Effect of soy protein supplementation on serum lipoproteins, blood pressure, and menopausal symptoms in perimenopausal women

Objective: To investigate the effect of soy protein supplementation with kn own levels of phytoestrogens on cardiovascular disease risk factors and men opausal symptoms in perimenopausal women. Methods: A randomized, double-blind crossover trial was conducted in 51 wom en consuming isocaloric supplements containing 20 g of complex carbohydrate s (comparison diet), 20 g of soy protein containing 34 mg of phytoestrogens given in a single dose, and 20 g of soy protein containing 34 mg of phytoe strogens split into two doses. Women were randomly assigned to one of the t hree diets for 6-week periods and subsequently were randomized to the remai ning two interventions to determine whether differences existed between the treatment diets for cardiovascular disease risk factors, menopausal sympto ms, adherence, and potential adverse effects. Results: Significant declines in total cholesterol (6% lower) and low densi ty lipoprotein cholesterol (7% lower) were observed in both soy diets compa red with the carbohydrate placebo diet. A significant decline in diastolic blood pressure (5 mm Hg lower) was noted in the twice-daily soy diet, compa red with the placebo diet. Although nonsignificant effects were noted for a number of measures of quality of life, a significant improvement was obser ved for the severity of vasomotor symptoms and for hypoestrogenic symptoms in the twice-daily group compared with the placebo group. No significant ef fects were noted for triglycerides, high density lipoprotein cholesterol or frequency of menopausal symptoms, Adherence was excellent in all groups. Conclusions: Soy supplementation in the diet of nonhypercholesterolemic, no nhypertensive, perimenopausal women resulted in significant improvements in lipid and lipoprotein levels, blood pressure, and perceived severity of va somotor symptoms. These data corroborate the potential importance of soy su pplementation in reducing chronic disease risk in Western populations, (Men opause 1999;6:7-13. (C) 1999, The North American Menopause Society.).