Last Updated: 2008-01-16 14:40:26 -0400 (Reuters Health)
By Anne Harding
NEW YORK (Reuters Health) - Older people who eat plenty of protein may be protecting themselves from the loss of skeletal muscle that accompanies aging, a new study shows.
"Protein intake is important for older adults," lead investigator Dr. Denise K. Houston of the Wake Forest University School of Medicine in Winston-Salem, N.C., told Reuters Health.
While many people may think Americans have no problem getting enough protein, she added, about 40 percent of US adults 70 or older get less than the recommended 0.8 grams per kilogram of body weight per day. Older people may cut down on their animal protein intake due to cost, difficulty chewing, or concerns about the high cholesterol or fat content of these foods, she added.
People tend to lose lean body mass as they age, which can increase the risk of disability and mortality, Houston and her team note in the American Journal of Clinical Nutrition. To investigate whether protein consumption might play a role in this process, they followed 2,066 men and women in their 70s for three years.
Study participants in the top 20 percent for protein consumption took in about 1.1 grams per kilogram of body weight daily (18.2 percent of total calories), while those in the bottom 20 percent were eating an average of 0.7 grams per kilogram each day (11.2 percent of total calories).
People who consumed the most protein lost 40 percent less lean mass than those who consumed the least, Houston and her team found. Among those who had lost weight during the course of the study, low protein intake was associated with greater lean mass loss. People who gained weight put on more lean mass if they were consuming more protein.
"Dietary protein appears to be associated with the partitioning of body mass in those who gain and lose weight," the researchers note.
While the study can't answer the question of whether dietary protein recommendations for older people should be increased, as some experts have suggested, they underscore the importance of meeting current requirements, Houston said.
Further studies are needed to determine if older people who eat more protein retain more lean mass, she added, and if this in turn reduces disability and mortality risk.
SOURCE: American Journal of Clinical Nutrition, January 2008.
It has been known for a long time that muscle wasting is a primary factor that decreases quality of life for the elderly. Other studies have indicated that the elderly require more protein than adults because increased cortisol levels are tearing down protein at a much faster rate as you age. This is why the Zone Diet is so beneficial to extending the quality of life. It provides adequate protein, without over-stimulation of insulin.