Natural compounds found in apple peel and green tomatoes could fight off muscle loss and weakness in old age, a study by U.S. researchers indicates.
The activity of a protein known as ATF4, associated with depletion of muscle protein synthesis, strength and mass in old age can be decreased by the compounds known as ursolic acid and tomatidine, scientists at the University of Iowa say.
"By reducing ATF4 activity, ursolic acid and tomatidine allow skeletal muscle to recover from effects of aging," says study senior author Christopher Adams, a professor of internal medicine.
Ursolic acid is found in apple peel, while tomatidine is present in green tomatoes.
In experiments using older mice, the compounds were found to significantly reduce age-related muscle atrophy and weakness, increasing muscle mass by 10 percent and muscle quality by 30 percent in just two months, the researchers report in the Journal of Biological Chemistry.
The mice were put on a diet containing either 0.2 percent ursolic acid or 0.05 percent tomatidine.
"Based on these results, ursolic acid and tomatidine appear to have a lot of potential as tools for dealing with muscle weakness and atrophy during aging," Adams says.
In humans, problems with muscles and strength can have significant impacts on the quality of life, he notes.
"Many of us know from our own experiences that muscle weakness and atrophy are big problems as we become older," he says.
Previous studies had shown the compounds could prevent serious muscle wasting association with malnutrition or an extremely sedentary lifestyle, while the new findings suggest they can also be effective in reducing age-related weakness and atrophy in muscles.
That could lead to improved therapies aimed at keeping older adults physically fit and active for longer, the researchers suggest.