Keeping your strength up

It's all too common to see a loss of skeletal muscle mass in the elderly, a condition known as sarcopenia. It's a strong risk factor for both disability and mortality. We also know, from studies in the young, that magnesium supplementation can help increase muscle strength, and that the elderly tend to be magnesium-deficient. Scientists in Palermo, Italy wondered if the two, magnesium deficiency and muscle strength, might be related in the elderly as well as the young (Am J Clin Nutr 2006;84(2):419-26).

To find out, a team from the Department of Internal Medicine and Geriatrics at the University of Palermo recruited 1,138 men and women, of whom 77% were over 65 years of age. None of the participants had kidney disease, cognitive impairment, or hypercalcemia (overly high blood calcium levels). Their Body Mass Index, level of exercise, muscle area, and muscle density were recorded, along with age and sex, as variables.

Each participant's strength was tested at four different points: handgrip strength, knee extension, single leg extension, and ankle extension, and their blood was tested for serum magnesium levels.

Even after adjusting for age, sex, and BMI, the researchers found that physical strength was highly correlated with serum magnesium levels: the stronger the subject, the higher the blood levels of magnesium.

What this means for you:

The typical Western diet is often magnesium-deficient, and other studies have shown that magnesium intake decreases with age. Magnesium deficiency can also cause irregular heartbeats. The Recommended Daily Allowance of magnesium is 320mg for women and 400mg for men. Make sure you're getting enough magnesium in your diet by referring to this list of foods containing magnesium.

First posted: September 1, 2006