Whey protein: no fat--and may fight cancer.

Whey protein, once thought to be a useless by-product of cheese production, has recently become one of the most popular protein supplements. This is due, in part, to the development of several methods for distilling whey into a high-quality powder that is fat- and lactose-free. Although it's the most expensive of the three protein powders (whey, casein and soy), whey has a number of advantages over other protein supplements.

One of the greatest benefits of whey protein is that it enhances glutathione production ... one of the body's natural antioxidants. Therefore, in addition to supplying protein, whey can help to protect against free-radical damage. Whey protein also has the highest levels of branched-chain amino acids (BCAAs), and it has been shown to boost the immune system. And because whey protein exits the stomach much faster than proteins such as casein, it can be absorbed more quickly into fire bloodstream through the intestines. This provides a substantial rise in blood amino acids in a short amount of time, which is important during exercise and recovery. Finally, whey protein dissolves easily in water, making it convenient for a protein drink when you're on the go.

Whey protein contains the highest concentration (about 25 percent) of BCAAs of any single protein source. This BGAA content is important because BCAAs are an integral part of muscle development and are the first amino acids sacrificed to provide energy during high-intensity exercise.

Whey-protein isolate contains quadra-peptides (short protein chains containing four amino acids), which have been shown to have pain-killing effects. This is another powerful functional ...