HSN: Report #8

[Aaron_F]

Just something for people to discuss really
In the latest HN report (well I just got around to reading it, been busy )
there is bryans interpretation of a paper. Here is a copy of it

Quote[/b] ]Does the Anabolic Effect of Pre and Post Exercise Protein Supplementation Lead to a Net Increase in Muscle Protein?
Title: Acute response of net muscle protein balance reflects 24-h balance after
exercise and amino acid ingestion.
Researchers: Tipton KD, Borsheim E, Wolf SE, Sanford AP, Wolfe RR.
Institution: Metabolism Unit, Shriners Hospitals for Children, Galveston, Texas
Source: Am J Physiol Endocrinol Metab. 2003 Jan;284(1):E76-89.
Summary: The purpose of this study was to determine if the acute anabolic muscle response to resistance exercise and essential amino acids (EAA) reflects the response
over 24 h.
Methods: Seven subjects participated in the following two 24-h studies: 1) resting (REST) and 2) rest plus resistance exercise and consumption of pre- and post essential amino acids (ES). Net balance (NB) across the leg was determined for four amino acids. [(13)C(6)]phenylalanine was infused to determine mixed muscle fractional synthetic rate (FSR).
Results: Twenty-four-hour FSR was significantly greater for ES than for REST (P = 0.003). Exchange of phenylalanine across the leg was -194 74 (SE) mg for ES and -371 88 mg for REST (P = 0.07) over 24 h and 229 42 mg (ES) and 28 15 mg (REST; P < 0.01) over 3 h corresponding to exercise and EAA consumption for ES. The difference in phenylalanine exchange between REST and ES was not different for measurements over 24 and 3 h. Increases in NB during ES were primarily the result of increases in protein synthesis. Results for other amino acids were similar.
Conclusion: The acute anabolic response of muscle to EAA intake and exercise is additive to the response at rest and thus reflects the 24-h response.
Discussion: This study may seem confusing at first, but once you know the background assumptions that gave them the idea to perform this study, it all makes sense.
It is known that as you increase your daily protein intake, your body will compensate by increasing protein losses during the night.(1-4) So there is a diurnal regulation of protein balance. This is the reason why simply eating more protein doesnt make you bigger and bigger. The more protein you eat, the more protein your body gets rid of while you sleep.
Despite this observation, it is also known that carefully timing your protein intake around your training can significantly increase protein synthesis in muscle tissue. (5,6) So, it begs the question, does the anabolic effect of pre and post exercise protein supplementation lead to a net increase in muscle protein? The results of this study confirm that it does!

Being nitpicky, what do you guys think of Bryans interpretation of this paper.
Think, there was a small group of people that were involved in 2 seperate 24hr protein synthesis experiments. One time they ate a set diet for about 3-4days then took part in an experiment (with 2 meals during it) and during this time they were measured for protein synthesis and did absolutely nothing but rest. The second time (or first depending on randomisation) they did exactly the same thing, but they had a session of resistance training (which increases protein synthesis) and an additional 30g of essentail amino acids.
With bruans interpretation being

Quote[/b] ]Despite this observation, it is also known that carefully timing your protein intake around your training can significantly increase protein synthesis in muscle tissue. (5,6) So, it begs the question, does the anabolic effect of pre and post exercise protein supplementation lead to a net increase in muscle protein? The results of this study confirm that it does!
The increased protein synthesis that occurs with pre-and post exercise protein supplementation lead to durable increases in muscle protein over a 24 hour period, even in light of the diurnal regulation of whole body protein balance. The nighttime protein losses did not reflect the additional protein taken in as a pre- and post workout supplement. Thus the acute stimulation of muscle protein by exercise and protein ingestion is additive to the balance that normally occurs in resting muscle.

What would you say?

 

[shakeel]

what is the link to this report?

 

[micmic]

Do you mean that we can't know whether the findings were the result of pre/post supplementation + exercise or exercise alone ? And that protein synthesis could very well go up without any eaa supplementation ?

 

[Aaron_F]

There is no link, well not yet anyway, Bryan hasnt gotten above #4 on the webpage

Ive still got the email if you want it

and micmic

Bingo

 

[micmic]

We have the frequently cited McDougall study, and now this Tipton study. As far as I know, what these studies refer to as MPS and FSR respectively, is the same thing, namely a measurement of the incorporation into muscle of a specific amino acid (without taking into account muscle protein degradation rate or whole body protein synthesis rate). Doesn't this latter study indicate that the bulk of amino acid uptake happens in the 3-hour window following exercise, and so contradicts the first one ?

 

[ZMT]

List Builder - Error
'xxx@sfd.pl' (my email) is already subscribed to this mailing list.
and I don't have any new reports

 

[Aaron_F]

Not really

The first one was fasted with a resistance trainign session.
Tiptons latest study shows that the rise in protein synthesis happens, and that the incorporated aminos are still there 24 hours later.

THe main reason they done this, is that all of his previous work was done over 3hrs, and they couldnt assume that a transient rise in FSR would match the whole 24hrs. And it does when compared to rest.
Its 11pm here, and I should sleep (been playing spongebob on the PS2 ) I will think of some more tomorrow.

 

[Bryan Haycock]

Quote[/b] (micmic @ Aug. 07 2003,1:25)]Do you mean that we can't know whether the findings were the result of pre/post supplementation + exercise or exercise alone ? And that protein synthesis could very well go up without any eaa supplementation ?

This study was trying to see if the "combination" of exercise and the temporary increase in protein synthesis that accompanies it if additional protein is made available (through ingestion) would cause an equal increase in diurinal protein loss, as other protein meals do when not accompanied by exercise.

 

[Bryan Haycock]

Here are a few background studies/papers on how the body maintains protein "balance" despite increased protein intake:

Wagenmakers, AJ. Protein and amino acid metabolism in human muscle. Skeletal Muscle Metabolism in Exercise and Diabetes. ed. Richter et. al. Plenum Press: New York, 1998.

Waterlow, JC. Protein turnover with special reference to man. Q J Exp Phys (1984) 69: 409-438.

Fern, EB et. al. Effects of exaggerated amino acid and protein supply in man. Experientia (1991) 47: 168-172.

Millward, DJ et. al. Physical activity, protein metabolism and protein requirements. Proc Nutr Soc (1994) 53: 223-240.

 

[Aaron_F]

Quote[/b] (Bryan Haycock @ Aug. 08 2003,3:15)]Millward, DJ et. al. Physical activity, protein metabolism and protein requirements. Proc Nutr Soc (1994) 53: 223-240.

The millward paper and one authored by Tipton and Wolfe are interesting, because they are falling along the side of there is a lack of evidence showing resistance trained athletes require additional protein.

Quote[/b] ]This study was trying to see if the "combination" of exercise and the temporary increase in protein synthesis that accompanies it if additional protein is made available (through ingestion) would cause an equal increase in diurinal protein loss, as other protein meals do when not accompanied by exercise.

or more nitpicky

The purpose of the present study was to determine if the response of net muscle protein metabolism to resistance exercise and amino acid ingestion measured acutely was reflective of that measured over a full 24-h day.

Now if they could compare resistance trained+food without aminos, to resistance trained+food+aminos, it would be more interesting, especially over 24hrs (and not this 2 meal malarky - I know it helps their isotope work, but it doesnt really reflect real life much)