I remember when I was little, my mom and teachers at school would always tell me: “an apple a day will keep the doctor away.” While there may not be concrete scientific evidence that supports the accuracy of this saying, Dr. Christopher Adam and his colleagues from the University of Iowa have found evidence that consuming apples and tomatoes will keep our muscles strong and healthy.
Video courtesy of CNN NewsByJim’s
Scientists have identified age-related muscle weakness and atrophy as a common trend in both humans and animals. Such phenomenon is often caused by disuse or denervation of muscles. Generally, muscle strength will start to decline between the ages of 30 to 40, and continue to decrease for the next several decades until the age of 70, when it begins to accelerate. Simultaneously, muscle mass is also decreasing, but at a slower rate. This loss of muscle mass and strength will consequently reduce the individual’s quality of life, and increase mortality. Up until now, exercise and healthy eating are the only approved approach to slow muscle atrophy.
Video courtesy of Mayo Clinic
Researchers at the University of Iowa have recently discovered two compounds that reduce muscle mass and quality due to starvation and inactivity in elderly mice: ursolic acid in apple peel and tomatidine in green tomatoes. Both these compounds are believed to turn off genes activated by the harmful ATF4 proteins that is partly responsible for the age-related muscle loss and weakness. When this protein is expressed, it causes changes in gene expression so that protein synthesis is suppressed and protein degradation is elevated for muscle cells.
In their study, the researchers fed elderly mice with age-related muscle weakness and atrophy a diet either containing or lacking 0.27% ursolic acid, or 0.05% tomatidine for two months. The results of this study were significant. When the researchers measured the muscle mass of the elderly mice fed with either ursolic acid or tomatidine, they found that the mice increased their muscle mass by 10%, and their muscle strength by 30%.
These finding are significant as they can potentially increase the lifestyle and mobility of elderly people with muscle weakness and atrophy. The next step for the researchers is to continue their investigation in human clinical trial, and see if ursolic acid and tomatidine have the same effect in elderly humans as they do in mice. Ursolic acid and tomatidine can furthermore be developed into pharmaceutical supplements than can help with muscle strengthening.
Julia He
