Effects of Dairy Calcium Supplementation on Adiposity Plasma Leptin and Glucose in Obese Postmenopausal Women
Dina H. Fakhrawi
Department of Nutritional Sciences, University of Connecticut, Storrs, CT, USA.
Carol J. Lammi-Keefe
Department of Nutritional Sciences, University of Connecticut, Storrs, CT, USA and College of Agriculture, LSU, Agricultural Center, and Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA.
W. Lawrence Beeson
School of Public Health, Loma Linda University, Loma Linda, CA, USA and Center for Health Disparities and Molecular Medicine, School of Medicine, Loma Linda University, USA.
T. Allan Darnell
School of Public Health, Loma Linda University, Loma Linda, CA, USA.
Anthony Firek
JL Pettis Memorial VA Medical Center, Endocrinology, Loma Linda, CA, USA.
Zaida R. Cordero-MacIntyre *
School of Public Health, Loma Linda University, Loma Linda, CA, USA and Center for Health Disparities and Molecular Medicine, School of Medicine, Loma Linda University, USA and Whittier College, Department of Kinesiology and Nutrition, Whittier, CA, USA.
*Author to whom correspondence should be addressed.
Abstract
The inclusion of low or non-fat dairy products which additional calcium in the diet may promote increased weight loss and improve insulin resistance. Therefore supplementing dairy products to obese subjects on a caloric restricted diet may be a useful strategy to enhance weight loss and improve insulin resistance. We therefore tested the short term effects of supplementing 56 overweight or obese (body mass index [BMI] >26 kg/m2) post menopausal women on a caloric restricted diet (1,400 kilocalories [kcal]) with two levels of dairy as yogurt on body composition, blood insulin, leptin and glucose concentration. The group consuming four supplemented dairy servings (DS-4) group were provided ~1400 mg Ca/day, and the group consuming two supplemented dairy servings (DS-2) were provided ~800 mg Ca/day.
Over the 3-months daily energy intake averaged 51% carbohydrate, 20.7% of protein and 27.6% of fat for both groups. At 3 months, the DS-4 group demonstrated decreased weight (87.7 to 86.2 kg, P=0.001), BMI (33.5 to 32.8 kg/m2, P < 0.001), total fat (36.1 to 34.7 kg, P<0.001), trunk fat (18.3 to 17.6 kg, P < 0.001). There were non-significant decreases in plasma glucose (74.7 to 71.1 mg/dl, P=0.494), leptin (32.5 to 31.3 µg/L, P=0.231) and insulin. For the DS-2 group there was decreased weight (86.4 to 84.4 kg, p<0.02), BMI (32.5 to 31.8 kg/m2, P=0.002), total fat (37.3 to 35.4 kg, P=0.003), trunk fat (17.1 to 16.5 kg, P = 0.27) and plasma leptin (27.8 to 25.2 µg/L, P=0.114). The DS-2 group demonstrated a surprising and significant increase in the fasting blood glucose with a marginal significant increase in insulin resistance as measured by HOMA at 3 months. We observed a significant treatment effect between the DS-2 and DS-4 groups for: % energy from fat (P=0.025), % energy from protein (P=0.047) and leptin (P=0.044).
Our study demonstrated the expected weight loss with caloric restriction but a paradoxical increase in blood glucose levels with dairy supplementation provided to maintain baseline calcium intake. Increasing dairy supplementation abrogated this small increase in fasting blood glucose and insulin resistance. The benefits of dairy calcium supplementation may be dependent on both the dose and the context of over all caloric intake.
Keywords: Hormones, calcium, weight loss, body composition, dual x-ray absorptiometry, human study.