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.
It is unknown whether isoflavones combined with an aerobic program could prevent cardiovascular disease risks. This study demonstrated that 6 months of exercise combined with isoflavones improved body composition and sex hormone-binding globulin levels to a greater extent than exercise alone.
From the 1Research Centre on Aging, Sherbrooke; and 2Faculty of Physical and Education of Sports, and 3Faculty of Medicine, University of Sherbrooke, Sherbrooke, QC, Canada.
Received September 27, 2006; revised and accepted November 7, 2006.
Funding/support: This study was supported by the Canadian Institutes of Health Research and the Research Centre on Aging. M.A.L. and I.J.D. are supported by the Canadian Institutes of Health Research, and A.K. is supported by Fonds de la recherche en sante` du Que`bec. Isoflavone and placebo capsules were provided by Arkopharma (Arkopharma Ltd, France).
Financial disclosure: None reported.
Address correspondence to: Isabelle J. Dionne, PhD, Research Centre on Aging, 1036 Belvédère Sud, Sherbrooke, Québec, Canada, J1H 4C4. E-mail: isabelle.dionne@USherbrooke.ca.