Conclusions : Isoflavone treatments exert a moderately beneficial effect against  estrogen-deficient bone loss in women .
The effect appears dependent on whether isoflavone treatments are in aglycone form ; we conclude that beneficial effects against bone loss may be enhanced for isoflavone aglycones
Background : Age-related estrogen deficiency leads to accelerated bone resorption .
There is evidence that , through selective estrogen receptor modulation , isoflavones may exert beneficial effects against  estrogen-deficient bone loss .
Isoflavone aglycones show higher bioavailability than their glycosidic counterparts and thus may have greater potency .
Objective : To summarize evidence , we executed a systematic review and meta- analysis examining isoflavone therapies and bone mineral density ( BMD ) loss in peri- and postmenopausal women .
High dietary phytoestrogen intake is associated with higher bone mineral density in postmenopausal but not premenopausal women.
Animal studies demonstrated that phytoestrogen had a protective effect against  bone loss after ovariectomy . However , data on dietary phytoestrogen intake as well as its relationship with bone mineral density ( BMD ) in human are not available . Six hundred fifty southern Chinese women , aged 19 to 86 yr , were recruited to determine their dietary phytoestrogen intake by a food frequency question naire . BMDs at the lumbar spine and hip region were measured using dual energy x-ray absorptiometry . The subjects were analyzed according to various tertiles of phytoestrogen intake . Among the postmenopausal women ( n = 357 ) , significant differences in the lumbar spine ( L2 - 4 ) BMD ( 0.820 + /- 0.145 vs. 0.771 + /- 0.131 g/cm2 , P < 0.05 ) and Ward 's triangle BMD ( 0.450 + /- 0.151 vs. 0.415 + /- 0.142 g/cm2 ; P < 0.05 ) were found between the highest and lowest intake of isoflavone after adjusting for age , height , weight , years since menopause , smoking , alcohol consumption , HRT usage , and daily calcium intake . Women with the highest intake of isoflavone had significantly lower levels of serum PTH ( 19.38 + /- 14.61 vs. 26.56 + /- 11.19 pg/ml ; P < 0.05 ) , osteocalcin ( 4.95 + /- 3.61 vs. 6.69 + /- 5.05 mg/liter ; P = 0.05 ) , and urinary N-telopeptide ( 34.18 + /- 25.31 vs. 49.66 + /- 41.00 nmol bone collagen equivalents/mmol creatinine ; P < 0.05 ) when compared with those with the lowest intake of isoflavone . No association between dietary phytoestrogen intake and BMDs was seen in the premenopausal women with high endogenous E ( n = 293 ) . In conclusion , postmenopausal women with habitually high intake of dietary isoflavone are associated with higher BMD values at both the spine and hip region . Customarily high isoflavone intake may help to reverse the state of secondary hyperparathyroidism associated with E withdrawal and hence lower the rate of bone turnover in postmenopausal women
Conclusions : Isoflavone treatments exert a moderately beneficial effect against  estrogen-deficient bone loss in women .
The effect appears dependent on whether isoflavone treatments are in aglycone form ; we conclude that beneficial effects against bone loss may be enhanced for isoflavone aglycones
Background : Age-related estrogen deficiency leads to accelerated bone resorption .
There is evidence that , through selective estrogen receptor modulation , isoflavones may exert beneficial effects against  estrogen-deficient bone loss .
Isoflavone aglycones show higher bioavailability than their glycosidic counterparts and thus may have greater potency .
Objective : To summarize evidence , we executed a systematic review and meta- analysis examining isoflavone therapies and bone mineral density ( BMD ) loss in peri- and postmenopausal women .