The Effects of Soy Isoflavones on Metabolic Status of Patients With Polycystic Ovary Syndrome.
What this study found
Overall, 12 weeks of soy isoflavone supplementation produced a favorable metabolic, hormonal, and oxidative stress profile in women with PCOS. Insulin resistance markers improved, with significant time-by-group effects for insulin and HOMA-IR both < .001, and hormonal status improved as SHBG increased from 38.0 ± 8.7 to 41.9 ± 7.9 nmol/L, FAI fell from 0.12 ± 0.08 to 0.09 ± 0.06, and mFG scores declined from 14.7 ± 4.6 to 13.5 ± 4.1. Triglycerides also improved relative to placebo (time-by-group = .04), while total cholesterol, LDL-cholesterol, HDL-cholesterol, and hs-CRP showed no…
- Study & population
- Randomized, double-blind, placebo-controlled trial in women aged 18 to 40 years with polycystic ovary syndrome diagnosed by Rotterdam criteria.
- Intervention
- Women received 50 mg/day soy isoflavones orally as capsules for 12 weeks.
- Key limitation
- The trial was small, single-center, and short in duration, which limits confidence in durability and generalizability.
View source
Open PDFOriginal abstract
CONTEXT Limited data are available evaluating the effects of soy isoflavones on metabolic status of patients with polycystic ovary syndrome (PCOS). OBJECTIVE The current study was performed to determine the effects of soy isoflavones on metabolic status of patients with PCOS. METHODS This randomized, double-blind, placebo-controlled trial was performed on 70 women diagnosed with PCOS according to the Rotterdam criteria who were 18-40 years old. Participants were randomly allocated into two groups to take either 50 mg/d soy isoflavones (n = 35) or placebo (n = 35) for 12 weeks. Metabolic, endocrine, inflammation, and oxidative stress biomarkers were quantified at the beginning of the study and after the 12-week intervention. RESULTS After 12 weeks of intervention, compared to the placebo group, soy isoflavone administration significantly decreased circulating serum levels of insulin (-1.2 ± 4.0 vs +2.8 ± 4.7 μIU/mL; P < .001) and homeostasis model of assessment-estimated insulin resistance (-0.3 ± 1.0 vs +0.6 ± 1.1; P < .001) and increased the quantitative insulin sensitivity check index (+0.0009 ± 0.01 vs -0.01 ± 0.03; P = .01). Supplementation with soy isoflavones resulted in significant reductions in free androgen index (-0.03 ± 0.04 vs +0.02 ± 0.03; P < .001) and serum triglycerides (-13.3 ± 62.2 vs +10.3 ± 24.5 mg/dL; P = .04) compared to the placebo group. There was a significant increase in plasma total glutathione (+96.0 ± 102.2 vs +22.7 ± 157.8 μmol/L; P = .04) and a significant decrease in malondialdehyde levels (-0.7 ± 0.8 vs +0.8 ± 2.3 μmol/L; P = .001) by soy isoflavone intake compared with the placebo group. We did not observe any significant effect of soy isoflavone intake on other lipid profiles and inflammatory and oxidative stress markers. CONCLUSION Soy isoflavone administration for 12 weeks in women with PCOS significantly improved markers of insulin resistance, hormonal status, triglycerides, and biomarkers of oxidative stress.