Effects of Green Tea and Coffee Polyphenols on Cardiometabolic Function in Women with Polycystic Ovary Syndrome

Green tea (catechins, GTC) and coffee polyphenols (chlorogenic acids, CGA) have been associated with reduced diabetes and cardiovascular risk. However, detailed investigations in at risk populations are needed to corroborate their efficacy and understand the underlying mechanisms. This study aimed to evaluate the effects of a combined supplementation of GTC and CGA on insulin sensitivity (SI), nitric oxide (NO) production and cardiometabolic risk factors in women with polycystic ovary syndrome (PCOS), a condition characterized by insulin resistance, endothelial dysfunction and increased cardiometabolic risk. In a 16-week, single-blind, unilateral crossover trial, 12 PCOS women (mean ± SD: age, 28 ± 10 y; BMI, 35 ± 7 kg/m2; fasting insulin, 97 ± 52 pmol/L) underwent 8 weeks of placebo treatment followed by 8 weeks of active treatment (tablets providing 2093 mg GTC and 220 mg CGA/day). At baseline, post-placebo and post-active treatments participants undertook glucose tolerance and oral nitrate tests for is...