Objective: Polycystic ovary syndrome (PCOS) is the most common female endocrine disorder. Affected women present a higher risk of type 2 diabetes. The objectives of this study were to investigate the effects of omega-3 fatty acids on obesity status, insulin resistance, and serum levels of visfatin in PCOS patients.

Methods: This double-blind, randomized, controlled clinical trial was conducted on 61 women who were diagnosed with PCOS, had a body mass index (BMI) between 25 and 40 kg/m², and were from 20–35 years old. Thirty of the subjects had taken four 1-g omega-3 fatty acids capsules per day, providing 1200 mg n-3 long chain polyunsaturated fatty acids (n-3 LC PUFA), and 31 were given a placebo over 8 weeks. Fasting blood samples, anthropometric measurements, and dietary intake data were collected at the baseline and at the end of the trial. Data were analyzed by independent t test, paired t test, Pearson correlation test, and analysis of covariance.

Results: Omega-3 fatty acids had no significant effects on weight, BMI, waist circumference, and waist to hip ratio at the end of the study. Omega-3 fatty acids significantly decreased glucose (by 11.4%, p < 0.001), insulin (by 8.4%, p < 0.05), and homeostatic model assessment for insulin resistance (by 21.8%, p < 0.001) compared with placebo. Changes in serum visfatin levels were not significant in either of the groups.

Conclusion: Omega-3 fatty acids improved insulin sensitivity in PCOS patients. This beneficial effect was not associated with alteration in anthropometric measurements and serum visfatin levels.