Human studies on soy isoflavones and bone maintenance

Most of the studies are cross-sectional, population studies in Japanese or Chinese pre- or postmenopausal women, investigating the correlation between dietary intake of soy products and measurements of BMD or biomarkers of bone turnover (Table 6.1). Several studies showed a positive correlation between high intake of soy products and improved BMD, especially at the 

Authors Population Correlation beween isoflavone intake and bone measurements 

Tsuchida et al., 1999 Japanese premenopause n = 995 Dietary intake of soybeans(at least 2 servings/ wk) correlated with higher BMD (4.5%) of the second metacarpal bone 

Horiuchi et al., 2000 Japanese postmenopause n = 85 Women with a high soy protein intake showed less bone loss and higher BMD at the lumbar spine Biomarkers urinary deoxypyridinoline (bone resorption) decreased 

Mei et al., 2001 Chinese postmenopause n = 357 premenopause n = 293 Significant differences found in BMD of the lumbar spine and hip between highest and lowest tertile of isoflavone intake for postmenopausal but not for premenopausal women 

---