Effect of 6 months of exercise and isoflavone supplementation on clinical cardiovascular risk factors in obese postmenopausal women: a randomized, double-blind study.

OBJECTIVE: To investigate whether 6 months of exercise combined with isoflavone supplementation could improve clinical risk factors that predispose to cardiovascular disease in obese postmenopausal women.

DESIGN: This was a randomized, double-blind, controlled trial in which 50 healthy obese postmenopausal women were divided into two groups and assigned to isoflavone supplementation (n=25) or a placebo (n=25) for 1 year. For the last 6 months, both groups participated in an exercise program (three times per week), at the end of which cardiovascular disease risk factors were compared between groups. Body composition (using dual-energy x-ray absorptiometry), metabolic profile (blood lipids, fasting insulin, fasting glucose, sex hormone-binding globulin, C-reactive protein) were determined at baseline and at 6 and 12 months.

RESULTS: We observed a significant effect of exercise and isoflavone supplementation on body weight, total and abdominal fat mass (kilograms and percentage), body mass index, appendicular fat-free mass, fat-free mass/fat mass ratio, and sex hormone-binding globulin, but not with exercise alone. No difference was observed for other biochemical characteristics, although the quantitative insulin sensitivity check index increased equally in both groups. Conversely, although not significant, we observed a tendency for a treatment effect on body mass index (P=0.07) and on absolute (kilograms) (P=0.07) and percentage of (P=0.053) abdominal fat mass, whereas no effect of treatment was found for other variables using the Mann-Whitney test.

CONCLUSIONS: Compared to an aerobic exercise program alone, 70 mg/day of isoflavones combined with exercise may promote significant improvements in body composition parameters that are known to influence cardiovascular disease risk in postmenopausal women.