Calcium and dairy products inhibit weight and fat regain during ad libitum consumption following energy restriction in Ap2-agouti transgenic mice.

"We demonstrated previously that dietary calcium suppression of calcitriol reduces adipocyte Ca, suppresses lipogenesis, and increases lipid utilization during energy restriction. Notably, dairy calcium sources exert markedly greater effects," researchers in the U.S. report.

"To determine the effects of dietary calcium and dairy products on energy partitioning during subsequent refeeding, we induced obesity in Ap2-agouti transgenic mice with a high-fat/high-sucrose diet, then restricted energy intake from a high-calcium (1.3%) diet for six weeks to induce fat loss, and then provided free access to a low-calcium (0.4%) diet or to high-calcium (1.3%) diets that utilized either calcium-fortified foods or dairy products (milk or yogurt) for six weeks," said Xiaocun Sun and Michael B. Zemel at the University of Tennessee. "Re-feeding the low-calcium diet caused the regain of all weight and fat, whereas all high-calcium diets reduced fat gain by 55% (p<0.01)."

"All high-calcium diets stimulated adipose tissue uncoupling protein (UCP)2 and skeletal muscle UCP3 expression (p<0.001) and slightly increased core temperature (p=0.136), but only the dairy-based diets elicited a marked (>10-fold, p<0.001) increase in skeletal muscle peroxisome proliferator-activated receptor-alpha expression," reported Sun and Zemel. "All three high-calcium diets produced significant increases in lipolysis, decreases in fatty acid synthase expression and activity, and reduced fat regain (p<0.03), but the two dairy-containing high-calcium diets exerted significantly greater effects on regain (p<0.01)."

The researchers concluded, "Thus, high-calcium diets elicit a shift in energy partitioning and reduction of weight gain during re-feeding, with dairy calcium sources exerting markedly greater effects."

Sun and Zemel published their study in the Journal of Nutrition (“Calcium and dairy products inhibit weight and fat regain during ad libitum consumption following energy restriction in Ap2-agouti transgenic mice.” J Nutr, 2004;134(11):3054-3060).

For additional information, contact Michael B. Zemel, Department of Nutrition, University of Tennessee, Knoxville, TN 37996. E-mail: mzemel@utk.edu.