Simply put, we become less able to synthesize muscle protein as we age.
Adults over the age of 50 require a higher protein intake in their diet if they
want to maintain muscle mass than adults in their 20s, 30s or 40s. And they
also require more protein in their post-workout meal if they want increase
And, unfortunately, many older adults are simply not getting that extra protein
in their diet. They tend to eat smaller meals and often avoid meats because of
The result is that they lose muscle mass year after year until the simple act of picking up a grandchild or a sack of groceries represents a struggle. And because of the loss in muscle mass they become unsteady on their feet and prone to falls.
I’ve talked about this previously in my health tip “Protein Needs Increase
As We Age”, which is archived at http://www.chaneyhealth.com.
It also turns out that the naturally-occurring amino acid leucine is an
important ally in the battle to maintain or increase muscle mass in older adults.
In addition to its role as a protein building block, leucine specifically stimulates muscle protein synthesis.
As part of a diet providing adequate protein, leucine has been shown to help
maintain muscle mass in older adults and help increase muscle mass in adults
who are doing weight bearing exercises.
And, it’s not just older adults who benefit from leucine. It has also been
shown to help maintain muscle mass on low calorie, weight loss diets.
I’ve described these effects of leucine in more detail in my health tips
“Protein Needs Increase As We Age” and “The Importance of
Leucine”, which are archived at http://www.chaneyhealth.com.
The study that I am discussing today (Casperson et al, Clinical Nutrition,
doi:10.1016/j.clnu.2012.01.005) takes the leucine story one step further.
In this study the researchers asked the question of whether leucine
supplementation would help older adults maintain muscle mass even if they did
not work out or change the rest of their diet to increase protein intake.
They enrolled 8 healthy, but sedentary, older adults with an average age of 68
into the study. The study specifically excluded any adults who were working
out. The subjects were given 12 grams of leucine every day for a two week
period and told not to make any changes to their normal exercise and eating
On the day before and the day after the two-week leucine supplementation they
were given a test meal containing 7 grams of essential amino acids and 10 grams
of sucrose dissolved in a diet soda. The researchers designed this “meal” to be equivalent to approximately a half a chicken breast and a half cup of rice, which they considered to be a typical meal for someone in that age group. (I don’t know about you, but I would have preferred the chicken and rice).
The researchers then took a series of muscle biopsies over the next several hours
and measured the percentage of the amino acids from the test “meal”
that were incorporated into muscle protein (something called “mixed muscle
fractional synthesis rate” or FSR).
The results were pretty clear cut. Two-weeks of leucine supplementation significantly increased the FSR following ingestion of the test “meal”. The researchers concluded that “The amino acid leucine may help older people synthesize muscle in reponse to lower protein diets”
So what is the bottom line for you?
1) While this study suggests that supplemental leucine may be able to help
preserve muscle mass even in sedentary older adults consuming a relatively low protein
diet, previous studies suggest that the extra leucine will be even more
effective when the protein intake is also increased.
I personally prefer a holistic approach rather than just looking for the one
magic “pill” that will take care of everthing. My recommendation
would be to work out on a regular basis and consider a protein supplement
containing the extra leucine to make sure that protein intake is also where it
needs to be.
2) We also need to remember that the test “meal” was pretty high in
protein. Leucine supplementation is unlikely to help build muscle mass
following a muffin and coffee for breakfast or a salad for lunch.
To Your Health!
Dr. Stephen G Chaney
Please share how you you keep your muscle mass.