Apples, green tomatoes can help you fight ageing

Eating apples and green tomatoes may help you fight symptoms of ageing, suggests a new study which found a protein that causes muscle weakness and loss during ageing.
As we grow older, we lose strength and muscle mass. However, the cause of age-related muscle weakness and atrophy has remained a mystery.
Scientists at the University of Iowa have discovered the first example of a protein that causes muscle weakness and loss during ageing.
The protein, ATF4, is a transcription factor that alters gene expression in skeletal muscle, causing reduction of muscle protein synthesis, strength and mass.
The UI study also identifies two natural compounds, one found in apples and one found in green tomatoes, which reduce ATF4 activity in aged skeletal muscle.

The findings could lead to new therapies for age-related muscle weakness and atrophy.

"Many of us know from our own experiences that muscle weakness and atrophy are big problems as we become older," said Christopher Adams, professor of internal medicine in the UI Carver College of Medicine, and senior study author.
Previously, Adams and his team had identified ursolic acid, which is found in apple peel, and tomatidine, which comes from green tomatoes, as small molecules that can prevent acute muscle wasting caused by starvation and inactivity.
Those studies set the stage for testing whether ursolic acid and tomatidine might be effective in blocking the largest cause of muscle weakness and atrophy: ageing.

In their latest study, Adams' team found that ursolic acid and tomatidine dramatically reduce age-related muscle weakness and atrophy in mice.
Elderly mice with age-related muscle weakness and atrophy were fed diets lacking or containing either 0.27 per cent ursolic acid, or 0.05 per cent tomatidine for two months.
The scientists found that both compounds increased muscle mass by 10 per cent, and more importantly, increased muscle quality, or strength, by 30 per cent.
The sizes of these effects suggest that the compounds largely restored muscle mass and strength to young adult levels.
"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 ageing," Adams said.

Adams' team investigated the molecular effects of ursolic acid and tomatidine in aged skeletal muscle. They found that both compounds turn off a group of genes that are turned on by the transcription factor ATF4.
This led them to engineer and study a new strain of mice that lack ATF4 in skeletal muscle. Like old muscles that were treated with ursolic acid and tomatidine, old muscles lacking ATF4 were resistant to the effects of ageing.
"By reducing ATF4 activity, ursolic acid and tomatidine allow skeletal muscle to recover from effects of ageing," said Adams.
The study was published in the Journal of Biological Chemistry.