Figure 4.

The association between dietary fiber and IBS-D varied by the relative abundance of Faecalibacterium prausnitzii.

Interaction between fiber (continuous variable in g/d) and F. prausnitzii (continuous variable in relative abundance) was assessed using a binomial model adjusted for sex, age, education, smoking, menopausal status, menopausal hormone therapy, antibiotic use, probiotic use, BMI, and total energy intake. For visualization, F. prausnitzii was categorized to quartiles of taxa relative abundance. (a) The probability of having IBS-D was estimated by quartiles of F. prausnitzii while keeping other covariates constant. P-value was adjusted for multiple testing using Benjamini-Hochberg method (q-value). Among metabolic pathways contributed by F. prausnitzii, (b) Superpathway of β-D-glucuronide and D-glucuronate degradation, (c) D-galacturonate degradation I, (d) starch degradation V, (e) Superpathway of N-acetylglucosamine, N-acetylmannosamine and N-acetylneuraminate degradation were the major pathways involved in driving the modifying role of F. prausnitzii in IBS-D response to dietary fiber. Interactions between fiber and each pathway, as well as each enzyme involved in the pathways, was tested in a binomial model adjusted for the above covariates. For visualization, stratified odds ratio (OR) and 95% confidence intervals were estimated for fiber-IBS-D associations according to the median relative abundance of pathways and enzymes. EC, enzyme commission number.