Milk, cheese and other calcium-rich foods have long been recognized for their importance in developing and maintaining strong bones. But teen-agers and women, two groups most in need of calcium, have often shunned milk and other dairy products because of the foods’ image as "fattening." That image is about to be shattered.
According to research by Michael Zemel, director of nutrition at the University of Tennessee’s Nutrition Institute, calcium – particularly from calcium-rich dairy products – shows promise as a weight-control tool. As keynote speaker at the Colorado Dietetic Association annual meeting last month, Zemel discussed his work, which showed that three to four servings of dairy products (particularly low-fat dairy products) each day can help adjust your fat-burning machinery so you burn more fat.
Zemel said he initially observed the anti-obesity effect of dairy foods 14 years ago. "In a 1988 year-long study involving obese African-American men, we added 2 cups of yogurt to the dietary regime we had them on and saw a drop of 11 pounds of body fat," Zemel said.
He and other researchers reviewed other nutrition studies and found them in agreement – calcium-rich diets correlated with lower weight. Women who consumed the least amount of dairy foods had the highest amount of body fat; preschool children who ate low-calcium diets had the most body fat; and in a study of lactose-tolerant and lactose-intolerant African-American women, those who consumed the most dairy products were the leanest.
Zemel and others now are looking into the mechanism for this phenomenon, which is thought to have to do with alterations in intracellular calcium transport and metabolism in response to dietary intake of calcium, such that low intakes promote fat storage and high intakes actually cause fat cells to burn more and store less fat.
Regardless of the mechanism, there is now more reason than ever to ensure your diet includes three to four servings of calcium-rich foods each day, something women and teens often miss. Dairy products (milk, cheese, yogurt, etc.) are our most concentrated food sources of calcium. One cup of milk contains about 300 milligrams of calcium and one cup of plain yogurt around 400 milligrams. Even people who are lactose intolerant often can enjoy fermented, aged and lactase-treated dairy products, including yogurt, hard cheese and lactase-treated milk. Those who must avoid dairy products due to allergies or severe lactose intolerance still can consume significant amounts of calcium from dry beans, fish with edible bones, tofu (if processed with calcium sulfate), calcium-fortified orange juice and dark green vegetables such as broccoli, kale and collards.
For people who are unable to obtain sufficient calcium through diet, supplements such as calcium carbonate, calcium citrate, calcium lactate or calcium gluconate may also be of benefit. These supplements, however, don’t seem to be quite as effective in promoting the burning of fat in fat cells as do changes in diet to include more low-fat, calcium-rich foods.