I have been curious about this and looked for some info on the net. I ran across the website
http://www.hypertrophy-specific.com/hsn_ar...oteinmyths.html If you'll notice Myth #2 he has a reference by "If you could only assimilate 30 grams of
protein at a time, why would researchers be using in excess of 40 grams of
protein to stimulate muscle growth?". I looked up that reference on the net and read it. Here it is:
Post-exercise net
protein synthesis in human muscle from orally administered
amino acids. Tipton, Kevin D., Arny A. Ferrando, Stuart M. Phillips, David Doyle, Jr., and Robert R. Wolfe. Metabolism Unit, Shriners Burns Institute and Departments of Surgery and Anesthesiology, University of Texas Medical Branch, Galveston, TX 77550
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APStracts 5:0272E, 1998.
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We examined the response of net muscle
protein synthesis to ingestion of
amino acids following an bout of resistance exercise. A primed, constant
infusion of ring-[2H5]phenylalanine was used to measure net muscle
protein balance in three male and three female volunteers on three occasions. Subjects consumed, in random order, one L of: 1) a mixed amino acid (40g) solution (MAA), 2) an essential amino acid (40g) solution (EAA), and 3) a placebo solution (PLA). Arterial amino acid concentrations increased [sim]150-640% above baseline during ingestion of MAA and EAA. Net muscle
protein balance was significantly (p<0.05) increased from negative during PLA (-50_23 nmol(min -1(100mL leg volume-1 ) to positive during MAA (17_13 nmol(min -1(100mL leg volume-1 ) and EAA (29_14 nmol(min -1(100mL leg volume-1). Since net balance was similar for MAA and EAA, it does not appear necessary to include nonessential
amino acids in a formulation designed to elicit an anabolic response from muscle following exercise. We conclude that ingestion of oral essential
amino acids results in a change from net muscle
protein degradation to net muscle
protein synthesis following heavy resistance exercise in humans similar to that seen when the
amino acids were infused.
Received 18 August 1998; accepted in final form 30 November 1998.
APS Manuscript Number E378-8.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1998 The American Physiological Society.
Published in APStracts on 18 December 1998
I decided to e-mail Stuart M. Phillips (found his e-mail address associated with some other studies) and here is what I asked him:
I have read that the body can only digest around 20 - 30 grams at a time. I guess what I mean by "at a time" is drinking down a
protein shake. I noticed you were involved with a study where subjects were given the following: 1) a mixed amino acid (40g) solution (MAA), 2) an essential amino acid (40g) solution (EAA), and 3) a placebo solution (PLA). I suspect that how much the body can handle at one time may depend on when it is taken, the health of the individual and the type or types of
protein (whey,
casein, etc) among other things. But, in general does it make sense to try and put a number on how much one can take at a time?
Here is his answer:
Richard,
Not sure, have we ever met? You will notice that in the study you refer to that in susequent studies the group I was working with has achieved similar responses with only 6g of EAA. That is, from what we can see now, a dose as large as 40g of EAA is far too large to stimulate a response that can be achieved with only 6g. Some data that we have now obtained suggests that whey+casein blend in a ratio very similar to that found in milk is the optimal to stimulate
protein synthesis - bottom line all those purified shakes are likely too large. Insofar as I can see one need not ingest more than 15-20g of
protein at any one time.
Some studies for you to look at:
Med Sci Sports Exerc. 2003 Mar;35(3):449-55.
Independent and combined effects of
amino acids and glucose after resistance exercise.
Miller SL, Tipton KD, Chinkes DL, Wolf SE, Wolfe RR.
http://www.ncbi.nlm.nih.gov/entrez/query.f...t_uids=12618575 Am J Physiol Endocrinol Metab. 2003 Jan;284(1):E76-89. Epub 2002 Sep 11.
Acute response of net muscle
protein balance reflects 24-h balance after exercise and amino acid ingestion.
Tipton KD, Borsheim E, Wolf SE, Sanford AP, Wolfe RR.
http://www.ncbi.nlm.nih.gov/entrez/query.f...t_uids=12388164 Am J Physiol Endocrinol Metab. 2002 Oct;283(4):E648-57.
Essential
amino acids and muscle
protein recovery from resistance exercise.
Borsheim E, Tipton KD, Wolf SE, Wolfe RR.
http://www.ncbi.nlm.nih.gov/entrez/query.f...t_uids=12217881 Am J Physiol Endocrinol Metab. 2001 Aug;281(2):E197-206.
Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise.
Tipton KD, Rasmussen BB, Miller SL, Wolf SE, Owens-Stovall SK, Petrini BE, Wolfe RR.
http://www.ncbi.nlm.nih.gov/entrez/query.f...t_uids=11440894 Med Sci Sports Exerc. 2001 Dec;33(12):2044-52.
Creatine-dextrose and protein-dextrose induce similar strength gains during training.
Tarnopolsky MA, Parise G, Yardley NJ, Ballantyne CS, Olatinji S, Phillips SM.
http://www.ncbi.nlm.nih.gov/entrez/query.f...t_uids=11740297 Best of luck with your training.
Regards,
Stuart
Sorry so long, but just wanted to share this with everyone.
Judge yourself with the same eye you judge others. You'll either find you're not as great as you think or others really aren't that bad.
human body CAN'T digest more than 30g protein/hour, true / false ??
