Think only twenty-something bodybuilders need to worry about their protein intake? Think again. A small study published this month in the American Journal of Physiology: Endocrinology and Metabolism reveals that you might want to double the recommended daily amount of protein you’re eating as you age.
Protein is essential for building and maintaining muscle. But as you get older, you’ll naturally start to lose some of your muscle mass and strength due to a combination of factors—less physical activity, diet, and changing growth hormones. This can affect your balance and gait, leading to a greater risk of fall and fractures. Yet, scientists are beginning to discover that this type of physical decline in old age may not be as inevitable as we once thought. And one secret weapon to longevity and strength could be the amount of protein you’re eating.
Previous guidelines established by The Institute of Medicine recommend that adults consume .8g/kg of protein per day. This means a 140-pound person would require 50 grams of protein, roughly the equivalent of a whole chicken breast.
“The RDA [recommended daily amount] represents the lowest amount of protein that can be eaten to avoid symptoms of deficiency in most normal individuals,” says study author Il-Young Kim, PhD, research instructor in the Department of Geriatrics at the University of Arkansas. Hitting those levels is clutch because protein can curb your appetite and prevent weight gain, while also keeping your bones, skin and blood in tip-top shape. But it turns out we may have been underestimating how much protein seniors really need.
How much is enough?
For their study, researchers analyzed a group of 20 men and women, ages 52 to 71, over the course of four days. Each individual was randomly assigned to one of four test groups and given prepared meals for the duration of the study.
Ten individuals ate 0.8g/kg of protein a day, the current recommended daily amount. Half of those participants ate an uneven distribution of protein throughout the day (15% at breakfast, 20% at lunch and 65% at dinner). The other half spaced out their consumption evenly throughout the day (one-third at breakfast, lunch and dinner).
In another group, 10 individuals ate 1.5g/kg (0.7 g/lb) of protein a day—or twice as much as the current recommended daily levels for that age group. To help them hit this higher level of protein intake, researchers supplemented participants’ diets with milk protein concentrate. Half of these participants also consumed protein at uneven levels throughout the day, while the other half divided their protein consumption equally between meals.
Powered by protein
At the end of the study, the participants who ate twice the recommended daily level of protein experienced significantly greater levels of muscle protein synthesis and net protein balance, two important factors in muscle mass. Protein synthesis reflects the rate of production of new muscle protein, says Dr. Kim.
Surprisingly, the percentage of protein intake per meal did not have a significant effect on protein synthesis, though previous studies have shown that an even distribution of protein across meals was more beneficial.
While there’s no simple answer to why muscle mass decreases as someone ages, this study adds to a body of research investigating ways to boost longevity and strength in older adults. And one thing is clear: “Our results are consistent with a large and growing literature that the optimal level of protein intake is greater than the RDA for all adults,” says Dr. Kim.
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