bone-density-loss-and-diet

bone density loss and diet

High Protein Diets May Trigger Bone Density Loss

A new study finds that bone density loss can be accelerated in diets that contain a lot of meat-based proteins.

By Emily Main

Topics: low-carb diets, bone health

Step away from the chicken and reach for some dried beans and whole-grain rice.

Fill up on fruits, veggies, and grains: Too much protein could cause bone loss.

RODALE NEWS, EMMAUS, PA—Looking to lose weight after menopause? A new study suggests that going vegetarian may be a healthier alternative than trying out the more popular high-protein diets, such as Atkins. The findings, published in the Journal of Gerontology: Medical Sciences, suggest that eating a lot of meat could acceleratebone density loss in postmenopausal women, while sticking with more common protein amounts, primarily from plant and dairy sources, did not.

THE DETAILS: This two-part study involved postmenopausal women whose body mass indices defined them as either overweight or obese. For the first part of the study, 54 women were separated into two groups that went on two separate calorie-restricted diets: a high-protein diet that contained 30 percent of calories from pork and a "normal protein" diet, in which 18 percent of calories came from vegetarian sources of protein, including milk, eggs, beans, and whole grains.

More about bone density loss, from Prevention.com:
60-Second Bone Builder: Turn your daily walk into a bone boosting bonanza.
Bone up on D: Learn how vitamin protects your bones—if you get enough of it.
Beat the Osteoporosis Odds: Know how to lower your risk of a fracture.

In the second study, 54 overweight or obese postmenopausal women were divided into four groups: one group that ate their normal diet with no calorie restrictions or protein requirements; a vegetarian group that got 16 percent of calories from plant, dairy, or egg protein; a beef group; and a chicken group—the last two getting 26 percent of calories from their respective animal proteins. To ensure that everyone was receiving the same amount of calcium, which can affect bone density, the high-protein dieters in both studies were given supplements that equaled the amount of calcium eaten by the vegetarian group.

In both studies, the higher-protein diets were linked with lower bone density scores, despite the fact that everyone (except the group that ate their normal diets) lost roughly the same amount of weight. While the vegetarian dieters saw no declines in bone mineral density, the high-protein meat eaters averaged a 1.4 percent decrease in densities over the course of their respective diets. In the second study, the group that didn't change its eating patterns maintained the same levels of bone density as well.

WHAT IT MEANS: Sticking to a high-protein diet could accelerate bone loss as you age. And why that is, isn't exactly clear, says the study's lead author, Wayne Campbell, PhD, professor in the Department of Foods and Nutrition at Purdue University. "The acidity that is associated with foods containing amino acids [such as meat] may promote the loss of calcium," he says. "And the way our kidneys handle that acid can influence calcium regulation." Another explanation could be that meat proteins influence the continual breakdown and buildup of bones. "Basically, all women, particularly postmenopausal women, experience a high turnover of calcium in their bones," he says. "They're always building bone and breaking down bone, and our studies suggest that bone breakdown is exceeding bone buildup in these high-protein diets."