Effects of soy isoflavones on markers of bone turnover in premenopausal and postmenopausal women
Abstract
Soy isoflavones are hypothesized to exert hormonal effects in women and thus may play a role in bone metabolism throughout life. In 2 randomized, cross-over studies, 14 pre- and 17 postmenopausal women were given 3 soy protein isolates containing different amounts of isoflavones [control, 0.13; low isoflavone (low-iso), 1.00; and high-iso, 2.01 mg/kg body wt/day, averaging 8, 65, and 130 mg/day, respectively], for over 3 months each. Food records, blood samples, and 24-h urine collections were obtained throughout the studies. The endpoints evaluated included plasma or serum concentrations of bone-specific alkaline phosphatase, osteocalcin, insulin-like growth factor-I (IGFI), IGF binding protein-3 (IGFBP3), and urine concentrations of deoxypyridinoline cross-links and carboxy-terminal telopeptide of type I collagen. In premenopausal women, IGFI and IGFBP3 concentrations were increased by the low-iso diet, and deoxypyridinoline cross-links was increased by both the low- and high-iso diets during certain phases of the menstrual cycle. In postmenopausal women, bone-specific alkaline phosphatase was decreased by both the low- and high-iso diets, and there were trends toward decreased osteocalcin, IGFI, and IGFBP3 concentrations with increasing isoflavone consumption. Although soy isoflavones do affect markers of bone turnover, the changes observed were of small magnitude and not likely to be clinically relevant. These data do not support the hypothesis that dietary isoflavones…
How strong is the evidence?
Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 17 participants or records.
Read the paper
Related studies
- Benign periarticular, bone and joint lipomatous lesions
- A review of the physiological and histological effects of laser osteotomy
- Quality of bone healing: perspectives and assessment techniques
- Effects of bioactive lipids and lipoproteins on bone
- Bone structure and function
- Quantifying bone structure, micro-architecture, and pathophysiology with MRI.
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.