Background: The present study aimed to evaluate the effects of dietary soy intake on weight loss and metabolic status of patients with polycystic ovary syndrome (PCOS).
Methods: A randomised clinical trial was conducted among 60 women with PCOS. Participants were randomly assigned into two groups to receive either a test diet (n = 30) or a control diet (n = 30) for 8 weeks. Participants in the test group consumed a diet containing 0.8 g protein kg-1 body weight (35% animal proteins, 35% soy protein and 30% vegetable proteins) and participants in the control group consumed a similar diet containing 70% animal proteins and 30% vegetable proteins.
Results: Adherence to the test diet, compared with the control diet, resulted in significant decreases [mean (SD)] in body mass index (BMI) [-0.3 (0.6) versus +0.1 (0.5) kg m-2 , P = 0.02], fasting plasma glucose [-0.2 (0.5) versus +0.1 (0.3) mmol L-1 , P = 0.01], total testosterone [-0.3 (0.7) versus +0.3 (0.3) mmol L-1 , P < 0.001], insulin [-15.0 (18.0) versus +4.8 (18.6) pmol L-1 , P < 0.001] and insulin resistance [-0.6 (0.6) versus +0.2 (0.7), P < 0.001], as well as a significant increase in quantitative insulin sensitivity check index [+0.01 (0.01) versus -0.002 (0.02), P = 0.01]. In addition, significant decreases in triglycerides [-0.1 (0.4) versus +0.2 (0.3) mmol L-1 , P = 0.01] and malondialdehyde (MDA) [-1.2 (1.0) versus +0.2 (1.2) μmol L-1 , P < 0.001] and significant increases in nitric oxide (NO) [+13.6 (14.1) versus +0.9 (24.3) μmol L-1 , P = 0.01] and glutathione (GSH) [+170.1 (175.5) versus +24.2 (168.7) μmol L-1 , P = 0.002] were seen in the test group compared to the control.
Conclusions: Adherence to test diet among subjects with PCOS significantly decreased BMI, glycaemic control, total testosterone, triglycerides and MDA, and significantly increased NO and GSH compared to the control diet.
Keywords: metabolic status; polycystic ovary syndrome; soy diet; weight loss.
© 2018 The British Dietetic Association Ltd.