A whole-grain diet reduces cardiovascular risk factors in overweight and obese adults: A randomized controlled trial

Abstract

Background: Increased dietary whole-grain intake may protect against cardiovascular disease (CVD). Objective: The objective was to evaluate the efficacy of whole grains compared with refined grains on body composition, hypertension, and related mediators of CVD in overweight and obese adults. Methods: We conducted a double-blind, randomized, controlled crossover trial in 40 overweight or obese men and women aged < 50 y with no known history of CVD. Complete whole-grain and refined-grain diets were provided for two 8-wk periods, with a 10-wk washout between diets. Macronutrient composition was matched, except for the inclusion of either whole grains or refined grains (50 g/1000 kcal in each diet). Measurements included blood pressure, body composition, blood lipids and adiponectin, and markers of inflammation and glycemia. Results: Thirty-three participants (6 men and 27 women) completed the trial [mean±SD age 39±7 y, mean±SD body mass index (in kg/m2) 33.1±4.3]. Decreases in diastolic blood pressure were -5.8 mm Hg (95% CI: -7.7, -4.0 mm Hg) after the whole-grain diet and -1.6 mm Hg (95% CI: -4.4, 1.3 mm Hg) after the control diet (between effect, P = 0.01). Decreases in plasma adiponectin were 20.1 (95% CI: -0.9, 0.7) after the whole-grain diet and -1.4 (95% CI: 22.6, 20.3) after the control diet (between effect, P = 0.05). Decreases in diastolic blood pressure correlated with the circulating adiponectin concentration (r = 0.35, P = 0.04). Substantial reductions in body weight, fat loss, systolic blood pressure, total cholesterol, and LDL cholesterol were observed during both diet periods, with no relevant difference between them. Conclusions: The improvement in diastolic blood pressure was > 3-fold greater in overweight and obese adultswhen they consumed a whole-grain compared with a refined-grain diet. Because diastolic blood pressure predicts mortality in adults aged < 50 y, increased whole-grain intake may provide a functional approach to control hypertension. This may benefit patients at risk of vascular-related morbidity and mortality.