In a two-year study of 54 women ages 18 to 31, the researchers found that higher calcium intakes may reduce overall levels of body fat and slow weight gain for women in this age group.
And women who consume calcium from dairy products, or who consume at least 1,000 milligrams per day, may reap the most benefits.
"Our study is the first to show that, when overall calorie consumption is accounted for, calcium not only helps keep weight in check, but can be associated specifically with decreases in body fat," says Dorothy Teegarden, assistant professor of foods and nutrition at Purdue.
She presented her findings Tuesday (4/20) in Washington at a conference of the Federation of American Societies for Experimental Biology.
The women in the study were within normal weight ranges and followed no specific diet, Teegarden says. Dietary intake was assessed by diet records, and participants' body composition was measured using a method called dual energy X-ray absorptiometry, which provides measurements of muscle and fat mass of different areas of the body.
The researchers found that the women in the study who consumed less than 1,900 calories per day with a daily calcium intake of at least 780 milligrams, either had no increase in body fat or lost body fat mass over the two-year period. The women who consumed less than 1,900 calories per day but averaged less than 780 milligrams of calcium gained body fat mass over the same period.
"Women who consumed an average of 1,000 milligrams of calcium per day, which is slightly below the recommended daily allowance for this age group, showed an overall decrease in body weight as high as six to seven pounds," Teegarden says.
The study showed that exercisers and non-exercisers benefited equally from high calcium intakes, but that women who consumed more than 1,900 calories per day did not benefit.
"There appears to be some sort of interaction with higher-calorie diets," Teegarden says. "When we looked at the data for the women with calorie intakes of more than 1,900, we found that the calories take over, and any potential benefits of weight-control from calcium are lost."
The researchers also found that women in the study who got their calcium from dairy sources, such as milk, yogurt and cheese, showed more benefits of the weight control measures than did those who primarily used non-dairy sources -- such as dark green leafy vegetables, nuts and beans -- or calcium supplements.
"This difference may be attributed to the fact that women who use non-dairy sources would have to eat significant amounts of those foods to produce the effect, or, it may suggest that there is something in milk that works to help regulate body weight," Teegarden says.
Teegarden says that if these findings are confirmed, it may prompt recommendations to increase calcium consumption, especially from dairy sources, and lower overall calorie intake to prevent increases in body weight and body fat in young women.
These findings may or may not apply to women over 30, Teegarden says. "This is the first time this weight-regulation effect has been documented in people. We cannot speculate on how it might effect women in other age groups."
Working with Teegarden on the research were Connie Weaver, head of the Department of Foods and Nutrition at Purdue, Roseann Lyle, associate professor of foods and nutrition, George McCabe, professor of statistics, and graduate student Y-C Lin.
Teegarden's research is supported by the National Dairy Council.
Source: Dorothy Teegarden
765-494-8246
teegarden@cfs.purdue.edu