Protein: Recent Research on Maintaining Muscle Mass

I get asked a lot about protein in and outside of the workplace. I’ve done a couple of posts on protein thus far (check them out here and here). In order to avoid repeating myself, I’m going to explore protein in a slightly different light: how to consume protein to maintain muscle mass throughout life and into older adulthood.

Protein Basics: Are We Getting Enough?

Our muscles are constantly in balance between anabolism (growth) and catabolism (breakdown). It is the net effect that dictates muscle gain vs. loss over time. For anabolism to take place, we need to fuel muscles with protein and exercise.

Are we getting enough? According to the 2004 Canadian Community Health Survey, ~ 99% of Canadian Males and Females aged 19-70+ met acceptable macronutrient distribution range (AMDR) for protein. This is great! However, does this seem too good to be true? Maybe. The problem? The AMDR = 10-30% of calories from protein. This means that this data does not express the absolute intake of protein, and instead expresses a wide range of intakes.

Several groups now calling for higher DRI’s:
• EUGMS/PROT-AGE study group recommendations (Bauer et al, 2013):
• ≥ 1.0-1.2 g/kg/day for all older adults
• ≥ 1.2 g/kg/day for exercisers/active individuals
• 1.2-1.5 g/kg/day for acute or chronic diseases

So, there is a possibility that we actually need more protein than we’re getting now. However, we need to pay attention to more than just the amount of protein to maintain muscle mass, according to some new research.

New Research

• Several studies suggest that protein timing plays increasingly important role in maintaining muscle mass.
• Paddon-Jones and his team have been investigating how North American eating habits pertaining to protein affect the maintenance of muscle mass during aging. After giving subjects a 30-gram serving of protein and measuring how their muscles responded over the next four hours, they found that aging doesn’t inevitably impair our ability to turn dietary protein into muscle.
• While a moderate amount of protein (30 grams/meal) can increase muscle protein synthesis, there may be a ceiling effect. For most adults, consuming more than 30 grams/meal provides additional energy, but it isn’t likely to provide further increase in muscle protein synthesis.
• When young adults halve their protein intake at mealtime, their muscle protein synthesis is reduced by approximately 50%.

Unfortunately, North American distribution of protein is skewed – most protein is consumed at supper and less at breakfast and lunch. This eating pattern fails to maximize muscle growth and repair. We get the greatest benefit by distributing protein evenly across meals: about 30 grams at each meal. Perhaps the AMDR should be changed from a daily model to a per-meal model, as it does not accurately reflect this 30-30-30 notion.

Make sure to emphasize high quality protein at meals. Try to ramp up your breakfast protein intake by consuming milk, greek yogurt, cottage cheese, eggs, salmon, sardines, chicken, ect.  Supplements, including breakfast drinks, meal replacement supplements, and protein isolates may be a valuable option, in terms of both protein content, and convenience. However, try to meet your protein needs through food first!

In addition to protein, other key nutrients, including vitamin D, magnesium, and possibly omega-3 fatty acids, could play a role in the health of the muscle, and in healthy and successful aging.

Happy Aging!