A randomized cross-over trial on soy intake and serum leptin levels in women with metabolic syndrome

Soy consumption may affect serum leptin levels and exert its beneficial effects in this way. This study was conducted to assess the effect of soy consumption on serum leptin levels in postmenopausal women with metabolic syndrome. Methods and This was a randomized cross-over clinical trial on 42 postmenopausal women with the metabolic syndrome. Three kinds of diets were consumed by the patients: control diet (Dietary Approaches to Stop Hypertension= DASH), soy protein diet, or soy nut diet, each for eight weeks. Serum leptin level was measured by ELISA method. No significant changes in the weight of patients were seen during three phases of trial. There was not significant difference between the end values of serum leptin concentrations following these diets (Geometric mean ±SD: 16.9±2.5 ng/ml at the end of control diet, 16.1±1.6 ng/ml at the end of soy protein diet, and 15.9±1.7 ng/ml at the end of soy nut diet). Percent difference compared to control for serum leptin levels showed that neither soy protein nor soy nut diets could significantly alter this variable (P=0.32). The results of the present study showed neither soy protein, nor soy nut could affect weight and serum leptin levels in postmenopausal women with metabolic syndrome.