New research indicates that diets rich in fiber enhance the release of the appetite-suppressing gut hormone peptide tyrosine tyrosine (PYY) in the small intestine, irrespective of food structure.
Methodology:
Researchers studied the impact of low- and high-fiber diets on the release of PYY and glucagon-like peptide 1 (GLP-1). Ten healthy volunteers were randomly assigned to one of three diets: high-fiber intact foods (e.g., peas, carrots), high-fiber foods with disrupted structures (same foods mashed or blended), or low-fiber processed foods. Participants underwent each diet for four days with a washout period between, ensuring each participant experienced all diets. Diets were matched for energy and macronutrients, with high-fiber diets containing 46.3-47.9 grams of fiber daily and the low-fiber diet containing 12.6 grams.
Findings:
Both high-fiber diets significantly increased PYY release compared to the low-fiber diet during the 0-240-minute postprandial period, particularly when food was in the small intestine. Contrary to expectations, intact food structures did not significantly differ in stimulating PYY compared to disrupted food structures. Participants reported reduced hunger at 120 minutes with high-fiber diets compared to the low-fiber diet. High-fiber diets also elevated ileal stachyose levels, and disrupted high-fiber diets increased specific ileal amino acids.
Implications:
“Ileal metabolites influenced by dietary intake play a critical role in PYY release,” noted the authors. This finding suggests potential for designing diets that enhance satiety through high fiber content, regardless of food structure.
Source:
The study, led by Aygul Dagbasi, PhD, from Imperial College London, was published online in Science Translational Medicine.
Limitations:
Limitations include a small participant pool and differences in gastric emptying rates affecting sample timing. Organoid availability restricted the number of experiments. While useful, organoids have inherent limitations.
Disclosures:
Funding was provided by BBSRC, Nestle Research, and Sosei Heptares. Imperial College London’s Section for Nutrition received additional support from UKRI and other bodies. Several authors disclosed affiliations with Melico Sciences and industry relationships beyond this study.
This study underscores the influence of high-fiber diets on PYY release, highlighting potential applications in satiety-promoting dietary strategies.