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As with any dietary change, no matter how big or small, the gut will feel the effect of adopting veganism relatively swiftly. In the case of a vegan diet, there can be both a positive and negative impact on gut health.
The good news is that a vegan diet tends to be higher in prebiotics, the fuel used by good bacteria in the gut. Prebiotics supports the bacteria that are already living in the digestive tract; you'll find prebiotics in plant foods such as apples, onions, garlic, leek, beans, and grains. So if your diet includes a good variety of plant foods, it's likely you'll have your prebiotic intake covered.1
A vegan diet is also likely to be high in antioxidants and anti-inflammatory foods such as fruits, vegetables, nuts, seeds, and legumes. These foods can help to protect the gut from inflammation and damage.2
Unfortunately, there are also some aspects of a vegan diet that could be problematic for gut health. Even a healthy vegan diet has the potential to be deficient in a number of gut-supportive nutrients which most plant-based foodstuffs lack. A vegan diet also excludes common sources of probiotic foods such as yogurt, which can be a problem since it's these probiotic foods that provide good bacteria and maintain a positive balance of bacteria in the gut.3 There are alternative options though, like soy yogurt and coconut yogurt.
Some people may also find that an underlying gut concern is exacerbated by a vegan diet. Fructose malabsorption and IBS are two examples of conditions that could be exacerbated by a higher plant food intake. If you've already been diagnosed with these conditions, you may want to give your decision to adopt veganism wholesale some further consideration.4, 5
The quality of your diet will always affect the gut. If you're unsure about what to eat, a good starting point is to make sure you're eating a balanced diet focused on wholefoods. By doing so, you'll be less likely to experience as many issues - but if you're eating unhealthy foods like Oreos and other 'accidentally vegan' processed foods daily, you're at a much higher risk of deficiencies and other gut issues.
There are a few key nutrients to consider when it comes to a vegan diet and gut health.
One of the most important is zinc. Zinc is a mineral that's found mostly in animal products. It's of particular concern in a vegan diet as its competing nutrient, copper, is naturally higher in a plant-based diet.
Zinc plays many roles within the gut. It's an essential nutrient for the immune system, with deficiency leaving the gut vulnerable to bad bacteria. It can also have anti-inflammatory effects throughout the body, inclusive of the digestive tract. One recent discovery is that zinc helps to maintain tight gap junctions, protecting against leaky gut syndrome.6, 7
Next, glutamine is an amino acid that is essential for maintaining the gut lining. Without sufficient glutamine, the gut can become leaky, leading to a range of health issues.8 Many of the dietary sources of glutamine are animal-based, so a plant-based diet may become deficient.
Omega-3 fatty acids are another potential issue with a plant-based diet. An omnivore can consume sufficient omega-3s with just 2-3 servings of fatty fish per week; however, reaching this goal can be more difficult when excluding all animal products.
Omega-3s play an essential role in reducing inflammation throughout the body, including the digestive tract.9 In fact, the omega-3 intake of a parent may even affect the gut bacteria of their offspring.10 Research has also shown that an omega-3 rich diet can increase the levels of beneficial bacteria within the gut.11
These potential issues might seem overwhelming; however, the good news is there are simple tweaks you can make to support your gut health on a vegan diet.
One of the best things to start with is consuming probiotic foods. There are plenty of options that are vegan-friendly. Sauerkraut, kimchi and pickled vegetables are good options for foods, or you could include drinks like kombucha and water kefir. Some brands even offer dairy-free yoghurt options such as coconut yoghurt. As always, just make sure you read the label and check that they contain live cultures.
Increasing your intake of gut-supporting nutrients is another easy change. For zinc, your best sources include pumpkin seeds, beans, nuts, seeds, and oats.12 To get your glutamine, include some beans, nuts, and cabbage. Plant-based omega-3 sources include chia seeds, flaxseeds, walnut and algae such as spirulina.13
If you are experiencing digestive symptoms such as bloating, gas and abdominal pain, seek out your health practitioner's advice. Although digestive disorders can be exacerbated by a vegan diet, your health practitioner can help you to tailor your diet to relieve symptoms whilst hopefully remaining within the parameters of a vegan lifestyle.
When looking to support your gut, eating a balanced diet should always be the first step you take. A supplement can never compensate for a diet that is high in processed foods or low in nutrition, but if you want to give your gut some extra support while eating a vegan diet, there are a few to consider.
A probiotic supplement can help to encourage a variety of healthy gut bacteria to grow in the gut. Although some probiotics contain animal-derived products, there are vegan options available.
Nothing beats a healthy, balanced diet to provide all the nutrients we need. But when this isn't possible, supplements can help. This article isn't intended to replace medical advice. Please consult your healthcare professional before trying supplements or herbal medicines.
1Craig, W.J. (2009). Health effects of vegan diets. The American journal of clinical nutrition, 89(5), pp.1627S-1633S.
2Glick-Bauer, M. and Yeh, M.C. (2014). The health advantage of a vegan diet: exploring the gut microbiota connection. Nutrients, 6(11), pp.4822-4838.
3Guarner, F., Perdigon, G., Corthier, G., Salminen, S., Koletzko, B. and Morelli, L. (2005). Should yoghurt cultures be considered probiotic? British Journal of Nutrition, 93(6), pp.783-786.
4Shepherd, S.J. and Gibson, P.R. (2006). Fructose malabsorption and symptoms of irritable bowel syndrome: guidelines for effective dietary management. Journal of the American Dietetic Association, 106(10), pp.1631-1639.
5Barrett, J.S., Gearry, R.B., Muir, J.G., Irving, P.M., Rose, R., Rosella, O., Haines, M.L., Shepherd, S.J. and Gibson, P.R. (2010). Dietary poorly absorbed, short-chain carbohydrates increase delivery of water and fermentable substrates to the proximal colon. Alimentary pharmacology & therapeutics, 31(8), pp.874-882.
6Wapnir, R.A. (2000). Zinc deficiency, malnutrition and the gastrointestinal tract. The Journal of nutrition, 130(5), pp.1388S-1392S.
7Skrovanek, S., DiGuilio, K., Bailey, R., Huntington, W., Urbas, R., Mayilvaganan, B., Mercogliano, G. and Mullin, J.M. (2014). Zinc and gastrointestinal disease. World journal of gastrointestinal pathophysiology, 5(4), p.496.
8Larson, S.D., Li, J., Chung, D.H. and Evers, B.M. (2007). Molecular mechanisms contributing to glutamine-mediated intestinal cell survival. American Journal of Physiology-Gastrointestinal and Liver Physiology, 293(6), pp.G1262-G1271.
9Teitelbaum, J.E. and Walker, W.A. (2001). The role of omega 3 fatty acids in intestinal inflammation. The Journal of nutritional biochemistry, 12(1), pp.21-32.
10Myles, I.A., Pincus, N.B., Fontecilla, N.M. and Datta, S.K. (2014). Effects of parental omega-3 fatty acid intake on offspring microbiome and immunity. PLoS One, 9(1), p.e87181.
11Noriega, B.S., Sanchez-Gonzalez, M.A., Salyakina, D. and Coffman, J. (2016). Understanding the impact of omega-3 rich diet on the gut microbiota. Case reports in medicine, 2016.
12Dietitians of Canada. What You Need to Know about Zinc. UnlockFood.ca.
13National Institutes of Health Omega-3 Fatty Acids Fact Sheet for Consumers.