Protein is made up of building blocks called amino acids. The amino acids are strung together into longer chains like beads on a string. Each amino acid is joined to the next by strong peptide bonds. When you consume dietary protein, your stomach breaks the peptide bonds and your intestinal tract absorbs the amino acids into your bloodstream. From there, your muscles, can use the amino acids to build new muscle protein and for muscle repair. Of course, amino acids are used to make other proteins too, but we’ll focus on muscle protein.
Thank goodness we have amino acids to repair our muscles after a workout, as a workout creates micro-tears in muscle fibers that must be mended. Muscles are in a constant state of turnover. Old muscle is broken down and new muscle built under the influence of a variety of hormones and signaling molecules. Muscle turnover is impacted by factors such as age, diet, and physical activity. But your body doesn’t keep around what it doesn’t need. If you stop exercising, you no longer require that thick layer of muscle, so you’ll lose some muscle tissue. In that case, you would break down that muscle tissue.
Most concerning for muscle health would be an accident or illness that forces you to stay on bedrest for weeks at a time. During extended bed rest, muscle loss can be substantial, especially in the elderly, who already may be in a catabolic state. An older adult confined to bed due to trauma or illness can lose enough muscle mass that recovery will be difficult. Many older adults are already sarcopenic and losing more muscle mass can be catastrophic. During periods of long inactivity, most of the muscle loss is from the lower body. So, it’s not surprising that older adults confined to bed experience problems walking and carrying out functional activities after a hospital stay.
Maintaining Muscle Mass
Older adults who are laid up in bed often can’t exercise, so they have to depend on nutrition to help maintain as much muscle as possible. This includes protein. Recommendations are that healthy adults consume 0.36 grams of protein per pound of body weight each day. However, there’s evidence that healthy, older adults benefit from more and an adult at risk of losing significant muscle mass due to illness need as much as double this amount. Most older adults, especially bed-ridden ones don’t get this quantity of dietary protein. So, it’s not surprising that they emerge from bedrest frailer than they were before. Protein helps alleviate some of the muscle loss.
Does the type of protein older adults get matter? A study from McMaster University in Canada suggests that whey protein is the best form for seniors who are confined to bed. In the study, the researchers compared whey protein to collagen protein in older adults. They recruited older, non-diabetic adults between the ages of 65 and 80. For five weeks they asked the participants to consume a low-calorie diet (calories were cut by 500 kcals daily) and walk no more than 750 steps per day. These changes are similar to what an older adult in the hospital might face. One group consumed whey protein and the other collagen protein.
At the end of five weeks, both groups lost a similar amount of muscle, irrespective of the type of protein they consumed. But, when the adults returned to their normal activities, the group that consumed whey protein regained muscle faster. So, at least in older adults who aren’t active, whey protein may be a better alternative than collagen protein.
Why was whey protein superior in the study? Whey is a protein derived from dairy. It contains all the essential amino acids the body needs but can’t make. In contrast, collagen peptides, the type used in the study, is an incomplete protein. It lacks one or more amino acids that the body needs but can’t manufacture on its own. It’s also low in leucine, a branched chain amino acid that helps jumpstart muscle growth. In fact, it’s the “head honcho” for turning on muscle protein synthesis through a pathway called the mTOR pathway. Muscle builders are aware of this. In fact, some bodybuilders take branched-chain amino acids in supplement form to boost how much leucine their muscles are exposed to. Seniors need it too to help them get back on their feet.
Whey Protein and Muscle Health
Whey protein helps seniors preserve and even gain muscle even when they don’t exercise. In a study, two groups of older men took a whey protein supplement or a placebo. During the first 6 weeks, they didn’t exercise. Despite not exercising, the guys gained modest amounts of muscle. Then, they took part in a 12-week exercise program that involved twice weekly resistance training and HIIT while continuing the whey or placebo. The men who took the whey and exercised gained even more muscle mass.
The advantage of whey, as mentioned, is its higher leucine content. In a study in rodents, older rats had a decreased response to leucine and its signals to boost muscle protein synthesis relative to younger rats. This is similar to the anabolic resistance that older humans experience. The older rats require greater quantities of leucine to turn on the synthesis of new muscle protein. The same appears to be true in older humans. Consuming more leucine, of which whey is an excellent source, helps overcome anabolic resistance and boost the body’s ability to make muscle proteins.
The Bottom Line
Older adults need more protein and whey protein is a good choice because it contains leucine and other branched-chain amino acids. Plus, studies show whey also modestly boosts immune function after a workout. That can be helpful for seniors as well. It’s possible to get sufficient protein from food alone, but for older adults who are bedridden, whey protein is a good option. But it’s important for everyone of all ages to get enough protein.
Today’s Dietitian. “Study Suggests Whey Protein Best for Seniors Rebuilding Muscle”
Curr Opin Clin Nutr Metab Care. 2010 Jan; 13(1): 34–39. doi: 10.1097/MCO.0b013e328333aa66
Medical News Today. “What are the benefits and risks of whey protein?”
HealthLine.com. “Whey Protein Shakes May Help Build Muscle Mass in Seniors”
J Physiol. 2006 Aug 15; 575(Pt 1): 305–315.
J Int Soc Sports Nutr. 2014; 11: 61.
The American Journal of Clinical Nutrition, 2018; DOI: 10.1093/ajcn/nqy193.