Vegan Diet for IBS: Is It Possible to Make the Low FODMAP Diet Vegan?

Do you follow a vegan diet, but also struggle with irritable bowel syndrome (IBS) symptoms such as bloating, constipation, diarrhea, abdominal pain, or gas? You might have heard of the low FODMAP diet as a potential solution for your IBS. Since this diet primarily restricts plant based foods, people often wonder if it is possible to incorporate a vegan diet for IBS and whether you can get enough protein on a low FODMAP vegan diet. Let’s explore if this is possible, and if so how to go about it!

What is the low FODMAP diet?

First, it is true that the low FODMAP diet is one of the most effective tools in managing IBS is the low FODMAP diet; it can alleviate symptoms for up to 86% of IBS patients (1). The low FODMAP diet restricts Fermentable Oligosaccharides (fructans and galacto-oligosaccharides), Disaccharides (lactose), Monosaccharides (fructose), and Polyols (mannitol and sorbitol). These are carbohydrates poorly absorbed in the intestines, leading to gastrointestinal symptoms in some people (2). FODMAPs are found in many common foods such as wheat, apples, garlic, milk, honey, and cashews. The low FODMAP diet restricts these foods with the goal of identifying those which trigger an individual’s IBS symptoms.

Generally, the initial stage of the low FODMAP diet restricts virtually all FODMAPs. After the restriction phase, high FODMAP foods are gradually reintroduced into the diet to identify personal triggers. The third and final stage of the diet is the maintenance phase, in which individuals determine which foods to limit long term. The goal of this phase is to tailor the diet to reduce IBS symptoms while still eating a diverse diet (3). It is important to note that the low FODMAP diet should not be followed long term even if you experience symptom relief, as high FODMAP foods are vital for long term gut health (2). Luckily, this means that although this diet can be restrictive, it is only temporary! Given the complicated nature of the low FODMAP diet, all stages should be done with the guidance of a Registered Dietitian specialized in gastrointestinal disorders.

Unfortunately, the restriction phase can be quite challenging. It may be especially so for those with additional dietary restrictions, such as following a vegan diet. But don’t worry, it is completely possible to continue eating vegan while getting to the bottom of your IBS using the low FODMAP diet! Keep reading to find out how.

Low FODMAP Vegan Foods

You may be wondering what exactly you can eat if you wish to follow a low FODMAP vegan diet. Here is a list of foods and their quantities that meet these requirements (4, 5, 6)!

Nuts:

• 10 almonds
• ¼ cup almond meal
• 10 hazelnuts
• 32 peanuts
• 5 walnuts

Seeds

• 2 tsp sunflower seeds
• 1 tbsp flaxseed
• 2 tbsp tahini
• 2 tbsp chia seeds

Fruit:

• 1 unripe banana
• 1 orange or 2 mandarin oranges
• 2 kiwi
• ⅓ cup raspberries
• ¼ cup blueberries
• 1 cup pineapple

Vegetables

• 15 green beans
• ¼ red pepper
• ½ cob corn
• 1 cup eggplant
• ½ cup chopped kale
• ¾ cup broccoli
• 1 medium carrot
• 1 medium parsnip
• 1.5 cups spinach

Grains & Starchy Vegetables

• ½ medium potato
• 90g dry soba noodles
• ½ cup dried rolled oats
• 1 cup cooked (½ cup raw) brown rice or quinoa
• 3.5 cups popcorn

Legumes & Other Proteins

• 170g firm tofu
• 39g silken tofu
• 100g tempeh
• ½ cup shelled edamame
• ¼ cup green lentils
• ¼ cup drained canned chickpeas

Sweeteners:

• Table sugar
• Dark chocolate
• Maple syrup
• Rice malt syrup

High FODMAP Vegan Foods

While there is an abundance of foods that can be incorporated on a low FODMAP vegan diet, there are others that should be limited. Many high FODMAP foods are staples in a vegan diet, including some fruits, vegetables, whole grains, legumes, pulses, nuts, and sweeteners, which unfortunately must be entirely or partially restricted during some phases of the low FODMAP diet (6).

Some examples include:

• Fruits: apples, pears, mangoes, cherries, figs, watermelon, dried fruit, blackberries, peaches, plums
• Vegetables: artichoke, garlic, onion, leeks, mushrooms, cauliflower, snow peas
• Grains: wheat, rye
• Legumes & pulses: red kidney beans, split peas
• Nuts: cashews, pistachios
• Sweeteners: sugar alcohols (end in “ol” such as sorbitol, xylitol, erythritol), high fructose corn syrup, honey

What About Nutrient Deficiencies?

A common concern associated with following such a restrictive diet is the development of a nutrient deficiency. Luckily, the elimination phase (the most restrictive phase of the low FODMAP diet) should only be followed for up to 4 weeks before foods are reintroduced back into the diet (2). While it is possible to develop some types of deficiencies in a matter of weeks, many deficiencies take months to years to develop, significantly minimizing the risk of deficiencies (7). However, careful planning and guidance are still important!

Some key nutrients that those on a low FODMAP vegan diet are at higher risk of under consuming include calcium, protein, vitamin B12, iron, zinc, and omega 3. Below is a list of example sources of these nutrients to help you reach your requirements (6, 8):

• Calcium: calcium fortified almond, rice, soy, or other milk alternative
• Protein: firm tofu, tempeh, quinoa, nuts, seeds
• Vitamin B12: fortified milks, fortified cereals, soba noodles, fortified nutritional yeast
• Iron: nuts, seeds, tofu, tempeh, quinoa
• Zinc: nuts, seeds, fortified cereals, pulses, tahini
• Omega 3: flax seeds, chia seeds, hemp seeds, walnuts, canola oil, margarine, flaxseed oil, legumes

Other Considerations

FODMAP Stacking

You might have noticed that the portion sizes affect if a food is considered low FODMAP. This is because many low FODMAP foods still contain small quantities of FODMAPs. Likewise, if you eat small portions of several foods that contain the same type of FODMAP together can render the overall meal high FODMAP. For example, peanut butter and raspberries both contain small amounts of the FODMAP fructose. Although 2 tbsp of peanut butter and ⅓ cup of raspberries are both low FODMAP options, if consumed together, the total amount of fructose may be enough to trigger digestive distress in sensitive individuals (3). While a certain degree of FODMAP stacking is inevitable in a complete diet, it is still something to keep in mind as excess can trigger symptoms.

The Impact of Food Processing

Another consideration is the impact of food processing procedures which can increase or decrease the FODMAP content of a food. One study that compared the impact of cooking, sprouting, pickling, fermentation, activation, and canning found that pickling and canning reduced FODMAP content the most (9). Additionally, fermentation often lowers FODMAP content as the bacteria involved feed on the FODMAPs present. This explains why tofu is lower FODMAP than the soybeans they are produced from, as well as why sourdough bread is lower FODMAP than traditional loaves (10).

The Bottom Line

As you can see, eating low FODMAP and vegan are entirely compatible! Although it will require some hard work and planning, with the help of a Registered Dietitian, you can reduce your IBS symptoms without sacrificing your dietary preferences. Contact us or book an appointment to learn more about customizing a low FODMAP diet.

References

1. Nanayakkara WS, Skidmore PM, O’Brien L, Wilkinson TJ, Gearry RB. Efficacy of the low FODMAP diet for treating irritable bowel syndrome: the evidence to date. Clin Exp Gastroenterol.. 2016 Jun 17;9:131–42. https://doi.org/10.2147/CEG.S86798.
2. Barrett JS. How to institute the low‐fodmap diet. J Gastroenterol Hepatol. 2017 Feb 28;32(S1):8–10. https://doi.org/10.1111/jgh.13686.
3. Parrish CR. When a Registered Dietitian Becomes the Patient: Translating the Science of the Low FODMAP Diet to Daily Living. Pract Gastroenterol. 2018 May;42(5):20–37.
4. Varney DJ. Getting enough fibre [Internet]. Monash University; 2021. Available from: https://www.monashfodmap.com/blog/getting-enough-fibre/.
5. Wilson D, Adel K. All about low Fodmap vegan protein sources [Internet]. 2024.
   Available from: https://www.fodmapeveryday.com/all-about-low-fodmap-vegan-protein-sourc
   es/#.
6. High and low Fodmap foods [Internet]. Monash University. Available from: https://www.monashfodmap.com/about-fodmap-and-ibs/high-and-low-fodmap-foods/.
7. Johnson LE. Overview of vitamins [Internet]. Merck & Co ;. Available from: https://www.merckmanuals.com/professional/nutritional-disorders/vitamin-deficiency-dependency-and-toxicity/overview-of-vitamins.
8. Clarke E. Following a low fodmap and vegan diet [Internet]. Monash University; Available from: https://www.monashfodmap.com/blog/following-low-fodmap-and-vegan-diet/.
9. Tuck C, Ly E, Bogatyrev A, Costetsou I, Gibson P, Barrett J, et al. Fermentable short chain carbohydrate (FODMAP) content of common plant‐based foods and processed foods suitable for vegetarian‐ and vegan‐based eating patterns. J Hum Nutr Diet. 2018 Feb 23;31(3):422–35. https://doi.org/10.1111/jhn.12546.
10. McNamara L. Food processing and FODMAPS – what you need to know [Internet]. Monash University; 2017. Available from: https://www.monashfodmap.com/blog/food-processing-and-fodmaps-what-you/.