Effect of Oat Consumption on Blood Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background Current clinical trials have had controversial results regarding the effects of oat consumption on blood pressure (BP) in adults. Objective The meta-analysis was conducted to systematically evaluate the effects of oat consumption on BP in adults.Methods Electronic databases including PubMed, Web of Science, Scopus, Cochrane Library, and Embase were searched until December 13, 2021 for eligible randomized controlled trials (RCTs). RCTs published in English and that explored the effects of oat consumption on BP in adults under matched total energy intake were included. Meta -analysis using a random-effects model was performed. The pooled effect size was expressed as mean difference and 95% CI. I2 statistics were used to quantify heteroge-neity. The risk of bias was assessed using the Cochrane Risk-of-Bias Tool, version 2.Results Twenty-one RCTs involving 1,569 participants were included. The pooled re-sults indicated that consuming oats reduced systolic blood pressure (SBP) significantly (mean difference =-2.82 mm Hg; 95% CI-4.72 to-0.93 mm Hg; P = .004). Subgroup analyses indicated that oat consumption reduced SBP significantly in hypertensive participants, or when compared with control group participants who consumed refined grains. No significant reduction in diastolic blood pressure (DBP) was observed after oat consumption (mean difference =-1.16 mm Hg; 95% CI-2.37 to 0.04 mm Hg; P = .060). However, the sensitivity analysis of DBP, removal of individual studies, or "leave one out meta-analysis," showed a significant reduction in DBP, suggesting that the pooled result in the main analysis was not robust. Subgroup analyses showed that oat consumption did significantly reduce DBP in participants with baseline BP in the prehypertensive range. Both SBP and DBP were significantly reduced when the dosage of oat con-sumption was >= 5 g/day #-glucan, or the oat consumption duration was >= 8 weeks.Conclusions Oat consumption is effective in reducing SBP levels, particularly in in-dividuals whose baseline BP is in the hypertensive range or when compared with control group participants consuming refined grains at matched total energy intake.