Essentially, there are two things. First, protein turnover occurs and when protein breakdown supersedes protein synthesis, you lose muscle (which makes sense). Second, stimulating protein synthesis is a bit more difficult as you age. From what we know, stimulating the process of building new proteins requires a threshold; a threshold of protein and leucine.
For example, in young individuals, around 20-25 grams of high quality, bioavailable protein with 2-4 grams of leucine will stimulate protein synthesis. For older individuals however, it seems that even though protein synthesis can be stimulated, the actual response is lower. This means that for any given amount of protein, the muscle building response will be lower for older individuals. Thus, it makes sense that the first line of defense might be to simply increase the amount of protein being consumed during each meal or snack, to essentially overcome this decrement.
In this image, we see the protein synthetic response to just 20g of protein in both young and elderly individuals. As you can see, elderly still have the ability to stimulate protein synthesis, but the reaction is much lower. For younger individuals, the muscle building response to a given amount of protein is higher, compared to elderly consuming the same amount.
Essentially, this means that as you age, the response to protein diminishes and becomes weaker than when you're young. This means that ingesting higher amounts (like 40 grams instead of 20 grams) is probably adventageous for older individuals looking to stave off age-related muscle loss.
Eating Protein Before Bed And The Elderly
In response to the fact that with age, muscle loss occurs and protein synthesis decreases, a team of researchers tested how pre-bed protein ingestion might affect protein synthesis. Further, considering the fact that protein synthetic responses to food might diminish with age, they had multiple groups of varying protein ingestion amounts to observe any differences.
In this study, 48 older mean (mean age = 72) were randomly placed into 1 of 3 different testing groups.
Shortly after consumption, the subjects went to sleep while getting blood drawn (without waking) at regular intervals throughout the night to assess how their body's responded to the different protein amounts.
Essentially, this setup allows the researchers to first, observe how different dosages of protein influence protein synthesis and second, whether or not leucine is the major driver (group 3). This allows them to observe if the age-related decline is more associated with the total amount of amino acids present, or if it's an issue of stimulating the process in the first place.
The results showed that by and large, having a higher dose of protein before bed and even just a protein source, regardless of amount was beneficial in terms of stimulating the processes that prevent muscle loss
In these graphs, we see levels of amino acids that are in the blood, available to be used for building new proteins. As you can see, amino acid availability was highest and lasted the longest when 40 grams of protein were consumed.
In response to ingesting protein, it seems pretty cut and dry that at least consuming 20 grams of protein before bed time is very adventageous for older individuals looking to potentially reduce age-related muscle decline. Even further, when protein amounts were increased to 40 grams, protein synthesis was significantly higher, breakdown was lower and net balance (protein turnover) was overwhelmingly positive, meaning that synthesis was greater than breakdown.
Considering the findings, it seems quite clear that ingestion of some form of protein, at least casein in this case, can be quite beneficial for older individuals looking to reduce age-related muscle loss. While 20 grams will be better than nothing, it seems that having a higher amount is a bit better of an idea, simply because it's more effective.
If you have an elderly relative or friend, or happen to be in a position of providing advice to the elderly, suggesting that they begin using some form of protein supplement before bed may be extremely valuable in helping them retain their muscle mass and function. This could be further compounded if they decide to also use a resistance training protocol as well.
Why This Should Matter To You
Age-related muscle decline is a very real issue, and not only for males. While resistance training is one of the best ways to combat this issue, the simple act of consuming a protein shake is a bit easier and likely easier to get your grandparents to comply. Just the simple act of consuming protein before bed, regularly could be the difference between elderly individuals being able to take care of themselves, or potentially even prevent a future injury.
Considering the nature of the intervention in this study, the results are extremely relevant and fairly easy to employ for just about anyone.