Effects of Isoflavone and Exercise on BMD and Fat Mass in Postmenopausal Japanese Women: A 1-Year Randomized Placebo-Controlled Trial

Abstract

The combined intervention of isoflavone intake and walking exercise over 1 year in postmenopausal Japanese women exhibited a trend for a greater effect on prevention of bone loss at the total hip and Ward's triangle regions. Introduction:The additive effects of isoflavones and exercise on bone and lipid metabolism have been shown in estrogen-deficient animals. In this study, we determined the effects of isoflavone intake, walking exercise, and their interaction on bone, fat mass, and lipid metabolism over 1 year in postmenopausal Japanese women. Materials and Methods: A total of 136 postmenopausal women at <5 years after the onset of menopause were randomly assigned to four groups: (1) placebo, (2) walking (45 minutes/day, 3 days/week) with placebo, (3) isoflavone intake (75 mg of isoflavone conjugates/day), and (4) combination of isoflavone plus walking. BMD, fat mass, serum lipid, and serum and urinary isoflavone concentrations were assessed. Results: A significant main effect of isoflavone on the reduction in trunk fat mass was obtained at 12 months. Significant main effects of walking on the reduction in fat mass in the whole body and the trunk were observed at 3, 6, and 12 months and that in the legs and arms at 6 and 12 months. Serum high-density lipoprotein (HDL)-cholesterol concentration significantly increased by 12 months after the walking and the combined intervention. After 12 months, a significant main effect of isoflavone on BMD was observed only at Ward's triangle. Walking prevented bone loss at the total hip and the Ward's triangle to significant degrees. The effect of the combined intervention on BMD at total hip and Ward's triangle regions was greater than that of either alone. No significant interaction was observed between isoflavone and walking in any measurements recorded during the study. Conclusions: Our study suggest that combined intervention of 75 mg/day of isoflavone intake and walking exercise 3 times/week for 1 year showed a trend for a greater effect on BMD at total hip and Ward's triangle regions than either alone. Intervention with isoflavone in postmenopausal Japanese women showed a modest effect on BMD compared with those in Westerners. Further studies over longer treatment duration that include assessment of BMD at various regions are necessary to ascertain the clinical significance of the combined intervention of isoflavone plus walking in postmenopausal women.

Soy Reduces Bone Turnover Markers in Women During Early Menopause: A Randomized Controlled Trial

“…(17) Very few randomized controlled trials on soy isoflavones effects on bone have contained data for bCTX and P1NP, and those reported have generally not detected significant effects of soy isoflavone supplements on these bone turnover markers. (18) The heterogeneity of trial results are likely to be a combination of underpowered clinical trials and differences in habitual dietary intake of soy isoflavones, (19) the variable interval since the onset of menopause, (20) as well as the chemical forms and proportions of individual soy isoflavones. (21) The current study sought to minimize these variables by investigating a homogeneous large study population of women who were likely to be at maximal bone turnover by being within the first 2 years of their menopause.…”

Effects of Soy Protein and Isoflavones Intake on HDL Metabolism in Asian Populations

“…Wu et al studied the effects of isoflavone intake, walking exercise and their interaction on lipid metabolism over 1 year in postmenopausal Japanese women [15]. A total of 136 postmenopausal women at < 5 years after the onset of menopause were randomly assigned to four groups: placebo, walking (45 min/day, 3 days/week) with placebo, isoflavone intake (75 mg of isoflavone conjugates/day), and combination of isoflavone plus walking.…”

Scientific Opinion on the substantiation of health claims related to soy isoflavones and maintenance of bone mineral density (ID 1655) and reduction of vasomotor symptoms associated with menopause (ID 1654, 1704, 2140, 3093, 3154, 3590) (further assessmen

“…All were conducted in post-menopausal women, but were very heterogeneous regarding mean age, years since last menses, and bone status. Isoflavones were consumed in capsules in eight studies, either extracted from soy germ Wong et al, 2009), from soy beans/protein Huang et al, 2006;Levis et al, 2011), from an undisclosed source (Wu et al, 2006b), or provided as pure genistein from undisclosed origin Morabito et al, 2002). Soy isoflavones were consumed as part of soy foods (e.g.…”

“…Four studies each reported a statistically significant change in BMD at only one bone site among a number of sites measured (whole body (Wong et al, 2009); intertrochanter region of the hip (Kreijkamp-Kaspers et al, 2004); femoral neck ); Ward's triangle (Wu et al, 2006b)) in the soy isoflavone group compared to placebo, with no significant changes in markers of bone formation or resorption. The bone site at which a significant effect of soy isoflavones was reported was never the primary outcome of the study and differed between studies.…”

“…The Panel considers that this study does not show an effect of soy isoflavones at doses up to 120 mg/day on BMD in postmenopausal women. Wu et al (2006b) randomised post-menopausal women (mean age about 55 years) to consume daily 47 mg soy isoflavones with or without three 45-min walking sessions per week or placebo ( walking) for one year. The Panel notes that the origin and composition of soy isoflavones was not reported, that participants were not selected on the basis of bone status, and that the primary outcome of the study was not identified.…”