Treatment of Irritable Bowel Syndrome (IBS) is based around symptom management. If you follow a vegetarian or vegan diet, perhaps you’ve read about the low FODMAP diet as one option to managing your IBS. But you may be wondering if it’s suitable for you. If so, this article is just for you. I’ll be looking at whether following the low FODMAP diet for vegetarians and vegans can be done effectively and safely.
I’m here to explain more about the low FODMAP diet and how it can be a great way to get rid of embarrassing and frustrating gut symptoms quickly. But first, it’s a good idea to make sure you’ve considered some other first line dietary fixes. See my free guide for first line advice here.
Let’s start at the beginning…
Who created the low FODMAP diet and why should you consider it?
FODMAPs, a term coined in 2004 at Monash University in Australia. They are a group of fermentable carbohydrates known to cause IBS symptoms. These may include bloating, wind, constipation and/or diarrhoea. This is because we are not able to digest and absorb these complex molecules fully. The result is water being drawn into the bowel and fermentation by gut bacteria in the large intestine. This can lead to common IBS issues.
Almost 20 years of research has been put into the low FODMAP diet to identify FODMAP sources and their mechanisms of action. It is currently one of the main dietary treatments for IBS.
Before that, Dietitians were limited in how much they could help IBS sufferers. Although we knew of sensitivities to different foods, it is only now that we can provide specific and evidence-based advice to help significantly reduce suffering in IBS. Carbohydrate malabsorption is now known as a cause of diarrhoea, pain and bloating, amongst other IBS symptoms.
So, exactly what are FODMAPs?
Let’s have a look at each part of the word:
Fermentable – meaning we cannot fully digest and absorb them, so they are fermented in the gut by bacteria
Oligosaccharides – including fructans and galacto-oligosaccharides, found in wheat, rye and barley as well as legumes and some nuts
Disaccharides – including lactose, a milk sugar
Monosaccharides – including fructose, found in fruit, honey and agave nectar
And – they needed a conjunction!
Polyols – including sorbitol and mannitol, found in some fruits and vegetables as well as some sweeteners
How does the low FODMAP diet work?
The low FODMAP diet is a three-phase diet starting with a short-term exclusion phase of 4 to 8 weeks. After this, a period of reintroduction to test your tolerance to different FODMAPs is essential. The third phase is personalisation and long-term management. The low FODMAP diet is usually used as a second line treatment, following initial healthy eating and lifestyle changes and may not even be necessary for you.
Have a look at my free guide on diet and lifestyle changes to improve bloating and gut pain before you think about starting a vegetarian or vegan low FODMAP elimination phase:
Can you eat low FODMAP as a vegetarian or vegan?
The low FODMAP diet isn’t for everyone as it requires you to cut out a list of foods from your diet so some people find it too restrictive. However, it can be so useful for helping you to figure out just what you can and can’t eat. Even if you do follow a plant-based or mostly plants diet. You just need to take a bit of care to make sure you’re getting the nutrients you need throughout.
It’s also important to remember that low FODMAP diet is designed to be temporary. Reintroducing foods to your tolerance after the exclusion period is essential to ensure long-term health.
Studies have shown that up to 76 % of IBS sufferers have a significant improvement in their symptoms after following the low FODMAP diet. So if you’ve tried the first-line healthy eating advice and you’re still struggling with daily symptoms, it’s certainly worth considering.
Tolerance to different FODMAPs varies from person to person. The low FODMAP diet will help to identify which foods you can tolerate and how much so you can have as varied as possible a diet in the long-term. We know that eating a wide variety of plant-based foods of different colours is good for us, not just for the gut but for general health.
Should I worry about getting enough nutrients on a low FODMAP diet?
The good news is that some foods that would normally need to be cut out from the diet when following a low FODMAP eating pattern are already excluded from a plant-based diet, which makes it easier in some ways.
These include dairy (which contains the FODMAP lactose) and honey (which contains the FODMAP fructose) if you’re vegan. Lactose could still be causing some gut issues if you’re vegetarian and you may also still have sources of fructose in your food on any plant-based diet.
Protein and some vitamins and minerals need some careful planning to meet nutritional guidelines for on a low FODMAP and plant-based diet.
This is why the low FODMAP diet should be used as a temporary therapeutic diet to understand personal food tolerances. You can then use this to plan a healthy and balanced diet with a happy gut for the long-term.
Because this can be quite complex and overwhelming, it is best to get support from a Registered Dietitian trained in the low FODMAP diet to make sure you only need to do this once and you do it right.
Studies have shown better outcomes when IBS sufferers followed the low FODMAP diet with guidance from a Dietitian. This is particularly important for support in managing long-term health.
Low FODMAP protein sources on a plant based diet
Protein is essential for growth and maintenance of body functions. Following a high protein low FODMAP vegetarian or vegan diet can be tricky as we would normally rely on legumes, nuts, seeds and meat alternatives for protein. Legumes, including beans and lentils, are high FODMAP and are allowed only in smaller amounts, some more than others. Dairy and eggs are of course vegetarian, but many dairy foods are high FODMAP and may not be tolerated by some.
Unfortunately, on the low FODMAP diet, many of the protein sources are off-limits during the strict exclusion phase, including legumes, certain nuts and meat alternatives, depending on ingredients.
The good news is that you don’t have to miss out on protein during phase one, as there are still plenty of suitable sources of protein which are low FODMAP. It is a good idea to aim to include these three times per day and in snacks if possible to meet your requirements during the low FODMAP elimination phase and beyond.
Low FODMAP vegetarian protein sources and low FODMAP vegan protein sources on a plant-based diet include:
- Soya mince
- Mycoprotein (e.g. Quorn, garlic and onion free varieties)
- Small portions of legumes e.g. soya beans, lentils, canned kidney beans
- Tempeh
- Firm tofu
- Plant-based cheese and yoghurt
- Lactose free milk, cheese and yoghurt (for vegetarians)
- Spirulina
- Suitable nuts and nut butters
- Seeds
- Nutritional yeast
- Pea and rice protein isolates (in protein powders)
- Eggs (on a vegetarian diet)
You can also increase the availability of protein and reduce the FODMAP content of legumes using soaking, boiling, germination and fermentation.
How to avoid vitamin and mineral deficiencies on a low FODMAP diet
Due to multiple food trigger avoidances in people with IBS, nutritional deficiencies can be a risk during the low FODMAP exclusion phase but also long-term, particularly if unsupervised by a trained Dietitian.
IBS sufferers have been found to have either significantly lower intakes or blood levels of the following vitamins and minerals. This is compared to people without IBS or the recommended intakes (RNI for UK and DRI for USA).
- Vitamins: A, D, B1, B2, B6, B9 and B12
- Minerals: calcium, iron, magnesium and zinc
Include the following low FODMAP plant-based sources of these micronutrients in your meals to reduce your risk of deficiencies:
- Root vegetables of different colours
- Leafy green vegetables
- Whole grains
- Tofu and other soy-based products (in moderation)
- Yeast extract
- Fortified plant milks
- Fortified cereals
- Nuts and seeds
- Nutritional yeast
Any deficiency in intake of a specific micronutrient should only be temporary, with the goal of increasing dietary variety after the end of the exclusion period based on tolerance levels.
Interestingly, supplementation with vitamin D has been found to improve IBS symptom severity, including abdominal pain, distention and overall gastrointestinal symptoms compared to placebo, as well as quality of life scores.
Enough vitamin D in the body is important for being able to use calcium effectively. It’s a good idea for everyone to take a daily vitamin D supplement, particularly during the winter months as we are not able to make enough on our skin or get enough from food.
Unfortunately there are no official guidelines for vitamin D supplementation in IBS. So, I would recommend a daily supplement in line with general health guidance, which is 10-20 micrograms per day, depending on age. You might want to have this as part of a vegan friendly daily multivitamin and mineral supplement.
Conclusion
The low FODMAP diet offers a promising option for plant-based individuals struggling with the effects of Irritable Bowel Syndrome (IBS). Significant symptom improvement is achieved in up to 76% of people who follow it. Trying this short-term elimination diet can help IBS sufferers to identify personal food tolerances for good.
For those following a plant-based lifestyle, some planning during and after the FODMAP restriction phase is essential to avoid nutrient deficiencies. Working with a Registered Dietitian trained in the low FODMAP diet has been shown to improve outcomes and can help to address potential nutritional shortfalls. This paves the way for a varied, healthy and gut-friendly diet in the long term.
Thank you so much for reading. Please comment below to tell me what the most useful thing you learnt from this blog or to ask any questions. I’ll be adding some low FODMAP vegetarian and vegan recipes soon so sign up to my newsletter to get weekly updates:
If you’d like to discuss how I can help you manage your IBS, book a free discovery call with me. I’m looking forward to hearing from you!
