The Effects of Raw Red Onion Consumption on Serum Levels of Adiponectin, Leptin, and hs-CRP in Overweight/Obese Females with Polycystic Ovarian Syndrome: A Randomized Controlled-Clinical Trial

Background Chronic low-grade inflammation has been confirmed to be a major etiological factor in polycystic ovarian syndrome (PCOS). The anti-inflammatory effects of quercetin, a major flavonol in onion, have been suggested by experimental studies. However, lack of data exists to investigate the effects of onion on inflammatory markers in PCOS. Objectives This study aimed at assessing the effects of raw red onion consumption on inflammatory markers in PCOS. Methods Fifty-four overweight/obese patients with PCOS were randomly assigned to either High-Onion (HO; raw red onions: 2 (40 - 50 g/day) for overweight and 2 (50 - 60 g/day) for obese patients) or Low-Onion (LO; raw red onions: 2 (10 - 15 g/day)) group over 8 weeks in this randomized controlled trial (RCT). Serum adiponectin, leptin, and high-sensitivity C-reactive protein (hs-CRP) levels and their correlations with metabolic and anthropometric parameters were assessed at baseline and endpoint. Results The 2-month treatment with onion could not significantly effect mean serum levels of adiponectin, leptin, or hs-CRP. However, the percentage change of serum adiponectin was significantly different between the two groups after 8 weeks (-11.9% in LO vs. 48.32% in HO; P = 0.026). Percentage change of serum leptin and hs-CRP showed no significant differences between the 2 groups. Leptin had significant correlations with most anthropometric and metabolic variables of insulin resistance (P < 0.05). Adiponectin concentration correlated significantly with fasting glucose (r = -0.35; P < 0.05), while log hs-CRP had significant correlations with most of the anthropometric markers (P < 0.05). Conclusions The 8-week intervention with red onion could increase percentage changes of serum adiponectin level in overweight/obese females with PCOS. However, no such effect was observed for serum leptin as well as hs-CRP levels.