Soy Reduces Bone Turnover Markers in Women During Early Menopause: A Randomized Controlled Trial

What this study found

Soy protein with isoflavones produced a beneficial overall effect, reducing bone turnover markers and improving several metabolic risk markers versus soy protein alone. After 6 months, βCTX was 0.15 ± 0.09 µg/L in SPI versus 0.35 ± 0.13 µg/L in SP, and P1NP was also significantly lower with SPI (p<0.01). SPI also significantly reduced fasting glucose, fasting insulin, HOMA-IR, and systolic blood pressure, while lipids and hsCRP did not change significantly. A key safety concern was thyroid function: TSH rose from 1.58 (0.93) to 2.61 (1.24) mU/L and fT4 fell from 13.5 (2.2) to 11.2 (1.8)…

Study & population

Randomized controlled trial in healthy Caucasian women within 2 years of menopause onset.

Intervention

Women in the SPI arm received 15 g/day soy protein with 66 mg/day isoflavones, given orally as snack bars twice daily for 6 months.

Key limitation

The intervention was short term (6 months) and studied a narrow population of healthy Caucasian women early after menopause, which limits generalizability.

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