Associations of dietary diversity with constipation symptoms and gut microbiota features in individuals with functional constipation

Objectives Functional constipation (FC) is prevalent worldwide and is an increasingly prominent problem among Chinese. Dietary modifications are recommended for FC, yet little is known about the impact of dietary diversity and the relevance of the gut microbiota. The aim of this study was to evaluate the relationship between dietary diversity and constipation symptoms and gut microbiota profiles among individuals with FC. Methods This was a cross-sectional study among 250 participants with FC aged 18 to 70 y. Dietary intake was assessed using food frequency questionnaires. Dietary diversity score (DDS) was calculated based on the intake frequencies of food categories, ranging from 0 (low DDS) to 8 (high DDS). Gut microbiota was measured using a 16S ribosomal RNA amplification method. Results In our participants with FC, DDS was positively associated with bowel movement frequency (BMF) ( P = 0.012 for trend). Among all of the genera evaluated (121 in total), the Ruminococcus torques group was inversely correlated with BMF (β = –0.901, P < 0.001, false discovery rate P = 0.022) and potentially correlated with DDS (β = –0.142, P = 0.029, false discovery rate P = 0.116). Additionally, the genera distribution of gut microbial enterotypes differed by DDS level and weekly BMF. Conclusions In individuals with FC, high dietary diversity was associated with relief of constipation involving gut microbiota alterations.