Calcium May Curb Weight Gain in Young Women

April 1999

PURDUE STUDY: CALCIUM MAY CURB WEIGHT GAIN IN YOUNG WOMEN

WEST LAFAYETTE, Ind. -- Purdue University researchers have come up with yet another reason to "get" milk.

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 daily consumed less than 1,900 calories and at least 780 milligrams of calcium 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 but who 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 nonexercisers 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 of the weight control benefits than did those who primarily used nondairy 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 nondairy 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.

The 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 affect 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.

smg/teegarden.calcium/9904s2

Source: Dorothy Teegarden, (765) 494-8246, [email protected]

Writer: Susan Gaidos, (765) 494-2081, [email protected]

ABSTRACT Calcium Intake Relates to Change in Body Weight in Young Women

D. Teegarden, Y-C Lin, C. M. Weaver, R. M. Lyle, and G. P. McCabe

The relation of diet variables to 2-year changes in body composition in young females was investigated in a prospective study. Subjects were 56 Caucasian females, 18 - 31 years (mean 26.9 +/- 3.4 yr.) who were within normal weight range (mean 62.7 +/- 10.5 kg.) Dietary intake was assessed by 3-day diet records, and body composition was measured by DXA. Percent change in body weight ranged from -13.9% to 21.4% in two years. Linear regression analyses showed that percent change in body fat accounted for 68.5% of the variation of change in body weight, and change in lean mass only explained 15.0% of the variation. Calcium intake, corrected by total energy intake, significantly predicted change in body weight (p<0.01) and body fat (p=0.02) such that subjects with high calcium intake, corrected by total energy intake, gained less weight and body fat.