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The objective of this study is to assess self-reported gastrointestinal (GI) responses to three snack bars containing fiber/fiber blends vs. a control snack bar for 7 days each in adults using GLP-1 agonists.
This clinical trial tests whether daily fiber supplementation will change the mucosal microbiome of the colon. The microbiome are microorganisms that live in the human gut. They serve a vital role in maintaining health. Certain microbial strains are associated with the growth of colon polyps, which eventually could go on to form colon cancer. Giving dietary fiber supplements may help prevent precancerous polyps from ever developing.
This phase I trial studies how well fecal microbiota transplant and dietary fiber supplementation work in treating patients with gut graft versus host disease. Fecal microbiota transplant entails inoculating donor stool into a recipient's gastrointestinal tract. Changing the gut microbiome by fecal microbiota transplant and fiber supplementation may help treat gut graft versus host disease.
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 in 44 overweight/obese subjects randomly assigned to receive either a high fiber or a low fiber dietary intervention for four weeks in a parallel arm-repeated measures design. 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 in 26 subjects assigned to receive a high fiber intervention for 3 weeks in a repeated measures design. Relevance: These studies will significantly expand the understanding of mechanisms by which dietary fiber improves satiety and cardiometabolic health in humans.
The purpose of this study is to see how adding avocado to a breakfast meal affects blood sugar control and signals of hunger and fullness after eating. The investigators will test the effects of 3 breakfast meals on blood sugar control and signals of hunger and fullness after eating: 1. Whole-wheat bread and strawberry jam 2. Whole-wheat bread, strawberry jam, and avocado 3. Whole-wheat bread and strawberry jam (meal enriched with fat and fiber to mimic that of an avocado) Participants will undergo 3 test periods, each separated by a week. Each test period consists of one day with set meals that the investigators will provide (breakfast, lunch, and dinner), and then the next morning, participants will eat a breakfast meal and have blood drawn several times over 4 hours.
Dietary fiber has been shown to have beneficial effects on human health through its impact on microbes present in the gut. However, these effects can vary between individuals, and everyone may not reap the same health benefits by eating the same sources of fiber. Factors predicting how an individual's gut microbes as well as the beneficial metabolites produced by these microbes change in response to different sources of fiber would be helpful in developing precision nutrition approaches that maximize the benefits of dietary fiber. The objective of this study is to evaluate candidate predictors of gut microbiota response to fiber sources from either whole grains or fruits and vegetables.
The goal of this randomized, crossover, clinical trial is to link: 1) gastrointestinal motility patterns induced by acute consumption of whole and refined grains, 2) enteric microbial production of bioactive metabolites, and 3) circulating postprandial appearance of metabolites important to cardiometabolic health including glucose, triglycerides, and cholesterol. Participants will be asked to consume a Smartpill monitoring device that records metrics of gastrointestinal motility in response to whole or refined grains, monitor cardiometabolic metabolties over an 8 hour postprandial window, and provide a fecal sample for microbiome-related analyses.