Interesting study re protein supplementation and muscle loss

Azdak
Azdak Posts: 8,281 Member
in Fitness and Exercise
Skeletal muscle disuse atrophy is not attenuated by dietary protein supplementation in healthy older men, by Dirks, Wall, Nilwik, Weerts, Verdijk, and Van Loon, in The Journal of Nutrition, 2014

This study investigated whether protein supplementation could lessen the muscle loss experienced during inactivity.

23 healthy, older men (avg age 69) had one leg immobilized in a cast for 5 days. During that time 1/2 received a protein supplement of 20.7 g twice a day. The other 1/2 did not receive a supplement.

After 5 days, studies of muscle loss and maximal quadriceps muscle strength showed no significant difference between the supplement group and the control group

Like all studies of this type, the sample size was limited, and so this does not provide a definitive answer, but it does fit the idea that protein by itself does not "build muscle". Training builds muscle--you just need sufficient protein to supply the building blocks.

For the average person, 1.2-1.4 g of protein per kilogram of body weight is probably sufficient--either to build muscle or to conserve lean mass while on a weight loss program. Recommendatons that are higher than that amount are usually taken from recommendations for athletes and range from 1.4 to 2.0 g per kg body weight.

Replies

  • wild_wild_life
    wild_wild_life Posts: 1,334 Member
    Interesting, thanks for posting. Makes sense that protein might not automatically "go" to muscle that is not being used. I don't know what their baseline intake was, but there are plenty of other uses for protein that the body probably sees as higher priority than muscle that is not being used. Good reminder of the importance of activity and mobility in aging.
  • johnwhitent
    johnwhitent Posts: 648 Member
    Nice when science and logic agree!
  • Cherimoose
    Cherimoose Posts: 5,208 Member
    Not so fast. Atrophy is only just beginning after 5 days. So a 5-day study is rather useless for determining long-term results. I would want to see a 1 or 2 month study. Preferably with people who are not immobilized. It's possible that light use of a muscle + protein helps reduce atrophy, who knows. Until such a study is done, this is just confirmation bias.

    https://en.wikipedia.org/wiki/Confirmation_bias
  • Azdak
    Azdak Posts: 8,281 Member
    Not so fast. Atrophy is only just beginning after 5 days. So a 5-day study is rather useless for determining long-term results. I would want to see a 1 or 2 month study. Preferably with people who are not immobilized. It's possible that light use of a muscle + protein helps reduce atrophy, who knows. Until such a study is done, this is just confirmation bias.

    https://en.wikipedia.org/wiki/Confirmation_bias

    You are welcome to put YOUR leg in a cast for 2 months and report back to all of us. :laugh:

    All studies have limitations--the legitimate ones--like this one--acknowledge those limitations. No one study provides absolute proof of anything, and nowhere in the study did the authors suggest otherwise.

    A good study can only look at one thing at a time. Introducing "light use + protein" is different study--not this one. It's like criticizing "Casablanca" because it didn't have dancing penguins--and you really, really like dancing penguins.

    I didn't want to be overly long in my OP, but this study came to my attention in a tweet from Bret Contreras and was discussed in an email from him and Chris Beardsley. Far from being a case of "confirmation bias", the authors of the email said they expected the results to be completely the opposite.

    Speaking of "bias", are you sure you aren't just objecting because you don't like the results?
  • Cherimoose
    Cherimoose Posts: 5,208 Member
    Speaking of "bias", are you sure you aren't just objecting because you don't like the results?

    Oh i agree with the results, i just don't think they're very useful for predicting long-term results of ambulatory people like most of us. It's like assuming that since Casablanca was a black & white movie, all movies made after it were black & white. :wink:
  • wild_wild_life
    wild_wild_life Posts: 1,334 Member
    Speaking of "bias", are you sure you aren't just objecting because you don't like the results?

    Oh i agree with the results, i just don't think they're very useful for predicting long-term results of ambulatory people like most of us. It's like assuming that since Casablanca was a black & white movie, all movies made after it were black & white. :wink:

    I can't access the full article, but it doesn't sound like they are making any unfounded claims in the abstract. And it does sound like atrophy occurred within that 5 day period. You can't really criticize a study on apples for not making predictions about oranges...

    http://jn.nutrition.org/content/early/2014/06/11/jn.114.194217.abstract
  • SoLongAndThanksForAllTheFish
    SoLongAndThanksForAllTheFish Posts: 831 Member
    From that study, it appears you can only conclude with any relevance, that if you are older (69+/-1year), adding protein to your diet does not seem to help reduce muscle loss if immobilized for 5 days...not a very useful study at all, results are predictable, and immobilization for a relatively short time will cause some muscle loss for any group.

    One also needs to realize NO function/use is a much different state than SOME use, and that within 'some use', light function/use, is also different from light infrequent increased stimulation, which is also different than heavy regular increased stimulation, etc etc. That needs to be teased apart before making assumptions on whether increasing protein intake will help retain muscle.
  • WalkingAlong
    WalkingAlong Posts: 4,926 Member
    Skeletal muscle disuse atrophy is not attenuated by dietary protein supplementation in healthy older men, by Dirks, Wall, Nilwik, Weerts, Verdijk, and Van Loon, in The Journal of Nutrition, 2014
    So I can go on using my muscles and aiming for 60g protein a day and I'll be ok? :smile:
  • Azdak
    Azdak Posts: 8,281 Member
    Speaking of "bias", are you sure you aren't just objecting because you don't like the results?

    Oh i agree with the results, i just don't think they're very useful for predicting long-term results of ambulatory people like most of us. It's like assuming that since Casablanca was a black & white movie, all movies made after it were black & white. :wink:

    Each study is just another piece in a million piece puzzle--the fun part is deciding where each one fits.
  • Azdak
    Azdak Posts: 8,281 Member
    Speaking of "bias", are you sure you aren't just objecting because you don't like the results?

    Oh i agree with the results, i just don't think they're very useful for predicting long-term results of ambulatory people like most of us. It's like assuming that since Casablanca was a black & white movie, all movies made after it were black & white. :wink:

    I can't access the full article, but it doesn't sound like they are making any unfounded claims in the abstract. And it does sound like atrophy occurred within that 5 day period. You can't really criticize a study on apples for not making predictions about oranges...

    http://jn.nutrition.org/content/early/2014/06/11/jn.114.194217.abstract

    I like my dancing penguins analogy, but yours is much more succinct. I'll have to remember that.

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