Dairy products, calcium, and fat intake

The National Dairy Council would have you believe that three servings of dairy products per day will help you lose weight. That's not quite true, as the original research followed people who had not previously been getting enough calcium going on a reduced-calorie diet that included the recommended three servings of low-fat dairy products in their diet plan. Other research, however, suggests that calcium intake might actually help people lose weight by causing the body to not absorb dietary fat. Another possibility is that the body might burn fat more quickly because of the higher calcium intake.

Recently Danish researchers sought to identify which, if any, of those effects calcium might have on the individual (Am J Clin Nutr 2007;85(3):678-87). They recruited 18 men between the ages of 18 and 50 who were otherwise healthy but overweight. The men were randomly assigned to a sequence of four test meals eaten once every three weeks: three of the meals had varying levels of calcium (low, medium, and high) from dairy products, while a fourth had a high level of calcium from a calcium supplement. After eating the test meals, the subjects' blood was drawn repeatedly at regular intervals to assess their cholesterol levels, glucose levels, and the levels of fat in the blood, which indicate how much of the meal's fat the body is absorbing.

The scientists found that the meal containing a high amount of calcium from dairy products, but not from a calcium supplement, did indeed reduce the amount of fat in the bloodstream after the meal. This strongly suggests that it's not just the calcium by itself causing the body to not absorb dietary fat. Instead, the researchers theorize that the cause may be something about the type of the calcium in the dairy products or even other factors in the dairy products interacting with the calcium in the dairy products.

What this means for you

Unfortunately, this isn't a green light for eating more dairy foods in an effort to avoid absorbing fat. These high-calcium meals were not everyday meals for the participants, so we can't say for sure whether a person's body might not get used to a higher dietary calcium level and begin to absorb the dietary fat as it would normally. That said, many people would benefit from more calcium in their diet, and milk and dairy products are a good source of calcium, as are watercress, arugula, spinach, and collard greens.

First posted: March 13, 2007