Preventing Age-Related Muscle Loss: The Importance of Protein

by Nils Osmar. March 25, 2022

In a recent talk, Professor Gordon Lynch addresses a key question facing people who are getting older, i.e., how to preserve muscle mass and health as the years go by.

Lynch zeroes in on the key elements we need to think about, including:

Strength training
Aerobic exercise
Getting adequate protein
Getting enough of the amino acids leucine and glycine

According to Lynch, many older people actually need more protein, more leucine, and more glycine than is usually present in the diet to support muscle synthesis and prevent sarcopenia.

Re: strength training, he points out that exercise is key, but that as we get older, we may need lower the intensity of the exercise, as in more repetitions with less weight to prevent injury. The emphasis, in his opinion, should be on our ability to generate force and power, not necessarily about muscles becoming larger.

We Need More Protein, not Less, As We Age

Not getting enough protein is a significant problem for older people, both in the world at large, and in the anti-aging community. As Lynch mentions, low protein diets are a major driver of sarcopenia.

But what about mTOR?

Trying to optimize our protein consumption can be tricky for people interested in life extension, because eating a low protein diet (or a diet low in the amino acid leucine) is one proven strategy for life extension. Protein activates an enzymatic pathway called mTOR, which many people interesting in longevity view as being problematic. Low calorie, low protein and low leucine diets tend to activate AMPK, not mTOR, and are all associated with prolonged lifespans in lab animals.

But going overboard in the direction of too little protein or too little leucine is a prescription for frailty and for spending out last few years in a nursing home.

This has been observed in animals as well as people. The animals in lab studies showing an association between low protein and life extension do tend to live longer, but often at the cost of increased frailty and susceptibility to disease. This is somewhat masked because they’re protected from exposure to random diseases while in the lab.

Finding the Right Balance

I’ve personally known people who were committed to extreme life extension who started cutting their protein to the bone hoping to keep AMPK activated full time.

They went from the reasonable idea that “we need to balance the activation of mTOR and AMPK” to the more extreme notion that “mTOR is bad and AMPK is good”, quit eating leucine, cut protein from their diets, and begun losing muscle mass. They were actually courting age-related sarcopenia by lowering their protein so far that they were taking in too little to maintain health.

Making sure we’re getting enough protein, while doing weight training, will at least slow down the onset of sarcopenia. There’s no evidence, unfortunately, that optimal nutrition and exercise will totally prevent sarcopenia. It’ll take more extreme anti-aging interventions to accomplish that. But they will postpone it.

My thoughts

I think that optimal nutrition is key to living a healthy long life.
This may mean eating a “mostly” Mediterranean diet, but one that provides more protein than that diet usually does – particularly if we’re also working out and trying build muscle and prevent the onset of sarcopenia.
I’m not saying we have to eat massive amounts of protein, but we do need to make sure we’re getting enough.
It would be nice if there was a consensus about how much we should be eating at different ages. Even governmental authorities differ greatly in their recommendations. On the low end, some advocate eating 1/3 of a gram of protein per gram of body weight; but others recommend eating 1 gram per pound of lean (ideal) body weight, or 1 gram per centimeter of height.
Even Dr. Valter Longo, an advocate of eating very low protein diets to keep mTOR low and keep AMPK activated, has spoken recently of the importance of greatly increasing our percentage of protein after we reach 65, and greatly increasing it after the age of 70 or 80.
One person who advocates eating even more protein is Dr. Gabrielle Lyon. Lyon’s patients are mostly in their 70s and 80s, and she’s seen the devastating results of getting insufficient protein in folks in this age group. She views muscle as the organ of longevity and believes it needs to be prioritized if our goal is anti-aging. I’m not necessarily endorsing her recommendations, but I do think the points she makes need to be addressed and considered. See the article below for a summary of her thinking and her POV on this question.