It is a simple fact. As we age we lose muscle and strength. There's even a medical term for this — sarcopenia. It's derived from the Greek words "sarcos" (flesh) and "penia" (lack of).
Estimates of how much muscle is lost with age vary from 8 percent to about 50 percent of our muscles. Men seem to lose muscle faster than women. Strength is lost more rapidly than muscle.
Why is this important? When muscles get smaller, they get much weaker. Loss of strength is consistent with loss of mobility and independence, and the need for institutional care.
Although loss of muscle and strength with age is inevitable, there's interesting nutrition research that shows promise in slowing the progression. Protein intake — amount, type and timing through the day — seem to play a role.
Currently the Recommended Dietary Allowance (RDA) for protein is 0.8 gram per kilogram (g/kg) of body weight a day for men and women 19 years of age and older. This RDA was set in 2002.
Newer research is showing that higher levels are needed for adults age 65 and older. Between 1 and 1.2 g/kg a day seems to be the target for healthy adults. Those with sarcopenia may need 1.2 to 1.5 g/kg a day.
Studies show that 12 percent of men and 24 percent of women over age 70 eat significantly less than 0.8 g/kg a day. These higher recommendations do not translate into a lot of extra protein.
To figure out how much protein you'd need, take your weight in pounds and multiply it by 0.45. Then multiply by 1.2 to reach the recommended grams of protein per day. For a person who weighs 200 lb (90 kg), this would equal about 108 g of protein daily. Most meat, poultry and fish have about 7 grams of protein in an ounce. One cup of milk or one egg has about 8 grams.
The type of protein you eat also seems to play a role in preventing muscle loss. Dietary protein is made up many types of amino acids. The amino acid leucine has been shown to preserve body muscle. Leucine is found in higher amounts in animal foods: beef, lamb, pork, poultry, fish, eggs, milk and products made with milk. It's also found in soybeans and, to a lesser extent, other beans, nuts and seeds.
The best timing to eat protein remains a question. It's been shown that eating foods that contain protein throughout the day stimulates development of muscle. However, dietary habits show that most protein is eaten later in the day. The quantity of protein eaten — not the pattern of intake — has also been shown to be important in preserving muscle.
What's my take away? It doesn't take much more protein to achieve the higher goals. Eating 3 to 4 ounces of lean meat, poultry, fish, soy products, beans or legumes at each meal along with a cup or two of lower-fat milk daily can get you in the ballpark.
If your appetite isn't up to speed, or if you get full quickly, have smaller meals and snacks that have protein. Eat protein first, and eat processed carbs last (if at all). It can do your body good. Don't forget that weight-bearing exercise is just as important as protein in maintaining muscles.
May 01, 2015
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