original/file-20230403-24-w2xk2p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/518981/original/file-20230403-24-w2xk2p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/518981/original/file-20230403-24-w2xk2p.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">Lactose sensitivities tend to increase with age.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/little-blond-girl-dirty-chocolate-bunny-1937877997">Shutterstock</a></span>
</figcaption>
</figure>
<p>It’s worth noting that lactase enzyme activity dramatically declines as we age, with the highest activity in newborns and children. So lactose sensitivity or intolerance may not be such an issue for your kids and your symptoms may increase over time. Genetics also plays a major role in how sensitive people are to lactose.</p>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6815241/">Allergic reactions</a> to chocolate are usually due to the added ingredients or cross-contamination with potential allergens such as nuts, milk, soy, and some sweeteners used in the production of chocolate. </p>
<p>Symptoms can be mild (acne, rashes and stomach pain) or more severe (swelling of the throat and tongue and shortness of breath). </p>
<p>If you or your family members have known allergic reactions, make sure you read the label before indulging – especially in a whole block or basket of the stuff. And if you or your family members do experience symptoms of an allergic reaction after eating chocolate, <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/allergic-reactions-emergency-first-aid">seek medical attention</a> immediately.</p>
<h2>4 take home tips</h2>
<p>So, if you are like me and have a weakness for chocolate there are a few things you can do to make the experience a good one.</p>
<ol>
<li>keep an eye out for the darker chocolate varieties with higher cocoa solids. You may notice a percentage on labelling, which refers to how much of its weight is from cocoa beans. In general, the higher this percentage, the lower the sugar. White chocolate has almost no cocoa solid, and mostly cocoa butter, sugar and other ingredients. Dark chocolate has 50–100% cocoa beans, and less sugar. Aim for at least 70% cocoa<br></li>
<li>read the fine print for additives and possible cross-contamination, especially if allergies might be an issue</li>
<li>the ingredients list and nutrition information panel should tell you all about the chocolate you choosing. Go for varieties with lower sugar and less saturated fat. Nuts, seeds and dried fruits are better ingredients to have in your chocolate than sugar, creme, syrup, and caramel<br></li>
<li>finally, treat yourself – but keep the amount you have within sensible limits! </li>
</ol>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-history-of-chocolate-when-money-really-did-grow-on-trees-196173">The history of chocolate: when money really did grow on trees</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/202848/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Khalesi is supported by a Postdoctoral Fellowship (Award No. 102584) from the National Heart Foundation of Australia.</span></em></p>Good things can come in chocolatey packages, but read the fine print if you want to avoid potential side effects of eating Easter treats.Saman Khalesi, Postdoctoral Fellow of the National Heart Foundation & Senior Lecturer and Discipline Lead in Nutrition, School of Health, Medical and Applied Sciences, CQUniversity AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1832242022-06-21T19:55:37Z2022-06-21T19:55:37ZWhy does everyone seem to have food intolerances these days?<figure><img src="https://images.theconversation.com/files/468160/original/file-20220610-16-cs4ekx.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C5467%2C3615&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Most of you will have noticed hosting a dinner party is harder than it used to be. One friend is gluten-free, another is dairy-free, one can’t eat onion and two more are vegetarian. Are food intolerances increasing? Or do we just hear more about them now?</p>
<h2>What are food intolerances?</h2>
<p>Food intolerances are reactions to eating foods, in normal quantities, that do not involve the immune system. </p>
<p>They are very different to <a href="https://theconversation.com/what-are-allergies-and-why-are-we-getting-more-of-them-40318">food allergies</a> which is when the body mounts an immune response to a food that is either ingested or even touches the skin. This immune response is very quick (within 20 minutes to two hours) and releases chemicals that can affect the person’s breathing, gastrointestinal tract and heart.</p>
<p>Common food allergies include eggs, peanuts, wheat and shellfish. Allergies differ from intolerances in that the most severe allergies cause anaphylaxis: severe allergic reactions that are life-threatening.</p>
<p>The mechanisms behind food <em>intolerances</em> can vary greatly. One common mechanism is when people lack enzymes that are needed for breaking down nutrients.</p>
<p>In one of the most common food intolerances, lactose intolerance, people lack the enzyme “lactase” which is used to break down this carbohydrate naturally found in milk and some other dairy products. Lactose is broken down into glucose and galactose in the small intestine, and then absorbed. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/everything-you-need-to-know-about-coeliac-disease-and-whether-you-really-have-it-4928">Everything you need to know about coeliac disease (and whether you really have it)</a>
</strong>
</em>
</p>
<hr>
<p>Without lactase, lactose stays in the intestine, where it draws water in from the blood supply to dilute the amount of lactose. Initially this leads to diarrhoea, and then as the lactose enters the large intestine it is fermented by the bacteria in our gut, which results in gas causing abdominal bloating, pain and discomfort.</p>
<p>Other food intolerances due to the lack of enzymes include intolerances to histamine and caffeine. Some people are unable to break down histamine, which is found in red wine, strong and blue cheeses, tuna, tomatoes and pork products. </p>
<p>This can lead to symptoms such as itching, red flushing on the skin, abdominal pain, nausea, dizziness, headaches and migraines. Similarly, people can also have a sensitivity to caffeine (found in coffee and cocoa).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/468166/original/file-20220610-22-urwh81.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Person chopping onion" src="https://images.theconversation.com/files/468166/original/file-20220610-22-urwh81.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/468166/original/file-20220610-22-urwh81.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468166/original/file-20220610-22-urwh81.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468166/original/file-20220610-22-urwh81.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468166/original/file-20220610-22-urwh81.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468166/original/file-20220610-22-urwh81.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468166/original/file-20220610-22-urwh81.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">Some people can’t break down the fructan in onion.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Food intolerances are also different from auto-immune responses, such as in coeliac disease. In this case, people develop an auto-immune response in the small intestine to a protein in wheat called gluten. The auto-immune response also damages the villi, the small finger-like structures that absorb all the nutrients. </p>
<p>Many people who experience gastrointestinal symptoms in reaction to wheat products assume they have coeliac disease. However, they may have a sensitivity to fructan, a type of carbohydrate in wheat. Fructan is a naturally fermentable carbohydrate and a “<a href="https://theconversation.com/the-fodmap-diet-is-everywhere-but-researchers-warn-its-not-for-weight-loss-131550">FODMAP</a>” – which stands for Fermentable Oligo- Di- Monosacharides and Polyols, a group of nutrients that can cause sensitivity.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-fodmap-diet-is-everywhere-but-researchers-warn-its-not-for-weight-loss-131550">The FODMAP diet is everywhere, but researchers warn it's not for weight loss</a>
</strong>
</em>
</p>
<hr>
<p>Like in the case of lactose (which is also a FODMAP carbohydrate), some people are unable to absorb large amounts of fructans (also present in onions and garlic). Like lactose, this causes diarrhoea, and then the bacteria in the large intestine ferment the fructan, producing gas, abdominal pain and discomfort.</p>
<h2>So are food intolerances increasing?</h2>
<p>While it may seem as if food intolerances are increasing, we have no good evidence this is really the case. Data is lacking on actual numbers, perhaps as food intolerances generally do not lead to the requirement to take medications or seek urgent medical treatment. </p>
<p>A 2009 report suggests about <a href="https://onlinelibrary.wiley.com/doi/epdf/10.1111/apt.13041">20% of the population</a> has one or more food intolerances, with no apparent change since 1994. A <a href="https://www.cambridge.org/core/journals/public-health-nutrition/article/high-prevalence-of-food-intolerances-among-us-internet-users/B3335FA113FAAFA2CC01EE91AD5944E3">more recent survey from 2020</a> of self-reported intolerances in internet users indicated about 25% of the population. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/468167/original/file-20220610-17-c9wh2r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="People eating at a buffet" src="https://images.theconversation.com/files/468167/original/file-20220610-17-c9wh2r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/468167/original/file-20220610-17-c9wh2r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=322&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468167/original/file-20220610-17-c9wh2r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=322&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468167/original/file-20220610-17-c9wh2r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=322&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468167/original/file-20220610-17-c9wh2r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=404&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468167/original/file-20220610-17-c9wh2r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=404&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468167/original/file-20220610-17-c9wh2r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=404&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">There’s no evidence food intolerances are increasing over time.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>The perceived increase may reflect many other factors. Some people may self-diagnose a food intolerance from well-intended but misleading health advice from family and friends. </p>
<p>Additionally, people may incorrectly attribute medical symptoms to foods they have eaten. We also have an increased ability to self-diagnose, thanks to Dr Google. In other cases dietary requests may reflect ethical choices about food.</p>
<p>We all know from attending social events with food how often we need to provide our dietary requirements. This is also contributing to normalising food intolerances, compared to even a decade ago. Previously people would have suffered in silence or simply avoided consuming their problematic trigger foods at events. </p>
<p>Another factor could be the greater proportion of people of different ethnicities living in Australia, some of whom are <a href="https://pubs.rsc.org/en/content/articlehtml/2018/fo/c8fo00555a">genetically more likely</a> to have an intolerance.</p>
<p>If you suspect you have a food intolerance it’s best to get diagnosed by a doctor, to ensure you are not overlooking a potentially concerning medical problem. Also you may be needlessly avoiding a particular food group and missing out on essential nutrients required for optimal health.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-what-is-gluten-intolerance-25682">Explainer: what is gluten intolerance?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/183224/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Evangeline Mantzioris is affiliated with Alliance for Research in Nutrition, Exercise and Activity (ARENA) at the University of South Australia. Evangeline Mantzioris has received funding from the National Health and Medical Research Council, and has been appointed to the National Health and Medical Research Council Dietary Guideline Expert Committee.</span></em></p>It may seem as though everyone has food intolerances these days, but there could be a few factors at play.Evangeline Mantzioris, Program Director of Nutrition and Food Sciences, Accredited Practising Dietitian, University of South AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1738792022-02-14T13:22:23Z2022-02-14T13:22:23ZWhy do people get diarrhea?<figure><img src="https://images.theconversation.com/files/442542/original/file-20220125-23-5eakbl.jpg?ixlib=rb-1.1.0&rect=0%2C519%2C5058%2C2800&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">No matter its cause, diarrhea is uncomfortable.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/man-holding-toilet-tissue-roll-in-bathroom-royalty-free-image/1249645235">Rapeepong Puttakumwong/Moment via Getty Images</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
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<blockquote>
<p><strong>Why do people get diarrhea? – A.A.A., age 10, Philadelphia</strong></p>
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<p>The digestive system breaks down everything you eat and drink to absorb nutrients and make the energy your body needs. Whatever solids can’t be broken down and used get <a href="https://www.ncbi.nlm.nih.gov/books/NBK539732/">excreted as poop</a>.</p>
<p>Poop comes in many shapes, sizes, colors and consistencies.</p>
<p><a href="https://scholar.google.com/citations?user=mHFFJtUAAAAJ&hl=en&oi=ao">Doctors like me</a> who treat people with digestive issues use what’s called the <a href="https://dx.doi.org/10.1016%2Fj.jpeds.2011.03.002">Bristol stool scale</a> to grade poop texture. It goes from Type 1 – separate hard lumps – to Type 7 – liquid with no solid pieces. The texture of the best poops, Type 4, resembles a mushy banana.</p>
<p>When your <a href="https://blog.katescarlata.com/2021/04/19/common-disorders-associated-with-diarrhea/">poop is loose and watery</a> and comes out that way at least three times a day, you have <a href="https://www.who.int/news-room/fact-sheets/detail/diarrhoeal-disease">diarrhea</a>. It can be uncomfortable and inconvenient, because diarrhea tends to come out quickly and with little warning. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/442540/original/file-20220125-15-n9shj2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Illustration of the seven categories of poop, ranging from overly firm to liquid." src="https://images.theconversation.com/files/442540/original/file-20220125-15-n9shj2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/442540/original/file-20220125-15-n9shj2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/442540/original/file-20220125-15-n9shj2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/442540/original/file-20220125-15-n9shj2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/442540/original/file-20220125-15-n9shj2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/442540/original/file-20220125-15-n9shj2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/442540/original/file-20220125-15-n9shj2.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"></a>
<figcaption>
<span class="caption">The Bristol stool scale puts poop into seven categories that range from the hard pellets of constipation to the splotchy liquid of diarrhea.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/bristol-stool-chart-tool-for-faeces-type-royalty-free-illustration/1250463401">VectorMine/iStock via Getty Images Plus</a></span>
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<h2>Beware of bad germs</h2>
<p>By the time food passes out of the stomach, it’s a liquid that travels through the small intestine, where nutrients are absorbed. The leftovers flow into the large intestine, where water is absorbed and poop forms.</p>
<p>When the small intestine or the large intestine can’t do its job, poop will be liquid. </p>
<p>Diarrhea usually occurs because of infections caused by many different <a href="https://www.doi.org/10.4161/gmic.1.1.11036">viruses, bacteria and parasites</a>.</p>
<p>That’s why there are <a href="https://www.epa.gov/dwreginfo/drinking-water-regulations">rules about keeping drinking water clean</a> and <a href="https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/steps-keep-food-safe">food safe</a>. It’s also why you should wash your hands before eating. </p>
<p>These germs cause diarrhea a few different ways. Often, they irritate the intestines, interfering with water absorption. Some germs cause diarrhea by <a href="https://www.mayoclinic.org/diseases-conditions/cholera/symptoms-causes/syc-20355287">releasing chemicals</a> that make the intestines release fluid, making poop even more watery. When these <a href="https://www.cdc.gov/foodsafety/foodborne-germs.html">germs come from food</a>, symptoms can include vomiting, belly pain and diarrhea.</p>
<p>To be sure, not all microbes are bad.</p>
<p>In fact, your <a href="https://doi.org/10.1038/nature11053">digestive system is filled with billions of bacteria</a> and other germs that help you digest food and protect you from bad germs. <a href="https://doi.org/10.2217/17460913.3.5.563">Taking antibiotics for an infection can cause diarrhea</a> by killing off these good bacteria along with the ones that originally made you sick. But people usually get better once they finish prescribed antibiotics and the good bacteria have a chance to recover.</p>
<p>People with diarrhea need to consume lots of liquids to stay hydrated. Water is best. Avoid <a href="https://doi.org/10.1001/archpedi.1985.02140070077039">juice</a> and <a href="https://irritablebowelsyndrome.net/food/no-soda">soda</a>, which can worsen diarrhea. Also refrain from foods that can make your digestive system work harder, like dairy products.</p>
<p><a href="https://www.childrens.com/health-wellness/how-to-treat-diarrhea-in-kids">Eating sweet potatoes, oats, beets</a> and other high-fiber foods may help firm up loose poops. Never take a medication, even if doesn’t require a prescription, for diarrhea without asking a doctor first. </p>
<h2>Many other causes</h2>
<p>There are many other causes of diarrhea.</p>
<p>Some people are born with or develop conditions over the course of their lives that can cause diarrhea.</p>
<p>A common example is <a href="http://dx.doi.org/10.1136/gutjnl-2019-318404">lactose intolerance</a>. Lactose is a sugar that is in milk that requires a <a href="https://www.britannica.com/science/lactase">special enzyme, called lactase</a>, to digest it in the small intestine. There are people who have little, or even none, of this enzyme in their small intestine. As a result, lactose travels into their large intestine without being broken down and absorbed – leaving poop very runny.</p>
<p><a href="https://doi.org/10.3389/fped.2018.00350">Celiac disease</a> can also trigger diarrhea. People with it have <a href="https://www.health.harvard.edu/healthbeat/getting-out-the-gluten">trouble digesting gluten</a>, a protein found in wheat and additional grains. For people with celiac disease, eating gluten can damage the small intestine by activating their own immune system. This damage is reversible through a gluten-free diet, but diarrhea may continue until the small intestine heals and can do its job.</p>
<p>Others have <a href="https://doi.org/10.3389/fmed.2017.00261">digestive system allergies</a>. They need to avoid eating specific foods to prevent diarrhea and other symptoms. </p>
<p>Some medications make you poop more often.</p>
<p>There are also medical conditions, like <a href="https://doi.org/10.1053/j.gastro.2021.04.063">inflammatory bowel disease</a>, such as <a href="https://www.mayoclinic.org/diseases-conditions/crohns-disease/symptoms-causes/syc-20353304">Crohn’s disease</a> and <a href="https://www.mayoclinic.org/diseases-conditions/ulcerative-colitis/symptoms-causes/syc-20353326">ulcerative colitis</a>, in which the small intestine, large intestine or both become inflamed over a period of time.</p>
<p>Even your brain can play a role: Experiencing anxiety or <a href="https://www.healthline.com/health/anxiety-diarrhea">getting stressed out</a> can bring about loose poops. Some conditions, like <a href="https://doi.org/10.14309/ajg.0000000000001036">irritable bowel syndrome</a>, where the brain and the intestines do not communicate well with each other, can lead to belly pain and diarrhea, particularly amid stress. </p>
<p><a href="https://www.mayoclinic.org/diseases-conditions/cancer/in-depth/diarrhea/art-20044799">Certain cancers</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6867674/">some tumors</a> can cause diarrhea too. </p>
<p>Finally, for some people, eating spicy or fatty food or consuming artificial sweeteners or <a href="https://www.healthline.com/health/foods-that-cause-diarrhea#food-and-diarrhea">large amounts of caffeine</a> can result in diarrhea. </p>
<p>Even if you find it icky, I recommend you pay attention to your poop. If you’re having diarrhea all the time, rather than occasionally, you may need to see a doctor.</p>
<hr>
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<p class="fine-print"><em><span>Hannibal Person does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Poop comes in many shapes, sizes and textures. The kind that’s too runny might be the result of wayward germs, Crohn’s disease or lactose intolerance.Hannibal Person, Assistant Professor of Gastroenterology and Hepatology, School of Medicine, University of WashingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1586022021-05-19T20:15:21Z2021-05-19T20:15:21ZEvolutionary medicine looks to our early human ancestors for insight into conditions like diabetes<figure><img src="https://images.theconversation.com/files/401702/original/file-20210519-23-iftf0.jpg?ixlib=rb-1.1.0&rect=1477%2C0%2C3514%2C1970&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Our ancestors' environment and diets, and the limits of our biology, have led to adaptations that have improved human survival through natural selection. But we remain prone to illness and disease anyway.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Like all living things, humans are the product of a complex evolutionary history. Our ancestors’ environment and diets, and the limits of human biology, have led to adaptations that have improved our survival through natural selection. Despite these adaptations, our bodies remain prone to illness and disease. If we have evolved and adapted to our environment, why do we still get sick? </p>
<p>While remarkable at understanding the mechanisms of illness and disease, modern medicine can often overlook the underlying reasons for their emergence. <a href="https://evmed.asu.edu/blog/evolutionary-medicine-top-ten-questions">Evolutionary medicine</a> argues that understanding our ancestral history and the evolutionary reasons for illness can explain disease prevalence and provide insight for clinical care. </p>
<p>This evolutionary perspective counters the “bio-ethnocentrism” of modern medicine — the idea that what is “healthy” or “normal” is largely based on those of northern or western European descent. Our global population is incredibly diverse, so having one definition of “normal” just doesn’t make sense. </p>
<p>For example, the inability to digest lactose, resistance to malaria and the human affinity for high-fat and sugary foods are all products of evolution. Examining these conditions through an evolutionary lens can provide unique insight into how we understand disease, and how we can redefine “normal.” </p>
<h2>Lactose intolerance</h2>
<figure class="align-right ">
<img alt="Glass of milk" src="https://images.theconversation.com/files/401188/original/file-20210518-17-7a43j6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/401188/original/file-20210518-17-7a43j6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=896&fit=crop&dpr=1 600w, https://images.theconversation.com/files/401188/original/file-20210518-17-7a43j6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=896&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/401188/original/file-20210518-17-7a43j6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=896&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/401188/original/file-20210518-17-7a43j6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1126&fit=crop&dpr=1 754w, https://images.theconversation.com/files/401188/original/file-20210518-17-7a43j6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1126&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/401188/original/file-20210518-17-7a43j6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1126&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">Adult lactose intolerance is a global norm, not an exception or an illness.</span>
<span class="attribution"><span class="source">(Piqsels)</span></span>
</figcaption>
</figure>
<p><a href="https://www.mayoclinic.org/diseases-conditions/lactose-intolerance/symptoms-causes/syc-20374232">Lactose intolerance</a> occurs when we can’t digest milk sugars (lactose) in adulthood. This can cause nausea, cramping, gas and diarrhea, and is considered a medical condition. </p>
<p>Lactose is broken down by the enzyme lactase. Adult production of lactase evolved in human populations that domesticated animals about 10,000 years ago. These populations were found in northern and central Europe, and in pastoral communities in Africa. Milk is a calorie- and nutrient-dense food, meaning that people who could digest lactose would be better nourished, giving them a better chance at survival and reproduction. </p>
<p>Mutations allowing for adult digestion of lactose gradually spread over generations within these populations. However, those with ancestors from populations that did not regularly herd and milk domesticated animals, such as Indigenous populations in North and South America and most Asian populations, do not possess this ability. In fact, roughly <a href="https://doi.org/10.1098/rstb.2010.0268">65 per cent of adults worldwide remain lactose intolerant</a>. </p>
<p>If 65 per cent of the global population cannot digest lactose, why is it treated as an illness? There is nothing “wrong” with someone who is lactose intolerant; no intervention is needed other than to avoid or limit dairy consumption. Evolution tells us that lactose intolerance is perfectly normal. We simply need to redefine illness. </p>
<h2>Sickle cell disease</h2>
<p>Humans share a <a href="https://www.nature.com/scitable/topicpage/natural-selection-uncovering-mechanisms-of-evolutionary-adaptation-34539/">long evolutionary history with the parasite that causes malaria</a> (Plasmodium). Malaria infects and kills millions of people each year. Over time, humans have evolved adaptations to counter the parasite. One of these adaptations is a mutation in the beta hemoglobin gene.</p>
<p>There are two versions of the beta haemoglobin gene. One is normal, while the other is a mutation that causes sickle-shaped red blood cells. Carrying a copy of the mutated gene confers resistance to malaria, but those carrying two copies of the mutated gene also suffer from <a href="https://www.cdc.gov/ncbddd/sicklecell/facts.html">sickle cell disease</a> (SCD). </p>
<p>SCD is a heritable condition that causes dominant crescent-shaped red blood cells that cannot transport oxygen effectively. People with SCD can experience anemia, acute pain, organ damage and other life-threatening symptoms. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/399111/original/file-20210506-15-i4j34a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Four round red blood cells and one sickle-shaped red blood cell" src="https://images.theconversation.com/files/399111/original/file-20210506-15-i4j34a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/399111/original/file-20210506-15-i4j34a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=678&fit=crop&dpr=1 600w, https://images.theconversation.com/files/399111/original/file-20210506-15-i4j34a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=678&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/399111/original/file-20210506-15-i4j34a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=678&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/399111/original/file-20210506-15-i4j34a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=852&fit=crop&dpr=1 754w, https://images.theconversation.com/files/399111/original/file-20210506-15-i4j34a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=852&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/399111/original/file-20210506-15-i4j34a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=852&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Microscopic image of several normal red blood cells and a sickle cell.</span>
<span class="attribution"><span class="source">(Janice Haney Carr/CDC/ Sickle Cell Foundation of Georgia)</span></span>
</figcaption>
</figure>
<p>If natural selection removes mutations that negatively affect reproduction and survival, then genes like the mutated beta hemoglobin should have disappeared or become exceedingly rare. Yet sickle cell disease is relatively common, especially among people who descended from some regions of Africa. </p>
<p>The advantage of being resistant to malaria comes at the cost of having high rates of SCD in the population. Selection for malaria resistance is so strong that several mutations causing SCD have occurred independently in different regions of Africa. </p>
<p>The prevalence of malaria in these regions means that sickle cell disease predominately strikes those with African ancestry. The <a href="http://doi.org/10.1056/NEJMp2022125">societal implications</a> of this evolutionary history are profound. Lack of awareness of racial differences in SCD combined with generalized symptoms mean that the disease is easily missed by Western practitioners. </p>
<p>Understanding the evolutionary origins of this condition should be used to both educate health-care practitioners and to dismantle the bio-ethnocentrism of medicine.</p>
<h2>Mismatch diseases</h2>
<p>One of the fundamental concepts of evolutionary medicine is the idea that our bodies are adapted for a pre-industrial lifestyle, resulting in a “mismatch” to our current environment. Diseases stemming from this are appropriately referred to as <a href="https://doi.org/10.1093/emph/eoy023">mismatch diseases</a>. </p>
<figure class="align-left ">
<img alt="Illustration of stone age hunters" src="https://images.theconversation.com/files/401187/original/file-20210518-15-3whnxy.jpg?ixlib=rb-1.1.0&rect=224%2C274%2C16416%2C12399&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/401187/original/file-20210518-15-3whnxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/401187/original/file-20210518-15-3whnxy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/401187/original/file-20210518-15-3whnxy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/401187/original/file-20210518-15-3whnxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/401187/original/file-20210518-15-3whnxy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/401187/original/file-20210518-15-3whnxy.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">Our hunter-gatherer ancestors adapted to crave energy-dense foods and conserve physical energy. However, these traits are no longer advantageous in a post-industrial world, and are linked with conditions such as obesity and Type 2 diabetes.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Underlying many of these mismatch diseases is the energy imbalance that post-industrial life affords; eating too much and moving too little. Humans are adapted to avoid negative energy balance (burning more calories than we eat) because it reduces reproductive success and survival. </p>
<p>This requires a reduction in physical activity or an increase in the consumption of food. Because of this, <a href="https://news.harvard.edu/gazette/story/2021/01/daniel-lieberman-busts-exercising-myths/">humans have adapted to be fairly lazy</a>, and <a href="http://darwinian-medicine.com/the-reasons-you-crave-sugar-part-1/">crave energy-dense foods</a>.</p>
<p>These adaptations were not a problem when food was less abundant, and required significant effort to acquire. Fundamentally, obesity is the result of this positive energy imbalance. <a href="https://www.npr.org/transcripts/227777434">Type 2 diabetes is also the result of an energy imbalance</a>, often caused by chronic consumption of high-sugar and high-fat diets. </p>
<p>The <a href="https://dx.doi.org/10.1016%2Fj.psc.2011.08.005">difficulty associated with reducing diabetes and obesity</a> is the result of the modern environment. The most abundant foods are high in fat and sugars, and low in fibre. The wild meats and plant-based foods <a href="https://doi.org/10.1038/sj.ejcn.1601353">consumed by hunter-gatherer communities</a> have now been replaced by ultra-processed and refined foods. </p>
<p>On top of this, modern activity levels are relatively low. Elevators, escalators and cars have reduced the need to expend energy. And while activity levels are not as high as you might predict for hunter-gatherers, it’s more than today’s sedentary lifestyle.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/401704/original/file-20210519-19-1q0skki.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A reconstructed skull in the foreground and the head and shoulders of a skeleton in the background" src="https://images.theconversation.com/files/401704/original/file-20210519-19-1q0skki.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/401704/original/file-20210519-19-1q0skki.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=447&fit=crop&dpr=1 600w, https://images.theconversation.com/files/401704/original/file-20210519-19-1q0skki.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=447&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/401704/original/file-20210519-19-1q0skki.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=447&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/401704/original/file-20210519-19-1q0skki.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=562&fit=crop&dpr=1 754w, https://images.theconversation.com/files/401704/original/file-20210519-19-1q0skki.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=562&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/401704/original/file-20210519-19-1q0skki.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=562&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 reconstructed Neanderthal skeleton, right, and a model of a modern human skeleton, left, on display at the Museum of Natural History in New York.</span>
<span class="attribution"><span class="source">(AP Photo/Frank Franklin II)</span></span>
</figcaption>
</figure>
<p>Our preferences for high-fat, high-sugar and salty foods are a consequence of adaptations for avoiding a negative energy balance. It’s important to imagine that in a landscape where food was scarce, those who carried a genetically determined preference for energy-rich foods would have had an evolutionary advantage. </p>
<p>These mismatch diseases emphasize how quickly human cultural development has outpaced human evolution, and the negative consequences of easy living.</p>
<h2>Why does it matter?</h2>
<p>Understanding the evolution of humans and disease lays the foundation for developing treatments that address the underlying basis for illness and assesses differences in disease vulnerability stemming from ancestral diversity. </p>
<p>A more profound understanding of our evolution is necessary to offer better health care to our entire community. Before medicine can move forward, we must understand where we came from.</p><img src="https://counter.theconversation.com/content/158602/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Albrecht Schulte-Hostedde receives funding from the Natural Sciences and Engineering Research Council and the Ontario Ministry of Natural Resources and Forestry. </span></em></p><p class="fine-print"><em><span>Eric Boivin and Meghan McCue 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>Evolutionary medicine uses our ancestral history to explain disease prevalence and inform care for conditions like Type 2 diabetes. It also challenges the bio-ethnocentrism of western medicine.Albrecht Schulte-Hostedde, Professor - Applied Evolutionary Ecology, Laurentian UniversityEric Boivin, Graduate Student - Department of Psychology, Laurentian UniversityMeghan McCue, PhD Candidate, Biomolecular Sciences, Laurentian UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1144122019-04-11T10:43:52Z2019-04-11T10:43:52ZCan changing the microbiome reverse lactose intolerance?<figure><img src="https://images.theconversation.com/files/267689/original/file-20190404-123426-11oj065.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Reversing lactose intolerance might make it possible for adults to enjoy a milkshake again.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/drinking-milk-cocktail-father-daughter-together-1302644437?src=utJIocy_CFUrDAZ21kndJA-1-4">YAKOBCHUK VIACHESLAV / Shutterstock.com</a></span></figcaption></figure><p>After childhood, about two-thirds of the world’s human population <a href="http://doi.org/10.1007/s00439-008-0593-6">loses the ability to digest milk</a>. As far as we know, 100% of nonhuman mammals also lose this ability after weaning. The ongoing ability to digest lactose, the main sugar in milk, into adulthood is a biological abnormality.</p>
<p>Lactose cannot be directly absorbed in the intestinal tract and must, instead, be broken down into its two smaller component sugars by an enzyme called lactase. Normally, the activity of the gene that produces lactase, LCT, declines after infancy. New evidence suggests that this decline occurs not because the genetic code is changed, but because the DNA is <a href="http://doi.org/10.1038/nsmb.3227">chemically modified</a>
so that the <a href="http://doi.org/10.1038/s41598-018-23957-4">lactase gene is switched off</a>. Such modifications that affect gene activity while leaving the DNA sequence intact are called epigenetic. The epigenetic modification that <a href="http://doi.org/10.1038/nsmb.3227">turns off the lactase gene</a> does not happen in <a href="http://doi.org/10.1038/s41598-018-23957-4">lactose-tolerant individuals</a>. This new finding gives an important insight into how lactose intolerance develops with age or after trauma to the intestinal tract.</p>
<p><a href="https://biology.indiana.edu/about/faculty/foster-patricia.html">I’m a microbiologist</a>, and I became interested in the causes of lactose intolerance because it afflicts a close friend. He is of Norwegian descent and, like most Norwegians, is genetically lactose tolerant. But, he became permanently <a href="https://www.niddk.nih.gov/health-information/digestive-diseases/lactose-intolerance">lactose intolerant</a> at the age of 45 after a long regimen of antibiotics. </p>
<p>There are other cases of people who should be able digest lactose because of their genetics, but lose that ability late in life, either spontaneously or when <a href="https://www.mayoclinic.org/diseases-conditions/lactose-intolerance/symptoms-causes/syc-20374232">the small intestine is damaged by disease or other traumas</a>. In most cases, the lactose intolerance goes away when the underlying cause is treated, but some people become permanently lactose intolerant.</p>
<p>It seems possible, even probable, that such trauma to the digestive tract can trigger the same epigenetic change that normally turns off the lactase gene in childhood. Scientists have found other cases of such <a href="http://doi.org/10.1146/annurev-publhealth-040617-014629">environmentally induced epigenetic changes</a>, although more research is needed to establish the persistence and consequences of these alterations.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/267868/original/file-20190405-180010-1dua2bh.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/267868/original/file-20190405-180010-1dua2bh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/267868/original/file-20190405-180010-1dua2bh.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=219&fit=crop&dpr=1 600w, https://images.theconversation.com/files/267868/original/file-20190405-180010-1dua2bh.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=219&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/267868/original/file-20190405-180010-1dua2bh.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=219&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/267868/original/file-20190405-180010-1dua2bh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=276&fit=crop&dpr=1 754w, https://images.theconversation.com/files/267868/original/file-20190405-180010-1dua2bh.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=276&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/267868/original/file-20190405-180010-1dua2bh.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=276&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 lactase enzyme breaks down the sugar lactose into two smaller sugars that can be absorbed in the small intestine.</span>
<span class="attribution"><a class="source" href="http://www.evo-ed.com">http://www.evo-ed.com</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<h2>Lactose intolerance is mostly due to your genes</h2>
<p>While the ability to produce the lactase enzyme persists into adulthood in only about 35% of adults worldwide, this <a href="http://doi.org/10.1146/annurev-genom-091416-035340">proportion varies widely among ethnic groups</a>. In the U.S., the proportion of lactose-tolerant people is about <a href="http://doi.org/10.1016/S2468-1253(17)30154-1">64%</a>, reflecting the mixture of ethnic groups that populate the country. </p>
<p>The ability of adults to digest lactose appeared in humans relatively recently. Specific genetic changes – known as single-nucleotide polymorphisms, SNPs – conveying lactase-persistence arose independently in various populations around the same time as their domestication of dairy animals. None of these SNPs are in the lactase gene itself, but instead are in a nearby region of the DNA that <a href="http://doi.org/10.1007/s00439-017-1847-y">control its activity</a>. Scientists have been trying to figure out how these changes exert their influence over this gene’s behavior.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/267869/original/file-20190405-180036-1uyi5b6.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/267869/original/file-20190405-180036-1uyi5b6.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/267869/original/file-20190405-180036-1uyi5b6.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=740&fit=crop&dpr=1 600w, https://images.theconversation.com/files/267869/original/file-20190405-180036-1uyi5b6.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=740&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/267869/original/file-20190405-180036-1uyi5b6.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=740&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/267869/original/file-20190405-180036-1uyi5b6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=931&fit=crop&dpr=1 754w, https://images.theconversation.com/files/267869/original/file-20190405-180036-1uyi5b6.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=931&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/267869/original/file-20190405-180036-1uyi5b6.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=931&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 SNP, located 13910 base pairs in front of the lactase gene, has the DNA base pair C:G replaced by a T:A. The change apparently prevents the DNA from being methylated at this site, and so the lactase gene stays active.</span>
<span class="attribution"><a class="source" href="http://www.evo-ed.com">http://www.evo-ed.com</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>Recently researchers have shown that one of the SNPs changes the level of <a href="http://doi.org/10.1038/s41598-018-23957-4">epigenetic modification</a> of the DNA in <a href="http://doi.org/10.1038/nsmb.3227">the lactase gene control regions</a>. Specifically, the SNP prevents small chemical units, called methyl groups (which consist of one carbon and three hydrogen atoms) from being attached to the DNA. Methyl groups are especially important in regulating gene activity because when they are added to the DNA, they turn off the gene. </p>
<p>These studies imply that after early childhood, the lactase gene is usually shut off by DNA methylation. The SNPs that alter the DNA sequence in the control region, however, prevent this methylation from happening. This, in turn, results in the production of lactase because the gene is kept on.</p>
<p>To date, <a href="http://doi.org/10.1007/s00439-017-1847-y">five different SNPs have been strongly associated</a> with lactase persistence, and another 10 or so have been found in isolated populations. The estimated times of appearance of these SNPs in different cultures range from <a href="http://doi.org/10.1146/annurev-genom-091416-035340">3,000 (Tanzania) to 12,000 (Finland) years ago</a>. That the trait persisted and spread in these populations indicates that the ability to digest milk beyond infancy had a significant selective advantage.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/267634/original/file-20190404-123431-he5wvi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/267634/original/file-20190404-123431-he5wvi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=358&fit=crop&dpr=1 600w, https://images.theconversation.com/files/267634/original/file-20190404-123431-he5wvi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=358&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/267634/original/file-20190404-123431-he5wvi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=358&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/267634/original/file-20190404-123431-he5wvi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=450&fit=crop&dpr=1 754w, https://images.theconversation.com/files/267634/original/file-20190404-123431-he5wvi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=450&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/267634/original/file-20190404-123431-he5wvi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=450&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Lactic acid bacteria can digest the sugar lactose and produce lactic acid as a byproduct.</span>
<span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/8/86/Lactobacillus_paracasei.jpg">Dr. Horst Neve, Max Rubner-Institut</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Your microbiome and lactose intolerance</h2>
<p>The symptoms of <a href="https://www.niddk.nih.gov/health-information/digestive-diseases/lactose-intolerance">lactose intolerance</a> include diarrhea, stomach pain, cramps, bloating and flatulence, all of which result from failure to break down lactose in the small intestine. As undigested lactose moves into the large intestine, water enters to reduce the lactose concentration, producing diarrhea. The lactose is eventually eaten by microorganisms in the large intestine, producing, as byproducts, various gases that cause bloating, cramping and flatulence.</p>
<p>Recent studies have shown that the <a href="http://doi.org/10.1007/s12602-018-9507-7">symptoms of lactose intolerance can be relieved</a> in some people by <a href="http://doi.org/10.1073/pnas.1606722113">changing the population of their intestinal microbes</a>, called the microbiome, to encourage lactose-digesting bacteria. Specifically, bacteria, called “lactic acid bacteria,” eat the lactose but produce the byproduct lactic acid instead of gas. While lactic acid has no nutritional value, it does not produce the unpleasant symptoms of lactose intolerance. This <a href="http://doi.org/10.1073/pnas.1813608115">adaptation of the intestinal microbiome</a> may be how some ancient pastoral populations with no genetic evidence of lactase persistence tolerated a dairy-rich diet.</p>
<p><a href="http://doi.org/10.1007/s12602-018-9507-7">Ingesting lactic acid bacteria as a probiotic</a> can alleviate the symptoms of lactose intolerance, but these bacteria may not persist in the colon. A promising new strategy is to “feed” the lactic acid bacteria a complex sugar that they can digest but humans cannot. In initial clinical trials, subjects using this “prebiotic” reported <a href="http://doi.org/10.1186/1475-2891-12-160">improved lactose tolerance</a> and had a corresponding <a href="http://doi.org/10.1073/pnas.1606722113">shift in their intestinal microbiome</a>. <a href="https://www.clinicaltrials.gov/ct2/show/NCT03597516?term=NCT03597516&rank=1">Larger clinical trials are in progress</a>. </p>
<p>So there is hope for lactose-intolerant people that real ice cream may be on the menu again.</p><img src="https://counter.theconversation.com/content/114412/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Patricia L. Foster receives funding from the US Army Research Office. She is a member of the Union of Concerned Scientists and Concerned Scientists at Indiana University. </span></em></p>You may think that your milk-drinking, ice cream-licking days are behind you as you battle the discomfort of lactose intolerance. But there maybe be a way to reverse the situation.Patricia L. Foster, Professor Emerita of Biology, Indiana UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1020842018-08-29T10:15:20Z2018-08-29T10:15:20ZThe surprising role cheese played in human evolution<figure><img src="https://images.theconversation.com/files/234042/original/file-20180829-195298-c94cey.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">shutterstock</span></span></figcaption></figure><p>A solid white mass found in a broken jar in an Ancient Egyptian tomb has turned out to be the <a href="https://www.bbc.co.uk/news/world-africa-45233347">world’s oldest example</a> of solid cheese. </p>
<p>Probably made mostly from sheep or goats milk, the cheese was found several years ago by archaeologists in the <a href="http://time.com/5371503/ancient-egypt-tomb-old-cheese/">ancient tomb of Ptahmes</a>, who was a high-ranking Egyptian official. The substance was identified after the archaeology team carried out <a href="https://pubs.acs.org/doi/10.1021/acs.analchem.8b02535">biomolecular identification of its proteins</a>.</p>
<p>This 3,200-year-old find is exciting because it shows that the Ancient Egyptian’s shared our love of cheese – to the extent it was given as a funerary offering. But not only that, it also fits into archaeology’s growing understanding of the importance of dairy to the development of the human diet in Europe. </p>
<h2>Dairy in diets</h2>
<p>About two-thirds of the world’s population <a href="https://www.karger.com/Article/PDF/360136">is lactose intolerant</a>. So although dairy products are a daily part of the diet for many living in Europe, Northern India and North America, drinking milk in adulthood was only possible from <a href="https://depot.ceon.pl/bitstream/handle/123456789/13155/nature14507.pdf?sequence=2">the Bronze Age</a>, over the last 4,500 years. </p>
<p>For most of human history, adults lost the ability to consume milk after infancy – and the same is true of people who are lactose intolerant today. After weaning, people with lactose intolerance can no longer produce <a href="https://www.karger.com/Article/PDF/360136">the enzyme lactase</a>. This is necessary to break down the lactose sugars in fresh milk into compounds that can be easily digested. People with lactose intolerance experience unpleasant symptoms if they consume dairy products such as bloating, flatulence and diarrhoea. </p>
<p><a href="https://depot.ceon.pl/bitstream/handle/123456789/13155/nature14507.pdf?sequence=2">Ancient DNA analysis</a> on human skeletons from prehistoric Europe places the earliest appearance of the gene lactase gene (LCT) – which keeps adults producing lactase – to 2,500BC. But there is plenty of evidence from the Neolithic period (around 6,000-2,500BC in Europe) that milk was being consumed. </p>
<p>This is not totally surprising though, as the Neolithic marks the start of farming in most regions of Europe – and the first time humans lived closely alongside animals. And although they were unable to digest milk, we know that Neolithic populations were processing milk into substances they could consume. </p>
<h2>Archaeological evidence</h2>
<p>Using a technique called “<a href="https://www.nature.com/articles/nature07180">lipid analysis</a>”, sherds of ancient pottery can be analysed and fats absorbed into the clay identified. This then allows archaeologists to find out what was cooked or processed inside them. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/234044/original/file-20180829-195325-gf7shx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/234044/original/file-20180829-195325-gf7shx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/234044/original/file-20180829-195325-gf7shx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/234044/original/file-20180829-195325-gf7shx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/234044/original/file-20180829-195325-gf7shx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/234044/original/file-20180829-195325-gf7shx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/234044/original/file-20180829-195325-gf7shx.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">We have ancient ancestors to thank for the cheese we eat today.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Although it is not yet possible to identify the species of animal, dairy fats can be distinguished. It is also challenging to determine what techniques were being used to make dairy products safe to consume, with many potential options. Fermenting milk, for example, breaks down the lactose sugar into lactic acid. Cheese is low in lactose because it involves separating curd (from which cheese is made) from whey, in which the majority of the lactose sugars remain. </p>
<p><a href="https://www.nature.com/news/archaeology-the-milk-revolution-1.13471">Clay sieves from Poland</a>, similar to modern cheese sieves, have been found to have dairy lipids preserved in the pores of clay, suggesting that they were being used to separate curds from the whey. Whether the curds were then consumed or attempts made to preserve them by pressing into a harder cheese is unknown. Fermentation of milk was also possible to our ancestors, but harder to explore with the techniques currently available to archaeology. </p>
<h2>Early cheese making</h2>
<p>While the techniques from bioarchaeology have provided this fantastic detail on Neolithic diets, where the science stops, experimental archaeology can explore what was possible. </p>
<p><a href="https://www.youtube.com/watch?v=jVx-O9ZYa3A">We have been making cheese</a> using the <a href="http://www.prehistoricsociety.org/files/PAST_84_for_web.pdf">utensils, plants and techniques</a> available to Neolithic farmers. The aim of the experiments is not to faithfully recreate early cheeses, but to begin to capture some of the decisions available to early cheese makers – and the experiments have thrown up some interesting results. </p>
<p>By using these ancient techniques, we have discovered that a wealth of different means of curdling the milk would have been possible, each producing different forms, tastes and amounts of cheese. </p>
<p>And such specialist knowledge may have been akin to the spread of bronze smelting at the end of the Neolithic. Dairy may have had a special status among foodstuffs. For example, at the major late <a href="https://www.cambridge.org/core/journals/antiquity/article/feeding-stonehenge-cuisine-and-consumption-at-the-late-neolithic-site-of-durrington-walls/E60784FB3D83BFF8ED22A2E9393B5B3E">Neolithic feasting site of Durrington Walls</a>, not far from and contemporary with Stonehenge, dairy residues were found in a particular kind of pottery vessel and concentrated in the area around a timber circle – a form of Late Neolithic monument. </p>
<p>From the Bronze Age, however, lactase persistence offered an advantage to some people who were able to pass this on to their offspring. It also seems that this advantage was not solely because of increased calorie and nutrient intake alone – but because of the special status dairy foods may have had. The development of this biological adaption to fresh milk took place after humans had already found ways to safely include dairy products in the diet. </p>
<p>This shows that humans are not only able to manipulate their food to make it edible, but that what we consume can also lead to new adaptations in our biology.</p><img src="https://counter.theconversation.com/content/102084/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Penny Bickle receives funding from the AHRC. </span></em></p>Archaeologists have discovered the world’s oldest cheese, and it reveals how our ancestor’s cooking methods helped the human diet adapt.Penny Bickle, Lecturer in Archaeology, University of YorkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/942952018-05-24T20:04:03Z2018-05-24T20:04:03ZPlain, Greek, low-fat? How to choose a healthy yoghurt<figure><img src="https://images.theconversation.com/files/218000/original/file-20180508-46353-4spjww.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">With all the different types of yogurt on offer, making a decision on which one to buy can be difficult.</span> <span class="attribution"><span class="source">from shutterstock.com</span></span></figcaption></figure><p>Yoghurt is one of the oldest fermented dairy foods in the world. Its origins date back to the <a href="https://academic.oup.com/nutritionreviews/article/73/suppl_1/4/1819293">dawn of civilisation</a>. When humans began domesticating animals for milk production, milk’s short shelf life required solutions for storing it. </p>
<p>The word “yoghurt” itself <a href="https://www.elsevier.com/books/tamime-and-robinsons-yoghurt/tamime/978-1-84569-213-1">comes from Turkish</a>, meaning something like “curdled” or “thickened milk”, which is pretty much what happens to milk during yoghurt production.</p>
<p>Like milk, yoghurt is a rich source of calcium and protein. And it <a href="https://academic.oup.com/ajcn/article/99/5/1243S/4577504">provides other nutrients</a> such as iodine, vitamins D, B2 and B12, and zinc. </p>
<p>But yoghurt is actually more nutritious than milk. The main reason is that the fermentation process makes it easier to digest, so the nutrients can be absorbed more easily into the body.</p>
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Read more:
<a href="https://theconversation.com/from-bulgaria-to-east-asia-the-making-of-japans-yogurt-culture-76598">From Bulgaria to East Asia, the making of Japan's yogurt culture</a>
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<p>Yet with all the various types, like Greek and liquid yoghurts, and ones with added fruits and probiotics, how do you know which one is healthiest?</p>
<h2>Making yoghurt</h2>
<p>Yoghurt is made by introducing certain bacteria into fresh milk – typically <em>Streptococcus thermophilus</em> and <em>Lactobacillus delbrueckii subsp. bulgaricus</em>. </p>
<p>Usually, both these bacteria are present in yoghurt and form the yoghurt starter culture. Their synergistic relationship is a key factor in the consistency of the final product. These cultures may also provide some health benefits, such as reducing the <a href="https://www.ncbi.nlm.nih.gov/pubmed/14627358">severity and duration of diarrhoea</a>. </p>
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<a href="https://images.theconversation.com/files/217999/original/file-20180508-46364-gsqsl6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/217999/original/file-20180508-46364-gsqsl6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/217999/original/file-20180508-46364-gsqsl6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/217999/original/file-20180508-46364-gsqsl6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/217999/original/file-20180508-46364-gsqsl6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/217999/original/file-20180508-46364-gsqsl6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/217999/original/file-20180508-46364-gsqsl6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/217999/original/file-20180508-46364-gsqsl6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Yoghurt is made by introducing a starter culture of bacteria into milk.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/inthe-arena/10372695863/in/photolist-gNAM6R-a41WoE-axxDjL-a2qdFb-cJ4KiQ-zaiG5-9Y5u1V-bwktpH-dZ1WpZ-axxESN-PFwbv-9e57PA-6aaynh-quG5pa-4pQyL1-6Y4eiy-9ZSM8P-9AXD83-6LMsD4-aavUZL-oejucg-axxD3s-axuXvv-axuYuR-6LRBJL-axuXQx-6DnSyf-QDWHf4-6o6EZa-QGLYwE-axxDAj-5hSCbx-GmBLc-7A5ypG-dRGUct-7Szc93-8bhcPt-6eHCk5-29yKSq-7TwfT5-9v9n8t-SBbdNf-dtoEBA-buwu2p-9WgKAp-aoxrax-8ZFTF-eyrRok-9Deo3D-nZqQc">Andrew Seaman/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>The bacteria ferment the naturally occurring milk sugar (lactose) for energy and growth. During this process, lactose becomes lactic acid. The acidity development leads to the main milk protein, casein, breaking down and losing some of its elementary structure. </p>
<p>This partial breakdown results in the semi-solid, gel-like structure we know as yoghurt. The lactic acid is also responsible for yoghurt’s sour flavours, as well as helping it stay fresher for longer than milk. </p>
<h2>What makes yoghurt healthy?</h2>
<p>Yoghurt is easier to digest than milk because enzymes involved in the fermentation process break down substances, such as lactose, into <a href="https://academic.oup.com/ajcn/article/99/5/1243S/4577504">smaller compounds</a>, which can be readily absorbed and used by the body. And certain minerals, such as calcium, phosphorus and iron, are <a href="https://www.sciencedirect.com/science/article/pii/B9780128051344000018">better used by the body</a> when they come from yoghurt.</p>
<p>And because lactose is broken down and converted to lactic acid during fermentation, lactose-intolerant people can consume yoghurt without adverse effects. </p>
<p>Consuming yoghurt is associated with <a href="https://www.elsevier.com/books/yogurt-in-health-and-disease-prevention/shah/978-0-12-805134-4">many health benefits</a>, including maintaining a healthy microbiota (the colony of bacteria in your gut). Yoghurt can feed the good bacteria and help them fight against <a href="https://www.ncbi.nlm.nih.gov/pubmed/26995128">disease-causing microorganisms</a>.</p>
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Read more:
<a href="https://theconversation.com/explainer-what-is-the-gut-microbiota-and-how-does-it-affect-mind-and-body-40536">Explainer: what is the gut microbiota and how does it affect mind and body?</a>
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<p>Yoghurt consumption helps to maintain bone structure and has even been found to reduce the risk of <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/ijc.26193">certain cancers</a> and infectious diseases, as it enhances the immune response. Yoghurt <a href="https://academic.oup.com/ajcn/article/80/2/245/4690304">can help reduce symtpoms of conditions</a> such as constipation, inflammatory bowel disease, infection with a bacterium that can damage the stomach lining (<em>Helicobacter pylori</em>), <a href="http://www.who.int/en/news-room/fact-sheets/detail/diarrhoeal-disease">diarrhoeal diseases</a> and some allergic reactions, such as to certain foods. </p>
<h2>Types of yoghurt</h2>
<p>Cow’s milk is the most widely used raw ingredient for yoghurt manufacturing. But other types, such as sheep and goat milk yoghurt, are available. There are slight differences in the nutritional composition among these milk types. </p>
<p>Although cow’s milk is generally more appealing (as goat and sheep milk may have <a href="https://wakethewolves.com/goats-milk-vs-cows-milk-is-there-a-difference/">unpleasant smells</a>), the latter two may provide additional health benefits. For instance, <a href="https://www.sciencedirect.com/science/article/pii/S0308814612009971">goat’s milk is easier to digest</a> than cow’s milk and is less likely to cause an allergic reaction.</p>
<p>Non-dairy alternatives such as soy and coconut milk yoghurt are becoming increasingly popular too.</p>
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<a href="https://images.theconversation.com/files/218004/original/file-20180508-46364-qvpfkx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/218004/original/file-20180508-46364-qvpfkx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/218004/original/file-20180508-46364-qvpfkx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/218004/original/file-20180508-46364-qvpfkx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/218004/original/file-20180508-46364-qvpfkx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/218004/original/file-20180508-46364-qvpfkx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/218004/original/file-20180508-46364-qvpfkx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/218004/original/file-20180508-46364-qvpfkx.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>
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<span class="caption">Goat’s milk is easier to digest than cow’s milk.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
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<p>The most commonly known types of yoghurt are plain set yoghurt, flavoured yoghurt, Greek yoghurt, frozen yoghurt and drinking yoghurt.</p>
<p><em>Plain set yoghurt</em> is usually made from dairy ingredients and fermented in the cups or tubs with no sugar or sweeteners.</p>
<p><em>Flavoured yoghurt</em> is made by adding sugar and fruit or other flavourings to plain yoghurt. Often, the milk mixture is fermented in large vats, cooled and then stirred for a creamy texture with various fruits or other flavours. These stirred yoghurts are also known as Swiss-style yoghurts.</p>
<p><em>Greek yoghurt</em> is a thick yoghurt. It’s traditionally prepared by straining the water known as whey from plain yoghurt to make it thicker, richer and creamier. It contains more protein than regular yoghurt and has no added sugar.</p>
<p><em>Frozen yoghurt</em> is frozen ice milk with a typical yoghurt flavour. It tastes more like ice-cream with a hint of yoghurt.</p>
<p><em>Drinking yoghurts</em> are prepared from a yoghurt mix with reduced milk solids. They come in almost every variety and flavour. They’re usually more watery, but some thick varieties are also available. Kefir and lassi are the popular drinking yoghurt types.</p>
<h2>Added ingredients for health purposes</h2>
<p>Many yoghurts contain added ingredients. These include <a href="https://www.benecol.co.uk/our-products/yogurts/garden-fruits?utm_medium=cpc&utm_source=google&utm_term=benecol-yogurt&utm_content=text&utm_campaign=mec---brand---product---yogurt-(b)&gclid=CjwKCAjw2dvWBRBvEiwADllhn7saBYlt7KTGzuaG_kj7emog2j957TlcdEyjB46RLqqdjIfeKp5AzBoCV68QAvD_BwE&gclsrc=aw.ds">cholesterol-lowering compounds</a> (such as stanol and sterol esters) and <a href="https://www.ncbi.nlm.nih.gov/pubmed/26619790">fibre</a> aimed at improving gut health. </p>
<p>Some yoghurts also have added probiotics. These are <a href="http://www.mdpi.com/2311-5637/3/4/67">live microorganisms</a> that can help establish a healthy gut microbiota. The most widely used probiotics are the acidophilus strain, known as <em>Lactobacillus acidophilus</em>, and <em>Bifidobacterium</em>. These could be useful for people who have gastrointestinal problems such as <a href="https://link.springer.com/article/10.1007/s00535-016-1224-y">irritable bowel syndrome (IBS)</a>.</p>
<p>Probiotics can be more effective when <a href="https://www.sciencedirect.com/science/article/pii/S0963996909002749">consumed in yoghurt</a> than through capsules or <a href="https://www.sciencedirect.com/science/article/pii/S096399691300330X">other beverages</a>.</p>
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Read more:
<a href="https://theconversation.com/so-you-think-you-have-ibs-coeliac-disease-or-crohns-heres-what-it-might-mean-for-you-39128">So you think you have IBS, coeliac disease or Crohn’s? Here’s what it might mean for you</a>
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<p>The two bacteria in yoghurt starter culture – <em>S. thermophilus</em> and <em>L. delbrueckii</em> ssp. <em>bulgaricus</em> – are not <a href="https://www.elsevier.com/books/yogurt-in-health-and-disease-prevention/shah/978-0-12-805134-4">natural inhabitants</a> of the intestine and cannot survive the acidic conditions and bile concentrations in the gastrointestinal tract. So they don’t do much to change the microbiota in your gut. In contrast, probiotics can survive and colonise the large intestine.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/218012/original/file-20180508-46359-c4cs2i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/218012/original/file-20180508-46359-c4cs2i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/218012/original/file-20180508-46359-c4cs2i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/218012/original/file-20180508-46359-c4cs2i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/218012/original/file-20180508-46359-c4cs2i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/218012/original/file-20180508-46359-c4cs2i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/218012/original/file-20180508-46359-c4cs2i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/218012/original/file-20180508-46359-c4cs2i.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>
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<span class="caption">It’s healthier to add your own fruit to yoghurt than to buy fruity yoghurt.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/MFs_fEGsoqY">Peter Hershey/Unsplash</a></span>
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<p>Regular intake of yoghurt that contains microbial cultures such as probiotic acidophilus has also been found to potentially reduce the risk of coronary heart disease by helping to <a href="https://www.tandfonline.com/doi/abs/10.1080/07315724.1999.10718826">decrease cholesterol absorption</a>. </p>
<h2>Which yoghurt is better for you?</h2>
<p>When whole milk is used to produce plain yoghurts, these may contain 3.5-4.4 grams of fat per 100g. Low-fat yoghurt contains less than 3g of fat per 100g, and non-fat or fat-free yoghurts must contain less than <a href="http://www.legendairy.com.au/%7E/media/Legendairy/Documents/Health/Fact%20sheets/2012%20Proximate%20Composition%20Booklet.ashx">0.15g fat per 100g</a>. </p>
<p>High fat and high sugar in any food can lead to health problems. So, a low-fat and low-sugar yoghurt product, like a low-fat Greek yoghurt, would be ideal if you’re looking to keep healthy.</p>
<p>Yoghurt products incorporating fruit or nuts can provide additional nutritional and health benefits, but many of these can also contain added sugar. Adding fresh fruit or nuts to a yoghurt yourself is a healthier option.</p>
<p>If you would like to have probiotic effects, you can choose a product with acidophilus or bifidobacteria. </p>
<p>You should check the product label as it is a legal requirement to list all the ingredients, cultures and nutritional information in commercial yoghurts. When it comes to probiotic yoghurts, it’s always better to choose a fresh product rather than one closer to the expiry date, as <a href="http://www.mdpi.com/2311-5637/3/4/67">probiotics die during storage</a>.</p><img src="https://counter.theconversation.com/content/94295/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Duane Mellor is a director, council member and spokesperson of the British Dietetic Association</span></em></p><p class="fine-print"><em><span>Nenad Naumovski, Said Ajlouni, and Senaka Ranadheera 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>Consuming yoghurt is associated with many health benefits. But with all the varieties of yoghurt, and added ingredients like fruits and probiotics, it can be hard to know which is best for your health.Senaka Ranadheera, Tutor, The University of MelbourneDuane Mellor, Senior Lecturer, Coventry UniversityNenad Naumovski, Asistant Professor in Food Science and Human Nutrition, University of CanberraSaid Ajlouni, Associate Professor, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/560842016-03-11T08:44:58Z2016-03-11T08:44:58ZWhy some humans developed a taste for milk and some didn’t<figure><img src="https://images.theconversation.com/files/114677/original/image-20160310-26268-1e7sfcm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">In the mood for a cold drink.</span> <span class="attribution"><span class="source">Alexander Chaikin</span></span></figcaption></figure><p>Imagine a dinner party somewhere in Italy to which, as it turns out, my dad has been invited. On the menu tonight is a sliced tomato, basil and mozzarella salad, pasta with a creamy mushroom sauce topped with parmesan cheese, and Italian gelato ice cream to finish. However, except for the sliced tomatoes and basil, my dad cannot eat anything on offer and is destined to leave the party hungry. My dad is, as I am, ethnically Chinese – and, like the majority of Chinese folk, lactose intolerant.</p>
<p>Although the inability to drink and eat dairy products (or more specifically the inability to digest lactose, the type of sugar found in milk) is commonly called “<a href="https://ghr.nlm.nih.gov/condition/lactose-intolerance">lactose intolerance</a>”, this is actually a misnomer. All humans are lactose tolerant in early life because we are mammals. Most humans only switch to being lactose intolerant in the transition to adulthood. </p>
<p>But if so many adults struggle to digest dairy, why did we start drinking the milk of other animals in the first place? Well, with the domestication of large mammals, in particular cows, sheep and goats, people began to realise that animals could provide nutrition from more than just their meat. In fact, drinking its milk greatly increases the amount of calories available from an animal during its life-span. Couple this with the subsequent development of cheese making, which allowed for the nutrients available from milk to be <a href="http://news.discovery.com/history/prehistoric-farmers-cheese-121212.htm">preserved in compact and portable form</a> and, voila, a new rich and renewable source of food was available to nascent herding communities.</p>
<p>The ability to digest dairy products as adults is likely to be adaptive owing to its increased nutritional benefits (sugars, as well as fat, protein and calcium) and milk’s role as an important drinking source in arid regions. Considering the symptoms of lactose intolerance, which include water loss from diarrhoea, individuals who had acquired the genetic adaptation of “lactase persistence” and could therefore metabolise dairy products, would have had a very strong selective advantage in areas where herding of cattle, sheep and goats occurred.</p>
<h2>Herd mentality</h2>
<p>So powerful was the selection pressure in herding societies to be able to consume milk and its related products, that the trait of lactase persistence actually emerged independently at least three times; <a href="http://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1000491">in northern Europeans</a>, emanating from what is now Denmark, and in <a href="http://ac.els-cdn.com/S0002929714000676/1-s2.0-S0002929714000676-main.pdf?_tid=b0313cf6-e6e5-11e5-8238-00000aab0f02&acdnat=1457631168_e20a5ee20e639222548a539e63f22726">two geographically distinct African populations</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/114716/original/image-20160310-26256-1l38c3r.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/114716/original/image-20160310-26256-1l38c3r.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/114716/original/image-20160310-26256-1l38c3r.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/114716/original/image-20160310-26256-1l38c3r.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/114716/original/image-20160310-26256-1l38c3r.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/114716/original/image-20160310-26256-1l38c3r.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/114716/original/image-20160310-26256-1l38c3r.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/114716/original/image-20160310-26256-1l38c3r.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=377&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Map of lactase persistence.</span>
<span class="attribution"><span class="source">Royal Society</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The incredible thing is that although the adaptation in the three cases involved different genetic changes, they all influence the same gene, <a href="http://www.medicinenet.com/script/main/art.asp?articlekey=9997">lactose dehydrogenase</a>, required for metabolising lactose into glucose.</p>
<h2>Chicken, pigs and tofu</h2>
<p>A key question is how have most other peoples around the world, such as Chinese folk like my dad, continued to thrive without this ability to digest lactose as adults? Certainly the climate in much of East Asia would not have precluded the herding of cattle. </p>
<p>In lieu of viable milking herds, alternative sources of easily renewable protein were identified. For instance, <a href="http://www.dailymail.co.uk/sciencetech/article-2850041/The-domestic-chickens-bred-northern-China-10-000-years-ago.html">chickens were first domesticated in China</a>. Chickens provided a key protein source, not only from their meat – but also from their eggs, which are, like milk and cheese, a rich, portable and renewable food source. Chickens are also far smaller and have a shorter lifespan compared to large mammalian species, making production less complicated.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/114682/original/image-20160310-26242-s0e3vk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/114682/original/image-20160310-26242-s0e3vk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/114682/original/image-20160310-26242-s0e3vk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/114682/original/image-20160310-26242-s0e3vk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/114682/original/image-20160310-26242-s0e3vk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/114682/original/image-20160310-26242-s0e3vk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/114682/original/image-20160310-26242-s0e3vk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">On the menu in China.</span>
<span class="attribution"><span class="source">janecat</span></span>
</figcaption>
</figure>
<p>Crucially, one of the key crops domesticated by the Chinese – in addition to rice, of course – was the soya bean, which also has a <a href="http://www.soyconnection.com/soy_foods/nutritional_composition.php">very high protein content</a>. Soya beans are a versatile crop and are the source ingredient for tofu and also soya milk. In much of East Asia today, chickens and pigs (<a href="http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=9436246">also first domesticated by the Chinese</a>) form the bulk of the meat consumed – and this is supplemented by a large number of soya-related products, including tofu, soya milk, fermented soya beans, and a dizzying array of different soy sauces.</p>
<h2>Decaf soya latte</h2>
<p>I spent a significant period of my childhood in Singapore, where fresh milk was almost non-existent, and although powdered milk was available, everyone drank soy milk. These days, of course, soy milk is big in the West, too – it is perceived by some to be healthier than cow’s milk as it has less fat and natural sugars and it is now widely available in all major supermarkets and in most coffee shops as a replacement for milk. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/114683/original/image-20160310-26279-1sx3tr0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/114683/original/image-20160310-26279-1sx3tr0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/114683/original/image-20160310-26279-1sx3tr0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/114683/original/image-20160310-26279-1sx3tr0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/114683/original/image-20160310-26279-1sx3tr0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/114683/original/image-20160310-26279-1sx3tr0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/114683/original/image-20160310-26279-1sx3tr0.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">Rise of the soy latte.</span>
<span class="attribution"><span class="source">Dave Newman</span></span>
</figcaption>
</figure>
<p>There’s a widespread belief in certain sectors of society that lactose intolerance is an indication that humans were not supposed to drink milk as adults. And certainly in some parts of the world, where this is the norm rather than the exception, this is certainly the case. But there’s no denying that the ability to digest cow (and goat and sheep and camel) milk and its products gave some humans the edge in the survival stakes and helped them thrive in early agricultural societies.</p>
<hr>
<p><em>The author will be giving a talk: <a href="http://www.sciencefestival.cam.ac.uk/events/starch-milk-and-alcohol-limited-returns-available-door">Starch, milk and alcohol</a>, as part of the <a href="http://www.sciencefestival.cam.ac.uk/">Cambridge Science Festival</a> which runs until March 20.</em></p><img src="https://counter.theconversation.com/content/56084/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Giles Yeo 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 ability to digest dairy products enabled humans in some parts of the world to survive and thrive.Giles Yeo, Principal Research Associate, director of Genomics/Transcriptomics, MRC Metabolic Diseases Unit, University of CambridgeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/93792013-03-04T19:33:42Z2013-03-04T19:33:42ZSoy versus dairy: which milk is better for you?<figure><img src="https://images.theconversation.com/files/20875/original/h44xxmtb-1362369342.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fresh, raw soy milk and fresh, raw animal milk are very different foods.</span> <span class="attribution"><span class="source">Timothy Valentine</span></span></figcaption></figure><p>There are good reasons why people may want to swap soy with dairy milk. The carbon, water and phosphate <a href="https://theconversation.com/soy-versus-dairy-whats-the-footprint-of-milk-8498">footprint of soy milk</a> is a fraction of the latter. But the main reason for the increasing popularity of soy milk seems to be health concerns, such as inflammatory bowel disease and lactose intolerance.</p>
<p>First, let’s look at what these milks are. The milk from a cow (or goat, or sheep) is complete food for the growth and development of a young animal. It contains all the essential amino acids (the protein building blocks that your body is unable to make for itself) as well as a complex mixture of fats, carbohydrates, vitamins and minerals including calcium, phosphate and vitamin B12. </p>
<p>A soy bean is also complete food – for the growth and development of a soy plant seedling. The nutritional needs of plants are obviously quite different from those of animals, and accordingly, the nutritional profile of unadulterated soy milk is very different from that of animal milks. </p>
<p>Fresh soy milk, made from grinding and then straining soaked dried soy beans, has less fat and carbohydrate than animal milks, and only a small amount of calcium. And it’s missing some of the vitamins present in animal milks as well. </p>
<p>The protein content of soy milk is similar to cow’s milk, and all the essential amino acids are present but in smaller amounts than in cow’s milk. Because it’s plant food, soy milk contains small amounts of fibre, and twice as much folate as animal milks.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/20877/original/r55jk4cg-1362369606.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/20877/original/r55jk4cg-1362369606.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=479&fit=crop&dpr=1 600w, https://images.theconversation.com/files/20877/original/r55jk4cg-1362369606.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=479&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/20877/original/r55jk4cg-1362369606.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=479&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/20877/original/r55jk4cg-1362369606.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=602&fit=crop&dpr=1 754w, https://images.theconversation.com/files/20877/original/r55jk4cg-1362369606.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=602&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/20877/original/r55jk4cg-1362369606.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=602&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The milk from a cow (or goat or sheep) is complete food for the growth and development of a young animal.</span>
<span class="attribution"><span class="source">jenny downing</span></span>
</figcaption>
</figure>
<p>The contrast between the two products is significantly reduced when comparing the commonly-available commercial brands of soy and cow’s milk. Both types of milk are heat-treated as part of production, to destroy bacteria and enzymes that may be harmful to health or shorten shelf life. They’re also nutritionally similar. </p>
<p>Supermarket soy milk products are mostly made from soy protein isolate powder (rather than ground whole soy beans), reconstituted with water and adjusted with oil and often sugar, to bring the fat and carbohydrate content to levels comparable with full-cream cow’s milk. A similar vitamin and mineral content is achieved by adding vitamins (including B12) and calcium. </p>
<p>Once this is done, the main differences between the products are in the type (rather than the amount) of carbohydrate, protein and fat.</p>
<p>The carbohydrate in cow’s milk is lactose, the milk sugar, which is digested by the enzyme lactase. In most animals (including human ones), the amount of lactase in the intestine naturally decreases after weaning. Once this has happened, milk cannot be digested properly, causing flatulence or diarrhoea. </p>
<p>In humans who continue to consume lactose-rich dairy products throughout their lives, lactase enzymes are maintained in the gut. But some unlucky individuals become lactose intolerant and, for them, soy milk is a useful alternative as it contains no lactose. </p>
<p>For everyone else, though, lactose has some advantages over other sugars because it has a very low glycaemic index. This means that it is released slowly into the blood, avoiding abrupt spikes in blood glucose levels.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/20878/original/gm4bbdgt-1362369757.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/20878/original/gm4bbdgt-1362369757.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/20878/original/gm4bbdgt-1362369757.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/20878/original/gm4bbdgt-1362369757.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/20878/original/gm4bbdgt-1362369757.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/20878/original/gm4bbdgt-1362369757.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/20878/original/gm4bbdgt-1362369757.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">Soy beans are the complete food for the growth and development of a soy plant seedling.</span>
<span class="attribution"><span class="source">Quinn Dombrowski</span></span>
</figcaption>
</figure>
<p>Both soy and dairy milk are good sources of protein, with different health advantages. Soy protein appears to have <a href="http://www.nejm.org/doi/full/10.1056/NEJM199508033330502">its own protective effect</a> on heart health, possibly due to its content of phytochemicals (beneficial plant substances). Some of these include phytoestrogens, whose weak oestrogen-like action can help soothe hormonal swings during menopause. </p>
<p>Cow’s milk consists of two proteins, casein and whey, both of which are popular among body-builders as effective muscle-building proteins. In controlled diets, dairy foods <a href="http://www.mdpi.com/2072-6643/1/1/83">appear to promote fat loss</a>, possibly due to the effect of their calcium content in conjunction with the dairy proteins and other substances in milk. This effect is not seen when the same nutrients are consumed as supplements.</p>
<p>The fat content is similar in both cow and soy milk, and low fat or “light” varieties are available for both. The type of fat in full-cream cow’s milk is butterfat, high in saturated fat, while soybean oil is mostly polyunsaturated. The fats added to soy milk are usually canola or sunflower oil, again rich in polyunsaturated and monounsaturated fats. This means that soy milk is a source of “good” fats. </p>
<p>The Heart Foundation <a href="http://www.heartfoundation.org.au/sitecollectiondocuments/dietary-fats-dietary-cholesterol-and-heart-health.pdf">recommends</a> we avoid saturated fats in order to control our cholesterol levels, but interestingly full-fat dairy foods <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2695872/">don’t appear to increase</a> the risk of heart disease in the same way as other sources of saturated fat. This may be due to the protective effect of other complex elements in milk (such as the proteins or minerals) or the unsaturated fats present.</p>
<p>Fresh, raw soy milk and fresh, raw animal milk are very different foods. But in the form usually purchased in the supermarket, there’s little difference in their nutritional profile. So rest assured that if you choose to replace some, or all, of your dairy milk intake with soy milk for environmental reasons, you will not be nutritionally disadvantaged.</p><img src="https://counter.theconversation.com/content/9379/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Suzie Ferrie 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>There are good reasons why people may want to swap soy with dairy milk. The carbon, water and phosphate footprint of soy milk is a fraction of the latter. But the main reason for the increasing popularity…Suzie Ferrie, Clinical Affiliate, University of SydneyLicensed as Creative Commons – attribution, no derivatives.