Protein Are you getting enough?
You are probably aware that dietary protein is important for stimulating muscle growth (through muscle protein synthesis, or MPS) and optimal recovery from training. But how does age affect this anabolic (muscle-building) response to protein?
Research suggests that younger individuals are very sensitive to the anabolic effects of amino acids. The old cliché of a young man who can seemingly put on muscle just by looking at a steak? Yeah, there’s probably something to it. The opposite might also be true, as several researchers have shown that comparatively large doses of amino acids are required to maximize the anabolic response in older individuals.
Why is this? It appears the decreased response may be explained by a decrease in the activity of the protein mTOR and the enzyme p70S6K, both of which are involved in initiating protein synthesis. Furthermore, it appears that the decreased anabolic response in the elderly may be due, at least in part, to the natural increase in oxidative stress that accompanies aging. Oxidative stress is the type of damage that all those antioxidants are meant to mitigate. As levels of certain molecules known as “reactive oxygen species” go up, levels of protein synthesis go down.
There is hope, however. Consuming a diet rich in protein—specifically, the amino acid leucine—can help prevent the age-related decline in muscle protein synthesis.
Muscle-building protein recommendations by age:
- < 18 years: 0.6-0.8 grams per pound of body weight
- 19-40 years: 0.8-1.1 grams per pound of body weight
- 41-65 years: 1.1-1.3 grams per pound of body weight
- > 65 years: 1.3-1.5 grams per pound of body weight
Even if you don’t measure out your protein to the gram, the lesson here is that as you age, you need more protein. If you can have it with antioxidant-rich foods, all the better. You can’t go wrong with a diet rich in meat, vegetables, fruits, nuts, and seeds here.