I'm an athlete who takes protein supplements. I'd like to know whether all dietary protein sources are the same. What about supplements: whey versus soy versus casein?
Different types of proteins are comprised of differing amounts of essential amino acids (EAA) and have different rates of digestion. For example, whey is more rapidly absorbed than casein. Soy protein contains fewer EAAs than whey or casein. The EAA leucine is a key "trigger" for building muscle, so leucine-rich foods with rapid digestive properties are best for recovery from resistance exercise. Animal proteins - including plain or chocolate milk, lean beef and tuna - are leucine-rich. Plant proteins contain leucine, but in lower amounts.
Because casein is absorbed slowly, consuming casein-rich foods before bedtime (such as cottage cheese) can help support muscle-building processes throughout the night. This may be particularly important for athletes seeking to maximise muscular growth during building seasons, such as during a pre-season training programme.
Nancy Clark is a sports nutritionist and a Fellow of the Academy of Nutrition and Dietetics in Chicago. Reprinted with permission from the American College of Sports Medicine Fit Society® Page