Effects of a Microbiome Restoration Strategy on Metabolic Markers in Healthy Adults

Abstract

ObjectivesIndustrialization has increased chronic disease prevalence, potentially due to lifestyle-induced disruptions of the gut microbiome. Decreased intake of dietary fibers is likely a key factor as they play an important role in chronic disease prevention and are growth substrates for the gut microbiota. Strategies that restore microbiome diversity, such as reintroducing health-promoting bacterial species and microbiota accessible carbohydrates (MACs), have been proposed to improve health but have not yet been systematically tested. The objective of this study was to determine the effects of a microbiome restoration strategy on metabolic markers in healthy adults. MethodsUsing a randomized controlled pilot study, 30 subjects consumed either a MAC-rich diet or their usual diet for three weeks each in a crossover fashion, with a three-week washout following each diet period. Participants were further divided into three groups and consumed either a single dose of one of two Limosilactobacillus reuteri strains, a rare species in industrialized microbiomes, or a placebo on day four of each diet period. Metabolic markers (standard lipid panel, glucose, insulin, C-reactive protein (CRP)) were assessed in blood collected at the start and end of each diet period. Data were analyzed using repeated measures ANOVA. ResultsCompared to baseline, the MAC-rich diet induced substantial metabolic changes, as it reduced total cholesterol (P < 0.0001), low density lipoprotein cholesterol (P < 0.0001), high density lipoprotein (HDL) cholesterol (P < 0.0001), non-HDL cholesterol (P < 0.0001), and glucose (P < 0.01). Other metabolic markers, such as insulin and CRP, were not significantly affected. Though the MAC-rich diet increased L. reuteri persistence in the gut for eight days (P < 0.05), the metabolic effects were independent of L. reuteri supplementation. ConclusionsOur results show that a MAC-rich diet significantly benefited metabolic markers and transiently enhanced the persistence of a lost bacterial species in the gut. Ongoing analyses are exploring how the gut microbiome specifically contributes to the observed health effects of the MAC-rich diet. Funding SourcesThis work was supported by the Weston Family Microbiome Initiative, CIHR, Alberta Innovates Postgraduate Fellowship, and Science Foundation Ireland.