NEW YORK - In a study in older adults, dietary intake of vitamins C and E was linked with muscle strength, leading the researchers to suggest at a meeting in Atlanta this past weekend that a diet high in antioxidants could play an important role in preserving muscle function in older adults.
"Muscle strength is really a marker of aging," one of the investigators, Dr. Anne Newman of the University of Pittsburgh, told Reuters Health. "Muscle strength starts declining when people are in their 40s, but it decreases dramatically after age 60."
This decline is "a major risk factor" for becoming frail and disabled, she said, but certain strategies may slow down the loss.
In previous work, Newman and her associates identified physical activity and, separately, dietary protein as important for maintaining muscle strength.
For their current study, to evaluate the potential benefits of micronutrients, the researchers asked more than 2,000 men and women in their 70s about their long term eating habits. They also measured participants' grip strength at the outset and two years later.
On Saturday at the Gerontological Society of America's annual meeting, the researchers reported a significant positive link between dietary intake of vitamins C and E and subsequent change in muscle strength, regardless of participants' initial strength levels.
At this point, it's not clear whether vitamins C and E specifically help preserve muscle strength, or if intake of these micronutrients is a marker of a healthy diet, Newman said. "Since they're in the food, they could be directly related, or they could be marking diets high in fruits and vegetables and low in sodium -- all of which would have beneficial effects."
The average daily dietary intakes of vitamins C and E in the study were 144 milligrams and 11 milligrams, respectively. "For vitamin E at least, our cohort's intake was on average a little lower than the recommended daily allowance," Newman pointed out. "So while it's possible to get enough of this micronutrient in the diet, you have to pay attention and be sure to include foods rich in that vitamin."
The team is trying now to determine "the optimal level of physical activity and optimal nutrients in the diet that will preserve muscle strength," Newman said.
Meanwhile, she added, the current findings provide "another reason for doctors to encourage patients to eat a balanced diet, rich in fruits and vegetables."
Newman cautioned consumers not to start taking high-dose supplement of vitamins C and E. "In clinical trials with very high doses of antioxidants, you don't see any benefits and in some cases, they're potentially harmful," the researcher said.