Resistance exercise in combination with increased amino acid availability has been demonstrated to be an effective way to promote muscle building and strengthening.
A group of researchers based in Texas and Missouri decided to prepare a blend of the 3 sources of protein and compared this to just a whey protein drink, their reasoning being that the blend will release amino acids for a prolonged time due to the different digestion rate of the proteins. The drinks were given to volunteers after exercise and phenylalanine transport and mRNA expression of select amino acids were measured.
They found that phenylalanine transport and mRNA expression increased in both groups, no surprises there then, but they also found that the phenylalanine transport in the group that had the blend lasted for a longer time than the group that only had whey.
Interesting results to be sure, but it would have been interesting to see the effect of a casein based protein drink aswell, as a paper was published that described how this can slow the digestion of proteins in the stomach.
The paper is available from the Journal of Applied Physiology.