tag:theconversation.com,2011:/africa/topics/farts-10836/articlesFarts – The Conversation2024-01-16T19:15:14Ztag:theconversation.com,2011:article/2163552024-01-16T19:15:14Z2024-01-16T19:15:14ZSpace travel taxes astronauts’ brains. But microbes on the menu could help in unexpected ways<figure><img src="https://images.theconversation.com/files/565638/original/file-20231213-27-4xr8mj.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5991%2C3000&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/smiling-man-astronaut-presents-shawarma-kebab-1128088580">studiostoks/Shutterstock</a></span></figcaption></figure><p>Feeding astronauts on a long mission to Mars goes well beyond ensuring they have enough nutrients and calories to survive their multi-year journey.</p>
<p>Providing astronauts with the right diet is also paramount in supporting their <a href="https://www.frontiersin.org/articles/10.3389/fncir.2023.1170395/full?trk=public_post_comment-text">mental and cognitive health</a>, in a way unlike previous missions.</p>
<p>So we need to radically rethink how we feed astronauts not only on a challenging mission to Mars, which could be on the cards in the late 2030s or early 2040s, but to prepare for possible settlement on the red planet. </p>
<p>That includes acknowledging the role of microbes in mental health and wellbeing, and providing astronauts with the right foods and conditions for a variety of these beneficial microbes to grow. Our research aims to do just that.</p>
<p>Here’s why a healthy balance of microbes is important under such challenging conditions, and how we could put microbes on the menu.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/was-going-to-space-a-good-idea-218235">Was going to space a good idea?</a>
</strong>
</em>
</p>
<hr>
<h2>Why are missions to Mars so challenging?</h2>
<p>Deep space missions will expose humans to immense physical and psychological challenges. These include prolonged isolation from loved ones, extreme space and resource constraints, and the difficulties of microgravity. </p>
<p>Disruption to astronauts’ circadian rhythms, prolonged radiation exposure and dietary changes can also lower their cognitive performance and wellbeing. </p>
<p>The hazardous conditions, combined with the psychological toll of potential spacecraft failures, can all contribute to mental health problems.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-to-live-in-space-what-weve-learned-from-20-years-of-the-international-space-station-144851">How to live in space: what we've learned from 20 years of the International Space Station</a>
</strong>
</em>
</p>
<hr>
<h2>Why is diet important for mental health?</h2>
<p>We already know the quality of people’s diet not only influences their physical health, but also their mental and brain health. </p>
<p>Diet quality is <a href="https://www.nature.com/articles/s41380-018-0237-8">consistently and independently linked</a> to the risk of depression or anxiety. Clinical trials <a href="https://pubmed.ncbi.nlm.nih.gov/35441666/">show</a> improving diet quality <a href="https://www.ncbi.nlm.nih.gov/pubmed/30720698">can lead to</a> profound improvements in depression and anxiety symptoms. </p>
<p>Diet also affects the size and function of a specific brain region – the hippocampus – that is crucial to learning and memory, as well as for maintaining <a href="https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-015-0461-x?report=reader">mental health</a>. When even young healthy adults eat “junk” foods, aspects of cognition linked to the hippocampus quickly <a href="https://royalsocietypublishing.org/doi/abs/10.1098/rsos.191338">decline</a>.</p>
<p>On the other hand, research shows a diet containing more and varied plant foods and seafood (which are rich in components called long-chain omega-3 fatty acids and flavonoids) leads to <a href="https://www.nature.com/articles/s41598-022-21927-5">better cognitive performance</a>. This study was conducted in a closed chamber for 45 days, designed to mimic conditions in space.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Plate of salmon on bed of green salad, with lemon slices, on blue wood table" src="https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A diet rich in plant food and seafood might help your brain, but how do you turn that into space food that will go the distance?</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/grilled-salmon-vegetables-366852431">Jacek Chabraszewski/Shutterstock</a></span>
</figcaption>
</figure>
<p>Diet can have such consequences by <a href="https://www.ncbi.nlm.nih.gov/pubmed/33144709">altering</a>:</p>
<ul>
<li>immune function</li>
<li>the size and functioning of the hippocampus </li>
<li>chemical messenger (neurotransmitter) systems</li>
<li>how our bodies respond to stress.</li>
</ul>
<p>Diet can also influence the many ways microbes in the gut affect the brain, a link known as the <a href="https://journals.physiology.org/doi/full/10.1152/physrev.00018.2018?rfr_dat=cr_pub">microbiota gut-brain axis</a>.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/essays-on-health-microbes-arent-the-enemy-theyre-a-big-part-of-who-we-are-79116">Essays on health: microbes aren't the enemy, they're a big part of who we are</a>
</strong>
</em>
</p>
<hr>
<h2>Not all foods make the grade</h2>
<p>Space foods need to appeal to a diverse crew and stay nutritious for an extremely long time (likely a three- to five-year mission). They also need to be lightweight and compact enough to fit on the spacecraft.</p>
<p>Once on Mars, challenges include growing fresh food and culturing protein sources. Beyond providing nutrients, we also need to consider providing more recently identified factors including phytonutrients (such as polyphenols), fermentation products and microbes. These will likely be crucial to sustain health and, indeed, life on deep space missions.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/humans-are-going-back-to-the-moon-and-beyond-but-how-will-we-feed-them-189794">Humans are going back to the Moon, and beyond – but how will we feed them?</a>
</strong>
</em>
</p>
<hr>
<h2>Why are microbes so important?</h2>
<p>If you’ve seen the film <a href="https://theconversation.com/the-martian-review-science-fiction-that-respects-science-fact-48373">The Martian</a>, you’ll know microbes are a crucial aspect of growing food, and are essential for keeping humans alive and functioning. </p>
<p>We have co-evolved with, and are hosts to, trillions of different microbes that live on our skin and in all our niches and cavities. This includes our mouths, nose, vagina, lungs and – crucially – our gut.</p>
<p>Most of these microbes are bacteria. The largest number are in the gut, where they influence our digestion, metabolism, and immune, endocrine (hormone) and nervous systems.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/YB-8JEo_0bI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">What is the human microbiome?</span></figcaption>
</figure>
<p>The relationship between gut microbes and <a href="https://journals.physiology.org/doi/full/10.1152/physrev.00018.2018?rfr_dat=cr_pub">mental health and behaviour</a> goes both ways. Gut microbes influence our mental health and behaviour, and these, in turn, influence our gut microbes. </p>
<p>Other components of our microbiomes – viruses, fungi and even parasites – and the oral and lung microbiome are also linked to mental and <a href="https://journals.physiology.org/doi/full/10.1152/physrev.00018.2018?rfr_dat=cr_pub">brain health</a>. </p>
<p>Importantly, we <a href="https://www.nature.com/articles/s41586-022-05620-1">share microbes</a> with others, including via the exchange of air, which is highly relevant in closed-environment systems such as inside spacecrafts.</p>
<p>So ensuring all astronauts have the healthiest and most diverse of microbes for the whole of the mission is vital.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-do-some-farts-smell-and-some-dont-and-why-do-some-farts-feel-hot-215064">Curious Kids: why do some farts smell and some don’t? And why do some farts feel hot?</a>
</strong>
</em>
</p>
<hr>
<h2>How could we encourage healthy microbes?</h2>
<p>It’s not just the food itself we have to think about. We also need to think about how we grow the food if we are to support healthy microbiomes. </p>
<p>Indeed, microbes play an essential role in the nutrient and phytochemical content of plants, and the microbes in soil, plants and humans are interconnected. Research published in 2023 confirms bacteria on vegetables and other plant foods find a home in the <a href="https://www.tandfonline.com/doi/abs/10.1080/19490976.2023.2258565">human gut</a>, enhancing microbe diversity. </p>
<p>But current ways of growing foods on spacecraft don’t use natural soil. Standard “vertical farming” methods grow plants in an alternative growth medium – imagine a next-generation hydroponics system. So we may need to add an optimised microbial cocktail to these systems to enhance the health properties of the foods astronauts grow and eat.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Growing tending plants in a vertical farm" src="https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=421&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=421&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=421&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=529&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=529&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=529&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This closed chamber mimics how astronauts will grow fresh crops in space.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/technology/tech-transfer-spinoffs/nasa-research-launches-a-new-generation-of-indoor-farming/">NASA</a></span>
</figcaption>
</figure>
<p><a href="https://www.cell.com/cell/fulltext/S0092-8674(22)01515-X?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS009286742201515X%3Fshowall%3Dtrue">Fermented protein</a> from microbes can be quickly produced in a bioreactor on board the spacecraft, even from food waste. Some types have a meat-like flavour and texture, and can provide all the amino acids humans need as well as useful byproducts from the microbes themselves. </p>
<p>Fermentation itself creates thousands of different bioactive molecules, including some vitamins, that have diverse <a href="https://www.tandfonline.com/doi/abs/10.1080/1028415X.2018.1544332">beneficial effects on health</a>, including possible benefits to mental health.</p>
<p>While we don’t yet know what types of fermented foods are possible in space, we could include fermented foods, such as kimchi and sauerkraut, in astronauts’ diets on Earth.</p>
<p>Probiotics and prebiotics as supplements may also be essential. Probiotics are live microbes that have demonstrated health benefits and prebiotics are food for these healthy microbes.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-kombucha-and-how-do-the-health-claims-stack-up-87180">What is kombucha and how do the health claims stack up?</a>
</strong>
</em>
</p>
<hr>
<h2>Benefits on Earth too</h2>
<p>We’re only at the start of learning how to optimise microbes to keep space crews healthy, which is crucial for long space flights and for possible settlement on other planets. </p>
<p>However, this research could have many other applications. We can use what we learn to help create self-sustaining and <a href="https://www.nasa.gov/technology/tech-transfer-spinoffs/nasa-research-launches-a-new-generation-of-indoor-farming/">sustainable food systems</a> on Earth to improve the environment and human health.</p><img src="https://counter.theconversation.com/content/216355/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Felice N Jacka is supported by a National Health and Medical Research Council investigator grant (#1194982). She has received: (1) competitive grant/research support from the Brain and Behaviour Research Institute, the National Health and Medical Research Council, Australian Rotary Health, the Geelong Medical Research Foundation, the Ian Potter Foundation, The University of Melbourne; (2) industry support for research from Meat and Livestock Australia, Woolworths Limited, the A2 Milk Company, Be Fit Foods, Bega Cheese; (3) philanthropic support from the Fernwood Foundation, Wilson Foundation, the JTM Foundation, the Serp Hills Foundation, the Roberts Family Foundation, the Waterloo Foundation and; (4) travel support and speakers honoraria from Sanofi-Synthelabo, Janssen Cilag, Servier, Pfizer, Network Nutrition, Angelini Farmaceutica, Eli Lilly, Metagenics, and The Beauty Chef. She is on the Scientific Advisory Board of the Dauten Family Centre for Bipolar Treatment Innovation and Zoe Limited. Felice Jacka has written two books for commercial publication.</span></em></p><p class="fine-print"><em><span>Dorit Donoviel is Executive Director, NASA-Funded Translational (moving products from lab-bench to practice) Research Institute for Space Health at Baylor College of Medicine. Dorit receives funding from NASA through Cooperative Agreement NNX16AO69A and disburses this funding to research groups and companies performing work to safeguard the health of humans in deep space.</span></em></p>Here’s why a healthy balance of microbes is important for astronauts when they travel to Mars and beyond.Felice Jacka, Alfred Deakin Professor, Deakin UniversityDorit Donoviel, Executive Director/Associate Professor, Baylor College of Medicine Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2150642023-12-06T00:00:07Z2023-12-06T00:00:07ZCurious Kids: why do some farts smell and some don’t? And why do some farts feel hot?<figure><img src="https://images.theconversation.com/files/563527/original/file-20231205-25-zu7j1t.jpg?ixlib=rb-1.1.0&rect=27%2C315%2C5979%2C3692&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://theconversation.com/drafts/219203/edit#">Shutterstock</a></span></figcaption></figure><blockquote>
<p><strong>Why do some farts smell and some don’t, and some feel hot? – Kian, age 6, from Maleny in Queensland</strong></p>
</blockquote>
<p><a href="https://theconversation.com/au/topics/curious-kids-36782"><img src="https://images.theconversation.com/files/291898/original/file-20190911-190031-enlxbk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=90&fit=crop&dpr=1" width="100%"></a></p>
<p>Hi Kian, thanks for your interesting questions!</p>
<p>Let’s start with the smell. Whether or not farts smell depends on what you’ve been eating and whether or not you have an upset tummy. </p>
<p>Having a tummy bug can also <a href="https://pubmed.ncbi.nlm.nih.gov/30191735/">change the smell of your poo</a>, especially if you have diarrhoea (runny poo). This is because of the smell of undigested food and the bugs, too.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-do-whales-fart-and-sneeze-159636">Curious kids: do whales fart and sneeze?</a>
</strong>
</em>
</p>
<hr>
<h2>Really smelly farts</h2>
<p>When you digest food your intestines produce gas as part of the normal process of breaking food down. </p>
<p>Most <a href="https://pubmed.ncbi.nlm.nih.gov/19830557/">gasses produced</a> – like carbon dioxide, nitrogen, hydrogen and methane – don’t smell at all. That is why you can fart sometimes and nobody really notices. </p>
<p>But there is one gas found in some farts that is <em>really</em> <em>really</em> smelly. It’s called <a href="https://www.health.wa.gov.au/articles/f_i/hydrogen-sulfide-and-public-health">hydrogen sulphide</a> and has the nickname “rotten egg gas” because that is exactly what it smells like. </p>
<p>This is why sometimes you can do a small fart but everyone has to hold their nose. These smelly farts contain <em>more</em> hydrogen sulphide.</p>
<h2>Food and farts</h2>
<p>If you eat foods that have a lot of sulphur, your gut will produce more hydrogen sulphide. </p>
<p>Some <a href="https://en.wikipedia.org/wiki/Brassica">vegetables</a> have a lot of <a href="https://www.healthline.com/nutrition/foods-with-sulfur#food-beverage-sources">sulphur</a>, such as broccoli, Brussels sprouts, cauliflower, cabbage, kale, turnips and Asian greens. </p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/10198924/">Meat</a> does too. If you eat a really huge piece of meat, your body can have trouble digesting it all at once. </p>
<figure class="align-center ">
<img alt="Digestive system" src="https://images.theconversation.com/files/563550/original/file-20231205-23-8elmtu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563550/original/file-20231205-23-8elmtu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563550/original/file-20231205-23-8elmtu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563550/original/file-20231205-23-8elmtu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563550/original/file-20231205-23-8elmtu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563550/original/file-20231205-23-8elmtu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563550/original/file-20231205-23-8elmtu.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">Food moves from our stomach, through our intestines, and out through the anus.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/medical-education-chart-biology-digestive-system-638539159">Shutterstock</a></span>
</figcaption>
</figure>
<p>As you digest food, it moves from your stomach into the <a href="https://www.healthdirect.gov.au/digestive-system#what-is">large intestine or colon</a>. Once the foods with sulphur get there, bugs in your gut break them down and produce the hydrogen sulphide gas. </p>
<p>If a lot of it builds up and gets released in a fart, it will be very, very smelly. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-much-food-should-my-child-be-eating-and-how-can-i-get-them-to-eat-more-healthily-130470">How much food should my child be eating? And how can I get them to eat more healthily?</a>
</strong>
</em>
</p>
<hr>
<h2>So why do farts sometimes feel hot?</h2>
<p>Farts sometimes feel hot because of the temperature difference between inside your body, which is a very warm 37 degrees, and the air temperature outside, which is usually cooler. </p>
<p>This means that fart gas feels hot as it moves from your large intestine, leaves through the opening in your bottom called the <a href="https://www.healthdirect.gov.au/digestive-system#what-is">anus</a>, and touches the cooler skin. </p>
<p>You’re not as likely to notice the temperature if farts comes out really fast because speedy ones don’t have as much contact with your bottom.</p>
<p>There is another reason why farts can feel hot. Sometimes people get a hot or burning feeling in their bottom after they eat really spicy food. This is due to a spicy food chemical called <a href="https://en.wikipedia.org/wiki/Capsaicin">capsaicin</a>. </p>
<figure class="align-center ">
<img alt="Older child eating spicy soup." src="https://images.theconversation.com/files/563551/original/file-20231205-15-82bjts.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563551/original/file-20231205-15-82bjts.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563551/original/file-20231205-15-82bjts.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563551/original/file-20231205-15-82bjts.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563551/original/file-20231205-15-82bjts.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563551/original/file-20231205-15-82bjts.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563551/original/file-20231205-15-82bjts.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">Sometimes farts feel hot after eating spicy foods.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/happy-boy-eating-noodles-long-hands-2370482909">Shutterstock</a></span>
</figcaption>
</figure>
<p>If you eat food that has chilli or hot spices in it, the capsaicin makes your mouth feel hot. When you eat lots and lots of spicy food, some of the capsaicin <a href="https://pubmed.ncbi.nlm.nih.gov/35644413/">travels all the way to your large intestine</a> and gets passed out in your poo. </p>
<p>The capsaicin then gives you a <a href="https://pubmed.ncbi.nlm.nih.gov/36601592/">hot feeling in your bottom</a> when you go to the toilet. The reaction is the same as that burning feeling in your mouth after eating spicy food, except it happens at the other end.</p>
<h2>Did you know there are fart-proof undies?</h2>
<p>Researchers did some experiments to test whether they could catch fart smells by getting people to wear <a href="https://pubmed.ncbi.nlm.nih.gov/15667499/">special undies</a> that can absorb hydrogen sulphide gas. </p>
<p>And the experiments worked! </p>
<p>Now a <a href="https://shreddies.com.au/about/">company in Australia sells</a> these undies to help people who have gut problems. Their company says it wants to help people “fart with confidence”.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-what-happens-when-you-hold-in-a-fart-98310">Health Check: what happens when you hold in a fart?</a>
</strong>
</em>
</p>
<hr>
<p><em>Hello, Curious Kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au</em></p><img src="https://counter.theconversation.com/content/215064/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Clare Collins AO is a Laureate Professor in Nutrition and Dietetics at the University of Newcastle, NSW and a Hunter Medical Research Institute (HMRI) affiliated researcher. She is a National Health and Medical Research Council (NHMRC) Leadership Fellow and has received research grants from NHMRC, ARC, MRFF, HMRI, Diabetes Australia, Heart Foundation, Bill and Melinda Gates Foundation, nib foundation, Rijk Zwaan Australia, WA Dept. Health, Meat and Livestock Australia, and Greater Charitable Foundation. She has consulted to SHINE Australia, Novo Nordisk, Quality Bakers, the Sax Institute, Dietitians Australia and the ABC. She was a team member conducting systematic reviews to inform the 2013 Australian Dietary Guidelines update and the Heart Foundation evidence reviews on meat and dietary patterns.</span></em></p>Kian, age 6, has some interesting questions about farts that we’re probably all wondering about.Clare Collins, Laureate Professor in Nutrition and Dietetics, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1930122022-11-29T02:03:17Z2022-11-29T02:03:17ZWhat did pregnancy do to my gut? From nausea to constipation and farting<figure><img src="https://images.theconversation.com/files/492934/original/file-20221102-23-ut9jtz.jpg?ixlib=rb-1.1.0&rect=1%2C0%2C997%2C666&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/pregnant-woman-nude-belly-holding-toilet-1867480576">Shutterstock</a></span></figcaption></figure><p>It’s two weeks after the birth of your healthy bub and you notice your gut isn’t feeling quite right. Maybe you feel a bit bloated. Maybe you’re farting more than usual.</p>
<p>What’s going on?</p>
<p>Pregnancy changes the structure and function of virtually every organ system, including some big changes to the gut. These changes can explain some common symptoms.</p>
<p>And no, you’re not imagining it. Some gut symptoms, such as constipation and gassiness, can hang around after you’ve given birth.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-what-causes-bloating-and-gassiness-107605">Health Check: what causes bloating and gassiness?</a>
</strong>
</em>
</p>
<hr>
<h2>Nausea is common</h2>
<p>The <a href="https://www.health.gov.au/resources/pregnancy-care-guidelines/part-i-common-conditions-during-pregnancy/nausea-and-vomiting">most common</a> gut symptom in pregnancy is nausea, which affects up to <a href="https://pubmed.ncbi.nlm.nih.gov/30786126/">85% of women</a> in the first trimester. </p>
<p>This is thought to be largely due to the effects of the hormone <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3676933">human chorionic gonadotropin</a>.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1586881849862733824"}"></div></p>
<p>Levels of the hormone are highest at the end of the first trimester and start to level off for the rest of the pregnancy. That explains why nausea tends to become less common <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3676933">as your pregnancy progresses</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-what-can-you-eat-to-help-ease-morning-sickness-in-pregnancy-55039">Health Check: what can you eat to help ease 'morning' sickness in pregnancy?</a>
</strong>
</em>
</p>
<hr>
<h2>Reflux can be painful</h2>
<p>Other hormonal changes can lead you to develop another common symptom, <a href="https://pubmed.ncbi.nlm.nih.gov/17662101">reflux</a>.</p>
<p>Levels of the hormone progesterone, for instance, steadily rise over the course of a pregnancy. This can lead to the oesophageal sphincter muscle – which is at the lower end of your food pipe, before it meets the stomach – to become more lax.</p>
<p>The loosening of this muscle makes it easier for stomach acid to move back up into the food pipe. This can cause a painful burning sensation in the upper part of your abdomen or just behind the breastbone.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1587582167294492674"}"></div></p>
<p>Later in the pregnancy, your growing uterus and baby can start to really push up on your stomach. </p>
<p>This can also lead to <a href="https://pubmed.ncbi.nlm.nih.gov/14705378">reflux</a> as direct pressure on the stomach forces stomach acid back into the food pipe.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-what-is-gastric-reflux-18791">Explainer: what is gastric reflux?</a>
</strong>
</em>
</p>
<hr>
<h2>Is constipation normal? And haemorrhoids?</h2>
<p>Increased levels of progesterone and the hormone oestrogen lead to a decrease in muscular contractions (peristalsis) throughout the gut. </p>
<p>This means you’re more likely to become constipated during pregnancy. Constipation affects about <a href="https://pubmed.ncbi.nlm.nih.gov/9609265">40% of pregnant women</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/493213/original/file-20221103-23-ldyjhf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Pregnant women sitting on toilet, holding tummy" src="https://images.theconversation.com/files/493213/original/file-20221103-23-ldyjhf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/493213/original/file-20221103-23-ldyjhf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/493213/original/file-20221103-23-ldyjhf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/493213/original/file-20221103-23-ldyjhf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/493213/original/file-20221103-23-ldyjhf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/493213/original/file-20221103-23-ldyjhf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/493213/original/file-20221103-23-ldyjhf.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">Constipation and haemorrhoids are common in pregnancy.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/constipation-pregnant-women-648533710">Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-what-causes-constipation-114290">Health Check: what causes constipation?</a>
</strong>
</em>
</p>
<hr>
<p>Increased levels of oestrogen also lead to your blood vessels and connective tissue (tissue that connect one type to another, such as ligaments) becoming softer. </p>
<p>This, plus pressure from the growing baby, and increased blood volume and flow, can contribute to the development of <a href="https://pubmed.ncbi.nlm.nih.gov/25633397">haemorrhoids</a> – columns of cushioned tissue and blood vessels found close to the opening of the anus.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-why-do-people-get-haemorrhoids-and-how-do-you-get-rid-of-them-94820">Explainer: why do people get haemorrhoids and how do you get rid of them?</a>
</strong>
</em>
</p>
<hr>
<p>Your body also needs more water and sodium in pregnancy to help produce amniotic fluid (liquid that surrounds the growing baby in the uterus) and build the blood supply of the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1595116">growing baby</a>. This necessary water and sodium is absorbed from your intestines and can contribute to constipation, and an increased risk of haemorrhoids. </p>
<p>Haemorrhoids are very common during pregnancy. <a href="https://pubmed.ncbi.nlm.nih.gov/6861574">One study</a> found 86% of pregnant women reported them.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-why-do-people-get-haemorrhoids-and-how-do-you-get-rid-of-them-94820">Explainer: why do people get haemorrhoids and how do you get rid of them?</a>
</strong>
</em>
</p>
<hr>
<h2>No wonder I feel full</h2>
<p>Oestrogen is thought to be <a href="https://journals.physiology.org/doi/full/10.1152/ajpregu.2001.280.5.R1546">responsible</a> for decreasing the movement of the stomach in pregnancy, keeping the food in the stomach longer and making it more likely you’ll feel full. </p>
<p>During the third trimester, your growing uterus and baby also start to really push up on the abdominal organs. No wonder you’re likely to feel pressure on your stomach and discomfort the closer you are to the end of your pregnancy.</p>
<p>You can also feel pressure at the other end of the gut. Pressure from the expanding uterus on the end part of the colon (the sigmoid colon) can also make you feel constipated even if you’re not. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/mega-study-confirms-pregnant-women-can-reduce-risk-of-stillbirth-by-sleeping-on-their-side-114601">Mega study confirms pregnant women can reduce risk of stillbirth by sleeping on their side</a>
</strong>
</em>
</p>
<hr>
<h2>I have incontinence. Is that because of how I gave birth?</h2>
<p>There has been a lot of debate about whether urinary or faecal incontinence is more likely after a vaginal or a caesarean birth.</p>
<p>However, the strongest evidence we have suggests the mode of birth <a href="https://obgyn.onlinelibrary.wiley.com/doi/full/10.1111/aogs.14027">makes no difference</a>. If you’ve had incontinence <a href="https://obgyn.onlinelibrary.wiley.com/doi/full/10.1111/aogs.14027">during pregnancy</a> this is the <a href="https://pubmed.ncbi.nlm.nih.gov/31273486/">strongest predictor</a> of having it afterwards.</p>
<p>Urinary incontinence that doesn’t improve within three months of giving birth is more likely to <a href="https://link.springer.com/article/10.1007/s00192-018-3577-7">persist</a>. So if you’ve experienced this during pregnancy, you might like to see a <a href="https://bjsm.bmj.com/content/48/4/299.short?casa_token=Kp_p41d8NRsAAAAA:nxhZxxJFfU1RpW44GFPYa2kr6tnV4ObnyxeLawhjSHWRYHozfUU_Zp5qiFXkrlWqEu6JynLcYhdt">pelvic floor physio</a>. </p>
<p>Fortunately, faecal incontinence after pregnancy is very uncommon, affecting only <a href="https://pubmed.ncbi.nlm.nih.gov/25803402">around 3%</a> of women. However if this persists, please seek medical attention.</p>
<h2>Why am I still constipated?</h2>
<p>A <a href="https://pubmed.ncbi.nlm.nih.gov/33030260/">study from Finland</a> on more than 400 women found constipation affected 47% of women in the first few days after a vaginal birth and 57% of women in the first few days after a caesarean.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1209260992011685888"}"></div></p>
<p>The researchers suggested this may be caused by too much physical inactivity and insufficient intake of fluids after birth, or the effects of anaesthetic and disturbance to the intestines during surgery. </p>
<p>One month after childbirth, constipation became less common. Some 9% of women were constipated after a vaginal birth and 15% after a caesarean.</p>
<h2>Feeling gassy? No, you’re not imaging it</h2>
<p>The Finnish study also found excess farting is extremely common a few days after birth. It affected 81% of women but this number dropped to 30% one month after birth. </p>
<p>Bloating is another common symptom found a few days after birth affecting 59% of women, and this decreases to 14% of women one month afterwards.</p>
<p>So why is this happening? We can look to your gut microbiome for clues. This is the unique universe of micro-organisms (bugs), and their genes, that live in your gut.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/YB-8JEo_0bI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Remind me again, what is the microbiome?</span></figcaption>
</figure>
<p>During and after pregnancy, there are <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5648614/">profound changes</a> to the gut microbiome. These may cause an increase in gas production or lead to constipation.</p>
<p>So the good news from the Finnish study is that normal bowel function is restored quickly after childbirth for most women, but might be a touch longer for women after a caesarean.</p>
<hr>
<p><em>If you’re concerned about gut symptoms during or after pregnancy, seek advice from a health-care professional, who can discuss treatment and referral options.</em></p><img src="https://counter.theconversation.com/content/193012/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kate Levett receives funding from an NHMRC Early Career Fellowship. </span></em></p><p class="fine-print"><em><span>Vincent Ho 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>Pregnancy changes the structure and function of virtually every organ system of the body. That includes some big changes to the gut.Vincent Ho, Senior Lecturer and clinical academic gastroenterologist, Western Sydney UniversityKate Levett, Research Fellow University of Notre Dame Australia; Adjunct Fellow (National Institute of Complementary Medicine), Western Sydney University, University of Notre Dame AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1909772022-11-14T23:51:50Z2022-11-14T23:51:50ZWhy am I bloated? Here are some possibilities to consider<figure><img src="https://images.theconversation.com/files/490750/original/file-20221019-22-3mizfu.jpg?ixlib=rb-1.1.0&rect=0%2C17%2C6000%2C3970&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.pexels.com/photo/person-suffering-from-a-stomach-pain-5938364/">Photo by Sora Shimazaki/Pexels</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>If your tummy seems to feel full or stretched and is rumbling all the time, you’re not alone. Up to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6824367/#CR2">30%</a> of people of all ages experience bloating, with symptoms such as gassiness, a sense of fullness and pressure.</p>
<p>This can be with or without <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6824367/pdf/12325_2019_Article_924.pdf">distention</a> (a visible increase in abdominal girth).</p>
<p>So what might be behind your bloating? </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-poo-dose-a-day-may-keep-bipolar-away-when-it-comes-to-mental-health-what-else-could-poo-do-177748">A poo dose a day may keep bipolar away. When it comes to mental health, what else could poo do?</a>
</strong>
</em>
</p>
<hr>
<h2>The role of gas</h2>
<p>Bloating is in fact a complex condition that can be caused by several direct and indirect factors. Gas often plays a role.</p>
<p>Gas production in the digestive system is part of the normal digestion process, and is released through the mouth (burps) or anus (farts). </p>
<p>On average, our gas expulsion is around <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3264926">600–700 millilitres</a> per day, resulting in around 14 farts a day. That said, there isn’t a set number for the normal amount of gas or expulsions; each body is different. </p>
<p>Bloating can occur as a result of retained gas, excess gas production, altered gas transit (changes in the speed and movement of gas), or intestinal hypersensitivity.</p>
<p>An imbalanced gut microbiome can lead to the overproduction of gas.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/YB-8JEo_0bI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">What is the human microbiome?</span></figcaption>
</figure>
<p>We have more than <a href="https://www.nature.com/articles/nature.2016.19136%5D">40 trillion microbes</a> living in and on our body. They can be helpful or harmful. The balance between these helpful and harmful microbes plays an important role in our immune response, metabolism and health.</p>
<p>These bacteria need food to survive. Their food comes from fermenting carbohydrates such as dietary fibre from the plants we eat. </p>
<p>One of the byproducts of this fermentation process is hydrogen gas. </p>
<p>Most of these microbes live in the lower parts of our intestine (colon). The upper parts of the intestine (small intestine) have far fewer microbes. </p>
<p>But if an excessive number of microbes colonise the small intestine (a condition known as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5347643/">small intestine bacterial overgrowth</a>), more gas is produced in the small intestine. </p>
<p>This can lead to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5350578/">bloating, abdominal discomfort, diarrhoea and nausea</a>.</p>
<h2>Could it be IBS, lactose issues or FODMAPs?</h2>
<p>Some disorders of the intestine and colon can affect the amount of gas and severity of bloating symptoms. </p>
<p>For example, in <a href="https://theconversation.com/health-check-what-causes-constipation-114290">constipation</a>, movement of stools is reduced, allowing more time for the bacteria to ferment the stool content, increasing gas production.</p>
<p>Bloating is also very common in people with irritable bowel syndrom (<a href="https://theconversation.com/explainer-what-is-irritable-bowel-syndrome-34039">IBS</a>). </p>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5350578/">Changes</a> in gut muscle tone and greater sensitivity to gas contribute to bloating in IBS sufferers.</p>
<p>Bloating may also occur because of poor digestion and malabsorption of some <a href="https://pubmed.ncbi.nlm.nih.gov/35565890/">carbohydrates</a>.</p>
<p>Lactose malabsorption (in those with lactose intolerance) is a common issue.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/491203/original/file-20221023-68927-dnas7u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Milk is poured into a bowl of cereal." src="https://images.theconversation.com/files/491203/original/file-20221023-68927-dnas7u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/491203/original/file-20221023-68927-dnas7u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/491203/original/file-20221023-68927-dnas7u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/491203/original/file-20221023-68927-dnas7u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/491203/original/file-20221023-68927-dnas7u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/491203/original/file-20221023-68927-dnas7u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/491203/original/file-20221023-68927-dnas7u.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 malabsorption (in those with lactose intolerance) can cause gut problems for some people.</span>
<span class="attribution"><a class="source" href="https://pixabay.com/photos/berry-breakfast-cereal-milk-cream-4336049/">Image by Bogdan Sanfira from Pixabay</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Symptoms may also occur with other digestive resistant short-chain carbohydrates known as <a href="https://pubmed.ncbi.nlm.nih.gov/25982757/">FODMAPs</a> (fermentable oligo-, di-, monosaccharides and polyols). </p>
<p>FODMAPs are found in a wide variety of foods, including certain fruit and vegetables, grains and cereals, nuts, legumes, lentils and dairy foods.</p>
<p>While these are good foods for our gut bacteria, they can add to gas production and trigger bloating symptoms, especially in people with digestive disorders (like IBS). They can also <a href="https://theconversation.com/the-fodmap-diet-is-everywhere-but-researchers-warn-its-not-for-weight-loss-131550">cause water to be drawn into the intestines</a>, causing distension. This can contribute to bloating.</p>
<h2>Other factors: salt, hormones or swallowing air</h2>
<p>There are of course other factors that could be behind bloating. </p>
<p>For example, consuming too much sodium or salt in your diet causes water retention, resulting in abdominal distention. But this may also <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7122060/">alter</a> the gut microbiome and influence gas production. </p>
<p>For many women, bloating can be linked to the menstrual cycle phase. This is most common at the onset of bleeding, when peak <a href="https://pubmed.ncbi.nlm.nih.gov/15808287/">fluid retention occurs</a>, but is also related to <a href="https://www.hindawi.com/journals/ogi/2011/138451/">underlying hormonal changes</a>. </p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/19602452/">Swallowing too much air</a>, especially when eating, can also increase the amount of gas entering the gastrointestinal tract and lead to bloating. </p>
<p>Talking while eating, eating in a rush, and carbonated beverages can also increase the amount of air swallowed.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/491204/original/file-20221023-17-7h24gx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two people walk and chat while eating." src="https://images.theconversation.com/files/491204/original/file-20221023-17-7h24gx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/491204/original/file-20221023-17-7h24gx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/491204/original/file-20221023-17-7h24gx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/491204/original/file-20221023-17-7h24gx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/491204/original/file-20221023-17-7h24gx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/491204/original/file-20221023-17-7h24gx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/491204/original/file-20221023-17-7h24gx.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">Talking while eating and eating in a rush can increase the amount of air swallowed.</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/women-eating-while-walking-at-the-park-8165247/">Photo by MART PRODUCTION/Pexels</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>How can I reduce bloating?</h2>
<p>Dietary strategies can be effective ways of managing bloating. While foods that trigger symptoms can be different for everyone, you could try to:</p>
<ul>
<li><p><a href="https://pubmed.ncbi.nlm.nih.gov/28846594/">eat fewer gas-producing FODMAP foods</a> such as onion, cabbage, brussels sprouts, cauliflower, dried beans and lentils</p></li>
<li><p>eat fewer foods containing lactose, like milk, ice-cream and some yoghurts (there are lactose-free alternatives for people with intolerance)</p></li>
<li><p>replace carbonated drinks such as soft-drinks with water, and drink less alcohol</p></li>
<li><p>consume more <a href="https://pubmed.ncbi.nlm.nih.gov/29460487/">probiotics</a> (such as yoghurt or certain fermented foods)</p></li>
<li><p>do more exercise, as mild physical activity enhances intestinal gas clearance and can <a href="https://pubmed.ncbi.nlm.nih.gov/17029608/">reduce symptoms of abdominal bloating</a></p></li>
<li><p>eat and drink more slowly; taking your time means you can enjoy your food, but will also help you swallow less air.</p></li>
</ul>
<p>See an accredited practising dietitian for personalised advice on managing symptoms using dietary strategies.</p>
<h2>When to see a GP</h2>
<p>Most of the time, bloating goes away soon enough and is no cause for concern. But consider seeing a doctor if:</p>
<ul>
<li><p>your gas is persistent and severe and it’s impacting your quality of life</p></li>
<li><p>your gas is associated with other symptoms such as vomiting, diarrhoea, constipation, unintentional weight loss or blood in the stool.</p></li>
</ul>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-should-healthy-people-take-probiotic-supplements-95861">Health Check: should healthy people take probiotic supplements?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/190977/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Khalesi was supported by a Postdoctoral Fellowship (Award No. 102584) from the National Heart Foundation of Australia. </span></em></p><p class="fine-print"><em><span>Chris Irwin 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>Gas often plays a role in bloating. On average, our gas expulsion is around 600–700 mL per day, resulting in around 14 farts a day.Saman Khalesi, Postdoctoral Fellow of the National Heart Foundation & Senior Lecturer and Discipline Lead in Nutrition, School of Health, Medical and Applied Sciences, CQUniversity AustraliaChris Irwin, Senior Lecturer in Nutrition and Dietetics, School of Health Sciences & Social Work, Griffith UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1596362021-05-03T20:07:24Z2021-05-03T20:07:24ZCurious kids: do whales fart and sneeze?<figure><img src="https://images.theconversation.com/files/398272/original/file-20210503-17-10vkbfa.png?ixlib=rb-1.1.0&rect=664%2C0%2C3329%2C2000&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Wes Mountain/The Conversation</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><blockquote>
<p>Do whales fart and sneeze? — Guy, age 8, Sydney</p>
</blockquote>
<p><a href="https://theconversation.com/au/topics/curious-kids-36782"><img src="https://images.theconversation.com/files/291898/original/file-20190911-190031-enlxbk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=90&fit=crop&dpr=1" width="100%"></a></p>
<p>I’ve waited a long time for a question like this! I usually talk about whale snot for my research (yes, whales have snot), and I’m so excited to look into this, too.</p>
<h2>Let’s start with the tail end first: farts</h2>
<p>Yes, whales do fart. Can you imagine the size and bubbles of a fart from the world’s biggest animal, the blue whale? </p>
<p>I’m yet to experience this, but I know of some lucky scientists who have seen a humpback whale fart. They tell me it looks like bubbles coming out underneath its body near the tail. That’s where the whale bum is — the smellier blowhole. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/5mEePulli3c?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Most likely a humpback whale fart. Sound effect added.</span></figcaption>
</figure>
<p>Whales are <a href="https://australian.museum/learn/species-identification/ask-an-expert/what-is-a-mammal/">mammals</a>, just like us. This means they breathe air, give birth to live young, provide their young with milk and have hair, usually in the form of whiskers around their mouth. They also have digestive processes to help break down their food. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-what-sea-creature-can-attack-and-win-over-a-blue-whale-98551">Curious Kids: What sea creature can attack and win over a blue whale?</a>
</strong>
</em>
</p>
<hr>
<p>Unlike us, whales don’t chew their food but swallow it whole. <a href="https://www.smithsonianmag.com/science-nature/history-toothless-whales-180964717/">Baleen</a> or toothless whales, for example, use long hair-like structures to feed on krill and fish. Their food is later broken down across four stomach chambers. </p>
<p>As their bodies break this food down (via stomach acid), it produces gases, which are released as farts and eventually poo. </p>
<p>In fact, whale poo is one of the coolest looking in the animal kingdom. Blue whale poo can be bright orange! </p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CN8x-_FDyBb/?utm_source=ig_web_copy_link","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>Back to the top end: do whales sneeze?</h2>
<p>The short answer, no. </p>
<p>Unlike us, whales need to think about breathing. When they want to take a breath, they need to swim to the surface. If they don’t, they could drown. </p>
<p>This means whales also <a href="https://www.scientificamerican.com/article/how-do-whales-and-dolphin/">sleep</a> differently to us. They can rest different parts of their brain at a time, and take naps before rising to the surface to breathe. </p>
<p>And unlike us, they can’t breathe through their mouth and instead use their blowhole or nose to breath. This is like having an inbuilt snorkel on top of their head. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-do-sharks-sneeze-77399">Curious Kids: Do sharks sneeze?</a>
</strong>
</em>
</p>
<hr>
<p>This makes it much easier for them to swim, breathe and eat — all at the same time. And they don’t have to worry about food going down the wrong way as their air and lung passages are separated. </p>
<p>We sneeze automatically and involuntarily if something tickles our nose. If whales get something caught in their noses, they could clear it using a big exhale through their blowhole, like blowing their nose. This would serve a similar function to our sneezing.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/397733/original/file-20210429-23-178ee7e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397733/original/file-20210429-23-178ee7e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397733/original/file-20210429-23-178ee7e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397733/original/file-20210429-23-178ee7e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397733/original/file-20210429-23-178ee7e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397733/original/file-20210429-23-178ee7e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397733/original/file-20210429-23-178ee7e.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">A humpback whale takes a breath in Antarctica.</span>
<span class="attribution"><span class="source">Dr Vanessa Pirotta</span></span>
</figcaption>
</figure>
<h2>BUT, if a whale were to sneeze…</h2>
<p>It would be big! For comparison, an adult human’s lungs can hold around six litres of air. But a humpback whale can hold over 1,000 litres — that’s a lot of bubbles! </p>
<p>You can actually see a whale’s breath: it’s a mixture of lung bacteria, hormones, proteins and lipids. It’s officially called “whale lung microbiota” — or whale snot — and looks like water droplets. </p>
<p>As a scientist, I use <a href="https://www.frontiersin.org/articles/10.3389/fmars.2017.00425/full">drones</a> to sample whale snot to learn more about whale health. </p>
<p>We found the whales off Sydney didn’t even know their snot was being collected through this method. This is much safer for the whales and us as researchers as we don’t need to get close to each other. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/edS1uhO4LUw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Humpback whale snot collection via research drone off Sydney.</span></figcaption>
</figure>
<p>Well there you have it, we’ve covered both ends of a whale. They’re incredible creatures who do enormous farts — thanks for the question! </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-have-people-ever-seen-a-colossal-squid-137398">Curious Kids: have people ever seen a colossal squid?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/159636/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vanessa Pirotta 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>Human farts and sneezes can be big — so imagine the size if they came from the world’s biggest animals?Vanessa Pirotta, Wildlife scientist, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1219592019-09-09T11:32:31Z2019-09-09T11:32:31ZWhy do burps make noise?<figure><img src="https://images.theconversation.com/files/291385/original/file-20190908-175678-cay7uu.jpg?ixlib=rb-1.1.0&rect=769%2C412%2C4618%2C3656&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Pardon me!</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/surprised-child-covering-his-mouth-isolated-1457690660">Gelpi/Shutterstock.com</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">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<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>
<hr>
<blockquote>
<p><strong>Why does burping make noise? – Henry E., age 8, Somerville, Massachusetts</strong></p>
</blockquote>
<hr>
<p>Burping is a normal part of everyday life.</p>
<p><a href="https://doi.org/10.1016/j.cgh.2012.09.006">Burps happen when air</a> from your stomach travels back up your food tube – called an esophagus – to your mouth. Air gets into your stomach during activities like eating or drinking. If you drink things that contain lots of gas – like the carbon dioxide in bubbly sodas, for example – you’ll probably burp more than usual since the gas you swallowed has to come back out somehow.</p>
<p>Burping is important. If you don’t let the air in your stomach up and out, it heads down deeper into your digestive system. It can cause a lot of bloating and discomfort in your intestines. </p>
<p>That explains <a href="https://doi.org/10.1007/s00455-015-9674-6">why people burp</a>. But why does a burp make noise? </p>
<p>As the burp travels up the esophagus, it hits up against a closed, valve-like structure called a sphincter. Trapped behind that sphincter muscle, the gas builds up a lot of pressure.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/291298/original/file-20190906-175700-ehc3pl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/291298/original/file-20190906-175700-ehc3pl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/291298/original/file-20190906-175700-ehc3pl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/291298/original/file-20190906-175700-ehc3pl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/291298/original/file-20190906-175700-ehc3pl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/291298/original/file-20190906-175700-ehc3pl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/291298/original/file-20190906-175700-ehc3pl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/291298/original/file-20190906-175700-ehc3pl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A burp is gas that’s risen up to your mouth from your stomach via your esophagus. The sphincter at the top of your esophagus is like a gate that either keeps that gas in or lets it free.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/belching-air-stomach-structure-esophagus-infographics-386247529">Timonina/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>It’s really hard to hold back a burp. When it finally forces its way through, the high-pressure air makes the structures in the upper esophagus and back of the throat vibrate – and that’s what causes the sound.</p>
<p>If you forcibly push the burp through, it increases the pressure in your esophagus, causing more intense vibrations and making the burp louder – more like a “BUURRRPP” or a “BRAAAPPP!” These are the belches that usually make your parents cringe and your friends give you high-fives.</p>
<p>If you gently open up your sphincter, it lowers the pressure in your esophagus and allows for less intense vibrations. These burps are more likely to be on the daintier side – more like a quieter “erp” – so probably your best bet for weddings or funerals.</p>
<p>The sound of the burp can take on even cooler and weirder tones depending on how you move your mouth and tongue around. This is how you can even form words or – for the truly talented – songs with burping. </p>
<p>So what happens if you have other gasses in the digestive system that are too far down to come up as a burp? <a href="https://doi.org/10.1136/gut.2004.048868">That gas can become a fart</a>. When you fart, gas leaves your body through another closed, valve-like structure – a different sphincter. This one happens to be called the anus.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/291386/original/file-20190908-175682-v6dxly.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/291386/original/file-20190908-175682-v6dxly.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/291386/original/file-20190908-175682-v6dxly.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=691&fit=crop&dpr=1 600w, https://images.theconversation.com/files/291386/original/file-20190908-175682-v6dxly.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=691&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/291386/original/file-20190908-175682-v6dxly.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=691&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/291386/original/file-20190908-175682-v6dxly.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=868&fit=crop&dpr=1 754w, https://images.theconversation.com/files/291386/original/file-20190908-175682-v6dxly.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=868&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/291386/original/file-20190908-175682-v6dxly.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=868&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Releasing gas is natural and healthy.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/little-child-girl-holding-white-paper-1119820913">GOLFX/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>As the gas builds up in pressure, often with a little help from your butt muscles, it causes that sphincter to finally open up. And the anus structures vibrate just like the structures in your throat during a burp. And there’s your fart.</p>
<p>So the next time someone says you’re burping too loudly, just reassure them that it was a perfectly normal mouth fart. That will probably go over well. You can always point out that at least it wasn’t a fart from the other end.</p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
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<p class="fine-print"><em><span>George Saffouri 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>Oh! Excuse me! Please pardon my sphincter, esophagus and throat.George Saffouri, Assistant Clinical Professor of Health Sciences, Gastroenterology & Hepatology, University of California, RiversideLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1147472019-05-13T01:24:45Z2019-05-13T01:24:45ZCurious Kids: can snails fart?<figure><img src="https://images.theconversation.com/files/273442/original/file-20190509-183083-1h0zppr.jpg?ixlib=rb-1.1.0&rect=17%2C0%2C5973%2C3988&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Scientists built a small database showing which animals do and don't fart. Not every animal in the world is on there, but it does have moon snails listed as a no.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/myfwcmedia/31644390107/in/photolist-QdiLGT-8idBmC-7aAYsr-5MNam6-24NRyyi-dBq6fs-6GwaZd-dBq69f-6q61K2-dFDzz-5MNa3g-6sa8Vr-24Q2AGN-otnouk-HYFZwH-d6aweo-zGDLd6-8cdZdZ-bVRLWE-2cUHMef-GGn5tw-bxCmZV-4fPMsg-799XZf-92Mpfc-793zTp-793zTi-PTKouj-2ewMS6L-fd6kdU-2e82rSS-nzG4HA-fsRcg7-2djh2dq-2a2cef4-fozGsj-fsRccS-GRpcR-fuZMUG-fd6kwd-5yPu5e-jS8aN-6wsShj-8chmkN-217nSjB-8hqzcx-iX6dfD-LjATey-CQNGjM-8iaqYF">Flickr/Florida Fish and Wildlife</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p><em><a href="https://theconversation.com/au/topics/curious-kids-36782">Curious Kids</a> is a series for children. If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.edu.au You might also like the podcast <a href="http://www.abc.net.au/kidslisten/imagine-this/">Imagine This</a>, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.</em> </p>
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<p><strong>Can snails fart? Thank you. – Avalon, age 9, Scotts Head, NSW.</strong></p>
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<p>Lots of animals fart because of what they eat, but it was not easy for me to find a clear answer on whether snails really do. <a href="https://scielo.conicyt.cl/scielo.php?pid=s0716-97602006000500010&script=sci_arttext">More research is needed</a> to know exactly how the digestive system of a snail really works. </p>
<p>You might have heard about methane. It is a gas found in a lot of animal farts. I did find one <a href="https://scielo.conicyt.cl/scielo.php?pid=s0716-97602006000500010&script=sci_arttext">study</a> that said that scientists kept some snails in a glass container for one day and one night and checked if they would produce methane. And the snails did not. </p>
<p>(For the adults in the audience, the paper noted that, “In this aspect, the structure of the microbiota and in consequence the functioning of the digestive microbial ecosystem of the snails differs markedly from those of vertebrates, especially herbivores.”)</p>
<p>You may have seen <a href="https://www.washingtonpost.com/news/animalia/wp/2017/01/11/scientists-are-building-an-animal-fart-database/?utm_term=.defcbeff3d59">reports</a> that scientists built a <a href="https://docs.google.com/spreadsheets/d/19gMMn4Wmw3BNLWMojEy7kgrjnjVB2JlMSwd1s-nYyUc/edit#gid=0">database</a> showing which animals do and don’t fart. Not every animal in the world is on there, but it does say that mussels and clams (which, like snails, are part of a group of animals called molluscs) do not fart. Moon snails, which live in the sea, were also listed as a no.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/273437/original/file-20190509-183080-1sl7bcb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/273437/original/file-20190509-183080-1sl7bcb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/273437/original/file-20190509-183080-1sl7bcb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/273437/original/file-20190509-183080-1sl7bcb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/273437/original/file-20190509-183080-1sl7bcb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/273437/original/file-20190509-183080-1sl7bcb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/273437/original/file-20190509-183080-1sl7bcb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/273437/original/file-20190509-183080-1sl7bcb.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"></a>
<figcaption>
<span class="caption">One thing we do know is that a snail’s bottom is right near its head.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/tamaki/1004370/in/photolist-24iYC6-67dSQX-8fJQ5r-9zmAeV-okLaNr-69yJ-6KsPi5-8TCGJU-SSXu6T-ehCvbY-c7Zvk1-6dkbT9-ehCyPw-82K8xC-ehwsmM-fv9Rfj-7Jy3RX-akKBie-ehwwuk-ehwvLV-8vuKQ9-oRL71m-J1qQmj-nkAKnZ-5sVWLm-Wdv82M-gJXaz-aDKcaM-ehwwSg-ehCsTu-85WRzn-2BBxnt-ehCe5W-sHXqfv-6uQtVR-8Vp5g-7Wczwa-eagc6-6BHzR5-5tmhDi-2j1eMY-mB4RFb-uet9f-cnyLA-oPRGU9-gXXuv-pJGun3-82kMKh-kABNVb-Wo3e3/">Flickr/Yamanaka Tamaki</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
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Read more:
<a href="https://theconversation.com/curious-kids-how-long-would-garden-snails-live-if-they-were-not-eaten-by-another-animal-114746">Curious Kids: How long would garden snails live if they were not eaten by another animal?</a>
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<p>One thing I can tell you is that a snail’s bottom is right over its head. This is because snails are very different from other molluscs (which includes things like octopus and squid as well). Because they are squashed into a protective shell, their body is twisted round to fit in. As a result, their bottom is just above and to the side of where their head comes out. </p>
<h2>Gassy molluscs</h2>
<p>Water snails, mussels and other molluscs do <a href="https://www.ncbi.nlm.nih.gov/pubmed/22830624">produce a gas</a> called <a href="https://www.theguardian.com/environment/shortcuts/2017/oct/16/are-flatulent-shellfish-really-contributing-to-climate-change">nitrous oxide</a> if they live in polluted water. </p>
<p>You might have heard of nitrous oxide. It’s also called “laughing gas”. But this can be a problem, as nitrous oxide is a greenhouse gas and lots of it will add to climate change.</p>
<p>These mussels, when they are not producing laughing gas, produce something called “pseudo-faeces” which literally means “false poo”. Because the food they eat (little plants and animals floating in the water which they suck in) can contain a lot of sand, they sometimes have to squirt it all out. This doesn’t come out of their bottom, but out of something called a siphon, through which they suck their food.</p>
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Read more:
<a href="https://theconversation.com/curious-kids-is-water-blue-or-is-it-just-reflecting-off-the-sky-113199">Curious Kids: is water blue or is it just reflecting off the sky?</a>
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<p><em>Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au</em></p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&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="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p><em>Please tell us your name, age and which city you live in. We won’t be able to answer every question but we will do our best.</em></p><img src="https://counter.theconversation.com/content/114747/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bill Bateman 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>One thing I can tell you is that a snail’s bottom is right over its head.Bill Bateman, Associate professor, Curtin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1076052019-01-29T08:06:16Z2019-01-29T08:06:16ZHealth Check: what causes bloating and gassiness?<figure><img src="https://images.theconversation.com/files/256029/original/file-20190129-127151-jj2o3o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">One in six healthy people report problems with bloating.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/95720971?src=0shmPAu3WYTp1m41U5daMw-1-22&size=huge_jpg">Alice Day/Shutterstock</a></span></figcaption></figure><p>Your trousers fit when you put them on in the morning. But come mid-afternoon, they’re uncomfortably tight – and you didn’t even overdo it at lunchtime. Sound familiar?</p>
<p>Around <a href="https://www.ncbi.nlm.nih.gov/pubmed/9772037">one in six people</a> without a health problem and <a href="https://www.ncbi.nlm.nih.gov/pubmed/11774947">three in four people</a> with irritable bowel syndrome (IBS) report problems with bloating. In fact, for people with IBS and constipation, bloating is their <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4893246/">most troublesome</a> symptom.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-what-is-irritable-bowel-syndrome-and-what-can-i-do-about-it-102579">Explainer: what is irritable bowel syndrome and what can I do about it?</a>
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<p>Bloating is, of course, a feeling of increased abdominal pressure, usually related to gas. It may or may not be accompanied by visible enlargement of the waist (known as abdominal distension).</p>
<p>But contrary to popular belief, bloating and abdominal distention isn’t caused by an excessive production of gas in the intestines.</p>
<h2>What causes intestinal gas?</h2>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3264926/">Gas in the upper gut</a> can come from swallowed air, chemical reactions (from neutralising acids and alkali) triggered by food, and dissolved gas moving from the bloodstream into the gut. </p>
<p>Food products that are <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3966170/">poorly absorbed</a> in the small intestine can travel lower down to the large intestine where they’re fermented by bacteria. This process can produce carbon dioxide, hydrogen or methane gas.</p>
<p><a href="https://www.ncbi.nlm.nih.gov/pubmed/16143143">Gas from the gut</a> can come out through belching or passing wind, or by being absorbed into the blood or consumed by bacteria. </p>
<h2>How much wind is normal?</h2>
<p>Back in 1991, researchers in the UK <a href="https://www.ncbi.nlm.nih.gov/pubmed/1648028">tracked the farts</a> of ten healthy volunteers. The volume of gas they expelled in a day varied from 214 mls (on a low-fibre diet) to 705 mls (on a high fibre diet). </p>
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Read more:
<a href="https://theconversation.com/health-check-what-happens-when-you-hold-in-a-fart-98310">Health Check: what happens when you hold in a fart?</a>
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<p>The participants passed wind an average of 14 to 18 times per day, and it was comprised mainly of carbon dioxide and hydrogen.</p>
<p>In the fasting state, the healthy gastrointestinal tract contains around 100 mls of gas which is <a href="https://www.ncbi.nlm.nih.gov/pubmed/17397409">distributed almost equally</a> among six segments of the gut: the stomach, small intestine, ascending colon, transverse colon, descending colon and lower (pelvic) colon. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/256022/original/file-20190129-108370-6vq3gn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/256022/original/file-20190129-108370-6vq3gn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=496&fit=crop&dpr=1 600w, https://images.theconversation.com/files/256022/original/file-20190129-108370-6vq3gn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=496&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/256022/original/file-20190129-108370-6vq3gn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=496&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/256022/original/file-20190129-108370-6vq3gn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=623&fit=crop&dpr=1 754w, https://images.theconversation.com/files/256022/original/file-20190129-108370-6vq3gn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=623&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/256022/original/file-20190129-108370-6vq3gn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=623&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="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/gastrointestinal-tract-stomach-small-intestine-colon-420418585?src=aH0t0KIDbMRxxQQvETeXig-1-5">Tefi/Shutterstock</a></span>
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<p>After eating, the volume of gas in the gut can <a href="https://www.ncbi.nlm.nih.gov/pubmed/17397409">increase by about 65%</a> and tends to be located around the pelvic colon. </p>
<p>As the <a href="https://www.ncbi.nlm.nih.gov/pubmed/12358237">stomach stretches and small bowel is stimulated</a>, the passage of gas accelerates and you might feel the urge to fart. </p>
<p>But for people with a high-fat diet, <a href="https://www.ncbi.nlm.nih.gov/pubmed/12198695">fats inside the small bowel</a> can delay this passage and make you retain the gas.</p>
<h2>Bloaters don’t produce more gas</h2>
<p>A <a href="https://www.ncbi.nlm.nih.gov/pubmed/1152877">1975 study</a> compared the amount of intestinal gas between people who reported being bloated and those who said they were not.</p>
<p>The researchers pumped (inert) gas through a tube directly into the participants’ intestines at a relatively high flow of 45 mls per minute. Then they recovered the gas via a plastic tube from their rectum. </p>
<p>The researchers found no difference in the levels of gas collected between the bloating and healthy subjects. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/256053/original/file-20190129-39344-1x7t8a0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/256053/original/file-20190129-39344-1x7t8a0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/256053/original/file-20190129-39344-1x7t8a0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/256053/original/file-20190129-39344-1x7t8a0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/256053/original/file-20190129-39344-1x7t8a0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/256053/original/file-20190129-39344-1x7t8a0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/256053/original/file-20190129-39344-1x7t8a0.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">Not everyone who feels bloated will have a distended stomach.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-woman-having-painful-stomachache-chronic-713425027?src=sx1GhzjfmfAgy9N1_yqxeg-1-66">siam.pukkato/Shutterstock</a></span>
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<p>More <a href="https://www.ncbi.nlm.nih.gov/pubmed/18802999">recent research</a> using abdominal CT scans has shown that people with bloating have similar volumes of intestinal gas as those who don’t feel bloated. </p>
<p>Likewise, although people with IBS experience more abdominal distention, they <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3264926/">do not produce</a> more intestinal gas than other people. </p>
<p>This leads us to believe the volume of gas in the gut itself isn’t the main mechanism for bloating. </p>
<h2>When gas gets trapped</h2>
<p>Most people tolerate intestinal gas really well because they can propel and evacuate gas very efficiently. As a result, only a <a href="https://www.ncbi.nlm.nih.gov/pubmed/9721151">relatively small amount</a> of gas remains inside the gut at a given time. </p>
<p>In <a href="https://www.ncbi.nlm.nih.gov/pubmed/12055580">one study</a>, researchers pumped just over 1.4 litres of gas in two hours into the mid-small bowel of healthy volunteers. This led to only a very small change in waist circumference: no more than 4mm. </p>
<p>On the other hand, people with abdominal conditions such as IBS or functional dyspepsia (indigestion), <a href="https://www.ncbi.nlm.nih.gov/pubmed/28508867">show impaired gas transit</a> – in other words, the gas ends up being trapped in different parts of the bowel rather than moving along easily. </p>
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Read more:
<a href="https://theconversation.com/whats-the-best-way-to-go-to-the-toilet-squatting-or-sitting-63991">What's the best way to go to the toilet – squatting or sitting?</a>
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<p>Studies show people with abdominal conditions tend to retain a relatively large proportion of gas pumped into the mid small bowel. They may even have notable increases in waist circumference without any gas being pumped in. </p>
<p>This impairment was confirmed in <a href="https://www.ncbi.nlm.nih.gov/pubmed/11115817">a study</a> comparing 20 participants with IBS to a control group of 20 healthy participants. All received gas pumped directly into the mid-small bowel. </p>
<p>Some 90% of IBS participants retained the gas in their intestines compared to only 20% of control subjects. The researchers found abdominal distension was directly correlated with gas retention.</p>
<p>Some people also have problems evacuating this gas, or farting. People with IBS and chronic constipation, for instance, may have difficulty relaxing and opening their anal sphincter to release farts. </p>
<p>This can lead to <a href="https://www.ncbi.nlm.nih.gov/pubmed/11408265">intestinal gas retention</a> and symptoms of bloating, abdominal pain and <a href="https://www.ncbi.nlm.nih.gov/pubmed/20179695">distension</a>. </p>
<h2>Pain without looking bloated</h2>
<p>Despite feeling extremely bloated, some people have minimal or no distension of their stomach. </p>
<p>Research among people with IBS suggests this pain and discomfort may be due to a <a href="https://www.ncbi.nlm.nih.gov/pubmed/12055583">heightened sensitivity</a> in the gut when a section of the abdomen stretches.</p>
<p>In fact, <a href="https://www.ncbi.nlm.nih.gov/pubmed/18455167">one study found</a> those with bloating alone had more abdominal pain than those who had symptoms of bloating and abdominal distension.</p>
<p>If you’re <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3264926/">sensitive to this stretching</a>, are unable to move gas throughout your gut, and can’t get rid of it, you’re likely to have bloating and pain, whether or not there’s any visual sign. </p>
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Read more:
<a href="https://theconversation.com/nervous-tummy-why-you-might-get-the-runs-before-a-first-date-106925">Nervous tummy: why you might get the runs before a first date</a>
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<img src="https://counter.theconversation.com/content/107605/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vincent Ho 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>People who bloat don’t produce more abdominal gas than others but they might have problems getting rid of it.Vincent Ho, Senior Lecturer and clinical academic gastroenterologist, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/983102018-09-10T02:03:46Z2018-09-10T02:03:46ZHealth Check: what happens when you hold in a fart?<figure><img src="https://images.theconversation.com/files/235515/original/file-20180910-90581-106ykm5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Better out than in.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/stunned-frightened-elderly-male-model-covers-1011504019?src=lQ3BO4dlLqYDBrcuNpS5lQ-5-19">Sementsova Lesia/Shutterstock</a></span></figcaption></figure><p>Ever been in a situation where passing wind is going to be hugely embarrassing and you’ve had to hold in a fart? Let’s face it – we all have.</p>
<p>Trying to hold it in leads to a build up of pressure and major discomfort. A build up of intestinal gas can trigger abdominal distension, <a href="https://www.ncbi.nlm.nih.gov/pubmed/19830557">with some gas reabsorbed into the circulation and exhaled in your breath</a>. Holding on too long means the build up of intestinal gas will eventually escape via an uncontrollable fart.</p>
<p>The research is not clear on <a href="https://www.ncbi.nlm.nih.gov/pubmed/51965">whether the rise in pressure</a> in your <a href="https://www.healthline.com/human-body-maps/rectum#1">rectum</a> increases your chance of developing a condition called <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/diverticulosis-and-diverticulitis">diverticulitis</a>, where small pouches develop in the gut lining and become inflamed – or whether it doesn’t matter at all. </p>
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Read more:
<a href="https://theconversation.com/health-check-the-ins-and-outs-of-burping-and-farting-26453">Health Check: the ins and outs of burping and farting</a>
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<h2>What is flatus?</h2>
<p><a href="https://en.wikipedia.org/wiki/Flatulence">Flatus</a>, farts and breaking wind refer to intestinal gases that enter the rectum due to the body’s usual gastrointestinal processes of digestion and metabolism and then leave via the <a href="https://en.wikipedia.org/wiki/Anus">anus</a>. </p>
<p>As your body digests food in the small intestine, components that can’t be broken down move further along the gastrointestinal track and eventually into the large intestine called the <a href="https://en.wikipedia.org/wiki/Large_intestine#Structure">colon</a>. </p>
<p>Intestinal <a href="https://www.ncbi.nlm.nih.gov/pubmed/19830557">bacteria break down some of the contents</a> by fermentation. This process produces gases and by products called fatty acids that are reabsorbed and used in metabolic <a href="https://www.ncbi.nlm.nih.gov/pubmed/29722430">pathways related to immunity and preventing disease</a> development. </p>
<p>Gases can either be reabsorbed through the gut wall into the circulation and <a href="https://www.ncbi.nlm.nih.gov/pubmed/19830557">eventually exhaled through the lungs or excreted</a> via the rectum, as a fart. </p>
<h2>How much flatus is normal?</h2>
<p>It can be challenging for researchers to get people to sign up for experiments that measure farts. But thankfully, ten healthy adults volunteered to have <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1378885/">the amount of gas they passed over a day</a> quantified. </p>
<p>In a 24-hour period all the flatus they expelled was collected via a rectal catheter (ouch). They ate normally but to ensure a boost in gas production they also had to eat 200 grams (half a large can) of baked beans. </p>
<p>The participants produced a median total volume of 705ml of gas in 24 hours, but it ranged from 476ml to 1,490ml per person. Hydrogen gas was produced in the greatest volume (361ml over 24 hours), followed by carbon dioxide (68ml/24 hr). Only three adults produced methane, which ranged from 3ml/24 to 120ml/24 hr. The remaining gases, thought to mostly be nitrogen, contributed about 213ml/24 hr.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/from-the-sumerians-to-shakespeare-to-twain-why-fart-jokes-never-get-old-41211">From the Sumerians to Shakespeare to Twain: Why fart jokes never get old</a>
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<p>Men and women produced about the same amount of gas and averaged eight flatus episodes (individual or a series of farts) over 24 hours. The volume varied between 33 and 125 ml per fart, with <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1378885">bigger amounts of intestinal gas released</a> in the hour after meals. </p>
<p>Gas was also produced while they were asleep, but at half the rate compared to during the day (median 16ml/hr vs 34ml/hr). </p>
<h2>Fibre and flatus</h2>
<p>In a study on <a href="https://www.ncbi.nlm.nih.gov/pubmed/15479674">dietary fibre and flatus</a>, researches investigated what happens to intestinal gas production when you put people on a high-fibre diet. </p>
<p>The researchers got ten healthy adult volunteers to eat their usual diet for seven days while consuming 30 grams of <a href="https://www.webmd.com/diet/compare-dietary-fibers">psyllium</a> a day as a source of soluble fibre, or not. In the psyllium week, they were asked to add 10 grams – about one heaped tablespoon – to each meal. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/235518/original/file-20180910-90581-1t252pz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/235518/original/file-20180910-90581-1t252pz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=580&fit=crop&dpr=1 600w, https://images.theconversation.com/files/235518/original/file-20180910-90581-1t252pz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=580&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/235518/original/file-20180910-90581-1t252pz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=580&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/235518/original/file-20180910-90581-1t252pz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=728&fit=crop&dpr=1 754w, https://images.theconversation.com/files/235518/original/file-20180910-90581-1t252pz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=728&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/235518/original/file-20180910-90581-1t252pz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=728&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">Not the best choice if you’ve been holding on.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/1104875048?src=nXvae4DlVDnnG4IzeWUbFw-1-7&size=huge_jpg">By GoodStudio</a></span>
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<p>At the end of each week, the participants were brought into the lab and, in a carefully controlled experiment, had an intra-rectal catheter inserted to quantify how gas (in terms of gas volume, pressure and number) moved through the intestine over a couple of hours. </p>
<p>They found the high psyllium-fibre diet led to longer initial retention of gas, but the volume stayed the same, meaning fewer but bigger farts. </p>
<h2>Where do the gases come from?</h2>
<p>Gas in the intestines <a href="https://www.ncbi.nlm.nih.gov/pubmed/16574342">comes from different sources</a>. It can be from swallowing air. Or from carbon dioxide produced when stomach acid mixes with bicarbonate in the <a href="https://en.wikipedia.org/wiki/Small_intestine">small intestine</a>. Or gasses can be produced by <a href="https://www.ncbi.nlm.nih.gov/pubmed/19830557">bacteria that are located in the large intestine</a>. </p>
<p>While these gases are thought to perform specific tasks that impact on health, producing excessive intestinal gas can cause bloating, pain, <a href="https://medical-dictionary.thefreedictionary.com/borborygmus">borborygmus</a> (which means rumbling sounds), belching and lots of farts.</p>
<p>The <a href="https://www.ncbi.nlm.nih.gov/pubmed/9771412">smelliest farts are due to sulphur containing gases</a>. This was confirmed in a study of 16 healthy adults who were fed pinto beans and <a href="https://en.wikipedia.org/wiki/Lactulose">lactulose</a>, a non-absorbable carbohydrate that gets fermented in the colon. The odour intensity of flatus samples was evaluated by two judges (pity them). </p>
<p>The good news was that in a follow-up experiment, the researchers identified that a charcoal-lined cushion was able to <a href="https://www.ncbi.nlm.nih.gov/pubmed/9771412">help quash the smell of the sulphur gases</a>.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-are-you-eating-the-right-sorts-of-fibre-20089">Health Check: are you eating the right sorts of fibre?</a>
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<p>Finally, some bad news for jet-setters: <a href="https://www.ncbi.nlm.nih.gov/pubmed/23463112">pressurised cabins on aeroplanes mean</a> you’re more likely to pass flatus due to the gas volume expanding at the lower cabin pressure, compared to being on the ground. With modern noise-reduction features, your fellow passengers are more likely than they used to be to hear you fart.</p>
<h2>What should you do?</h2>
<p>The next time you feel a large volume of intestinal gas getting ready to do what it does, try to move to a more convenient location. Whether you make it there or not, the best thing for your digestive health is to just let it go. </p>
<p>For some creative ideas (and a chuckle) on how to hold in a fart, check this <a href="https://www.wikihow.com/Hold-in-a-Fart">Wiki How to do anything</a>. </p>
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<a href="https://images.theconversation.com/files/235519/original/file-20180910-123131-rc9r0h.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/235519/original/file-20180910-123131-rc9r0h.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/235519/original/file-20180910-123131-rc9r0h.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=248&fit=crop&dpr=1 600w, https://images.theconversation.com/files/235519/original/file-20180910-123131-rc9r0h.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=248&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/235519/original/file-20180910-123131-rc9r0h.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=248&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/235519/original/file-20180910-123131-rc9r0h.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=311&fit=crop&dpr=1 754w, https://images.theconversation.com/files/235519/original/file-20180910-123131-rc9r0h.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=311&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/235519/original/file-20180910-123131-rc9r0h.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=311&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">Step 1: Clench your butt-cheeks.</span>
<span class="attribution"><a class="source" href="https://www.wikihow.com/Hold-in-a-Fart">Screen shot from wikihow.com</a></span>
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</figure><img src="https://counter.theconversation.com/content/98310/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Clare Collins is affiliated with the Priority Research Centre for Physical Activity and Nutrition, the University of Newcastle, NSW. She is an NHMRC Senior Research and Gladys M Brawn Research Fellow. She has received research grants from NHMRC, ARC, Hunter Medical Research Institute, Meat and Livestock Australia, Diabetes Australia, Heart Foundation, Bill and Melinda Gates Foundation, nib foundation and Greater Charitable Foundation. She has consulted to SHINE Australia, Novo Nordisk, Quality Bakers, the Sax Institute and the ABC. She was a team member conducting systematic reviews to inform the Australian Dietary Guidelines update and 2017 evidence review on dietary patterns for the Heart Foundation.</span></em></p>Holding on too long triggers a build up of intestinal gas that may eventually escape via an uncontrollable fart.Clare Collins, Professor in Nutrition and Dietetics, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/412112015-08-17T09:42:35Z2015-08-17T09:42:35ZFrom the Sumerians to Shakespeare to Twain: Why fart jokes never get old<figure><img src="https://images.theconversation.com/files/91925/original/image-20150814-2595-1u5fadw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">English caricaturist Richard Newton's 1798 cartoon depicts John Bull farting on the face of King George III. </span> <span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/e/ed/Newton_Bull_farts_G3.jpg">Library of Congress</a></span></figcaption></figure><p>Farting is a universal human experience, as routine as eating, breathing and sleeping. And it seems to be a cross-cultural and trans-historical fact that passing gas, at least in most social contexts, is rude and offensive. </p>
<p>There’s also the fundamental truth pertaining to the topic: farts are funny. But why is this the case? They’re often a source of discomfort and embarrassment, so why do they double as an inspiration for humor, even literary beauty?</p>
<h2>Literary giants let it rip</h2>
<p>Every culture in recorded history has had its preferred forms of humor relating to bodily functions, but none have been more reliable in stirring a reaction than fart jokes. In fact, according to British academic and poet Paul MacDonald, the <a href="http://www.reuters.com/article/2008/07/31/us-joke-odd-idUSKUA14785120080731">oldest joke in recorded history</a> – which dates back to the Sumerians in 1900 BC – was a fart joke: “Something which has never occurred since time immemorial; a young woman did not fart in her husband’s lap.” </p>
<p>Fart jokes have also found their way into some of the classics of Western literature. One of the most well-known appears in Chaucer’s <a href="https://books.google.com/books/about/The_Canterbury_Tales.html?id=Ek_-lNfzGUcC">Canterbury Tales</a>. In the Miller’s Tale, Nicholas and Absalom are vying for the same girl, and Nicholas decides to humiliate his rival. So he waits at the window for Absalom to beckon the girl. And just when he does, Nicholas’ rear protrudes to “let fly a fart with a noise as great as a clap of thunder, so that Absalom was almost overcome by the force of it.” </p>
<p>Even the great Bard of Avon himself, William Shakespeare, resorted to a flatulence pun in his play The Comedy of Errors, where Dromio of Ephesus <a href="http://shakespeare.mit.edu/comedy_errors/full.html">declares</a>, “A man may break a word with you, sir; and words are but wind; Ay, and break it in your face, so he break it not behind.” </p>
<p>Less surprisingly, the irreverent Mark Twain’s spoof entitled <a href="https://www.gutenberg.org/files/3190/3190-h/3190-h.htm">1601</a> features the flatus. In this imagined conversation between Queen Elizabeth’s court and a few renowned writers, someone among the company passes gas: “In ye heat of ye talk it befel yt one did breake wind, yielding an exceding mightie and distresfull stink, whereat all did laugh full sore.” </p>
<p>The queen inquires as to the source, and one Lady Alice declares her innocence: “Nay, ‘tis not I yt have broughte forth this rich o'ermastering fog, this fragrant gloom, so pray you seeke ye further.” </p>
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<img alt="" src="https://images.theconversation.com/files/91988/original/image-20150816-5098-yg2zxq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/91988/original/image-20150816-5098-yg2zxq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=778&fit=crop&dpr=1 600w, https://images.theconversation.com/files/91988/original/image-20150816-5098-yg2zxq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=778&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/91988/original/image-20150816-5098-yg2zxq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=778&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/91988/original/image-20150816-5098-yg2zxq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=977&fit=crop&dpr=1 754w, https://images.theconversation.com/files/91988/original/image-20150816-5098-yg2zxq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=977&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/91988/original/image-20150816-5098-yg2zxq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=977&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Jonathan Swift, otherwise known as Don Fartinando Puff-Indorst, Professor of Bumbast in the University of Crackow.</span>
<span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/5/5e/Jonathan_Swift_by_Francis_Bindon.jpg">Wikimedia Commons</a></span>
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<p>Meanwhile, Jonathan Swift, the author of the classic Gulliver’s Travels, devoted an entire <em>book</em> to the subject with <a href="https://books.google.com/books?id=sKdrMwAACAAJ&source=gbs_book_similarbooks">The Benefit of Farting Explained</a>. (Swift published it under the pseudonym “Don Fartinando Puff-Indorst, Professor of Bumbast in the University of Crackow.”) The title page asserts that the essay was “translated into English at the Request and for the Use of the Lady Damp-Fart, of Her-fart-shire” by “Obadiah Fizzle, Groom of the Stool to the Princess of Arse-Mini in Sardinia.” And an opening poetic ode refers to the flatus as “Cure of cholick, cure of gripes, tuneful drone of lower pipes.” </p>
<p>Swift then goes on to subject the fart to a detailed analysis – carefully describing its legal, social and scientific dimensions – before concluding that there are multiple species of fart, including “the sonorous and full-toned or rousing fart,” “the double fart,” “the soft fizzing fart,” “the wet fart” and “the sullen wind-bound fart.” </p>
<h2>The philosophy of fart jokes</h2>
<p>Clearly, as these examples show, flatulence humor is timeless. But <em>why</em> are farts universally funny? </p>
<p>We might begin by asking what makes anything funny. Historically, there have been <a href="http://plato.stanford.edu/entries/humor/">three major philosophical theories</a> about laughter. </p>
<ul>
<li><p>The <a href="http://www.richardwiseman.com/LaughLab/super.html">superiority theory</a> says that we laugh when we feel “sudden glory,” as Thomas Hobbes put it – a sudden sense of superiority over a person, especially someone to whom we ordinarily feel inferior. Cases of slapstick humor, such as the pie-in-the-face or someone slipping on a banana peel, fall into this category.</p></li>
<li><p>Kant and Schopenhauer argued on behalf of the <a href="http://www.richardwiseman.com/LaughLab/incon.html">incongruity theory</a>, which says we laugh at the juxtaposition of things that don’t ordinarily go together, such as a talking dog or a bearded woman. </p></li>
<li><p>And <a href="http://projects.eightron.net/laughter/theory3.php">relief theorists</a> like <a href="http://plato.stanford.edu/entries/spencer/">Spencer</a> and <a href="http://www.iep.utm.edu/freud/">Freud</a> maintain that laughter is how we relieve nervous tension regarding subjects or situations that are socially taboo or inappropriate. This explains the popular appeal of jokes based on sex, ethnicity and religion.</p></li>
</ul>
<p>But must we regard these theories as mutually exclusive? I suspect they are compatible explanations for different contexts of humor. </p>
<p>Philosopher John Morreall defends <a href="http://www.sunypress.edu/p-820-taking-laughter-seriously.aspx">a theory</a> that invites such a view. Morreall proposes that the common core to anything that prompts laughter is a “pleasant psychological shift.” If we apply this theory to flatulence, it becomes clear why farts are universally funny. It’s because they are capable of producing this effect in <em>all</em> of the ways identified by the three theories of humor. </p>
<p>And events that satisfy the criteria for all three forms of humor tend to be especially funny. For example, a few years ago, a YouTube post was made of Fox News anchor <a href="https://www.youtube.com/watch?v=3Rt6vqki_eE">Megyn Kelly passing gas</a> repeatedly on a live broadcast (to date, this clip has nearly 12 million views).</p>
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<figcaption><span class="caption">A moment of release for Fox News anchor Megyn Kelly.</span></figcaption>
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<p>Whether or not this actually happened, Kelly’s gaseous outburst certainly prompts a sudden sense of superiority in viewers, and it’s obviously incongruous with the formal context of a news broadcast. Moreover, the laughter this elicits (as it did even on the set of the broadcast) helps to relieve the nervous tension created by this social taboo.</p>
<p>But even where farts only satisfy one of the criteria for producing the “pleasant psychological shift” they are still humorous. And in most social contexts, they do at least this much. </p>
<p>This account of the universality of flatulence humor is, of course, a matter of debate. But one thing is beyond dispute: farts are funny. They always have been. And, it appears, they always will be.</p><img src="https://counter.theconversation.com/content/41211/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James Spiegel 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>They’re rude, crude and uncouth. So what makes farts so funny?James Spiegel, Professor of Philosophy & Religion, Taylor UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/264532014-06-16T04:41:55Z2014-06-16T04:41:55ZHealth Check: the ins and outs of burping and farting<figure><img src="https://images.theconversation.com/files/51114/original/grtfx345-1402881389.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">About 40% of people produce smelly gas because of a certain bacteria in their bowels.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/music_embassy/8382536548">HyoJung Kim</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>To understand why we fart, you need to know something about the volume of gases produced in the bowels first. </p>
<p>Imagine how much space 25 litres of gas would occupy – about one third of the interior of a small car. That’s how much gas you produce every day in your intestines. So it’s little wonder that farting, bloating and burping are relatively common.</p>
<p>Much of this gas production is recycled – by re-absorption and use within the gut, particularly by the almost two kilograms of bacteria in your colon. Indeed, almost 22.5 litres is absorbed by the gut, used by gut bacteria or expires through the lungs.</p>
<h2>Passing what remains</h2>
<p>The remaining two and a half litres is what you pass through your bowels every day. <a href="http://www.allenandunwin.com/default.aspx?page=94&book=9781864483215">On average</a>, men fart 12 times a day while women fart seven times – in portions of 30 to 120 millilitres. The total is the equivalent of a blown-up party balloon.</p>
<p>The number of times someone passes gas varies with the time of day; some pass more in the mornings and others more in the evening. But it largely depends on the sensitivity of the nervous system in the your rectum. If you have an increased sensitivity, perhaps because of a condition such as irritable bowel syndrome, you may fart more often. </p>
<p>Most of the gas your body produces has no aroma, although about 40% of the population has the capacity to produce smelly hydrogen sulphide gas from the left side of the bowel because they carry a particular bacteria. </p>
<p>Smelly farts are of no great medical significance except in somebody with <a href="http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Crohn's_disease_and_colitis_-_inflammatory_bowel_disease">colitis</a>, which is an inflammation of the large bowel or colon. A flare in colitis is often associated with the production of smelly gases, so have yourself checked out if you have smelly farts accompanied by diarrhoea or bleeding. </p>
<p>Previous pregnancy, particularly with complications, surgery and ageing may result in changes in the pelvic muscles that make it difficult to control gas. This can be socially awkward, especially if you pass smelly gas.</p>
<h2>What’s making you gassy?</h2>
<p>More gas is produced after meals, particularly those that contain lots of fibre, such as cereal, bread and pasta. Although there are many other foods, such as artichokes, beans, Brussels sprouts and eggplant, which also greatly influence the volume and aroma of farts.</p>
<p>Foods containing sulphur as a preservative, such as fruit juice, wine, processed meats and dried fruit also lead to more farting. These foods are used by the sulphur-producing bacteria in your guts to form hydrogen sulphide gas. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/51123/original/j4xkrrf4-1402881933.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/51123/original/j4xkrrf4-1402881933.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=404&fit=crop&dpr=1 600w, https://images.theconversation.com/files/51123/original/j4xkrrf4-1402881933.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=404&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/51123/original/j4xkrrf4-1402881933.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=404&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/51123/original/j4xkrrf4-1402881933.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=508&fit=crop&dpr=1 754w, https://images.theconversation.com/files/51123/original/j4xkrrf4-1402881933.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=508&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/51123/original/j4xkrrf4-1402881933.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=508&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">An average person expels enough gas each day to fill a party balloon.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/mich1008/13437719/in/photostream/">michibanban/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>There are a variety of dietary ingredients that may increase farting as well as bloating, particularly high-fibre foods which ferment in the colon to produce gas.</p>
<p>One of these is fructose (a sugar contained in fruits), which leads to more gas production because we don’t have an enzyme to break it down. If consumed in large amounts, fructose can contribute to increased gas when it reaches the colon where it’s fermented by bacteria. </p>
<p>This is particularly true of apples and pears, and their juice. Another culprit is stone fruit. When stone fruits are not quite ripe, they have higher pectin content, which is also fermented in the colon.</p>
<p>Then there are unripe bananas, which have a higher content of starch and less sugar than ripe ones. This passes to the colon as resistant starch producing more gas from gut bacteria. Orange pith can similarly contribute to excessive gas. </p>
<p>Often, as we age, the function of the pancreas gland, which is involved in digestion, slowly wanes and we can’t handle fruits and vegetables we previously were able to eat with the same ease. The pancreas produces insulin to control blood sugar levels and these important enzymes are required to digest fat, protein and carbohydrates.</p>
<p>We should accept that farting is normal for the vast majority of people. If you feel your farting is a problem then you should look first to your diet before consulting a general practitioner about the potential for an underlying gastrointestinal problem.</p><img src="https://counter.theconversation.com/content/26453/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Terry Bolin 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>To understand why we fart, you need to know something about the volume of gases produced in the bowels first. Imagine how much space 25 litres of gas would occupy – about one third of the interior of a…Terry Bolin, Associate Professor of Medicine, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.