Vegan Diets: Friend Or Foe To Your Gut?

A vegan diet is rich in fiber, water, vitamins, and minerals, and it lacks hard-to-digest foods such as red meat, dairy, and eggs. However, some people may experience digestive difficulties when transitioning to a plant-based diet. This can manifest as diarrhea, which is defined by the World Health Organization (WHO) as the passage of three or more liquid or loose stools per day.

There are several potential causes of diarrhea on a vegan diet:

- Low protein intake: A diet high in fiber and low in protein can lead to loose stools.

- Micronutrient deficiency: Severe zinc deficiency, which is more common in plant-based diets, can lead to diarrhea.

- Supplementation: Taking too many vitamin and mineral supplements can cause diarrhea.

- High levels of physical activity: Vigorous activity can trigger diarrhea, as it stimulates bowel activity.

- Irritable Bowel Syndrome (IBS): IBS is a condition characterized by abdominal pain and changes in bowel movements, including diarrhea.

- Food allergies and intolerances: Food intolerances, such as histamine intolerance and carb intolerance, can cause diarrhea.

- Small Intestine Bacterial Overgrowth (SIBO): SIBO is a syndrome where there is an over-proliferation of bacteria in the small intestine, which can lead to diarrhea.

- Irritable Bowel Disease (IBD): Inflammation of the bowels, including ulcerative colitis and Crohn's disease, can result in diarrhea.

To alleviate diarrhea on a vegan diet, it is recommended to:

- Ensure adequate protein and zinc intake.

- Consult a doctor and dietitian for tailored advice and to rule out any underlying conditions.

- Consider a low-FODMAP diet to limit poorly absorbed carbohydrates that can trigger diarrhea.

- Identify and avoid food intolerances through food journals and elimination diets.

- Focus on easy-to-digest foods, such as cooked legumes, leafy greens, root vegetables, herbal tea, and soaked grains.

- Choose raw nut butter over roasted, and avoid peanut butter if possible.

- Limit fat intake and avoid oils, opting for whole foods like flax, chia, avocado, and coconut instead.

High fibre intake

Vegan diets are typically high in fibre, which is great for digestive health. However, if you're not used to eating a lot of fibre, a sudden increase can cause some digestive issues, such as gas, bloating, and diarrhoea. This is because the bacteria in your gut that help to break down fibre can get overwhelmed, leading to an imbalance.

If you're experiencing diarrhoea after switching to a vegan diet, try reducing your fibre intake and then gradually increasing it again. This will give your gut bacteria time to adjust. Keep a food journal to help you identify any problem foods.

• Start with the basics: focus on whole foods like fruits, vegetables, and easy-to-digest grains (quinoa, millet, gluten-free oats, amaranth, and rice).
• Cook your legumes well and consider eating them in pureed forms, such as hummus or pea soup, instead of whole.
• Increase your leafy greens, as they promote gentle cleansing and reduce inflammation.
• Take it easy on raw vegetables, as they can be hard to digest. Cooking them makes them easier for your body to break down.
• Choose raw nut butter over roasted, as they contain live enzymes that aid digestion and are less likely to cause pain.
• Embrace root vegetables, as they are high in water and soluble fibre, which improve regularity and constipation.
• Soak your grains overnight before cooking to release phytic acid, which some people find hard to digest.
• Don't overdo the fat, as it can slow down digestion.

Remember, everyone's digestion is unique, so find what works best for you. If your diarrhoea persists, consult a healthcare professional to rule out any underlying issues.

Zinc deficiency

Zinc is an essential nutrient that our bodies use for fighting infections, speeding up chemical reactions, and supporting our immune system. A zinc deficiency could lead to hair loss, more infections, poor wound healing, impaired immune function, loss of appetite, and growth retardation. In more severe cases, zinc deficiency can cause diarrhea, delayed sexual maturation, eye and skin lesions, impotence, and hypogonadism in males. Weight loss, taste abnormalities, delayed healing of wounds, and lethargy can also occur.

Vegans tend to meet the RDA for zinc, but due to zinc being harder to absorb from plant foods, some vegans might need more than the RDA. If a vegan has found that while on the diet they easily catch colds, develop angular cheilitis (cracks in the corners of the mouth), diarrhea, or hair loss, then a modest zinc supplement of about 50-100% of the RDA might resolve such issues.

Full-blown zinc deficiencies are not common among vegans, but vegans tend to have lower zinc levels than meat-eaters. The World Health Organization lists zinc sulfate as a treatment for diarrhea in children.

Vegan sources of zinc include legumes, nuts, seeds, oatmeal, beans, wholemeal bread, and lentils. Fermenting soy foods enhances zinc absorption; tempeh and miso are fermented.

Food allergy or intolerance

A vegan diet can be a double-edged sword when it comes to food allergies and intolerances. On the one hand, it can help alleviate allergies and intolerances to animal products. On the other hand, it can also introduce new allergens and trigger reactions to plant-based foods.

Common Allergens in a Vegan Diet

Some of the most common food allergens for vegans include:

• Nuts: Almonds, Brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pine nuts, pistachios, and peanuts (which are legumes).
• Seeds: Sesame, mustard, sunflower, and poppy seeds.
• Soy: Tofu, tempeh, edamame, soy milk, yogurt, sauces, baked goods, and meat alternatives.
• Wheat/Gluten: Seitan, baked goods, pasta, cereal, crackers, beer, and various processed foods.

Oral Allergy Syndrome

Oral Allergy Syndrome (OAS) is a condition where people with allergies to certain raw fruits and vegetables also experience reactions to some raw plant-based foods. It's important to note that cooking these foods usually eliminates the allergen.

Managing Food Allergies and Intolerances on a Vegan Diet

If you suspect a food allergy or intolerance, it's essential to consult a doctor for diagnosis and guidance. Here are some general tips for managing these conditions on a vegan diet:

• Read labels carefully: Many processed and packaged vegan foods contain common allergens like nuts, soy, and gluten. Always check the ingredient list to identify potential triggers.
• Avoid cross-contamination: Keep your kitchen and utensils free from allergens. When eating out, inquire about allergen handling practices to minimize the risk of exposure.
• Explore alternative ingredients: There are often substitute ingredients you can use in recipes to avoid allergens. For example, you can use sunflower or olive oil instead of seed oils if you have a seed allergy.
• Get tested: Consider taking an at-home food intolerance test or working with a healthcare professional to identify specific food intolerances. This can help you tailor your diet to avoid problematic foods.

Small intestine bacterial overgrowth

Small Intestinal Bacterial Overgrowth (SIBO) is a common gastrointestinal disorder that affects 6-15% of healthy people and up to 80% of those with Irritable Bowel Syndrome (IBS). SIBO occurs when there is an imbalance and overgrowth of bacteria in the small intestine, which is normally where nutrients are absorbed. This can cause severe gastrointestinal distress and, if left untreated, may even be fatal.

SIBO can be caused by a variety of factors, including stress, food poisoning, issues with the immune system, low stomach acid, bile and enzyme issues, and antibiotic use. It is more common in older adults, as their bodies are less equipped to handle inflammation and fight off gastrointestinal distress.

The symptoms of SIBO include abdominal pain, gas, bloating, diarrhea, and sometimes constipation. In more severe cases, it can lead to weight loss due to vitamin deficiencies, as the overgrowth of bacteria can impede the absorption of nutrients and damage the intestinal lining.

SIBO can be challenging to manage on a vegan diet, as the bacteria that contribute to SIBO feed off fibre, which is abundant in plant-based foods. However, it is important to note that SIBO is not exclusive to vegans and can affect anyone, regardless of their dietary choices.

To manage SIBO on a vegan diet, it is recommended to reduce fibre intake and include more calorically dense or processed plant foods. This can include foods like sunflower seeds, hemp oil, and spirulina. It is also important to ensure adequate protein intake to prevent zinc or iron deficiencies.

Additionally, seeking professional medical advice and getting a proper diagnosis is crucial, as there are various treatment options available, including antibiotics, supplements, herbal antimicrobials, and dietary changes such as the Low FODMAP diet.

Irritable bowel syndrome

The low FODMAP diet is often recommended for people with IBS, as it can help manage symptoms in 70-75% of cases. FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols—these are simple sugars that are poorly absorbed and rapidly fermented by the gut, which can lead to bloating, pain, and diarrhoea.

The low FODMAP diet involves avoiding high-FODMAP foods for a limited time, then slowly reintroducing them to identify which ones may be causing digestive problems. It is possible to follow a low-FODMAP diet while remaining vegan, but it may be more challenging as legumes—a key source of protein for vegans and vegetarians—are high in FODMAPs.

• Meet with a dietitian to get individualised advice before altering your diet.
• Balance high-FODMAP legumes with lower-FODMAP grains or starches such as white potatoes, rice, and quinoa.
• Include a vegan protein source at each meal, such as firm tofu, tempeh (without high-FODMAP ingredients), small amounts of chickpeas and lentils, nuts, seeds, and nut/seed butters.
• Follow the low-FODMAP elimination diet for a shorter duration, such as one to two weeks, before reintroducing foods.
• Consider taking a multivitamin to ensure adequate nutrition.

It is important to note that this information is not a substitute for professional medical advice, and those experiencing IBS symptoms should consult a doctor or dietitian for individualised advice.

Frequently asked questions