Anabolic Eating For Your Age
By Layne Norton/11-03-11/MD.COM

“Young men think old men are fools; but old men know young men are fools.”

—George Chapman (1559-1634)

Much has been written about nutrition in the pages of MD over the decades. I’m sure many readers who began reading when they were teenagers are now entering their 30s and 40s. Countless pages have been devoted to describing nutritional protocols to maximize gaining muscle and losing fat. But I submit to you that we have all been fools— not just the young as George Chapman implies. There are fundamental metabolic differences between age groups— yet most nutritional recommendations for maximizing muscle don’t take age into account! In this young fool’s opinion, it’s time we all examined optimal anabolic eating for YOUR age, addressing each of the macronutrients.

Protein

We might as well get the big issue of protein intake out of the way first. If you read MD, you know high-protein meals increase muscle protein synthesis and this builds more muscle. The question is, how does age affect this anabolic response to protein? Research suggests that younger individuals are very sensitive to the anabolic effects of amino acids.1-3 However, as we age, we become less sensitive to the anabolic effects of amino acids.

Several researchers have shown that comparatively large doses of amino acids are required to maximize the anabolic response in the elderly, as opposed to the young subjects.1,2,5-9

It appears the decreased response in the elderly may be explained by a decrease in the muscle cell content and activity of mTOR and p70S6K, two kinases involved in directing protein synthesis.2,5 According to this research, older subjects require a greater amount of amino acids, specifically leucine (the amino acid responsible for stimulating protein synthesis), to maximize protein synthesis, as opposed to younger subjects.7-9 Furthermore, it appears that the decreased anabolic response in the elderly may be due, at least in part, to increased production of reactive oxygen species (ROS) with age.

ROS has been shown to decrease mTOR activity and inhibit protein synthesis.10 But there is hope— it has been demonstrated that supplementation with a combination of antioxidants (rutin, vitamin E, vitamin A, zinc and selenium) restores the anabolic effect of a meal to the same level as the young!11 So make sure you eat plenty of protein that is high in leucine (e.g., whey) and keep room in that pillbox of yours for some antioxidants, Grandpa!

Protein Recommendations:

<20 years old: 0.7-1 grams/pound bodyweight

21-40 years old: 0.9-1.2 grams/pound bodyweight

41-65 years old: 1.1-1.4 grams/pound bodyweight

>65 years old: 1.3-1.5 grams/pound bodyweight