Effects of an acute raw resistant potato starch supplement on postprandial glycemia, insulinemia, lipemia in healthy adults

The purpose of this study was to evaluate the lipid and glucose response after an acute intake of raw resistant potato starch. Ten healthy volunteers (6 males and 4 females, aged 19-27 years old, a body mass index of 22.4 +/- 0.8 kg(.)M-2) participate in the study after giving their written consent. They ingested on separate days a low fiber-low resistant starch meal (27 g proteins, 54 g carbohydrates, 24 g lipids and 390 mg cholesterol) supplemented (RSsup) or not (NoRS) with 30 g raw potato starch as a source of resistant starch. Fasting and postprandial blood data were analyzed for free fat acids, glucose, insulin, triglyceride, cholesterol, chylomicron triglyceride and cholesterol, and retinyl palmitate, during seven hours. The chylomicron was isolated and plasma retinyl palmitate (RP) was used as a tracer of chylomicron remnants clearance. The significant results, p<0.05, were: area under the curve of plasma glucose (AUC, mean normalized area against zero time) for NoRS=-32 and for RSsup=102 mmol(.)7h(.)L-1; AUC plasma retinyl palmitate NoRS=407 and RSsup=250 mg(.)7h(.)L-1; and AUC chylomicron-triglyceride NoRS=52 and RSsup=40 mmol(.)7h(.)L-1. The AUC for insulin, free fat acid, plasma triglyceride, cholesterol and chylomicron-cholesterol did not show statistical difference after both diets. The response over time for FFA was characterized by a delay insulin-driven fall with the RSsup that is an unexpected result. Sporadic intakes of potato raw resistant starch did not improve post prandial blood glucose. This unexpected conclusion must be considered with caution as the resistant starch used in this study is probably more digestible as suggested by in vitro study. However, the decrease of postprandial plasma triglycerides rich lipoprotein concentration due to a resistant starch supplement was related to an increase in the clearance of chylomicron. This finding is of interest in the coronary artery disease prevention.