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

BACKGROUND: Soy consumption may affect serum leptin levels and exert its beneficial effects in this way. The aim of this study was to evaluate the effect of soy consumption on serum leptin levels in postmenopausal women with metabolic syndrome. METHODS: In this clinical trial, 42 postmenopausal women with metabolic syndrome were included. The patients followed three kinds of diets: control diet (Dietary Approaches to Stop Hypertension= DASH), soy protein diet, or soy nut diet for eight weeks. Serum leptin level was measured by ELISA method. RESULTS: No significant weight change were seen in patients during three phases of trial. There was no 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). CONCLUSIONS: The results of the present study showed that neither soy protein, nor soy nut could affect weight and serum leptin levels in postmenopausal women with metabolic syndrome.