The effect of saffron supplementation on liver and kidney function, blood glucose and pressure in patients with diabetes and prediabetes: A grade assessed systematic review and meta-analysis of randomized controlled trials

Saffron has been traditionally used for various health benefits, but its effects on biomarkers of liver function, kidney function, and blood pressure in diabetes are not well understood. This meta-analysis aims to evaluate the impact of saffron supplementation on systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting blood glucose (FBG), liver enzymes (ALT, AST), and kidney function markers (BUN, creatinine) in patients with diabetes and prediabetes. A comprehensive search was conducted across multiple databases to identify randomized controlled trials (RCTs) assessing saffron/crocin supplementation on glycemic control, hepatic and renal function, and blood pressure regulation in patients with diabetes and prediabetes. Data were extracted and analyzed using random effects model to determine the effect sizes and 95% confidence intervals (CIs) for each biomarker. The GRADE framework was employed to assess the certainty of the evidence for each outcome. Thirteen studies were included in the meta-analysis. Saffron supplementation significantly reduced SBP (SMD = -0.57, 95% CI: -0.8 to -0.34, p = 0.036) with the high certainty of evidence, FBG (SMD = -0.57, 95% CI: -0.93 to -0.22, p = 0.001) with the low certainty of evidence, and AST (SMD = -0.49, 95% CI: -0.97 to -0.00, p = 0.049) with the low certainty of evidence. Other studied biomarkers were not affected significantly by saffron/crocin supplementation. Saffron/crocin supplementation is effective in decreasing AST, SBP, and FBG levels in patients with diabetes and prediabetes. However, it has no significant effect on ALT, renal function, and DBP. Our observed effect sizes on AST, SBP, and FBG are not clinically important.