The efficacy of sour tea (Hibiscus sabdariffa L.) on selected cardiovascular disease risk factors: A systematic review and meta-analysis of randomized clinical trials.

This study sought to summarize clinical evidence of sour tea (Hibiscus sabdariffa L.) administration on cardiovascular disease risk factors. PubMed, Scopus, Institute for Scientific Information Web of Science, and Google Scholar were systematically searched from inception to June 2019 to identify randomized clinical trials, which assessed the effect of sour tea consumption on lipid profiles, fasting plasma glucose, and blood pressure in adult populations. Mean and standard deviation for each parameter were extracted to calculate effect size. Cochrane Collaboration tools were used to evaluate risk of bias assessment. A total of seven randomized clinical trials consisting 362 participants were included in the meta-analysis. Pooled effect size demonstrated that sour tea consumption significantly reduces fasting plasma glucose (-3.67 mg/dl, 95% confidence interval, CI [-7.07, -0.27]; I = 37%), systolic blood pressure (-4.71 mmHg, 95% CI [-7.87, -1.55]; I = 53%), and diastolic blood pressure (-4.08 mmHg, 95% CI [-6.48, -1.67]; I = 14%). Although no significant effect was observed on triacylglycerol, total cholesterol, and high-density lipoprotein cholesterol following sour tea consumption, a trend toward a significant reduction was found in low-density lipoprotein cholesterol serum concentrations (p = 0.08). This systematic review and meta-analysis suggests that sour tea consumption could have beneficial effect in controlling glycemic status and blood pressure among adult population.