Sources of Protein – 7 Sources for Supplements
Sources of protein for supplements started in the 1950’s by Bob Hoffman. They were made from soybean protein and marketed to bodybuilders. Times have changed. These are the 7 sources known to be used now.
1. Whey Protein
Whey proteins are the most widely used sources of protein in supplements. It is isolated from milk as a by-product of the production of cheese. It is a very good source of the muscle-building branched-chain amino acids (BCAA) leucine, isoleucine, and valine. Whey protein is a fast digesting protein source and is low in glutamine and arginine. Whey has been isolated in THREE categories:
A. Whey Hydrolysate
Of all of the sources of protein available, this is the gold standard. This form of protein is predigested to speed up its absorption in the body. It is more expensive but is considered superior for post-workout nutrition.
B. Whey Isolate
Whey isolate is also a more expensive whey protein. It can be filtered enough times to be over 90% protein and lactose free, carbohydrate free, fat free, and cholesterol free.
C. Whey Concentrate
Whey concentrate is a more cost-effective protein and is the most widely used as a result. It requires less processing time, but will contain only 75 – 80% protein and more fat and lactose than the other forms.
2. Casein Protein
Milk contains two proteins, casein proteins (80%) and whey protein (20%). Comparing the two sources of protein from milk, casein is the slower digesting protein. This provides better nitrogen retention and use by muscles. Weight gainers prefer it at night to help maintain an anabolic state. Casein protein is used by the body to build muscle so it encourages the body to use carbs and stored fat for energy. Casein is very high in glutamine which is taken as a supplement by bodybuilders.
3. Egg Albumin
Egg albumin is the egg white. Egg whites are popular with bodybuilders because they contain a large number of essential amino acids and less cholesterol then egg yolks. Those who are lactose intolerant will tend to use this source.
4. Soy Protein
Soy protein is one of the high quality, fast absorbing sources of protein but is not as efficient as the previous sources. It has an average amino acid profile so is not used as much by bodybuilders. Soy protein isolate also exists and is more readily absorbed by the body but is of lower quality.
The one issue documented in research is the existence of isoflavones in soy that produces phytoestrogen in the body. This has shown negative effects, especially in males and pre/post menopausal women.
5. Goat Milk Protein
Of all of the sources of protein, goat milk has the highest bioavailability. It is extremely high in BCAA and is 100% lactose free.
6. Wheat Protein
Wheat protein (gluten) is a vegetarian alternative to dairy and egg-based proteins. Wheat is about 14% protein with a large amount of the remainder being starch. It is lactose and cholesterol free and is high in glutamic acid.
7. Pea Protein
Pea protein is a 100% gluten free protein source that is a great alternative for vegetarians. As with wheat protein, pea protein is lactose free and does not contain any cholesterol. It is very easy to digest and is rich in lysine but is low in cysteine and methionine.