Soy isoflavones, body composition, and physical performance.
OBJECTIVE
Physiologic changes, occurring during the process of aging, can have serious health consequences, such as increased risk of chronic disease and disability. Decline in estradiol levels after menopause is hypothesized to contribute to this risk. Thus, hormone therapy (HT) might prevent or delay those changes. However, HT has serious side effects and alternative approaches are needed.


METHODS
We performed a 12-month double-blind randomized trial comparing soy protein containing 99mg isoflavones (aglycone weights) with milk protein (placebo) daily in 202 postmenopausal women aged 60-75 years. Endpoints were body composition, and physical performance. Randomization resulted in reasonable well-balanced groups, 153 (76%) women completed the trial. Compliance was good (plasma genistein levels 55 +/- 101 and 1259 +/- 1610 nmol/L for placebo and soy group, respectively). The changes in the endpoints during the intervention period among the two intervention groups were analyzed.


RESULTS
Body mass index (BMI) and waist-to-hip ratio did not change during intervention. Handgrip strength at the final visit was slightly worse in the soy group compared to the placebo group (-0.45 kg (95% C.I.: -2.5, 1.6 kg; p = 0.7), but this difference was not statistically significant. Self-reported functional status, mobility and physical performance, all slightly improved during intervention but there were no differences between the groups.


CONCLUSIONS
The results of the present trial do not support the view that soy isoflavones have favorable effects on body composition and physical performance in postmenopausal women.
Kok
Linda
L
The Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, The Netherlands.
Kreijkamp-Kaspers
Sanne
S
Grobbee
Diederick E
DE
Lampe
Johanna W
JW
van der Schouw
Yvonne T
YT
D000368:Aged; D001823:Body Composition / Q000187:drug effects* / Q000502:physiology; D015992:Body Mass Index; D004311:Double-Blind Method; D015444:Exercise; D005260:Female; D006801:Humans; D007529:Isoflavones / Q000494:pharmacology*; D016014:Linear Models; D008875:Middle Aged; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D010919:Placebos; D017698:Postmenopause; D030262:Soybean Proteins / Q000494:pharmacology*; D011795:Surveys and Questionnaires; D049629:Waist-Hip Ratio
D007529:Isoflavones; D010919:Placebos; D030262:Soybean Proteins; C065753:isoflavanone