Which protein is whey better?

We can all agree that protein is one of the most necessary supplements for athletes as it provides the most convenient (i.e. liquid or bar) stimulus for muscle recovery/growth during and after exercise. Unfortunately, the number of options for these supplements and the variety of these ingredients are endless. Best option is to always keep it simple, and so we’ll focus on choosing the right type of protein.

First we’ll introduce the 3 major types of protein used in supplements; casein, whey, and soy. Casein is the major protein in cow milk, and is renowned for being the “slow” protein, due to its ability to form clots in the stomach and provide a more sustained release into the blood stream. A byproduct of this casein (or cheese) production is whey protein. Whey has the highest Biological Value of any known protein, meaning it is more efficiently digested and absorbed than even the “gold standard” of protein, which is egg. Because of this high bioavailability, amino acids from whey protein enter the blood stream faster than other protein sources. The third protein, soy, is derived from a long series of processes that extract the substance from the soybean, and such manufacturing results in soy being a “fast” protein like whey.

A 2009 study out of McMaster University in Ontario, Canada compared these 3 major types of protein and their effect on muscle protein synthesis, the major indicator of muscle repair and growth. At rest, the subjects using whey had a 9x greater muscle growth/repair than the casein group and 2x the soy group. A similar result was observed after exercise, with a 122% greater muscle protein synthesis in whey than casein and 31% greater than soy.

So the study found whey is far better than casein for a workout, and somewhat more effective than soy. However, there are factors other than muscle to consider when choosing your protein. In the past, soy has also been touted for its general health benefit, citing its lower fat and cholesterol content than animal proteins. However, soy is rated as the second most allergenic food to humans, with the first being peanuts. Soy also has the highest levels of phytic acid, which binds to certain nutrients in the intestine and reduces their absorption. In January 2006, an American Heart Association concluded a 10 year review, finding that soy does not reduce post menopause “hot flashes” in women, nor does it help prevent cancers of the breast, uterus, or prostate.

As an athlete, your first priority for a supplement should be protein during/after exercise, whether that is practice, games, or weightlifting. Whey is the fastest absorbed protein, and it has the largest effect on muscle protein synthesis, the marker for repair and growth. Along with this high absorption, whey also has a host of factors that boost the immune system and prevent the breakdown of muscle.

If you want to drink soy, just throw in some long distance running as well (see Sparta Point 12/31/08), to ensure you really hinder your recovery and performance gains.