Resistant starch from high-amylose maize increases insulin sensitivity in overweight and obese men

Abstract

This study evaluated the effects of 2 levels of intake of high-amylose maize type 2 resistant starch (HAM-RS2) on insulin sensitivity (SI) in participants with waist circumference ≥89 (women) or ≥102 cm (men). Participants received 0 (control starch), 15, or 30 g/d (double-blind) of HAM-RS2 in random order for 4-wk periods separated by 3-wk washouts. Minimal model SI was assessed at the end of each period using the insulin-modified i.v. glucose tolerance test. The efficacy evaluable sample included 11 men and 22 women (mean 6 SEM) age 49.5 ± 1.6 y, with a BMI of 30.6 ± 0.5 kg/m2 and waist circumference 105.3 ± 1.3 cm. A treatment main effect (P = 0.018) and a treatment 3 sex interaction (P = 0.033) were present. In men, least squares geometric mean analysis for SI did not differ after intake of 15 g/d HAM-RS2 (6.90 3 10-5 pmol-1 , L-1 × min-1) and 30 g/d HAM-RS2 (7.13 ×10-5 pmol-1 , L-1 ×min-1), but both were higher than after the control treatment (4.66 × 10-5 pmol-1 × L-1 × min-1) (P < 0.05). In women, there was no difference among the treatments (overall least squares ln-transformed mean 6 pooled SEM = 1.80 ± 0.08; geometric mean = 6.05 × 10-5 pmol-1 , L-1 × min-1). These results suggest that consumption of 15-30 g/d of HAM-RS2 improves SI in men. Additional research is needed to understand the mechanisms that might account for the treatment 3 sex interaction observed. © 2012 American Society for Nutrition.