Muscle Mass and Aging

Muscle Atrophy and Aging

Last week we explored how apples, Fuji for example, have ursolic acid and how eating those apples, including the peel where most of the ursolic acid resided, contributed to a lowering of triglycerides and a tendency to gain weight.

There is another side to ursolic acid that is part and parcel of its calorie redistribution. It helps muscles grow. The research was done in lab rats, where consumption of ursolic acid was shown to increase skeletal muscle mass, fast and slow muscle fiber size, grip strength, and exercise capacity.

As you can imagine, the body-building community is interested in this topic and research labs have jumped in to see if there are credible human results. Imagine a study in which 9 young men do a standardized exercise program, take leucine or ursolic acid, and then submit to a muscle biopsy to see if changes can be observed. That study showed marginal effects of ursolic acid but the amino acid leucine appeared to be beneficial in humans.

How does leucine fit? Leucine is one of our amino acids central to signaling to build muscle. Considering that you will lose some 40% of muscle mass when you have an episode of prolonged immobilization or underuse, rebuilding muscle after a prolonged illness is an important topic. Think over your own lifetime and consider when you spent a week or two down for the count and not able to exercise. Or how about 6 hours in front of the TV watching inane programs that mesmerize you with their content? Your only exercise is standing to go to the fridge for more food, or cheering when your team scores.

The combination of the two, ursolic acid and leucine might just be the ticket to building better muscles. Considering that aging by itself makes us lose about 1.5% per year of our muscle mass over age 55, some strategy to avoid that is key. With that idea in mind, a recent randomized trial from Brazil of 28 men doing an eight-week muscle-building program showed no benefit to the addition of ursolic acid, but good effects with leucine. Shucks. But that's where it stands.

www.What will Work for me. Leucine works. The best research says you need about 55 mg/kg/day or about 500 mg for a 200-pound man. The supplement HMB is a metabolite of leucine that also makes that stimulation. It is widely sold for its muscle-building capacity. Ursolic acid works in lab rats but here is a word of caution. Humans are different than lab rats, and the real problem is that we are living way past our biological/reproductive age. Nature starts to shut us down over age 50, and our challenge is to negotiate strategies that get us around that. I have a hunch that the extra protein older folks need is first in line. Then, peptides that stimulate growth hormone, mTor agonists and urolithin may be what we are left with. And the gym. Shoveling mulch once a year isn't enough. Sitting on a lawn mower doesn't qualify either. Pickleball might suffice. Leucine and extra protein for anyone over age 60 is likely in order, along with the gym.

References:J Physiology, Jr Nutrition, Foods, PLOS 1, Int Jr Molecular Medicine, Int Soc Sports Nutrition, Clinical Nutrition, Advances in Nutrition,Jr of Nutrition, Jr Cachexia and Sarcopenia,

Pop Quiz

1. As we age, what happens to our muscle mass?                   Answer: It shrinks by 1.5% per year.

2. What does extra protein do to reverse that?                  Answer: Helps, probably because you then get extra leucine.

3. What does leucine do for muscles?                    Answer: Stimulates growth.

4. If you are sick in bed for a month, how much muscle mass did you lose?                 Answer: Up to 40%.

5. If you spend 6 hours on the couch every day watching TV, what's happening to your muscles?           Answer: Come on, you know the answer. It's not good.