Strong support for a basic diet

Body builders and grannies take note: To preserve muscle, eat salads.

A new study by researchers at the federal Human Nutrition Research Center on Aging, at Tufts University in Boston, finds that diets rich in potassium appear to protect muscle. And fruits and veggies are a primo source of dietary potassium.

Bess Dawson-Hughes and her colleagues recruited nearly 400 men and women for a 3-year dietary trial on calcium and vitamin D. The researchers wanted to keep bones strong, so the participants—all 65 or older—would suffer fewer falls and disabling fractures. However, strong muscles also help prevent falls, and those muscles usually begin a seemingly inexorable wasting by age 40 (SN: 8/10/96, p. 90).

So the researchers correlated the amount of muscle with other components of the participants’ diets—and found a strong link to potassium. The more of it individuals consumed, the more muscle they had, all other things being equal, report the researchers in the March American Journal of Clinical Nutrition. Seen in people eating the most potassium, the protective effect appears to “be enough to offset a good chunk of, if not all of, the age-related decline in muscle that normally occurs,” notes Dawson-Hughes.

It boils down to pH (level of acidity). The body converts protein and cereal grains, major parts of the U.S. diet, to acid residues. Excess acid triggers breakdown of muscle into components that ultimately make ammonia, which removes the acids. Potassium-heavy diets, being alkaline, can buffer those acids without sacrificing muscle.

Janet Raloff is the Editor, Digital of Science News Explores, a daily online magazine for middle school students. She started at Science News in 1977 as the environment and policy writer, specializing in toxicology. To her never-ending surprise, her daughter became a toxicologist.

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