Table 3.
Author, year | Design | Subjects | Intervention type, dose, and duration | Outcome |
---|---|---|---|---|
Potter, 1998 22 | RCT with 3 groups: ISP low isoflavones, ISP high isoflavones, or casein placebo |
|
Both ISP supplements contained 40g/day soy protein.
Low isoflavone:56 mg/day. High isoflavone: 90 mg/day. Background diet NCEP Step 1 diet. Duration: 6 months |
Significant increases in BMC and BMD occurred in lumbar spine for high isoflavone group compared to placebo. |
Harkness, 2004 54 | RCT with cross-over design placebo and soy isoflavone capsule |
|
Soy isoflavone capsule contained 110 mg/day isoflavones (1.3:1.0:0.2 ratio of genistein: daidzein: glycitein)
Duration: 6 months |
Mean spine BMD significantly greater in treatment compared to control. |
Morabito, 2002 55 | RCT with 3 groups: HT, genistein, and placebo |
|
HT: 1 mg 17β-estradiol and 0.5 mg norethisterone acetate.
Genistein: 54 mg/day Duration: 1 year |
Both genistein and HT significantly increased BMD in the femur and lumbar spine. |
Alekel, 2000 56 | RCT with 3 groups: ISP with isoflavones (ISP+), ISP without isoflavones (ISP−), and control |
|
ISP+ contained 80mg/day isoflavones. Both ISP+ and ISP− contained 40g/day of soy protein.
Duration: 24 weeks |
Regression analysis showed that ISP+ treatment had a positive effect on change in BMD. |
Lydeking-Olsen,2004 57 | RCT with 4 groups: soymilk, transdermal progesterone, combination, and placebo |
|
Soymilk contained isoflavones.
Combination group consumed soymilk and used transdermal progesterone. Placebo group consumed isoflavone-free soymilk and progesterone-free cream. Duration: 2 years |
In the soymilk group, BMC and BMD did not differ from baseline, but significant bone loss occurred in placebo group and combination group. |
Chiechi, 2002 58 | RCT with 3 groups: Soy-rich diet, HT group, control group. |
|
Soy-rich diet group added 1 soy food serving per day and exchanged 2 meals 2 times a week with soy rich meals provided by the study.
Duration: 6 months |
Diet not as effective as HT in reducing bone turnover.
BMD significantly decreased only in the control group. Safety: endometrial thickness increased slightly in soy diet group, increased significantly in HT group. |
Chen YM, 2003 59 | RCT with 3 groups: placebo, mid-dose, and high-dose, in pill form |
|
All supplements contained 500mg/d calcium and 125 IU/d vitamin D.
Isoflavone amounts Placebo: 0 mg/day Mid-dose: 40mg/day High-dose: 80 mg/day Duration: 1 year |
Rate of change in BMC was significantly higher in high-dose group compared to placebo and mid-dose groups. Effect was mild and only found in women with initial BMC < median. |
Chen YM, 2004 60 | RCT with 3 groups: placebo, mid-dose, and high-dose, in pill form |
|
All supplements contained 500mg/d calcium and 125 IU/d vitamin D.
Isoflavone amounts Placebo: 0 mg/day Mid-dose: 40mg/day High-dose: 80 mg/day Duration: 1 year |
Rate of change in BMC was significantly effected by isoflavones in later postmenopausal women (years since menopause>4), lower body weight (<55.5 kg), and lower calcium intake. |
Uesugi, 2002 40 | RCT with 2 groups: soy isoflavone capsule and placebo |
|
Soy isoflavone capsule contained 61.8 mg of isoflavones.
Duration: 4 weeks |
Excretion of bone resorption markers was reduced significantly in the isoflavone group. BMC or BMD not tested. |
Kreijkamp-Kaspers, 2004 34 | RCT with 2 groups: ISP or casein protein |
|
ISP contained 25.6 g/day of soy protein and 99mg/day of isoflavones.
Duration: 12 months |
Bone mineral density did not differ between the groups after 1 year. |
Gallagher, 2004 36 | RCT with 3 groups: ISP with high, low, or no isoflavone |
|
High isoflavone 96mg/d
Low isoflavone 52 mg/d No isoflavone <4mg/d Duration: 9 months |
No effect of any of the ISP supplements on BMD in spine or femoral neck. |
Dalais, 1998 61 | RCT with crossover design and 2 arms: wheat/soy arm and wheat/linseed arm |
|
Wheat, linseed, and soy were baked into bread which was substituted for usual bread intake.
Duration: 12 weeks each diet |
No changes in BMD found between the groups. BMC increased by 5.2% after the soy phase (significant). No increases in BMC after wheat or linseed phase. |
Roughead, 2005 37 | Controlled feeding study with crossover design. 2 groups: control diet and soy diet |
|
In soy diet, 25g high-isoflavone soy protein was substituted for an equivalent amount of meat protein.
Duration: 7 weeks each diet |
Diet did not affect biomarkers of bone retention. |
Dalais, 2003 20 | RCT with 2 groups: ISP or casein placebo supplement |
|
ISP contained 40 g/day of soy protein and 118 mg isoflavones.
Duration: 3 months |
No significant differences in markers of bone resorption between placebo and control groups. |
Arjmandi, 2005 62 | RCT with 2 dietary treatments: soy or control |
|
Soy diet contained 25g soy protein/day and 60mg isoflavones. Control diet contained no soy or isoflavones.
Foods were provided to participants Duration: 1 year |
Both soy and control groups significantly decreased whole body and lumbar BMC and BMD. Both soy and placebo treatments positively affected markers of bone formation. |
Abbreviations: RCT=Randomized Controlled Trial, NCEP=National Cholesterol Education Program, ISP=Isolated Soy Protein, HT=hormone therapy