The effect of saffron supplementation on blood pressure in adults: A systematic review and dose-response meta-analysis of randomized controlled trials

Background: The favorable influences of saffron supplementation on metabolic diseases have previously been shown. We aimed to assess the effects of saffron supplementation on blood pressure in adults. Methods: A systematic search was performed in Scopus, Embase, and the Cochrane library databases to find randomized controlled trials (RCTs) related to the effect of saffron supple-mentation on blood pressure in adults up to March 2021. The primary search yielded 182 publications, of which eight RCTs were eligible. Results: Our results showed that saffron supplementation resulted in a significant decrease in systolic blood pressure (weighted mean difference (WMD): −0.65 mmHg; 95% CI: −1.12 to −0.18, p = 0.006) and diastolic blood pressure (DBP) (WMD: −1.23 mmHg; 95% CI: −1.64 to −0.81, p < 0.001). Moreover, saffron supplementation reduced DBP in a non-linear fashion, based on duration (r = −2.45, p-nonlinearity = 0.008). Conclusions: Saffron supplementation may significantly improve both systolic and diastolic blood pressure in adults. It should be noted that the hypotensive effects of saffron supplementation were small and may not reach clinical importance.