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

Abstract

Objective: To assess the effects of consuming foods containing oat b-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 130-179 mm Hg and/or diastolic blood pressure 85-109 mm Hg were randomly assigned to consume foods containing oat b-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 ¼ 0.037 and 0.034, respectively), with the b-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 ¼ 0.008) and diastolic (3.9 mm Hg, P ¼ 0.018) blood pressures were lowered in the b-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 b-glucan from oats on carbohydrate metabolism, and on blood pressure in obese subjects.

Minimizing Postprandial Oxidative Stress in Type 2 Diabetes: The Role of Exercise and Selected Nutrients

“…Finally, dietary assignment to food products that contained oat -glucan in hypertensive subjects showed a favorable effects on postprandial glucose and insulin levels, as well as blood pressure, after 12 weeks of treatment. (Maki, Galant et al, 2007). However, these beneficial effects were independent of differences in oxidative stress biomarkers.…”

Macronutrients and type 1 diabetes (revision number 6)

“…Five randomised controlled trials were identified that presented evidence on oat bran and β-glucans in relation to blood pressure (Swain et al, 1990;Saltzman et al, 2001;Davy et al, 2002b;He et al, 2004;Maki et al, 2007a), four of which were included in a metaanalysis (Saltzman et al, 2001;Davy et al, 2002b;He et al, 2004;Maki et al, 2007a). One trial could not be included in a meta-analysis as it did not report the necessary data (Swain et al, 1990).…”

“…All trials compared oat bran and/or oat meal containing diets to a refined wheat control. Two trials also supplemented subjects with refined oat β-glucan (Maki et al, 2007a;Charlton et al, 2012). One of the trials was a weight-loss trial (Saltzman et al, 2001).…”

“…Four randomised controlled trials were identified that presented evidence on β-glucan in relation to fasting insulin concentration, all of which were included in a meta-analysis (Saltzman et al, 2001;Chen et al, 2006;Maki et al, 2007a;Smith et al, 2008). Two trials were subsequently identified in the update search (Bays et al, 2011;Charlton et al, 2012) (Cardio-metabolic review, diabetes and glycaemia chapter p 311-312; Update search table 161).…”

“…Oat bran and β-glucans and fasting triacylglycerol concentration  Effect  Moderate evidence  The direction of the effect demonstrates higher consumption higher consumption of oat bran or β-glucan supplementation is beneficial to health  The effect is biologically relevant Fasting blood glucose 8.87. Four randomised controlled trials were identified that presented evidence on oat bran and β-glucan supplements in relation to fasting blood glucose concentration, all of which were included in a meta-analysis (Saltzman et al, 2001;Chen et al, 2006;Maki et al, 2007a;Smith et al, 2008). Two trials were subsequently identified in the update search (Bays et al, 2011;Charlton et al, 2012) (Cardio-metabolic review, diabetes and glycaemia chapter p 308-310; Update search table 155).…”