Resistant Starch from High-Amylose Maize Increases Insulin Sensitivity in Overweight and Obese Men1-3.

This study evaluated the effects of 2 levels of intake of high-amylose maize type 2 resistant starch (HAM-RS2) on insulin sensitivity (S1( 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 S1 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 ± 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 x sex interaction (P = 0.033) were present. In men, (east squares geometric mean analysis for S1 did not differ after intake of 15 g/d HAM-RS2 (6.90 × 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 higherthan afterthe 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 In-transformed mean ± 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 S1 in men. Additional research is needed to understand the mechanisms that might account for the treatment x sex interaction observed. [ABSTRACT FROM AUTHOR]