Microbes and Gut Health: Meet Some Tiny Friends

Microbes and Gut Health: Meet Some Tiny Friends

What’s a microbiome and why should I care?
How do microbes help keep us healthy?
What’s the difference between prebiotics and probiotics anyway?
Does the microbiome change as we age?

Join us on Thursday, August 4, from noon to 1 p.m. as Dr. Hannah Holscher, assistant professor in the Department of Food Science and Human Nutrition at the University of Illinois, discusses your questions about diet and the trillions of microbes that live inside of you during a one-hour chat on Twitter. Use the #askACES to ask your questions about the microbiome, how microbes keep us healthy, what foods we can eat to keep good microbes happy, and more!

Agave Inulin Supplementation Affects the Fecal Microbiota of Healthy Adults Participating in a Randomized, Double-Blind, Placebo-Controlled, Crossover Trial

Abstract

Background: Prebiotics resist digestion, providing fermentable substrates for select gastrointestinal bacteria associated with health and well-being. Agave inulin differs from other inulin type fibers in chemical structure and botanical origin. Preclinical animal research suggests these differences affect bacterial utilization and physiologic outcomes. Thus, research is needed to determine whether these effects translate to healthy adults.

Objective: We aimed to evaluate agave inulin utilization by the gastrointestinal microbiota by measuring fecal fermentative end products and bacterial taxa.

Methods: A randomized, double-blind, placebo-controlled, 3-period, crossover trial was undertaken in healthy adults (n = 29). Participants consumed 0, 5.0, or 7.5 g agave inulin/d for 21 d with 7-d washouts between periods. Participants recorded daily dietary intake; fecal samples were collected during days 16–20 of each period and were subjected to fermentative end product analysis and 16S Illumina sequencing.

Results: Fecal Actinobacteria and Bifidobacterium were enriched (P < 0.001) 3- and 4-fold after 5.0 and 7.5 g agave inulin/d, respectively, compared with control.Desulfovibrio were depleted 40% with agave inulin compared with control. Agave inulin tended (P < 0.07) to reduce fecal 4-methyphenol and pH. Bivariate correlations revealed a positive association between intakes of agave inulin (g/kcal) and Bifidobacterium (r = 0.41, P < 0.001). Total dietary fiber intake (total fiber plus 0, 5.0, or 7.5 g agave inulin/d) per kilocalorie was positively associated with fecal butyrate (r = 0.30, P = 0.005), tended to be positively associated withBifidobacterium (r = 0.19, P = 0.08), and was negatively correlated withDesulfovibrio abundance (r = −0.31, P = 0.004).

Conclusions: Agave inulin supplementation shifted the gastrointestinal microbiota composition and activity in healthy adults. Further investigation is warranted to determine whether the observed changes translate into health benefits in human populations. This trial was registered at clinicaltrials.gov as NCT01925560.