Intake of dietary phytoestrogen and indices of antioxidant and bone metabolism of pre- and post-menopausal Korean women

A group of 101 women, aged 40-65 years consisted of 48 premenopausal subjects and 53 postmenopausal ones living in Daegu and Gyeongbuk area in Korea were evaluated with their general characteristics, lifestyle factors, nutrient and phytoestrogen intakes, blood and urinary indices concerning antioxidant status and bone metabolism. Body mass index (BMI), waist hip ratio (WHR) and systolic blood pressure (SBP) of the postmenopausal women were significantly higher (23.8, 0.86, and 126.9 mmHg, respectively) than those of the premenopausal women (22.6, 0.82, and 115.9 mmHg; respectively). Nutrient intakes of the postmenopausal and premenopausal groups were not different except lower fat intake and higher dietary fiber and iron intakes in the postmenopausal group. Daily total phytoestrogen intake was significantly higher in the postmenopausal group (48.54 mg) than the premenopausal (31.41 mg) and was resulted mostly from higher intakes of daidzein and genistein from soy and soy products (45.42 mg vs 28.91 mg). Serum genistein level and excretion of enterolactone, major lignan metabolite, were not very different between the two groups. Serum retinal and α- tocopherol levels were higher in the postmenopausal group but TBARS levels were not different between the two groups. Serum osteocalcin (7.18 ng/mL) and urinary deoxypyridinoline (7.15 nmol/mmol creatinine), in the postmenopausal group were significantly higher than those in the premenopausal group (4.80 ng/mL, 5.95 nmol/mmol creatinine). Urinary excretion of enterolactone was positively correlated with serum osetocalcin in premenopausal women and serum genistein negatively correlated with the urinary DPD in postmenopausal women. Dietary phytoestrogen intake was negatively correlated with serum level of TBARS in all subjects. It is concluded that the effect of total phytoestrogen intake is beneficial on body antioxidant status in all middle-aged women regardless of menopause but the effect on bone metabolism appears different by the type of the phytoestrogen and the menopausal state.