Mechanisms linking dietary fiber, the microbiome, and satiety

PROJECT SUMMARY/ABSTRACT
This project supports the career development of Dr. Katherene Anguah in her path to become an
independent translational researcher focusing on how dietary components may benefit cardiometabolic
health through the control of appetite. The mentored plan builds on previous training by providing additional
technical, academic, and professional development skills to facilitate research independence. An
interdisciplinary team of mentors includes experts in human clinical feeding studies, functional magnetic
resonance imaging, microbiome analysis, and stable isotope labeled, targeted metabolomics. The 5-year
plan includes the opportunity to advance through both didactic instruction and experiences aimed at
expanding skills in research management and scientific writing. Rationale: Strong evidence supports the
association between high fiber (HiFi) diets (e.g. legumes, nuts, vegetables) and a reduced risk for chronic
conditions such as cardiovascular disease (CVD), type 2 diabetes and some forms of cancer. However, the
current U.S. average consumption of dietary fiber of 17g/day is significantly below the recommendation
level of 25g/d for women and 38g/d for men. Furthermore, fiber fermentation to produce short chain fatty
acid (SCFA) products and alterations in microbial composition and activity may be mechanisms linking a
HiFi diet to improved health. Importantly, much of the data, including findings supporting a beneficial role of
SCFA have been derived from animal studies. Human studies are now needed to advance the
understanding of the translational significance of rodent studies and the potential benefit of fiber on
microbial metabolites and cardiometabolic health, glucose regulation, appetite and satiety. The central
hypothesis is that that the mechanisms by which dietary fiber provides metabolic benefit include direct
physical effects in the upper gastrointestinal tract to slow nutrient absorption, and indirect effects to reduce
food intake mediated by SCFA-induced secretion of intestinal hormones resulting in increased satiety.
Design: Using fiber derived from peas, Aim 1 will test the effect of a HiFi diet on appetite, satiety, and
cardiometabolic health and whether elevated SCFA concentration mediates improved satiety. Aim 2 will
quantitate the changes in microbial composition and colonic SCFA production rate during HiFi feeding and
whether any changes are potential mediators of observed benefits on satiety and cardiometabolic risk
factors. Relevance: These studies will significantly expand the understanding of mechanisms by which
dietary fiber improves satiety and cardiometabolic health in humans.

Grant Number: 5K01HL155232-05
NIH Institute/Center: NIH
Principal Investigator: Katherene Anguah