Effects of Soy on Body Composition: A 12-Week Randomized Controlled Trial among Iranian Elderly Women with Metabolic Syndrome

BACKGROUND To examine the effects of soy [in the form of textured soy protein (TSP) and soy-nut] on body composition in elderly women with metabolic syndrome (MetS). METHODS A 12-week randomized clinical trial was conducted on 75 women between 60-70 years of age with MetS in rural health clinics around Babol, Iran in 2009. The participants were randomly assigned to one of the three groups of soy-nut (35g/d), TSP (35g/d) and control. Body fat, lean mass and anthropometric indicators were measured before and after intervention, too. RESULTS Participants were classified as overweight and showing android fat distribution. After 12 weeks of intervention, both soy-nut and TSP groups showed an increase of non-significant in lean mass (0.9 and 0.7 kg), hip circumference (0.45 and 0.28 cm), triceps skinfold (TSF) thickness (0.87 and 0.67mm) and reduction in BMI (-0.15 and -0.33), waist circumference (-0.83 and -1.2) and body fat (-1.5% and -1.7%). Significant increase in the mean change of TSF and lean mass was observed in the users of soy-nut compared to the control group (P<0.01, P<0.05). CONCLUSION 12-week intervention of soy had a mild favorable effect on body composition in elderly women with MetS.