To further complicate the issue, a number of reports have claimed antagonistic activities of various isoflavones , or the need for the presence of soy protein for isoflavones to exert their effects on BMD [8, 36, 37]. For example, Morabito et al. and Marini et al. reported that the ingestion of single isoflavone-genistein 54 mg/day for 1 
and 2 years LY3023414 order  resulted in a decline of bone resorption markers and an increase in bone formation markers and BMD of the lumbar spine and femoral neck. These outcomes were totally different from ours. RNA Synthesis inhibitor Because each subject in the isoflavone arm of the current study consumed 172.5-mg genistein and 127.5-mg daidzein/day, whether the discrepancy between our results and those of aforementioned authors is due to the antagonistic activities of various isoflavones requires selleckchem further clarification. We administered a relatively large dose of a common aglycone combination (57.5% genistein and 42.5% daidzein, without soy protein) and measured bone turnover markers and BMD both at the lumbar spine and proximal femur every 6 months. Our results did not show any significant effects throughout the 24 months, in the presence of markedly elevated serum levels of genistein and diadzein of the isoflavone-treated group. Thus, our results strongly suggest that soy isoflavones in the form
and dosage used in this study have no transient or long-term effect on bone in postmenopausal women. One of the participants in the isoflavone arm was diagnosed with breast cancer in the study period. According to the statistics of Taiwan Cancer Registry, Department of Health, Executive Yuan for the year 2006, the incidence rate of breast cancer in the entire female population aged 45–64 years in Taiwan was 141.9/100,000 person-year, which was apparently lower than the incidence rate of breast cancer in the isoflavone group of this study (230.4/100,000 person-year). This subject was treated with estrogen and progesterone for 3–4 years after
menopause and discontinued for more than 1 year prior to randomization in this study. The breast cancer of this subject might be incidental, and the causal relationship remains unclear. This study may have shortcomings. (1) The baseline serum Flucloronide levels of genistein and daidzein were higher than those reported in the Caucasian population [31, 38], which may mask the effects of the supplement. Nonetheless, the baseline levels were far lower than the post-treatment levels of the isoflavone-treated subjects, making this possibility less likely. (2) The supplement of vitamin D (125 IU of vitamin D3 daily) in this study may have been suboptimal. We did not measure plasma 25(OH)D level in this study. Consequently, the possibility of vitamin D deficiency or insufficiency and their impact on the effects of isoflavones could not be completely ruled out. However, all our participants were ambulatory.