To Your Health

Q. I am 55 years old and seem to be rapidly getting weaker with age, even though I'm exercising. Are there any specific nutrients that might help? A. Although progressive muscle weakness may represent a universal symptom of aging today, it should not be accepted as normal. A new word, sarcopenia, has recently begun popping up in medical texts and scientific research. It is probably as harmful as osteoporosis but less well known. The term "sarcopenia" is more descriptive than diagnostic. It simply means loss of muscle mass and function. Many factors, including reduced physical activity, decreased hormone levels, decreased protein synthesis, loss of nerve cells, and changes in mitochondrial activity may all contribute to sarcopenia. Fortunately, sarcopenia is partly reversible with appropriate exercise modification.

Muscle is one of the most metabolically active tissues in the human body, using a lot of calories. After age 45, loss of lean muscle mass accelerates, and this becomes the single most important factor in the gradual accumulation of body fat. Studies indicate that muscle mass declines by about 15% per decade in the 60s and 70s and even more rapidly after age 80. This dwindling of muscle occurs even in healthy individuals who exercise regularly, but it usually goes unnoticed because the body camouflages its loss by padding the affected areas with extra fat. Keeping a constant weight over time does not mean your muscle mass is not ebbing away. In one study of women in their 40s who maintained a constant weight over six years time, all lost some muscle mass, but those who went through menopause during this time lost six times more than those who did not.

There is consensus that sedentary people over 50 should begin an exercise program with strength training rather than aerobic training. Aerobic activity, such as walking or swimming, strengthens the heart but it should follow several weeks of strength and balance training. For more mature people the major health risks are immobility, falls, and fractures, which are all related to muscle weakness. Strength and balance training can help older adults build muscle and improve function so they can safely walk and do other aerobic activities.

Recent research provides evidence that chronic inflammation is one of the key reasons for the decline in muscle mass during the aging process. The blood concentration of interleukin-6, a marker for inflammation in the body, tends to increase with age. High levels of IL-6 predict the degree of disability in the elderly, and preliminary information indicates that IL-6 is associated with sarcopenia. If this is the case, there are a host of anti-inflammatory nutrients (see "To Your Health," June 20, 2003) with the potential to help prevent sarcopenia.

Rebuilding muscle mass requires protein, which older people sometimes do not readily digest and assimilate. Studies indicate that half of people over 60 don't consume an adequate amount of protein. For elderly adults this is 60 to 80 grams of protein daily. A clinical nutritionist can assist with ways to increase both the amount and the utilization of protein.

Our society protects older people from hard physical work, but that leads to problems such as sarcopenia. In the long run, physical activity helps older people maintain their good health.