Protein builds muscle in older adults too

NEW YORK (Reuters Health) - Older adults’ bodies seem to work as well as younger people’s when it comes to turning high-protein food into muscle, a small study suggests.

It’s common for people to lose muscle mass as they age, and in the elderly this can mean greater susceptibility to illness and falls. But it hasn’t been clear whether age itself impairs the body’s ability to synthesize muscle protein after a protein-rich meal.

In the new study, researchers at the University of Texas Medical Branch, found that older adults showed as much muscle-protein synthesis after eating a portion of lean grounded beef as younger adults did. This is “good news,” the researchers report in the American Journal of Clinical Nutrition, since it suggests that older adults can maintain adequate muscle by eating enough protein.

Proteins like meat, fish, poultry and dairy products are readily available, the researchers point out, and generally less expensive and more palatable than protein supplements.

“What we learned was really encouraging, because it suggests that elderly people actually can benefit from eating a moderate serving of protein-rich foods,” senior study author Douglas Paddon-Jones said in a statement.

However, he added, many older Americans -- up to 27 percent -- eat less than the recommended amount of protein each day.

Paddon-Jones is an associate professor of physical therapy and internal medicine at the University of Texas Medical Branch in Galveston.

He and his colleagues recruited 10 adults older than 65 years and 10 men and women in their 30s and 40s. The researchers took blood samples and biopsies of muscle tissue before and after serving each study participant a patty made of lean ground beef.

They found that within the 5 hours after the meal, older and younger adults showed a similar increase in muscle-protein synthesis.

Yet despite this similarity, older adults tended to have significantly less muscle mass than their younger counterparts. This discrepancy, according to Paddon-Jones, points to the importance of older adults’ getting enough protein in their diets on a daily basis.

The study was partially funded by the National Cattlemen’s Beef Association.

SOURCE: American Journal of Clinical Nutrition, August 2007.