J Nutr. 2024 Jan 12:S0022-3166(24)00027-0. doi: 10.1016/j.tjnut.2024.01.008. Online ahead of print.

ABSTRACT

BACKGROUND: Dietary fiber is an important health-promoting component of the diet, which is fermented by the gut microbes that produce metabolites beneficial for the host’s health.

OBJECTIVE: We studied the associations of habitual long-term fiber intake from infancy with gut microbiota composition in young adulthood by leveraging data from the Special Turku Coronary Risk Factor Intervention Project (STRIP), an infancy-onset 20-year dietary counselling study.

METHODS: Fiber intake was assessed annually using food diaries from infancy up to age 20 years. At age 26 years, the first post-intervention follow-up study was conducted including food diaries and fecal sample collection (N=357). Cumulative dietary fiber intake was assessed as the area under curve for energy-adjusted fiber intake throughout the study (age 0 – 26 years). Gut microbiota was profiled using 16S rRNA amplicon sequencing. The primary outcomes were 1) alpha diversity expressed as observed richness and Shannon index, 2) beta diversity using Bray-Curtis dissimilarity scores, and 3) differential abundance of each microbial taxa with respect to the cumulative energy-adjusted dietary fiber intake.

RESULTS: Higher cumulative dietary fiber intake was associated with decreased Shannon index (β = -0.019 per unit change in cumulative fiber intake, p = 0.008). Overall microbial community composition was related to the amount of fiber consumed (permutational analysis of variation R2 = 0.005, p = 0.024). The only genus that was increased with higher cumulative fiber intake was butyrate-producing Butyrivibrio (log2 fold-change per unit change in cumulative fiber intake 0.40, adjusted p = 0.023), while some other known butyrate producers such as Faecalibacterium and Subdoligranulum were decreased with higher cumulative fiber intake.

CONCLUSIONS: As early-life nutritional exposures may affect the lifetime microbiota composition and disease risk, this study adds novel information on the associations of long-term dietary fiber intake with the gut microbiota.

CLINICAL TRIAL REGISTRATION: NCT00223600, https://clinicaltrials.gov/study/NCT00223600.

PMID:38219864 | DOI:10.1016/j.tjnut.2024.01.008