Poster Topical Area: Dietary Bioactive Components
Location: Hall D
Poster Board Number: 257
In vitro studies suggest that polyphenols found in berries slow or reduce carbohydrate (CHO) absorption which could alter postprandial endocrine responses and appetite if extant in vivo. However, the impact of fortifying high-CHO foods with polyphenol-rich berries or berry extracts on appetite-mediating hormone responses and appetite is not well characterized.
Objectives: To determine whether fortifying a high-CHO snack bar with polyphenol-rich freeze-dried black raspberries or cranberry extract dose-dependently impacts postprandial appetite-mediating hormone concentrations and appetite.
Methods: In this randomized, cross-over, placebo-controlled trial, 20 volunteers (18 M/2 F; 24 +/- 5 yr; BMI: 27 +/- 3 kg/m2) consumed one of five bars containing: no berry ingredients (control), 10% or 20% total wt. freeze-dried black raspberries (0.7 g (LO-R) or 1.3 g (HI-R) polyphenols), and 0.5% or 1% total wt. cranberry extract (0.3 g (LO-C) or 0.5 g (HI-C) polyphenols) on trials separated by >/= 5 days. All bars were similar in energy and macronutrient content (451-466 kcal, 99-102 g CHO, 6-9 g fiber). Plasma glucagon-like peptide (GLP)-1 and acylated ghrelin concentrations, as well as subjective ratings of hunger and fullness, were measured before and for three hours after bar ingestion. Ad libitum energy intake at a provided meal was then measured. Dose-dependent effects of the raspberry powder and cranberry extract were examined separately by general linear models.
Results: The area under the curve for postprandial GLP-1, acylated ghrelin, hunger and fullness responses did not differ by raspberry or cranberry dose. A trend for a main effect of dose on ad libitum energy intake was observed within the raspberry, but not the cranberry treatment (P = 0.055). Post-hoc testing did not reveal dose-dependent effects between HI-R and LO-R, but indicated ad libitum energy intake trended towards being lower in LO-R relative to control (mean difference = 114 kcal [95% CI: -8, 237 kcal], P = 0.07).
Conclusion: Within the ranges studied, fortifying high-CHO foods with cranberry extract does not appear to impact appetite. In contrast, fortification with freeze-dried black raspberries may reduce appetite, but this effect does not appear to be dose-dependent or associated with changes in postprandial GLP-1 or ghrelin responses.
Views expressed herein are those of the authors and do not reflect the official policy of the Army, Department of Defense, or the US Government. U.S. Army Medical Research and Materiel Command