The efficacy of sour tea (Hibiscus sabdariffa L.) on selected cardiovascular disease risk factors: A systematic review and meta-analysis of randomized clinical trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized clinical trials
PubMed 31943427 · doi:10.1002/ptr.6541
What was done
A systematic review and meta-analysis was conducted searching PubMed, Scopus, Web of Science, and Google Scholar up to June 2019. The authors included randomized clinical trials assessing the effect of sour tea (*Hibiscus sabdariffa* L.) consumption on lipid profiles, fasting plasma glucose, and blood pressure in adults. Risk of bias was evaluated using Cochrane tools, and pooled effect sizes were calculated from reported means and standard deviations across seven trials totaling 362 participants.
What was found
Sour tea significantly reduced fasting plasma glucose by -3.67 mg/dL (95% CI [-7.07, -0.27]; I² = 37%), systolic blood pressure by -4.71 mmHg (95% CI [-7.87, -1.55]; I² = 53%), and diastolic blood pressure by -4.08 mmHg (95% CI [-6.48, -1.67]; I² = 14%). No significant effects were observed on triglycerides, total cholesterol, or HDL cholesterol, though a non-significant trend toward reduced LDL cholesterol was noted (p = 0.08).
Why it matters
This review provides quantitative evidence that sour tea may serve as a dietary adjunct for modest reductions in blood pressure and fasting glucose.
Limits
The total sample size was small across all seven included trials (362 participants). Moderate heterogeneity was present for systolic blood pressure (I² = 53%). The abstract does not report intervention duration, exact dosages, preparation forms, participant baseline characteristics, or adverse event data.
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