Effects of Soy Isoflavone Supplementation and Exercise on Bone Mineral Density and Urinary Deoxypyridinoline in Postmenopausal Women

ABSTRACT

We studied the effects of soy isoflavones supplementation with exercise on bone mineral density and the urinary excretion of deoxypyridinoline as an index of bone resorption rates in postmenopausal women. A total of 67 postmenopausal women were assigned to Isoflavone (90 mg/day) or placebo groups. These groups were further divided into groups that undergone a regular exercise or a rather sedentary state performing daily activity only. Four groups were Placebo-control group (n = 16), Placebo-exercise group (n = 16), Isoflavone-sedentary group (n = 19) and Isoflavone-exercise group (n = 16). After the intervention, we compared anthropometric mesurement, dietary recall, bone mineral density (femoral neck, lumbar spine), urinary deoxypyridinoline between the groups and between the pre and post studies. There were no significant differences between the four groups in terms of average age, height, weight, period after menopause at the baseline. The average age of the subjects were 55.2 yrs, average height, weight, period after menopause were 154.7 cm, 59.3 kg, 5.58 yrs, respectively. After eight week intervention period, there were no significant differences between the four groups in bone mineral density, but urinary deoxypyridinoline excretion was significantly decreased both in Isoflavone-sedentary and Isoflavone-Exercise groups. These results suggest that Isoflavone supplementation alone or with exercise may be preventive measures through the decrease of bone reabsorption rate in post-menopausal subjects. Whereas exercise alone did not appear to be an effective measure in bone loss with these subjects.