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 .
Soymilk or progesterone
for prevention of bone loss
Summary Background Given concerns over the use of hormone replacement therapy ( HRT ) , women are seeking natural alternatives to cope with the symptoms and effects of menopause . The bone sparing effects of soy protein and its isoflavones is well established in animal studies , while 5 previous human studies on soy and bone have yielded variable outcomes due in part to their short duration of study . Progesterone has been suggested as a bone – trophic hormone , but the effect of long – term , low dose transdermal progesterone is unknown . Aim The aim of the study was to compare for the first time the long – term effects of soymilk , with or without isoflavones with natural transdermal progesterone , or the combination , on bone mineral density in the lumbar spine and hip . Methods Postmenopausal , Caucasian women with established osteoporosis or at least 3 risk – factors for osteoporosis , were r and omly assigned , double – blind to one of four treatment – groups : soymilk containing isoflavones  ( soy+ , n = 23 ) ,  transdermal progesterone ( TPD+ , n = 22 ) , or the combination of soy+ and TDP+,(n = 22 )  or placebo ( isoflavone – poor soymilk , soy÷ and progesterone – free – cream TDP÷ , n = 22 ) . All subjects received comparable intakes of calcium , minerals and vitamins . Bone mineral content ( BMC ) and density ( BMD ) were measured in lumbar spine and hip by using dual – energy X-ray absorptiometry ( DEXA ) at baseline and after 2 years . Findings The percentage change in lumbar spine BMD and BMC respectively , did not differ from zero in the soy+ group ( + 1.1 % , + 2.0 % ) and TDP+ group ( ÷1.1 % , + 0.4 % ) but significant bone loss occurred in the control group ( ÷4.2%,÷4.3 % ) and the combined treatment group ( ÷2.8 % , ÷2.4 % ) . No significant changes occurred for femoral neck BMD or BMC .InterpretationDaily intake of two glasses of soymilk containing 76 mg isoflavones  prevents lumbar spine bone loss in postmenopausal women . Transdermal progesterone had bone – sparing effects but when combined with soy milk a negative interaction between the two treatments occurs result ing in bone – loss to a greater extent than either treatment alone
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 .