Living with irritable bowel syndrome (IBS) often necessitates dietary adjustments. For those drawn to veganism, which champions plant-based foods while excluding all animal products, the intersection of this lifestyle and IBS management presents a unique set of considerations. While veganism may appeal to those focused on health, animal rights, or environmental concerns, it's not a straightforward solution for IBS sufferers. Many plant-based foods can irritate the gastrointestinal (GI) system, potentially triggering or worsening IBS symptoms.
Understanding IBS and the Role of Diet
A cornerstone of managing IBS symptoms is understanding the impact of dietary choices. A 2017 study indicated that a significant majority of individuals with IBS, around two-thirds, attribute their symptoms to specific food intake. These symptoms commonly include bloating, diarrhea, gas, and constipation.
Given the large amount of online support networks and information out there, it is important to not self-diagnose. Before making any restrictive dietary changes, get properly tested for IBS by a gastroenterologist. Your gastroenterologist will be able to order tests and perform the proper work-up. Other conditions like celiac disease, IBD, diverticular disease, cancers, pelvic floor disorders, endometriosis, endocrine disorders, and more, are important to consider and must be ruled out.
The Vegan Diet: An Overview
A well-balanced vegan diet typically includes a variety of fruits, vegetables, whole grains, proteins from nuts, seeds, and legumes. However, many of these foods can be difficult to digest for those with IBS, as they often contain fermentable short-chain carbohydrates and sugar alcohols.
FODMAPs: A Key Consideration for IBS Management
Veganism for IBS may incorporate the low FODMAP diet. This acronym stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. These are the fermentable short-chain carbohydrates and sugar alcohols that may irritate your GI system.
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The low FODMAP diet measures foods by their ability to break down in the small intestine. Foods low in FODMAPs cause fewer GI reactions because your body breaks down food before it reaches the colon. Food that remains intact by the time it is in the colon requires extra water and causes more gas. These factors can produce uncomfortable IBS symptoms that can last for hours or days after eating a triggering food.
Adopting a diet that eliminates foods considered difficult to digest, such as the low FODMAP diet, may be a better way to control IBS symptoms than following a strictly vegan diet. You can adopt this diet and practice veganism, but it is best to work with a doctor or registered dietitian nutritionist to be sure your diet supports your overall health.
Low FODMAP Vegan Foods: Options and Examples
Navigating a vegan diet while minimizing FODMAP intake requires careful selection. Some examples of vegan foods that are low in FODMAPs include rice, firm tofu, ginger, and spinach. The low FODMAP diet does not exclude meat and dairy products, but you can adapt it so that it aligns with the principles of veganism.
Effectiveness of the Low FODMAP Diet for IBS
A 2016 study demonstrated that up to 86 percent of participants with IBS experienced fewer GI symptoms when adhering to the low FODMAP diet. However, the study stressed the importance of close adherence and collaboration with dietary professionals for optimal nutrition. Keep in mind that everyone reacts to various foods differently, so your experience with certain food types may differ from that of others with IBS.
Integrating Veganism and the Low FODMAP Diet
So you’re vegan and you’ve been told you have irritable bowel syndrome (IBS). Or you’ve been struggling with your IBS symptoms and are curious about the benefits of a plant-based diet. Now what? You might have heard that veganism and IBS can be a challenge. In fact, I’ve had clients whose health providers have told them they’re going to have to give up eating vegan.
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Following a vegan low FODMAP diet is within reach, and it may help you finally work out the cause of painful IBS symptoms. There’s also strong scientific evidence that many chronic diseases (type 2 diabetes, heart disease, certain cancers, and more) can be prevented and controlled with a healthy vegan diet. Often, people also have more energy, reduced inflammation, and they feel better overall after removing animal products from their diet.
The Elimination Phase of the Low FODMAP Diet
Typically, it is recommended to stay low FODMAP for two to six weeks while your gut recuperates. During the elimination phase, you should aim to exclusively eat low FODMAP foods. It can certainly be trickier to eat plant-based as many vegan staples are high in FODMAPs. On a vegan elimination diet plan, the basics don’t change. I still suggest you eat plenty of fruits and veggies, choose whole grains, and enjoy a variety of healthy protein foods. Remember to watch your portion sizes. A low FODMAP food can quickly become a high FODMAP food when you eat a large quantity!
Other Healthy Modifications to Make
The gluten-free diet has gained popularity among the IBS community, in part due to perceived symptom improvements on a gluten free diet. However, gluten and FODMAPs (especially fructans) co-exist in grain and cereal foods. This pattern might explain the benefits that people report on a gluten-free diet. These might be wrongfully attributed to the removal of gluten, when in fact it’s the reduction of FODMAP intake! A combination of veganism and gluten-free could be unnecessarily restrictive for you.
Fibre is important for gut health. However, it can also be a culprit for symptoms in IBS. Fibre can either be consumed through diet (from foods such as fruit, vegetables, breads and cereals), or taken as a supplement (for example bran, psyllium and methylcellulose). FIbre is also divided into two categories: soluble and insoluble. If you experience constipation (IBS-C), soluble fibers like oats, psyllium, and linseeds can help loosen things up. You should work with a dietitian to slowly increase the amount of fermentable fibers you eat. Typically, insoluble fibers (like wheat bran) are ineffective and may exacerbate abdominal pain and bloating. If you experience frequent loose stools (IBS-D), try reducing your insoluble fibre intake.
Alcohol does have gastrointestinal effects. I have many clients who also report poor tolerance to alcohol. Despite this, little is known about whether alcohol causes IBS symptoms and at what level. Caffeine also has gastrointestinal effects. However, there is virtually no research that suggests manipulating caffeine intake improves IBS symptom control. It is quite individual and you should work with your dietitian to figure out what’s best for you.
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Lifestyle Factors in Managing IBS
Keys to managing IBS start with what and when you eat, how much you exercise, and how much water you drink. Here are some ways you can factor in these considerations in your daily life if you have IBS:
- Eat breakfast, lunch, and dinner, as well as snacks as needed, according to a regular schedule.
- Make meal plans that pack a nutritional punch, and adhere to your diet.
- Watch your food portions and avoid huge meals and long gaps between mealtimes.
- Eat slowly and chew your food carefully before swallowing.
- Exercise at least 150 minutes per week if engaging in moderate activity.
- Drink 6 to 12 cups of water per day.
- Avoid processed foods.
- Consume sugary or spicy foods in moderation, as they could potentially trigger your IBS.
- Keep a journal of your symptoms and note if you suspect any foods or beverages triggered your IBS.
The Broader Impact of Diet on IBS: A Study from NutriNet-Santé
There is growing interest in using diet counselling in the management of patients with irritable bowel syndrome (IBS). Among new emerging diets, vegetarian diets (VD) seem to be experiencing an important popularity, partly because of their alleged health benefits.
The NutriNet-Santé Study is a web-based prospective observational cohort. It aims to investigate the relationships between health and nutrition. At baseline, participants completed self-administered questionnaires about socio-economic, lifestyle, health status, diet, physical activity, and anthropometrics data. During follow-up, additional questionnaires are regularly performed in accordance with the declaration of Helsinki and were approved by the institute Review Board of the French Institute for Health and Medical Research and the Commission Nationale de l’Informatique et des Libertés. A questionnaire assessing presence of FGIDs was sent to the whole cohort on 21 June 2013, and the questionnaire was available for completion up to the 6 November 2013, including data on medical digestive history and symptoms using the Rome III criteria. IBS and subtypes of the disease (IBS-Constipation, IBS-C, IBS-Diarrhea, IBS-D, IBS-Mixed, IBS-M and IBS-undefined, IBS-U), were defined according to the Rome III criteria and had to be present at least for the last 6 months.
The study suggests that a long term VD could be associated with IBS. Vegetarian diet (VD), that includes the partial or total removal of meat, poultry, fish from the diet, (vegans also exclude dairy products and eggs), is increasingly widespread among the general population. The reasons for adopting this dietary profile are attributable to ethical, environmental, and social concerns. Health aspects of such a diet are also more and more emphasized. Indeed, health benefits of the VD, especially on ischemic heart disease and cancer have been widely reported by cross-sectional and prospective cohort studies during the last 50 years. Generally speaking, vegetarians tend to be more health conscious, with a lower body mass index (BMI), and in better health when compared with omnivores, giving this type of diet a clear appeal in the population of subjects suffering from chronic diseases.
Given the lack of scientific evidence supporting specific dietary advice for patients with IBS, they tend to adopt new diets, guided by various way of life (empirical, philosophical, etc), and spread via the media. These changes include exclusion diets like VD. Adopting a VD pattern could induce some effects on the digestion process, and even on digestive diseases: Crowe and colleagues have shown that consuming a VD and a high intake of dietary fibre were both associated with a lower risk of admission to hospital or death from diverticular disease. A recent cross-sectional study performed among the rural Indian population found that participants with a predominant VD were more at risk for having IBS than those with a non-VD.
In the NutriNet-Santé Study, 57,037 individuals filled the FGIDs questionnaire. Among them, 52,028 completed information on VD before answering the FGIDs questionnaire. Among them, 50,446 subjects had at least three 24H records available for analysis. The 8,538 participants that reported any organic diseases (stomach, esophagus or colorectal cancers, familial adenomatous polyposis coli, Crohn’s disease, coeliac disease, ulcerative colitis) or alarm symptoms (melena, hematemesis, rectal bleeding or significant unintentional weight loss in the past 3 months) were excluded. The final sample included 41,682 subjects. Subjects included were mainly women (78.0%) and the mean age was 49.8 +/-14.3 years. Overall 2,264 (5.4%) subjects reported an IBS, with a higher prevalence in women compared to men (5.6% vs 4.8%, p = 0.03).
Overall 1.9% (n = 805) subjects declared they followed a VD, mostly women (2.1% vs 1.4%, p<0.001). Vegetarians also had lower consumption of soft sugary drinks and alcoholic beverage, while they had significantly higher consumption of eggs, fruits and vegetables, wholegrain products, pulses, cereals, dry fruits, legumes, oil and non-sugared beverages.
The vegetarians reported lower total energy intake, with lower percent energy from fat and proteins, and higher percent energy from carbohydrates. Vegetarians had lower daily intakes of saturated fatty acids (SFA), cholesterol and animal proteins and they tended to reach the recommended level in fibres (>25g/day) more often than omnivorous. Conversely, they had higher intakes poly unsaturated fatty acids (PUFA), Omega 3, Omega 6 and vegetal proteins. Consumption of calcium, iron, potassium, magnesium, beta carotene, Vitamins A, B1, B6, B9, C and E were significantly higher in vegetarians compared to omnivores.
No significant association was observed between vegetarians and IBS. When studying vegetarians who declared at least three times they followed a VD, significant associations were shown with IBS (aOR 2.60 95%CI: 1.37-4.91), with IBS mixed (aOR 2.97 95%CI: 1.20-7.36), and with IBS-diarrhoea (aOR 2.77 95%CI: 1.01-7.59). Sensitivity analyses, including vegans showed similar results, plus an association between VD and IBS diarrhoea (aOR 1.55 95%CI: 1.02-2.34). A VD was associated with IBS, IBS-M and IBS-D in consistent vegetarians, i.e. when participants declared at least three times they were vegetarians in the Nutrinet study.
Numerous approaches to dietary management of IBS have been investigated, including an increase of dietary fibre intakes, identification and management of lactose intolerance, and more recently exclusion of food containing Fermentable Oligo-, Di-, Monosaccharides And Polyols FODMAPs.
The role of dietary fibres on IBS is complex. An increased proportion of certain types of carbohydrates in diet can also worsen IBS symptoms. In particular sugars (mono and disaccharides) and polyols which are slowly absorbed from the small intestine rather than digested, and can lead to a luminal distension by various mechanisms (water fermentation, rapid fermentation, gas,…) Although lactose malabsorption does not appear to be a cause of IBS or to be more prevalent in individuals with IBS than in the general population, lactose is not well digested and absorbed by a majority of adults throughout the world, and individuals with and without IBS may report increased symptoms, similar to those of IBS, following ingestion of lactose-containing foods. Thus, the low lactose intakes of vegetarians could help to improve IBS symptoms.
We found a positive association between consistent VD and IBS (aOR = 2.58, 95%CI 1.36-4.87 with p = 0.004), IBS-M (aOR = 2.94, 95%CI 1.19-7.31 with p = 0.02) and IBS-D (aOR = 2.77, 95%CI 1.01-7.59 with p = 0.047). Similar results were shown by including vegans in the outcome, with in addition a significant association with IBS-D with VD (at least once).
Dr. Chanu Dasari and the Mind-Gut-Immunity Method
Irritable Bowel Syndrome (IBS) can turn everyday meals into a minefield of discomfort. Many people flock to vegan diets hoping that “plant-based IBS management” will soothe symptoms by removing inflammatory animal products.
Dr. Vegan plant-based diets eliminate arachidonic acid and saturated fats found in meat and full-fat dairy-pro-inflammatory compounds that can exacerbate IBS. Yet, in practice, “vegan diet for IBS” often ends up being a high-carb, low-protein regimen heavy on processed foods.
Whole vegetables, berries, nuts, and herbs deliver antioxidants and anti-inflammatory phytonutrients. Vegan plans often skew high in carbs. To “maximize vegan IBS results,” aim for roughly 40-50% of calories from healthy fats (e.g., avocados, flaxseeds) and 20-25% from plant proteins (lentils, tofu, tempeh).
IBS is driven by microbial imbalances-too many harmful bugs bustling on the wrong substrates. Generic vegan diets are rarely specific enough to shift this ecology. Even plant foods can provoke IBS. Beans, lentils, cruciferous vegetables, and sugar alcohols frequently show up on sensitivity tests-and being “vegan” doesn’t shield you from reactions.
True success isn’t about rigid veganism; it’s about a resilient, individualized strategy. After the initial healing phase, we teach clients how to “monitor IBS diet progress” and gradually re-expand their food repertoire. IBS relief isn’t about following a one-size-fits-all vegan program-it’s about addressing the root causes of gut inflammation with precision.
The Gut Microbiome and IBS Subtypes: Insights from the ZOE PREDICT 1 Study
The role of diet and the gut microbiome in the etiopathogenesis of irritable bowel syndrome (IBS) is not fully understood. Therefore, we investigated the interplay between dietary risk factors and gut microbiota in IBS subtypes using a food frequency questionnaire and stool metagenome data from 969 participants aged 18-65 years in the ZOE PREDICT 1 study, an intervention study designed to predict postprandial metabolic responses.
Participants with IBS-D (n = 59) consumed more healthy plant-based foods (e.g. whole grains, leafy vegetables) and fiber, while those with IBS-C (n = 49) tended to consume more unhealthy plant-based foods (e.g. refined grains, fruit juice) than participants without IBS (n = 797). Microbial diversity was nominally lower in patients with IBS-D than in participants without IBS or with IBS-C.
The gut microbiome alpha-diversity was different across IBS subtype, with a slightly lower alpha-diversity in IBS-D as compared to IBS-C subtype and non-IBS. Compared to non-IBS, healthy commensal anaerobes were depleted in IBS-D, including Faecalibacterium prausnitzii and Firmicutes bacterium CAG 110. IBS-C was associated with an elevated relative abundance of opportunistic pathogens, such as Escherichia coli.
Our study also suggests that the gut microbiota could potentially modify the association between diet and IBS subtypes. Specifically, the positive associations between dietary fiber and iron intake and IBS-D were stronger when the relative abundance of F. prausnitzii was higher, which was potentially driven by several glycan metabolic pathways.
Practical Considerations for Plant-Based Diets and IBS
Many people are trying to follow a plant-based diet or increase their intake of plant-based foods for health, ethical or sustainability reasons. But can you do this if you have irritable bowel syndrome (IBS)? Although symptoms such as diarrhoea, constipation, bloating and abdominal pain can indicate that you have IBS, these symptoms can, also, be related to other conditions such as Coeliac disease and inflammatory bowel disease (IBD).
A plant based diet is a diet which is made up of foods as fruit and vegetables, legumes, wholegrains and nuts and seeds, with little or no animal sources in the diet. A plant-based diet can include vegetarian and vegan diets. The low FODMAP diet has been found to reduce IBS symptoms in up to 70% of those with IBS1, and has three phases; a FODMAP reduction phase which lasts four to eight weeks, a re-introduction phase to identify trigger foods and a long term modified diet which avoids the trigger foods personal to you. The restriction phase restricts a number of foods including wheat, high lactose dairy foods, certain fruit and vegetables, onions and garlic. However, there are plenty of foods that you can eat whilst following the diet and any foods cut out during the restriction phase should be replaced by suitable alternatives e.g.
Following a plant-based diet can already be restrictive if not well planned and a vegan diet, especially, can lead to Vitamin B12, iodine, calcium and omega-3 deficiencies. Doing the low FODMAP diet on top of this could lead to social restrictions and nutritional deficiencies.
Seeking Professional Guidance
Consider working with a registered dietitian nutritionist or a doctor if you live with IBS and experience uncomfortable symptoms. Changes to your diet that include veganism or a low FODMAP diet may be healthy options for you. A professional’s expertise can help you plan a well-rounded diet that takes into account your nutritional needs. Adopting a low FODMAP diet may require a period of time where you eliminate certain foods and slowly add potentially triggering items back over time. A healthcare professional can make sure you do this safely.