And some more about protein supplements...

Here are summaries of two more studies covering whey protein supplements.  In the first, Pasiakos et al conducted a thirteen day, randomized, crossover study to assess postexercise muscle protein synthesis (MPS), whole-body protein turnover, and anabolic intracellular signaling responses to the effect of essential amino acids in supplements (1).  The eight adult volunteers were tested on days 8 and 13.  The two groups were given two different concentrations of leucine:  Group 1, the experimental group, were given 3.5g leucine (L-EAA) and Group 2, the control group, was given 1.87g leucine (EAA) (1).  Both groups consumed their supplements during exercise.  The leucine for both groups was dissolved in 500mL of water with an artificial sweetener (1).

The volunteers were active-duty military personnel who regularly participated in both endurance and resistance exercise at least 3-4 days per week.  They were all recreationally fit with no medications, no injuries, and no abnormalities (1).  While the study was run with 9 men and 1 woman, the data used in the report was for 7 men and 1 woman (1).  The volunteers were directed to do two separate bouts of cycle for 60 minutes at 60% VO2 peak (1).

The researchers discovered that the muscle protein synthesis was 33% greater after L-EAA than EAA.  Also, the whole-body protein breakdown and synthesis was down and the oxidation was up for the L-EAA group (1).  The mammalian target of rapamycin phosphorylation was up with the L-EAA group 30 minutes after exercise (1).  The researchers concluded that L-EAA supplementation increases leucine availability and spares endogenous protein stores to a greater extent during endurance-type exercises (1).

In the second study, West et al measured the effect of whey protein on myofibrillar protein synthesis (MPS) after exercise (2).  This study observed eight men who were recreationally active, not endurance athletes.  They were randomly assigned into two groups:  Group 1 was given a single bolus of 25g (BOLUS) and Group 2 was given small, “pulsed” drinks of ten drinks of 2.5g every 20 minutes (Pulsed) (2).  The drinks were prepared in water with no additives, like artificial sweetener.  The BOLUS consisted of 12.8g EAA, 3.5g leucine, 0 carbohydrate, and 0 fat; the PULSE drinks were the same formula administered in the pulsed manner (2).

The researchers found the BOLUS increased blood essential amino acid (EAA) concentrations 162% 60 minutes after exercise, and the PULSE increased EAA 53% (2).  Also, with the BOLUS, the blood EAA concentrations were greater at the 80-minute mark.  However, the EAA concentrations were greater with PULSE at 180, 200, and 240 minutes (2).  The same results were found for blood leucine concentrations.  There was no change in insulin for PULSE, but the insulin was greater for BOLUS at 20, 40, and 60 minutes (2).

The researchers concluded that muscle anabolism was better benefitted by bulk delivery of amino acids post-exercise (2).  The researchers also speculate that more fat and/or more carbohydrates would slow protein absorption (2).

Below is the information gathered from five studies thus far.  The chart includes the dosage, timing, and form of protein for each study.  A few of the studies compared different types of proteins or different ways of administering the proteins.  I did not include conclusions from the studies in this chart; however, I will be getting to those in the next few weeks.

	Protein Supplement Study Protocols
Number	Dosage	Timing	Form	Study
1	1.5g/kg	daily for 14 days	Whey or Carbohydrate	Cooke et al, 2010
2	20g	pre- or post-exercise	Whey	Tipton et al, 2007
3	237g	1 hr post workout	FF milk
	237g		Whole milk	Elliot et al, 2006
	393g		FF milk isocaloric with whole milk
4	3.5g	during exercise	leucine
	1.87g		leucine	Pasiakos et al, 2011
5	25g-single	post exercise	Whey	West et al, 2011
	25g-pulsed

1.  Pasiakos, Stefan M.; McClung, Holly L.; McChung, James P.; Margolis, Lee M.; Anderson, Nancy E.; Coutier, Gregory L.; Pikosky, Matthew A.; Rood, Jennifer C.; Fielding, Roger A.;  Young, Andrew J.  Leucine-enriched essential amino acid supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis.  The American Journal of Clinical Nutrition  2011; 94: 809-818

2.  West, Daniel WD; Burd, Nicholas A.; Coffey, Vernon G; Baker, Steven K; Burke, Louise M; Hawley, John A; Moore, Daniel R; Stellingwerff, Trent; Phillips, Stuart M.  Rapid aminoacidemia enhances myofibrillar protein synthesis and anabolic intramuscular signaling responses after resistance exercise.  American Journal of Clinical Nutrition  2011; 94: 795-803