Scientists from the University of Iowa have found that apples and green tomatoes both contain substances that can help reduce muscle weakness and restore lost muscle mass.
Most people experience muscle mass and strength loss in their old age, due to depletion of a protein called ATF4. This protein is responsible for binding DNA, elements, and CREB-like proteins. It changes the information of genes typically observed in the muscle wasting common in older people.
The recent study finds that ursolic acid in apple peel and tomatidine in green tomatoes starve ATF4 levels in muscles, leading to an increase in muscle strength.
Over a period of two months, the research team fed a group of elderly mice suffering from muscle weakness and atrophy diets with 0.27 percent ursolic acid or 0.05 percent tomatidine. Another group of mice was fed a diet with lower or no levels of these substances.
The mice with the diet high in ursolic acid and tomatidine experienced a 10 percent increase in muscle mass and a 30 percent increase in muscle strength.
While well-known for its presence in apple peels, urolic acid is a phytochemical also present in grape skins, cranberries, holy basil, licorice, yerba mate, and stinging nettle. It also is being investigated for its anti-cancer therapeutic potential and antiglycative protective effects for individuals suffering from diabetes.
Tomatidine is a steroidal alkaloid found in the skins and leaves of tomatoes. This small molecule has antibacterial properties and stimulates signaling and anabolism, leading to accumulation of protein and mitochondria, eventually resulting in cell growth.
The recent University of Iowa study was done in collaboration with Emmyon, Inc., a UI-based biotechnology company. They are now working to translate ursolic acid and tomatidine into foods, supplements, and pharmaceuticals that will help preserve and recover muscle strength and mass as people age.