Effects of consuming foods containing oat β-glucan on blood pressure, carbohydrate metabolism and biomarkers of oxidative stress in men and women with elevated blood pressure

Objective: To assess the effects of consuming foods containing oat beta-glucan on blood pressure, carbohydrate homeostasis and biomarkers of oxidative stress. Design: A randomized, double-blind, controlled clinical trial. Setting: The trial was conducted at two clinics. Subjects and interventions: Ninety-seven men and women with resting systolic blood pressure 130-179mm Hg and/ or diastolic blood pressure 85-109mm Hg were randomly assigned to consume foods containing oat beta-glucan or control foods for 12 weeks. Resting blood pressures, insulin and glucose values before and after standard breakfast meals, and four biomarkers of oxidative stress were measured before and at the end of the treatment period. Results: Changes from baseline to week 12 in mean peak insulin and incremental area under the insulin curve differed significantly between groups (P = 0.037 and 0.034, respectively), with the beta-glucan group showing declines and the control group remaining essentially unchanged. Blood pressure responses were not significantly different between groups overall. However, in subjects with body mass index above the median (31.5 kg/m(2)), both systolic (8.3 mm Hg, P = 0.008) and diastolic (3.9mm Hg, P = 0.018) blood pressures were lowered in the beta-glucan group compared to controls. No significant differences in biomarkers of oxidative stress were observed between treatments. Conclusions: The results of the present trial suggest beneficial effects of foods containing beta-glucan from oats on carbohydrate metabolism, and on blood pressure in obese subjects.