Efficacy and safety of dietary polyphenol administration as assessed by hormonal, glycolipid metabolism, inflammation and oxidative stress parameters in patients with PCOS: a meta-analysis and systematic review

Background The current knowledge about the efficacy and safety of dietary polyphenol administration in patients with polycystic ovarian syndrome (PCOS) is divergent.Objective To evaluate the pooled efficacy and safety of dietary polyphenol administration in the treatment of patients with PCOS.Methods The pubmed, Embase, Scopus, Cochrane Library, and Web of Science databases were searched for randomized controlled trials (RCTs) of dietary polyphenol administration for the treatment of PCOS. English-language RCTs involving adults with PCOS were thoroughly searched in electronic databases from the time of their establishment to May 2024. Random-effects models were used because heterogeneity was derived from differences in intervention materials and study duration, among other confounding factors. The effect sizes of the outcomes in the pooled analysis are expressed as weighted mean differences (WMDs) and 95% confidence intervals (CIs).Results A total of 15 RCTs involving 934 patients were finally included. Compared with control treatments, dietary polyphenol administration significantly reduced luteinizing hormone (LH) (WMD: −0.85, 95% CI [-1.32 to −0.38], p = 0.00), and prolactin levels (WMD: −3.73, 95% CI [-6.73 to −0.74], p = 0.01). Dietary polyphenol administration significantly reduced insulin levels (WMD: −0.85, 95% CI [-1.32 to −0.38], p = 0.00). Regarding lipid metabolism, dietary polyphenol administration only reduced triglyceride levels (WMD: −8.96, 95% CI [-16.44 to −1.49], p = 0.02). Malondialdehyde (MDA) (WMD: −0.65, 95% CI [-0.68 to −0.62], p = 0.00), tumor necrosis factor (TNF-α) (WMD: −1.39, 95% CI [-2.41 to −0.37], p = 0.01) concentrations were significantly reduced by dietary polyphenol administration. None of the interventions significantly affected weight, body mass index (BMI), waist circumference (WC), homeostatic model–insulin resistance (HOMA-IR), fasting blood sugar (FBS), glycated hemoglobin (HBA1c), follicle-stimulating hormone (FSH), testosterone (T), dehydroepiandrosterone (DHEA), estradiol (E2), anti-Müllerian hormone (AMH), quantitative insulin-sensitivity check index (QUICKI), sex hormone-binding globulin (SHBG), total antioxidant capacity (TAC), C-peptide, C-reactive protein (CRP), high-density lipoprotein (HDL), low-density lipoprotein (LDL), cholesterol, cholesterol/HDL, acne score, thyroid-stimulating hormone (TSH), aspartate aminotransferase (AST), alanine aminotransferase (ALT) or alkaline phosphatase (ALP).Conclusion Dietary polyphenol administration was efficacious in patients with PCOS in our study. This review might provide new insight into the treatment of patients with PCOS and the potential of daily polyphenol supplementation in patients with PCOS. Nevertheless, these results must be interpreted carefully as a result of the heterogeneity and risk of bias among the studies and we expect that more high-quality RCTs evaluating the efficacy and safety of dietary polyphenol adnimistration in patients with PCOS will be conducted in the future.Systematic review registration CRD42024498494