Regional Dietary Patterns Tied to Global Prevalence, Severity of IBS

New research is shedding light on a significant association between dietary patterns and the global prevalence and severity of irritable bowel syndrome (IBS).1

Findings from the analysis of Rome Foundation Global Epidemiology Study (RFGES) data suggest diet has a notable influence on the development and severity of IBS, which is estimated to affect anywhere from 5-10% of the global population. Specifically, the study identified 4 dietary pattern clusters adjusted by age, country and religion, that were associated with differences in both the global prevalence and severity of IBS.1,2

“In recent years there has been increasing interest in the complex relationship between diet and IBS,” Dipesh Vasant, PhD, of the division of diabetes, endocrinology, and Gastroenterology at the University of Manchester, and colleagues wrote.1 “However, habitual dietary intakes vary considerably worldwide and study into the role of diet in the development of IBS have been limited to a few specific geographic locations, thus the need for global perspective on this issue.”

To address this gap in research, investigators assessed data for 54,127 participants from 26 countries who completed online questionnaires on Rome IV IBS criteria, healthcare utilization, and psychosocial factors potentially linked to the prevalence of IBS as part of the RFGES. The IBS Symptom Severity Scale (IBS-SSS), the Patient Health Questionnaire-12 (PHQ-12/15) for non-gastrointestinal physical symptom burden, and the Patient Health Questionnaire-4 (PHQ-4) for anxiety and depression were also included.1

Participants were asked to record on average how many days a week they consumed 3 food groups, including fruits, vegetables/legumes, and milk products, as well as 7 types of foods: rice, bread, pasta, meat, fish, tofu, and eggs.1

A total of 2195 participants (4.1%; 95% CI, 3.9–4.2) met Rome IV criteria for IBS across the 26 countries in the RFGES. Using latent class analysis (LCA), investigators identified 4 unique dietary pattern clusters with significant differences in the mean weekly food frequencies of all 10 surveyed foods. These 4 clusters were also significantly different in Rome IV IBS prevalence and IBS-SSS scores.1

Dietary cluster A mostly included participants from Egypt, Brazil, and Colombia and had the highest overall IBS prevalence (5.6%; 95% CI, 5.2% - 6.0%) with the highest IBS severity (mean IBS-SSS, 261.1 ± 106.4). Additionally, this group had the highest weekly food frequency for pasta, meat, and eggs when compared with all other clusters.1

Cluster B had the second highest IBS prevalence (4.5%; 95% CI, 4.2% - 4.8%) and was predominantly represented by Argentina, Germany, Poland and the US. Investigators noted this group had lowest weekly food frequency for fruit, vegetables/legumes, eggs, meat, and fish compared with the other clusters.1

Participants in cluster C, comprised mostly of participants from Australia, the UK, the Netherlands, Spain, Sweden, France, and Belgium, were older than those in the other clusters and had the highest weekly food frequency for fruit, vegetables/legumes, bread, and milk, and the lowest frequency for rice. The prevalence of IBS in this cluster was 3.4% (95% CI, 3.1% - 3.7%).1

Cluster D had the lowest prevalence of IBS (2.6%; 95% CI, 2.3% - 2.9%), and almost all participants from Asian countries belonged to this dietary cluster: China (99.8%), Japan (97.2%), South Korea (98.4%), and Singapore (96.7%). The dietary pattern in this cluster was characterized by the highest weekly food frequency for rice, fish, and tofu, and the lowest frequency for bread, pasta and milk compared with all other clusters. Investigators pointed out this group also had the lowest BMI and the lowest IBS severity score (mean IBS-SSS, 236.5 ± 94.1).1

Compared to those without IBS, participants with IBS had a significant difference in pasta intake frequency in all 4 clusters, whereas bread intake was higher in those with IBS within Clusters A and B, fruit intake was lower in those with IBS within Cluster A and vegetable intake was lower in those with IBS within Cluster D.1

Using multivariable logistic regression, participants aged 40-64 years (odds ratio [OR], 0.74; 95% CI, 0.68-0.81; P <.001) and those ≥65 years of age were less likely to have IBS compared with participants aged 18-39 years (OR, 0.34; 95% CI, 0.29- 0.41; P <.001). Females had significantly greater odds of having IBS (OR, 1.79; 95% CI, 1.64-1.96; P <.001).1

Further analysis revealed that compared with Cluster C, Cluster D participants had the lowest odds of IBS (OR, 0.67; 95% CI, 0.58-0.78; P <.001), whereas Clusters B (OR, 1.16; 95% CI, 1.03-1.29; P = .012) and A had higher odds of IBS (OR, 1.47; 95% CI, 1.31-1.66; P <.001).1

Investigators pointed out those within dietary Cluster A had the greatest IBS severity, somatic, psychological symptom scores and worst quality-of-life compared with the other clusters, and the highest medication use.1

“In conclusion, this study should raise awareness of regional international dietary patterns and their association with variations in the worldwide prevalence and severity of IBS,” investigators wrote.1 “Comprehensive quantitative dietary data is needed to further elucidate associations between diet and IBS.”

References

1. Jaafari H, Houghton LA, West RM, et al. Dietary patterns are associated with variations in the global prevalence and severity of Rome IV Irritable Bowel Syndrome. Clin Gastroenterol Hepatol. doi:10.1016/j.cgh.2025.06.004

2. International Foundation for Gastrointestinal Disorders. IBS Facts and Statistics. Accessed June 26, 2025. https://aboutibs.org/what-is-ibs/facts-about-ibs/