Staple Foods Consumption and Irritable Bowel Syndrome in Japanese Adults: A Cross-Sectional Study

BACKGROUND Carbohydrates can cause gastrointestinal symptoms due to incomplete absorption in the small bowel. Thus, high-carbohydrate diets may induce symptoms of irritable bowel syndrome (IBS). OBJECTIVE This observational and cross-sectional study assessed the association between consumption of several carbohydrate-enriched staple foods, such as rice, Japanese wheat noodles, Chinese noodles, bread, pasta, and buckwheat noodles, and the prevalence of IBS in Japanese adults. SUBJECTS AND METHODS One thousand and eighty-two (837 men) Japanese adult employees aged 19-85 were included in this cross-sectional study conducted in 2011. IBS diagnosis was based on the Rome III criteria. Consumption of staple foods was assessed using a brief self-administered diet history questionnaire, and divided into three categories (low, middle, high) depending on their distribution. RESULTS In the multivariate analysis, daily consumption of rice (odds ratios [ORs] and [95% confidence interval (CI)]: middle, 1.36 [0.93-1.99]; high, 1.67 [1.12-2.49]; P for trend = 0.01), bread (middle, 1.88 [1.28-2.75]; high, 1.63 [1.10-2.41]; P for trend = 0.01), pasta (middle, 1.47 [1.01-2.15]; high, 1.68 [1.12-2.52]; P for trend = 0.01), and buckwheat noodles (middle, 1.76 [1.18-2.61]; high, 1.98 [1.31-3.00]; P for trend = 0.001) were associated with higher prevalence of IBS after adjustment for socio-demographic, anthropometric, and lifestyle-related factors. Buckwheat noodles, but not other staple foods, retained an association with the prevalence of IBS even after adjustment for daily intake of carbohydrates or plant proteins. CONCLUSIONS This cross-sectional study demonstrated that the consumption of staple foods, such as rice, bread, pasta, and buckwheat noodles is associated with the prevalence of IBS. Of these, the consumption of buckwheat noodles, but not other staple foods, is associated with IBS independent of carbohydrate or plant protein contents.