Routine stool tests and information about what people eat, could help doctors identify which patients with inflammatory bowel disease are most likely to experience a sudden flare, according to a study published in the journal Gut.
The research, led by the University of Edinburgh, UK, followed more than 2,600 people with IBD across 47 centres over a period of four years.
Inflammatory bowel disease, which includes Crohn’s disease and ulcerative colitis, affects nearly one in a hundred people in the UK. It is characterised by long periods of relative calm, broken by sudden and often debilitating episodes of pain, diarrhoea and fatigue. Predicting when those flares will strike has long been a challenge.
The study, known as PREdiCCt, asked participants to complete dietary questionnaires and provide blood and stool samples at the start of the study, then tracked them monthly for symptoms over several years. The stool test measured faecal calprotectin, a marker of inflammation in the gut that is already used routinely in NHS care.
The results showed that elevated calprotectin levels at the outset, even in people who felt perfectly well, strongly predicted future flares. In people with ulcerative colitis, the risk of a confirmed flare within two years rose from around 11% in those with low calprotectin levels to 34% in those with high levels.
Diet also played a role, at least in ulcerative colitis. People who ate the most meat had roughly double the risk of a confirmed flare compared to those who ate the least. This link was not seen in Crohn’s disease, and no consistent associations were found between flares and fibre intake, ultra-processed foods, alcohol or polyunsaturated fats.
Because the study was observational, it cannot prove that eating meat directly causes flares. But the researchers say the findings are strong enough to justify future clinical trials testing whether cutting down on meat, alongside regular inflammation monitoring, could help prevent relapses in ulcerative colitis.
“This major study is the first of its kind to properly track the relationship between habitual diet and disease flares in such a large, prospective way. It has been a massive team effort over the past decade to recruit and follow more than 2,600 people living with IBD across the UK. Our results provide a new framework for management: using objective biomarkers to catch subclinical inflammation early and identifying specific dietary factors that may help prevent debilitating relapses. This is exactly the kind of personalised evidence-base we need to improve the lives of people living with Crohn’s and colitis,” said Professor Charlie Lees, Professor of Gastroenterology at the University of Edinburgh.
Constantine-Cooke N, Gros B, Plevris N, et al (2026) Associations between demographic, clinical and dietary factors and flares in inflammatory bowel disease: the PRognostic effect of Environmental factors in Crohn’s and Colitis (PREdiCCt) prospective cohort study. Gut, doi: 10.1136/gutjnl-2025-337846