Ultraprocessed Grain Intake Linked to Higher Global IBD Risk

Key Clinical Summary

• A prospective analysis of 124,590 adults from 21 countries in the Prospective Urban Rural Epidemiology (PURE) study found that higher ultraprocessed grain intake was associated with an increased risk of incident inflammatory bowel disease (IBD).

• Participants consuming ≥19 g/day of ultraprocessed grains had an 86% higher risk of IBD than those consuming <9 g/day (HR, 1.86; 95% CI, 1.26–2.61; P trend = .0003).

• Greater overall ultraprocessed food consumption was also associated with substantially higher IBD risk, whereas fresh bread and rice were associated with a lower risk of developing IBD.

Inflammatory bowel disease (IBD) risk may be influenced by the quality and degree of processing of dietary grains, according to findings from the Prospective Urban Rural Epidemiology (PURE) study published in the American Journal of Gastroenterology.

Study Findings

The prospective analysis included 124,590 participants from the multinational PURE cohort who completed validated food frequency questionnaires. Investigators categorized ultraprocessed grain intake into three consumption levels and examined its association with incident IBD using multivariable Cox proportional hazards models.

The analyses adjusted for multiple potential confounders, including age, sex, smoking status, eating habits, and physical activity. The primary endpoint was the development of IBD, including both CD and UC.

Participants consuming ≥19 g/day of ultraprocessed grains had a significantly greater likelihood of developing IBD than those consuming <9 g/day, with an adjusted hazard ratio (HR) of 1.86 (95% CI, 1.26–2.61; P trend = .0003).

The study also evaluated overall ultraprocessed food consumption. Individuals consuming ≥5 servings of ultraprocessed foods per day experienced nearly a fourfold higher risk of developing IBD compared with participants consuming <1 serving per day (HR, 3.95; 95% CI, 2.74–5.71; P trend < .0001).

In contrast, consumption of fresh bread and rice was associated with a lower risk of IBD, suggesting that the observed associations may relate more to the degree of food processing than to grain consumption itself.

Clinical Implications

These findings add to growing evidence linking ultraprocessed foods with adverse gastrointestinal outcomes and suggest that ultraprocessed grains may represent a modifiable dietary risk factor for IBD. Although the study demonstrates an association rather than causation, its large multinational cohort and prospective design strengthen the observed relationship.

For clinicians caring for patients at elevated risk of IBD or those seeking dietary guidance, the results support emphasizing overall dietary quality and limiting foods that undergo extensive industrial processing. The apparent protective association observed with fresh bread and rice also highlights that not all grain-based foods carry equivalent risk.

The authors note that additional research is needed to identify which specific components of ultraprocessed grains—including additives, emulsifiers, preservatives, or other processing-related factors—may contribute to intestinal inflammation and disease development.

Expert Commentary

The study authors concluded that higher intake of ultraprocessed grains was associated with a significantly increased risk of developing IBD. They further stated that "a healthy eating pattern should minimize consumption of ultraprocessed grains" and emphasized that additional studies are needed to determine which components of ultraprocessed grains may be detrimental to gastrointestinal health.

Results from the multinational PURE study suggest that greater consumption of ultraprocessed grains is associated with an increased risk of incident IBD, while less processed grain foods may be associated with lower risk. Further mechanistic and interventional studies are needed to clarify causality and identify the dietary components driving these associations.

Reference

Narula N, Wong ECL, Mente A, et al. Ultraprocessed grains and risk of IBD: Results from the Prospective Urban Rural Epidemiology Study. Am J Gastroenterol. 2026;121(6):1445-1454. doi:10.14309/AJG.0000000000003700