Effects of genistein on blood pressure: A systematic review and meta-analysis

Genistein (4',5,7-trihydroxyisoflavone) is a phytoestrogen with potential health benefits in the prevention of cardiovascular disease. However, the evidence regarding its effects on hypertension has not been conclusive. Therefore, we examined the impact of oral genistein supplementation on systolic blood pressure (SBP) and diastolic blood pressure (DBP) via a systematic review and meta-analysis of randomized controlled trials (RCTs). PubMed, ISI Web of Science, Scopus and the Cochrane library databases (until August 2019) were searched to identify potential RCTs with information on genistein supplementation and hypertension. Weighted Mean Difference (WMD) was pooled using a random-effects model. Pooling four RCTs (four treatment arms) together did not show any significant reduction of SBP (WMD: -5.32 mmHg, 95% CI: -14.59 to 3.96) and DBP (WMD: - 2.06 mmHg, 95% CI: -6.41 to 2.28) compared to that of the placebo group. However, subgroup analysis by intervention duration suggested that more than 6 months genistein supplementation in metabolic syndrome patients can significantly decrease SBP (WMD: -13.73 mmHg, 95% CI: -18.10 to -9.37) and DBP (WMD: - 5.18 mmHg, 95% CI: -6.62 to - 3.74). Generally, present study indicated that genistein supplementation had no effect on hypertension, but it seems that longer intervention duration of more than 6 months especially among metabolic syndrome patients may lead to the effectiveness of genistein.