Milk is a source of multiple forms of protein, including whole-milk protein, which is made via a filtration process that removes much of the carbohydrate and fat from whole milk.
Because it’s made via filtration, biologically valuable fractions like alpha lactalbumin, glycomacropeptides, lactoferrin and lactoperoxidase, among others, remain. These are health promoting for the immune system and aid in recovery from strenuous exercise. Milk proteins are good for everything except immediately post-workout because they are relatively slow to absorb. Two forms of whole-milk protein are:
Milk Protein Concentrate (MPC) $$$
This contains both the whey and the casein fractions of milk. Good all-around protein, except immediately post-workout.
Milk Protein Isolate (MPI) $$$
Further processing yields a protein virtually devoid of carbohydrate and fat, so it’s good for dieting. Not ideal for post-workout use.
Whey protein is king of the protein heap. In general, whey proteins are digested quickly, which makes them good for most uses except slow, sustained delivery of amino acids.
Whey Protein Concentrate (WPC) $$
Used as a base protein by many bodybuilders, WPC contains some carbohydrate and fat. It’s created via ion exchange and/or a filtering process, sometimes called microfiltration or ultrafiltration. Filtered whey concentrate usually contains much of the vital fractions of whole-milk proteins. Ion exchange uses an electrical charge to separate protein from carbs and fat, resulting in highly purified protein.
Whey Protein Isolate (WPI) $$$
Isolate is purer, and it’s valued for its lower carbohydrate and fat content, which is useful when dieting.
Whey Protein Hydrolysate (WPH) $$$$
The protein is hydrolyzed, in which enzymes break some amino-acid bonds, for faster digestion and absorption. WPH can range from 3% to 50% hydrolyzed. Despite the bad taste, WPH is excellent for people who want a fast-absorbing protein post-workout.
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Casein protein is the other part of the protein in milk. It’s harder to digest and absorb than whey, so it’s slower to deliver amino acids to the blood and muscles. This can be an advantage when you want a constant supply of amino acids available for muscle repair, recovery and growth – such as before bedtime. It’s also often low-carb and low-fat. The caseinate forms, made from acidification during cheese production, similar except for the different minerals included.
Calcium Caseinate $$
This will give you extra calcium.
Sodium Caseinate $$
Avoid this if you need to limit sodium.
Potassium Caseinate $$
The potassium may relieve muscle cramping.
Rennet Casein $$$
Made using rennet, an enzyme, to separate the casein from the whey. Similar to micellar casein in slow digestion and prolonged delivery of amino acids.
Micellar Casein $$$
It has the ability to clot in the stomach, delaying absorption for slow, steady delivery of amino acids.
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