Effect of Spirulina Supplementation on Systolic and Diastolic Blood Pressure: Systematic Review and Meta-Analysis of Randomized Controlled Trials

Spirulina is a microalga that presents various important pro-health properties, for instance lowering blood pressure in the research. The study aims to appraise the efficacy of Spirulina administration on systolic (SBP) and diastolic blood pressure (DBP). Randomized controlled trials (RCTs) were retrieved by a systematic search of PubMed, Web of Science, and the Cochrane Library databases from inception to June 2021 according to a standardized protocol. The effect size of each study was counted from mean and standard deviation before and after the intervention and shown as Un-standardized mean difference and 95% confidence interval. Sensitivity analyses were performed. Meta-analysis on 5 RCTs with 230 subjects was eligible. The amount of Spirulina ranged from 1 to 8 g per day, and intervention durations ranged from 2 to 12 weeks. Data analysis indicated that Spirulina supplementation led to a significant lowering of SBP (Mean Difference (MD): -4.59 mmHg, 95% Confidence Interval (CI): -8.20 to -0.99, I square statistic (I-2) = 65%) and significant lowering of DBP (MD: -7.02 mmHg, CI: -8.86 to -5.18, I-2 = 11%), particularly in a subgroup of hypertensive patients. Spirulina administration might have a supportive effect on the prevention and treatment of hypertension. More exact randomized controlled trials are needed to clarify the effect of Spirulina supplementation on blood pressure.