ST. LOUIS -- For senior citizens and those fast approaching their golden years, doctors at Washington University would like to have a word with you: Protein.
Starting at age 50, people lose nearly a half percent of their muscle mass every year, making them less mobile, more prone to fractures and at higher risk for life-threatening falls. To help compensate, seniors should add protein to their diet along with resistance exercise, the doctors say.

This is particularly important in light of their latest finding: For the first time, scientists have shown that it is more difficult for older women to replace lost muscle mass than men because of key differences in the way their bodies process food.

In a paper published late last month in Public Library of Science One, researchers at Washington University and the University of Nottingham in the United Kingdom found that postmenopausal women are less able to use protein from their diets to build muscle mass. Men of the same age were able to store more dietary protein in muscle.

"It is important to maintain muscle mass throughout life to preserve strength and to reduce the risk of falls," said Dr. Bettina Mittendorfer, an associate professor of medicine at Washington University and a co-investigator. "Falls are one of the major causes of premature death in elderly people. Half who suffer a serious fall will die within two years."

The researchers studied 13 men and 16 women ages 65 to 80 who fasted overnight. The next day, investigator took muscle biopsies from each subject. Then, they gave them a protein drink along with an intravenous infusion of amino acids with a special tracer that could easily be detected in muscle. Three hours later, the researchers took another biopsy.

"When ingesting the drink, much less protein was built in the women's muscle," Mittendorfer said. "We believe hormonal changes related to menopause may be influencing this because these differences between men and women do no occur in young individuals. It may help explain our other preliminary research findings that show post-menopausal women are less able to build muscle following resistance exercise like lifting weights."

Mittendorfer theorizes that estrogen is needed in maintaining muscle mass as well as preserving strong bones. She says the findings highlight the need for the elderly -- particularly women -- to eat plenty of eggs, fish, chicken and other protein-rich foods along with the exercise.

Until now, scientists have been unable to detect differences in the way men's and women's bodies build muscle. The new research indicates that once a woman hits 65, her body's response to food and exercise starts to decline. Making matters worse is the fact that women usually have less muscle and more fat to begin with.

Rather than eating more food, the researchers say older people should focus on eating a higher proportion of protein, which, along with exercise, could reduce the loss of muscle over time. Hormone replacement therapy might help, too, but that must be weighed against the risks it may produce, including heart disease.

Source: Belleville News-Democrat, Ill. Distributed by McClatchy-Tribune Information Services. Powered by YellowBrix.

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