Anyone who wants to increase muscle mass knows: the secret is to consume a lot of protein in the form of eggs, shakes and nutritional supplements combined with training in the gym. However, if you are getting older and have passed the age of 65, you may think that physical activity is no longer necessary to such an extent and that nutritional supplements are sufficient to maintain muscle mass and strength. In that case, we have bad news: according to studies published in the American Journal of Clinical Nutrition, protein supplements are not enough – you have to work hard if you want to preserve muscle mass.
It’s all the kidneys’ fault
Starting around age 40, muscle strength begins to decline as the kidneys begin to lose their ability to filter blood and efficiently excrete acids through urine. To compensate for this loss, the body begins to break down muscle tissue to release alkaline substances that neutralize the acid. We know from past studies that protein stimulates muscle synthesis and that increased protein intake combined with exercise increases strength. However, what no one has previously investigated is whether increased protein intake alone is sufficient to increase strength and muscle mass in already well-nourished older adults.
Not enough protein
To find out, the authors surveyed 141 people over the age of 65 in the Boston area, asking them to take pills containing either a placebo or whey protein, which was most effective at stimulating muscle growth. In addition, some participants also took potassium bicarbonate, an antacid, to see if acid neutralization promotes muscle recovery. After 24 weeks, nothing had changed: the participants’ strength remained unchanged, with or without potassium bicarbonate. The reasons are not clear, but the authors hypothesize that the changes in muscle mass were so subtle that the tests conducted could not detect them, or that, in the absence of exercise, the body did not know how to use the excess protein. In the future, study coordinator Lisa Ceglia would like to study the combination of exercise and protein supplementation to see if the two factors are more effective than exercise alone.
