Eat more unprocessed foods, which are linked to a lower risk of Crohn’s disease

Eating more unprocessed or minimally processed foods was associated with a lower risk of Crohn’s disease without an established association with ulcerative colitis, according to data from participants in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort.

Among over 400,000 participants, the highest quartile of unprocessed or minimally processed food consumption was associated with a lower risk of Crohn’s disease than the lowest quartile (adjusted HR 0.57, 95% CI 0.35-0.93, P-trend<0.01), reported Franck Carbonnel, MD, PhD, from Bicêtre University Hospital in Paris, and colleagues.

In particular, the consumption of fruit and vegetables was negatively associated with the risk of Crohn’s disease (aHR for the fourth vs. first quartile 0.54, 95% CI 0.34-0.87 and aHR 0.55, 95% -CI 0.34–0.91), they found Clinical gastroenterology and hepatology.

However, no association was observed between consumption of unprocessed or minimally processed foods and risk of ulcerative colitis (aHR 0.89, 95% CI 0.65-1.21), nor was there an association between consumption of ultra-processed foods and the risk of Crohn’s disease (aHR 1.48, 95% CI 0.79-2.76) or ulcerative colitis (aHR 0.93, 95% CI 0.61-1.43), said Carbonnel and his team.

“This study suggests that there is a benefit in favoring consumption of unprocessed/minimally processed foods in relation to CD [Crohn’s disease] Risk; particularly in individuals who are at high risk of this disease, such as first-degree relatives of CD patients,” they concluded.

The incidence of inflammatory bowel disease (IBD) has been increasing, particularly among older adults, and previous research has suggested a link between diet and risk of IBD, Carbonnel’s group noted.

Consumption of ultra-processed foods has also increased globally and has been linked to risks of high blood pressure, obesity, diabetes and cancer, among others. Previous results from the EPIC cohort found that a dietary pattern high in sugar/soft drink consumption and low in vegetable consumption was associated with the risk of ulcerative colitis, while the PURE study found that consumption of ultra-processed foods and fried foods was associated with a higher risk of IBD, but with no differences between subtypes. Other recent studies have found a link between Crohn’s disease and a non-Mediterranean diet.

For this study, Carbonnel and colleagues examined data from 413,590 healthy volunteers who completed a validated food intake frequency questionnaire in eight European countries participating in EPIC. Participants were grouped into processed food consumption categories — ultra-processed or unprocessed/minimally processed — and then further stratified into quartiles based on the NOVA classification system. Researchers adjusted for location, age, gender, BMI, physical activity, education level, energy intake, alcohol consumption, and smoking status.

The mean age at baseline was 51.7 years and 68.6% were women. Over a median follow-up of 13.2 years, 431 participants developed ulcerative colitis and 179 developed Crohn’s disease.

While the results remained unchanged after excluding the first few years of follow-up in a sensitivity analysis, a positive correlation between ultra-processed food intake and Crohn’s disease was observed (aHR for the fourth vs. first quartile of consumption 2.02, 95% CI 1.00–4.06, P=0.06).

Carbonnel and colleagues acknowledged that residual confusion may have arisen from unmeasured factors. Although IBD cases were based on self-reports that were subsequently reviewed, some cases may have been missed, they noted. In addition, diet was only assessed at baseline and may have changed over time, and results may not generalize to younger subjects.