Effect of Prebiotic Intake on Gut Microbiota in Healthy Adults

Overview

In recent years, the importance of the gut microbiota to human health has been demonstrated. In adulthood, the microbial profile is relatively stable, yet can be transiently altered by factors such as diet or antibiotic treatment. Such changes may be beneficial, as gut microbiota has been shown to differ in normal versus disease states including inflammatory bowel disease, obesity, type 2 diabetes and fatty liver disease. Given this relationship, there is intense interest in designing interventions that positively influence the gut microbial profile. Prebiotics are non-digestible, fermentable oligo- and polysaccharides that alter the colonic environment in favour of health-promoting bacterial species, such as bifidobacteria which selectively ferment prebiotics. Given the ability of prebiotics to beneficially alter the microbial profile, there is a need to identify the dosing requirements to positively modulate the gut microbiota. This study will test the effect of two doses of prebiotic on gut microbiota taxonomy and diversity.

The primary objective is to determine the effect of 4 week intake of a moderate dose (7 g/d) or low dose (2.5-3 g/d) of prebiotic on gut microbiota profiles in healthy adults compared to a non-prebiotic containing control. The primary outcome is change in microbial composition (measured via 16S rRNA sequencing). The secondary outcomes are change in gastrointestinal (GI) tolerance (measured via questionnaire); change in fecal short chain fatty acids; and change in quality of life. This study will consist of two separate trials of 12 week duration. Each trial will be performed in a double-blind, randomized, placebo-controlled crossover manner with a 4 week intervention period followed by a 4 week wash-out period and final 4 week cross over.