A mild favorable effect of soy protein with isoflavones on body composition--a 6-month double-blind randomized placebo-controlled trial among Chinese postmenopausal women.
BACKGROUND
In vitro and animal studies suggested that soy protein and isoflavones promote weight and body fat loss. However, clinical trials in humans were few and the effects remained uncertain.


OBJECTIVE
To examine whether soy protein with isoflavones and isoflavone extracts exert beneficial effects on body composition among postmenopausal women.


METHODS
A double-blind randomized placebo-controlled trial was conducted among 180 postmenopausal Chinese women with mild hyperglycemia. After a 2-week adaptation, participants were randomly assigned to one of the three arms to receive 15 g soy protein and 100 mg isoflavones (Soy group), or 15 g milk protein and 100 mg isoflavones (Iso group), or 15 g milk protein (placebo group) on a daily basis for 6 months.


RESULTS
We observed a mild but significant favorable effect of soy protein with isoflavones on the changes of body weight (BW), body mass index, and body fat percentage relative to isoflavone extracts and milk protein after 6-month supplementation. The mean differences of BW between the Soy and the Iso groups were -0.75 kg (95% CI: -1.363 to -0.136, P=0.017), and between the Soy and the placebo groups were -0.60 kg (95% CI: -1.209 to -0.019, P=0.047). The mean difference of change percentage in body fat percentage between the Soy and the Iso groups was -3.74% (95% CI: -6.88 to -0.60%, P=0.02), and between the Soy and the placebo groups was -2.54% (95% CI: -5.69 to 0.12%. P=0.08).


CONCLUSIONS
Six-month supplementation of soy protein with isoflavones had a mild favorable effect on body composition in postmenopausal women.
Liu
Z-m
ZM
School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong SAR.
Ho
S C
SC
Chen
Y-m
YM
Ho
Y P
YP
D000273:Adipose Tissue / Q000033:anatomy & histology / Q000187:drug effects; D000368:Aged; D044466:Asian People; D001786:Blood Glucose / Q000187:drug effects / Q000502:physiology; D001823:Body Composition / Q000187:drug effects* / Q000502:physiology; D015992:Body Mass Index; D001835:Body Weight / Q000187:drug effects; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006943:Hyperglycemia / Q000097:blood / Q000188:drug therapy; D007529:Isoflavones / Q000378:metabolism / Q000494:pharmacology*; D008875:Middle Aged; D008894:Milk Proteins / Q000008:administration & dosage; D010919:Placebos; D017698:Postmenopause; D011236:Prediabetic State / Q000097:blood; D030262:Soybean Proteins / Q000378:metabolism / Q000494:pharmacology*; D016896:Treatment Outcome
D001786:Blood Glucose; D007529:Isoflavones; D008894:Milk Proteins; D010919:Placebos; D030262:Soybean Proteins