Oat beta-glucans consumed at breakfast improve glucose tolerance acutely and after a subsequent lunch - a randomized dose-response study in healthy young adults.

Abstract

Oat beta-glucans (OBGs) lower postprandial blood glucose by increasing gastrointestinal viscosity, delaying gastric emptying, and slowing glucose absorption. While the European Food Safety Authority (EFSA) recommends a minimum intake of 4 g of OBGs per 30 g of available carbohydrates (avCHO) for a significant reduction in glycaemic response, this poses formulation challenges. This study investigated the effects of a commercially available OBG ingredient on postprandial glycemia and appetite sensations immediately after ingestion and following a standardized lunch 3.5 hours later, also exploring whether doses below 4 g of OBGs per 30 g of avCHO could be effective. Nineteen healthy subjects consumed test drinks containing 0 g (Ref), 2 g (BG2), 3 g (BG3), or 4 g (BG4) of OBGs, each providing 30 g of avCHO, in a crossover study. BG2 and BG4 reduced the incremental glucose peak (iPeak) compared to Ref (P < 0.05), with BG3 showing a trend (P = 0.09). BG4 reduced an early glucose incremental area under the curve (iAUC 0-60 min) and improved the post-lunch glycaemic response compared to Ref (P < 0.05). Insulin iPeaks and iAUC (0-120 min) were lower for BG3 and BG4 (P < 0.05). BG4 enhanced satiety and reduced hunger throughout the experimental period (P < 0.05). Doses below 4 g of OBGs per 30 g of avCHO improved postprandial glycemia and appetite, and OBG intake at breakfast enhanced post-lunch glycaemic regulation, suggesting that a lower threshold may be effective in blood glucose management and appetite control.