Does saffron supplementation have favorable effects on liver function indicators? A systematic review and meta-analysis of randomized controlled trials.

Several pharmaceutical and non-pharmaceutical approaches have been suggested to improve liver health. There is a large discrepancy in the effects of saffron supplementation on liver function in adults. To fill this knowledge gap, this systematic review and meta-analysis of randomized controlled trials (RCTs) assess the effects of saffron supplementation on liver enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP). A systematic search current to August 2020 was performed in PubMed/Medline, Scopus, Web of Science, and Google Scholar using relevant keywords to detect eligible articles. A random-effects model was used to estimate the weighted mean difference (WMD) and 95% confidence (95% CI). Nine eligible trials were included in the final analysis. The pooled analysis revealed that serum ALT concentrations were significantly reduced using saffron compared to placebo (WMD: -2.39 U/L; 95% CI: -4.57 to -0.22; P = 0.03, I2= 87.9%, P < 0.001). However, saffron supplementation did not affect levels of serum AST (WMD: 1.12 U/L; 95% CI: -1.42 to 3.65; P = 0.39) or ALP (WMD: 4.32 U/L; 95% CI: -6.91 to 15.54; P = 0.78). In the dose-response analysis, we did not find a significant dose-response relationship between dosage and duration of saffron supplementation on serum levels of ALT, AST, and ALP. We found that saffron supplementation can reduce ALT serum concentrations without significant effects on other liver function indicators, including AST and ALP. Nevertheless, future large RCTs on diverse populations are needed to understand better the effects of saffron and its constituents on these enzymes.

Effects of saffron (Crocus sativus L.) supplementation on inflammatory biomarkers: A systematic review and meta-analysis.

The effect of saffron supplementation on subclinical inflammation remains inconclusive. We performed a systematic review and meta-analysis to summarize available findings on the effect of saffron supplementation on inflammatory biomarkers (C-reactive protein [CRP], tumor necrosis factor-α [TNF-α], and interleukin-6 [IL-6]) in adults. We searched PubMed/Medline, Scopus, Web of Science, and Google Scholar databases up to November 2019 using relevant keywords to identify eligible trials. All randomized controlled trials (RCTs) that examined the effect of oral saffron supplementation on plasma concentrations of CRP, TNF-α, and IL-6 were included. For each outcome, mean differences and SDs were pooled using a random-effects model. Overall, eight RCTs were included in this meta-analysis. The pooled results showed that saffron supplementation did not result in significant changes in serum CRP (weighted mean difference [WMD]: -0.43 mg/L; 95% confidence interval [CI]: -1.04 to 0.17; p = .16), serum TNF-α (WMD: -1.29 pg/mL; 95% CI: -4.13 to 1.55; p = .37), and IL-6 concentrations (WMD: 0.11 pg/mL; 95% CI: -0.79 to 1.00; p = .81). Subgroup analysis indicated a significant reduction in serum CRP levels in studies with baseline CRP of ≥3 mg/L, saffron dosage of ≤30 mg/day, and intervention duration of <12 weeks, as well as trials that used crocin. Similarly, saffron was found to decrease TNF-α in studies that recruited non-diabetic subjects, subjects with baseline levels of ≥15 pg/mL, and participants with <50 years old, as well as trials that administered saffron at the dosage of ≤30 mg/day. We also found a significant non-linear effect of saffron dosage on serum CRP concentrations (pnon-linearity = .03). The overall results indicated that saffron supplementation did not affect inflammatory cytokines. Further high-quality studies are needed to firmly establish the clinical efficacy of supplemental saffron on inflammatory biomarkers.