The Effects of Omega-3 Fatty Acids and Vitamin E Co-Supplementation on Indices of Insulin Resistance and Hormonal Parameters in Patients with Polycystic Ovary Syndrome: A Randomized, Double-Blind, Placebo-Controlled Trial

Exp Clin Endocrinol Diabetes. 2017 Jun;125(6):353-359. doi: 10.1055/s-0042-117773. Epub 2017 Apr 13.


This study was conducted to determine the effects of omega-3 fatty acids and vitamin E co-supplementation on indices of insulin resistance and hormonal parameters in women with polycystic ovary syndrome (PCOS). This randomized double-blind, placebo-controlled trial was done on 68 women diagnosed with PCOS according to the Rotterdam criteria aged 18-40 years old. Participants were randomly assigned into 2 groups to receive either 1 000 mg omega-3 fatty acids from flaxseed oil containing 400 mg α-Linolenic acid plus 400 IU vitamin E supplements (n=34) or placebo (n=34) for 12 weeks. Hormonal parameters were quantified at the beginning of the study and after 12-week intervention. After 12 weeks of intervention, compared to the placebo, omega-3 fatty acids and vitamin E co-supplementation resulted in a significant decrease in insulin (-1.0±3.5 vs. +2.7±6.6 µIU/mL, P=0.004), homeostasis model of assessment-estimated insulin resistance (-0.2±0.8 vs. +0.6±1.5, P=0.005), homeostasis model of assessment-estimated B cell function (-4.3±14.3 vs. +10.5±24.5, P=0.004) and a significant increase in quantitative insulin sensitivity check index (+0.006±0.02 vs. -0.01±0.04, P=0.008). Supplementation with omega-3 fatty acids plus vitamin E led to significant reductions in serum total testosterone (-0.5±0.7 vs. -0.1±0.5 ng/mL, P=0.008) and free testosterone (-1.2±2.1 vs. -0.2±1.7, P=0.04) compared to the placebo group. We did not observe any significant effect of omega-3 fatty acids and vitamin E co-supplementation on fasting plasma glucose and other hormonal profiles. Omega-3 fatty acids and vitamin E co-supplementation for 12 weeks in PCOS women significantly improved indices of insulin resistance, total and free testosterone.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Adult
  • Dietary Supplements*
  • Double-Blind Method
  • Fatty Acids, Omega-3 / administration & dosage*
  • Female
  • Hormones / blood*
  • Humans
  • Insulin Resistance*
  • Polycystic Ovary Syndrome / blood*
  • Polycystic Ovary Syndrome / drug therapy*
  • Vitamin E / administration & dosage*


  • Fatty Acids, Omega-3
  • Hormones
  • Vitamin E