Ultra-Processed Food Consumption and Long-Term Risk of Irritable Bowel Syndrome: A Large-Scale Prospective Cohort Study

Background & Aims The considerable disease burden of irritable bowel syndrome (IBS) has coincided with the increase of ultraprocessed food (UPF) consumption over the past few decades. However, epidemiologic evidence is lacking. We aimed to examine the long-term risk of IBS associated with UPF consumption in a large-scale prospective cohort. Methods Participants who completed 24-hour dietary recalls during 2009 to 2012 from the UK Biobank, and free of IBS, celiac disease, inflammatory bowel disease, and any cancer at baseline, were included (N = 178,711; 53.1% female). UPF consumption was defined according to the NOVA food classification system, expressed as a percentage of UPF content in the total diet intake (as grams per day). The primary outcome was incident IBS. A Cox proportional hazard model was performed to estimate associated risk. Results The mean UPF consumption was 21.0% (SD, 11.0%) of the total diet. During a median of 11.3 years of follow-up evaluation, 2690 incident IBS cases were identified. An 8% higher risk of IBS (hazard ratio, 1.08; 95% CI, 1.04–1.12) was associated with each 10% increment of UPF consumption. Compared with the lowest quartile of UPF consumption, the highest quartile was associated with a significantly increased risk of incident IBS (hazard ratio, 1.19; 95% CI, 1.07–1.33; Ptrend < .001). Subgroup analyses by age, sex, body mass index, smoking, and alcohol drinking status also showed similar results, except for the never/previous drinking subgroup. Further sensitivity analyses confirmed the positive association with a higher UPF consumption. Conclusions Our findings provide evidence that a higher UPF consumption is associated with an increased risk of incident IBS, with a significant dose-response relationship.