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.