Whole grain food diet slightly reduces cardiovascular risks in obese/overweight adults: a systematic review and meta-analysis

BACKGROUND: The effects of whole grain diet on cardiovascular risks in obese and overweight adults is not well established. Our goal was to conduct a systematic review and meta-analysis on the effect of whole grain diet on cardiovascular risks in obese/overweight adults. METHODS: PubMed, Embase and Cochrane were systematically scanned for randomized controlled trials (RCTs), and studies were selected based on certain inclusion and exclusion criteria. The primary outcome was the effectiveness of whole grain food consumption in reducing body weight. The secondary outcomes were the effect of whole grain food consumption on cardiovascular disease (CVD) risk factors including plasma low-density lipoprotein cholesterol (LDL-C), insulin resistance index, blood pressure, body mass index (BMI), C-reactive protein (CRP), and waist circumference in obese/overweight adults. RESULTS: Our results showed that whole grain consumption was associated with lower body weight (mean difference (MD) = − 0.5, 95% confidence intervals (CI) [− 0.74, 0.25], I(2) = 35%, P < 0.0001) and lower CRP (MD = -0.36, 95% CI [− 0.54, − 0.18], I(2) = 69%, P < 0.0001), compared with the control group. However, there were no significant differences in LDL-C (MD = -0.08, 95% CI [− 0.16, 0.00], I(2) = 27%, P = 0.05), waist circumference (MD = -0.12, 95% CI [− 0.92, 0.68], I(2) = 44%, P = 0.76), systolic blood pressure (MD = -0.11, 95% CI [− 1.55, 1.33], I(2) = 3%, P = 0.88), diastolic blood pressure (MD = -0.44, 95% CI [− 1.44, 0.57], I(2) = 15%, P = 0.39), and fasting glucose (MD = -0.05, 95% CI [− 0.12, 0.01], I(2) = 31%, P = 0.11) between the two groups. CONCLUSION: This study suggests that whole grain food consumption can slightly reduce body weight and CRP in obese/overweight population.