Polycystic ovary syndrome (PCOS) is a common endocrine disorder that affects metabolic, hormonal, and oxidative stress pathways. Soy isoflavones, due to their phytoestrogenic and antioxidant properties, are being explored as a potential intervention to improve these underlying disturbances in PCOS.
Protocols Studied in Research
The Effects of Soy Isoflavones on Metabolic Status of Patients With Polycystic Ovary Syndrome [1]
- Protocol: In this randomized, double‑blind, placebo‑controlled trial, 70 women with PCOS (aged 18–40 years, diagnosed per Rotterdam criteria) received either 50 mg/day soy isoflavones or placebo for 12 weeks. Metabolic, endocrine, inflammatory, and oxidative stress biomarkers were measured at baseline and after the intervention.
- Outcome: Compared with placebo, soy isoflavone supplementation significantly decreased serum insulin (−1.2 vs. +2.8 μIU/mL, P < 0.001) and HOMA‑IR, while increasing the QUICKI index. It also significantly reduced the free androgen index and serum triglycerides (−13.3 vs. +10.3 mg/dL, P = 0.04). Additionally, there was a significant increase in plasma total glutathione and a decrease in malondialdehyde levels, indicating improved oxidative stress status. No significant changes were observed for other lipid profiles or inflammatory markers.
Is There a Role for Soy Isoflavones in the Therapeutic Approach to PCOS? – A Pilot Study [2]
- Protocol: In this pilot prospective study, 12 obese, hyperinsulinemic, and dyslipidemic Caucasian women with PCOS were treated with 36 mg/day of genistein (a soy isoflavone) for 6 months. Assessments included ultrasonographic pelvic examinations, hormonal and lipid profiles, an oral glucose tolerance test, and a euglycemic hyperinsulinemic clamp at baseline, 3, and 6 months.
- Outcome: Genistein supplementation significantly improved lipid parameters by reducing total cholesterol, lowering LDL cholesterol, and decreasing the LDL‑HDL ratio. Triglycerides showed a trend toward decrease, although VLDL levels remained unchanged. However, genistein did not significantly affect anthropometric measures, the hormonal milieu, menstrual cyclicity, or glycoinsulinemic metabolism. These findings suggest that the metabolic benefits of phytoestrogens in PCOS may be primarily limited to improvements in the lipid profile.
Research Interpretation: Summary and Conclusion
Soy isoflavone supplementation in women with PCOS appears to improve metabolic markers, notably reducing insulin levels, insulin resistance, free androgen index, and triglycerides, while also enhancing antioxidant status. A pilot study with genistein further supports lipid profile improvements, although it showed no significant effects on hormonal levels or menstrual regularity.
In simple terms, these findings suggest that soy isoflavones may offer metabolic and oxidative benefits for PCOS management, though their impact on hormonal balance remains to be fully established.
