Iranian J Publ Health, Vol. 41, No.4, Apr 2012, pp. 9-18 Original Article Effects of Soy on Body Composition: A 12-Week Randomized Controlled Trial among Iranian Elderly Women with Metabolic Syndrome *A Bakhtiari 1, 2, Z Yassin 3, P Hanachi 4, A Rahmat 3, Z Ahmad 5, P Sajadi 6, S Shojaei 7 1. Institute of Gerontology, University Putra Malaysia, Serdang, Selangor, Malaysia 2. Dept. of Midwifery, Faculty of Medicine, Babol University of Medical Sciences, Iran 3. Dept. of Nutrition, Faculty of Medicine & Health Sciences, University Putra Malaysia, Serdang, Selangor, Ma- laysia 4. Dept. of Biology, Biochemistry unite, Faculty of Basic Science, Alzahra University Tehran, Iran 5. Dept. of Family Medicine, Faculty of Medicine & Health Sciences, University Putra Malaysia, Serdang, Selangor, Malaysia 6. Dept. of Nutrition, Faculty of Medicine, Babol University of Medical Sciences, Iran 7. Dept. of Biochemistry, Faculty of Medicine, Shiraz University of Medical Sciences, Iran (Received 09 Oct 2011; accepted 19 Feb 2012) Abstract 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 inter- vention, 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. Keywords: Soy, Metabolic syndrome, Body composition, Older women Introduction Aging is associated with several physiological lean mass (1). These changes in body composition changes. One of them is a change in body compo- and metabolic effects indicate an increase the risk sition, which is characterized by an increase in ab- of serious diseases and subsequent loss of func- dominal obesity and fat mass and a decrease in tional capacity and independence (2). On the *Corresponding Author: Tel: 0111 2192033, E-mail address: [email protected] Bakhtiari et al.: Effects of Soy on Body Composition … other hand, aging is considered as a major risk fac- guidelines which are as follows: 1) waist circumfe- tor for metabolic syndrome (MetS) development; rence >80 cm; 2) serum HDL-C <50 mg/dL; 3) a constellation of cardiovascular disease risk fac- triglyceride ≥150 mg/dL; 4) fasting blood glucose tors, which through increased visceral fat as the ≥100 mg/dL; and 5) systolic blood pressure ≥130 underlying cause of this syndrome can cause in- mmHg and diastolic ≥85 mmHg (14). To be creased mortality and morbidity in the elderly peo- qualified for this study, the subjects had to have at ple (3). An increase in visceral fat is also seen spe- least three of the above-mentioned criteria with- cifically in older women due to the lack of estro- out having to take any medication for the treat- gen (2). The use of estrogen during the postme- ment of diabetes, hypertension, or hyperlipidemia. nopausal period might have beneficial effects on The exclusion criteria were current or previous body fat distribution (4, 5). However, hormone use of estrogen therapy, the consumption of soy therapy is associated with some serious side ef- products or supplements, treatment with insulin fects, therefore its risk to benefit ratio is discussed or oral hypoglycemic, antilipemic, antihyperten- (6). sive agents, aspirin, history of CVD, hyper and Soy products as rich sources of phytoestrogen hypothyroidism, kidney, liver, infectious diseases, may be a good substitute for creating beneficial cancer, vegetarian, smoking or allergic reaction to effect on regional body fat and lean tissue distri- soy consumption. Finally, 75 women between 60- bution. Soy is rich in isoflavone, dietary fiber, 70 years old who met the inclusion criteria were leading to increased satiety. Therefore, soy-based chosen for this study. foods help reduce fat mass (7). Reports on the All participants were provided with the informed effects of soy isoflavone on body composition in written consent form to sign. The present study elderly women are sparse. Experimental studies on was approved by the Ethical Committee of the animals showed its beneficial effects (8-10), while University of Putra Malaysia as well as Babol Uni- clinical studies have shown controversial results (7, versity of Medical Sciences in Iran. 11-13). To the best of our knowledge, no compre- hensive reports are available comparing the effects Study procedures of soy-nut, the natural state of soybean, with tex- This study was a 12-week parallel-randomized tured soy protein (TSP) as a processed soy prod- controlled trial. The data were collected between uct on body composition of women above 60 July and December 2009. A questionnaire on years old with MetS. demographic characteristics was completed at This research is aimed to evaluates the effects of baseline. The participants were randomized into two types of soy on weight, BMI (body mass in- three groups by the proportional randomization dex), circumferences, TSF, fat mass and lean mass method using a table of random numbers gener- among older women with the MetS. ated by Microsoft Excel. Group A (n=25) re- ceived 35 g soy-nut and group B (n=25) 35 g TSP Materials and Methods daily for three months. Group C (n=25), the con- trol group, received nothing instead, since the par- In July 2009, a cohort of 240 potential participants ticipants in the treatment groups were consuming was recruited through community advertisement. natural soy products not pills, so it was impossible Posters were distributed in the Rural Health Clin- to apply any placebo for the control group. Soy- ics affiliated with the Babol University of Medical nut and TSP were packed and given to the partici- sciences, Iran. After a primary assessment in terms pants in small 490-gram bags for use in 2 weeks of exclusion criteria, 200 eligible women between and they were provided a soy dose of 35 grams 60-70 years old were selected to be screened for daily. The participants in group B, were trained MetS. The MetS was determined according to the how to prepare their meal with TSP. First, TSP criteria set by Adult Treatment Panel (ATP) III was soaked in tepid water for about 2-3 minutes and then drained. Then, it was cooked with tur- 10 Iranian J Publ Health, Vol. 41, No.4, Apr 2012, pp.9-18 meric powder and limejuice for 2 minutes. The BMI were measured with composition analyzer participants were strongly advised to take the (Omron HBF-306 body fat analyzer). We deter- completely prepared TSP during the intervention. mined abdominal fat indirectly by measuring waist The soy-nut and TSP used in this study were pro- circumference (WC) just above the iliac crest. Hip duced and packed by Max Soy Company in Te- circumference (HC) was also assessed at the level hran, Iran. The nutrient composition of soy con- of the greater trochanter. From these the waist-to- sumed in the study, based on Max Soy Company hip ratio and waist-to-height was calculated. These analysis, is shown in Table 1. ratios give a measure for upper body adiposity. The mid-arm circumference (MAC) was measured, Table 1: Nutrient composition of soy-nut and with the right arm held at a vertical angle (90 de- TSP used in the intervention grees), between the tip of the shoulder and elbow bone. Then triceps skinfold (TSF) thickness was Nutrients per 35 g S o y - nu t T S P measured to the nearest millimeter in this area by Protein (g) 13.8 18.2 lifting a fold of skin and the subcutaneous fat Fat (g) 8.7 0.45 away from the underlying muscle and bone with a Total carbohydrate (g) 11.5 11.4 skin fold calliper (Holtain, Crymych, UK). Meas- Fiber (g) 10.5 11.9 urements were repeated three times and the mean Isoflavones (mg) 117.2 96.2 values were taken. Mid-arm muscle circumference Diadzein (mg) 47.6 38.5 (MAMC) was calculated in mm from the follow- Genistein (mg) 60.2 48.8 ing equation: MAMC (mm) = MAC (mm)–[3.14 x Glycitein (mg) 9.45 8.9 triceps skinfold (mm)] (15). The measurements The participants were asked not to change their were recorded before and after the 12-week inter- habitual diet and physical activity levels during the vention. study period. To assure there were no changes in Fasting blood samples were collected from each diet and activity, food intake and physical activity volunteer for diagnosis of MetS. Five ml of ven- levels were measured at the outset as well as dur- ous blood was collected in test tubes. Serum was ing the intervention in a monthly basis. Each par- separated by centrifugation within 15 minutes of ticipant brought back her 3-d dietary and physical collection.