Dairy Calcium Intake Enhances Weight Loss in Overweight Diabetic Patients

High intake of low-fat dairy products enhances weight loss in overweight patients with diabetes who are following isocaloric-restricted diets, according to the results of a study reported in the March issue of Diabetes Care.

"Recent studies suggest that calcium metabolism and perhaps other components of dairy products may contribute to weight reduction in animal and human models," write Danit R. Shahar, RD, PhD, of the Ben-Gurion University of the Negev in Beer-Sheva, Israel, and colleagues. "In addition, an accumulating body of evidence suggests that calcium-rich diets play a direct role in the prevention of obesity."

This was an ancillary study of a 6-month randomized clinical trial evaluating the effect of 3 isocaloric diets in type 2 diabetic patients: mixed-glycemic index carbohydrate diet, low-glycemic index diet, and modified Mediterranean diet. Based on personal choice, intake of low-fat dairy products varied within and across the groups. Dietary consumption, weight, cardiovascular (CVD) risk factors, and diabetes indices were measured at baseline and at 6 months.

The investigators enrolled 259 diabetic patients of average body mass index (BMI) more than 31 kg/m2, and mean age of 55 years. At baseline, there was no difference between the intervention groups in CVD risk factors, diabetes indicators, macronutrient intake, and nutrient intake from dairy products.

Dairy calcium intake was associated with percentage of weight loss. Compared with the lowest tertile of dairy calcium intake, the highest tertile had an odds ratio of 2.4 for weight loss of more than 8% (P = .04), after controlling for nondairy calcium intake, diet type, and the change in energy intake from baseline. Except for triglyceride levels, there was no apparent association between dairy calcium and other health indexes.

"A diet rich in dairy calcium intake enhances weight reduction in type 2 diabetic patients," the authors write. "Such a diet could be tried in diabetic patients, especially those with difficulty adhering to other weight reduction diets."

Study limitations include the fact that it is an ancillary study.

"Before recommending an increase in dairy consumption, it is important to take into consideration the possible negative effect of dairy products on prostate and breast cancer," the authors conclude. "The recommendation of a diet rich in low-fat dairy products seems highly appropriate for weight loss among diabetic patients, in general, and female diabetic patients in particular."

Tnuva Research Institute in Rehovot, Israel, supported this study. The costs of publication of this article were defrayed in part by the payment of page charges, mandating that it must therefore be marked "advertisement" solely to indicate this fact.

Diabetes Care. 2007;30:485-489.