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 .
Effects of genistein and hormone-replacement therapy on bone loss in early postmenopausal women: a randomized double-blind placebo-controlled study.
The natural isoflavone phytoestrogen genistein has been shown to stimulate osteoblastic bone formation , inhibit osteoclastic bone resorption , and prevent bone loss in ovariectomized rats . However , no controlled clinical trial has been performed so far to evaluate the effects of the phytoestrogen on bone loss in postmenopausal women . We performed a r and omized double-blind placebo-controlled study to evaluate and compare with hormone-replacement therapy ( HRT ) the effect of the phytoestrogen genistein on bone metabolism and bone mineral density ( BMD ) in postmenopausal women . Participants were 90 healthy ambulatory women who were 47 - 57 years of age , with a BMD at the femoral neck of < 0.795 g/cm2 . After a 4-week stabilization on a st and ard fat-reduced diet , participants of the study were r and omly assigned to receive continuous HRT for 1 year ( n = 30 ; 1 mg of 17beta-estradiol [ E2 ] combined with 0.5 mg of norethisterone acetate ) , the phytoestrogen genistein ( n = 30 ; 54 mg/day ) , or placebo ( n = 30 ) . Urinary excretion of pyridinoline ( PYR ) and deoxypyridinoline ( DPYR ) was not significantly modified by placebo administration either at 6 months or at 12 months . Genistein treatment significantly reduced the excretion of pyridinium cross-links at 6 months ( PYR = -54 + /- 10 % ; DPYR = -55 + /- 13 % ; p < 0.001 ) and 12 months ( PYR = -42 + /- 12 % ; DPYR = -44 + /- 16 % ; p < 0.001 ) . A similar and not statistically different decrease in excretion of pyridinium cross-links was also observed in the postmenopausal women r and omized to receive HRT . Placebo administration did not change the serum levels of the bone-specific ALP ( B-ALP ) and osteocalcin ( bone Gla protein [ BGP ] ) . In contrast , administration of genistein markedly increased serum B-ALP and BGP either at 6 months ( B-ALP = 23 + /- 4 % ; BGP = 29 + /- 11 % ; p < 0.005 ) or at 12 months ( B-ALP = 25 + /- 7 % ; BGP = 37 + /- 16 % ; p < 0.05 ) . Postmenopausal women treated with HRT had , in contrast , decreased serum B-ALP and BGP levels either at 6 months ( B-ALP = -17 + /- 6 % ; BGP = -20 + /- 9 % ; p < 0.001 ) or 12 months ( B-ALP = -20 + /- 5 % ; BGP = -22 + /- 10 % ; p < 0.001 ) . Furthermore , at the end of the experimental period , genistein and HRT significantly increased BMD in the femur ( femoral neck : genistein = 3.6 + /- 3 % , HRT = 2.4 + /- 2 % , placebo = -0.65 + /- 0.1 % , and p < 0.001 ) and lumbar spine ( genistein = 3 + /- 2 % , HRT = 3.8 + /- 2.7 % , placebo = -1.6 + /- 0.3 % , and p < 0.001 ) . This study confirms the genistein-positive effects on bone loss already observed in the experimental models of osteoporosis and indicates that the phytoestrogen reduces bone resorption and increases bone formation 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 .