One of the most common questions for doctors treating people with ulcerative colitis (UC), a type of inflammatory bowel disease (IBD), is whether changing diet really helps. For a long time, the standard answer was: “We don’t really know.” But recent science is increasingly pointing to diet — especially how much animal protein and sulfur we eat — as an important factor in UC.
Newer research suggests that hydrogen sulfide (H₂S), a gas produced in the colon, may play a role in worsening UC. Diets high in sulfur-containing amino acids — which are abundant in meats — can boost H₂S in the gut, and that might damage the colon lining or trigger inflammation. While this line of research is still growing, it aligns with older observations linking high animal-protein diets to more frequent relapses in IBD.
Reducing sulfur-rich animal proteins may therefore be helpful. In practical terms, lowering meat intake can reduce how much dietary sulfur the body needs to process, which might reduce harmful effects in the colon.
Evidence for Plant-Based Diets in UC
Over the past few years, several studies — especially from Japan — have supported the idea that a plant-based diet (PBD) helps in UC, both for inducing remission and for maintaining it.
1. Educational Hospitalisation Study (Japan):
• Researchers admitted UC patients for two weeks to teach them a plant-based diet, giving guidance and support.
• At the end of hospitalisation, 77% of patients saw improvements, such as reduced or no bloody stool.
• Over the next few years, relapse rates were impressively low: only 2% at one year, 4% at two, 7% at three, and ~19% by five years.
• The patients’ adherence to the diet (“plant-based diet score”) remained significantly higher than their baseline, even years later.
• This suggests that the “educational hospitalisation” model not only improves short-term symptoms but also helps people stick to a healthier diet long-term.
2. Therapeutic Advances in IBD (Japan):
• A group of gastroenterologists developed a lacto-ovo-semi-vegetarian diet, a kind of plant-based diet, to counter the modern “Westernised” diet, which they suggest is one of the environmental triggers for IBD.
• Their data showed that in UC, even without heavy medication, about one-third of mild UC patients achieved remission with just the diet.
• Over the years, relapse rates remained low: in one cohort, the 1-year relapse rate was only 14%, and the 5-year relapse rate was ~27%.
3. Severe UC Case Report:
• In 2022, doctors reported a 21-year-old man with severe UC who was treated with infliximab (a biologic drug) plus a plant-based diet.
• After three infusions of infliximab and diet therapy, his symptoms improved markedly. Later, corticosteroids (prednisolone) were added, and he reached clinical and endoscopic remission.
• The authors suggest that combining a plant-based diet with standard drugs may be a promising “first-line” strategy, even in severe UC.
4. Broader Reviews & Expert Opinion:
• A 2023 review argued strongly that our modern “Westernised” diet — rich in animal protein, fat, and low in fibre — may be the most ubiquitous environmental factor driving IBD.
• Another editorial (2023) in Inflammatory Bowel Diseases discussed data from a large registry: they found that plant-based diet patterns (especially those with very little animal products) were associated with lower odds of active disease, though this was clearer for Crohn’s disease than UC in that particular analysis.
• A more recent summary (2024) reinforces that plant-based diets in IBD have few to no adverse side effects, making them a safe adjunct or alternative to more toxic medications.
Why This Matters for India?
• Changing Diets in India: India is seeing a rapid dietary transition. Traditional diets in many regions are being replaced by more “Westernised” eating: more processed foods, more meat, less fibre. This shift may contribute to rising IBD rates in India.
• Affordability & Safety: A plant-based diet — especially whole-food, minimally processed — can be cost-effective in the Indian context (lentils, beans, seasonal vegetables, millets). Unlike expensive biologic drugs, a diet change carries a very low risk of side effects.
• Long-Term Health Gains: Beyond ulcerative colitis, a plant-based diet also helps with other chronic diseases prevalent in India, like heart disease, diabetes, and hypertension.
Why a Plant-Based Diet Might Work?
1. Fibre Feeds Gut Microbiota: Plant-based diets are rich in dietary fibre. Good fibre feeds beneficial gut bacteria, which produce short-chain fatty acids (like butyrate) that support colon health, reduce inflammation, and strengthen the gut barrier.
2. Less Dietary Sulfur: By reducing animal protein, you reduce sulfur-containing amino acid intake, which may lower production of H₂S in the colon. Excess H₂S is toxic to colon cells and may contribute to flares.
3. Microbiome Modulation: A plant-based diet may help rebalance the gut microbiome, making it less “pro-inflammatory.” Studies suggest that Western diets cause gut microbial dysbiosis, promoting inflammation; PBDs may reverse this.
4. Synergy with Medications: In case reports and small trials, combining a plant-based diet with standard drugs (like infliximab) improved outcomes, suggesting the diet may boost the effectiveness of medical treatment.
Limitations and Cautions
• Not all studies are randomised controlled trials (RCTs). Many are single-group trials, case reports, or observational. For example, the educational hospitalization study was a single-group design.
• Adherence can be a challenge: shifting long-term dietary habits is hard, even with hospitalisation-based education.
• During acute flares, very high-fibre foods may be difficult to tolerate. Some patients may need to modulate fibre intake based on symptoms and gut tolerance.
• While diet can be powerful, it may not be sufficient for everyone. Some patients will still need medications, biologics, or other therapies. The severe UC case report mentioned above needed both infliximab and steroids in addition to diet.
• Cultural and socioeconomic factors matter: not everyone has access to a wide variety of fresh vegetables, fruits, or whole grains.
Practical Tips
• Start gradually: If you or someone you know with UC wants to try a plant-based diet, begin by reducing meat and increasing legumes, vegetables, millets, and whole grains.
• Seek guidance: Work with a gastroenterologist and a dietitian familiar with IBD. They can help tailor a PBD that is nutritionally complete and realistic for your lifestyle.
• Monitor carefully: Regular check-ups, blood tests, and possibly a colonoscopy are needed. Diet is not a “magic cure,”; but it can be a powerful partner.
• Be patient: Habit change takes time. Programs like “educational hospitalization” (or shorter versions) might help build sustainable habits.
• Leverage tradition: Use traditional Indian foods (lentils, beans, seasonal greens, millets) that are both healthful and culturally familiar.
Conclusion
Emerging research increasingly supports a plant-based diet as a valuable tool in managing ulcerative colitis. Unlike many drug therapies, it’s low-risk, potentially cost-saving, and aligns well with traditional Indian food patterns. While more large-scale trials are needed — especially in different geographic and ethnic settings — the evidence so far is promising. For many with UC in India, adapting to a plant-based way of eating, under medical supervision, may offer a powerful, sustainable path to better gut health.
References
1. Dutta AK et al., Indian Journal of Gastroenterology — nutritional and functional status of UC patients, 2024.
2. Ye J. et al., pilot Reduced Sulfur (RS) diet: RS diet reshapes microbiome and fecal metabolome (pilot), 2025.
3. Day AS. et al., 4-SURE diet reduces protein fermentation and H₂S in UC (2025 advance article).
4. Nieva C. et al., ECCO/JCC review: diet modulates microbiota — implications for IBD (2024).
5. Shankar S. et al., narrative review of IBD evolution in South Asia/India — rising burden and role of environmental/dietary change (2024).