Abstract
Objectives
The objective of this study was to determine whether a novel fiber supplement consumed by healthy individuals with a habitual diet low in fiber (<15 g/day) increases the proportion of saccharolytic gut microbiota which is associated with the increase in the production of SCFA and their related genes in stool without changing their usual diet.
Methods
Twenty individuals were enrolled in this double-blinded, randomized order, placebo-controlled, cross-over study. Participants were young, healthy, normal to overweight (BMI 23.0–32.0) and consumed < 15 g/day of fiber. All participants consumed a fiber and placebo supplement for a period of 4 weeks each, with a 4-week washout between intervention arms in random order. Participants recorded their diet for 3 days using 24-hour diet record at each 2-week segment. The diet was patternized each week (i.e., participants were asked to consume the same meals and foods for the 3 days prior to each test day) without significantly changing the participants’ usual diet. The fiber packets contained 12 g/serving per day as a powder containing resistant starch, fructooligosaccharide, sugarcane fiber, and inulin while the placebo packets contained 12 g/serving per day of a powder that matched the fiber supplement in taste and appearance. The powder packet was mixed with water for consumption. Stool samples were collected every 2 weeks throughout the study, and metagenomic sequencing and SCFA analysis was performed.
Results
The concentration of SCFA measured in the stool sample did not change after the intervention. However, the relative abundance of one of the well known saccharolytic bacteria, Bifidobacterium, increased after the fiber supplementation. Genes related to acetate and lactate production, poxB (P = 0.04) and ldh (P = 0.07) respectively, showed tendency to increase which aligns with the increase in the relative abundance of Bifidobacterium in stool samples. No significant changes and correlations were found with anthropometrics and diet records.
Conclusions
A small amount of fiber supplemented on a daily basis to individuals consuming low fiber diets resulted in an increase in the relative abundance of the beneficial gut microbial genus, Bifidobacterium.
Funding Sources
I would like to acknowledge Usana Health Sciences, Inc. for the support in this research.