Whey Protein vs. Casein Protein: Which Is Best For What?

When you go supplement shopping, have you ever actually looked at what type of protein you’re buying? I typically purchase whey protein, but there are other proteins out there, specifically casein.

As humans, we can break down all the different types of protein, but for this article we will keep it simple and look at the two most-purchased proteins - whey and casein. You will learn how each protein acts in the body and how each has a unique benefit to you as an athlete.



The Science of Protein

All proteins contain carbon, hydrogen, oxygen, and nitrogen. Some proteins even have sulfur in them. These elements make up the building blocks of proteins - the amino acids. There are twenty basic types of amino acids.

Proteins are composed of both essential and nonessential amino acids:

Essential amino acids must be obtained through food as the body cannot synthesize these.
Nonessential amino acids are still important to construct our body’s proteins. The name just means it is not necessary for us to ingest them because our bodies can synthesize them.

The Effects of Calorie Intake and Training

Protein can be metabolized as a source of energy when you are experiencing a negative caloric balance. That means when you eat fewer calories than you expend.

There is an inverse relationship between your caloric intake and your actual protein requirement. When caloric intake goes down, protein requirement goes up and vice versa. In addition, individuals who have a negative caloric balance and consume lower-quality proteins will need an even higher amount of protein than would normally be consumed.

"There is an inverse relationship between your caloric intake and your actual protein requirement. When caloric intake goes down, protein requirement goes up and vice versa." 

For athletes, protein requirements are increased due to training. Both aerobic endurance training and resistance training can increase protein need. For aerobic athletes, protein is required for tissue repair and the use of branched-chain amino acids for fuel. For strength athletes, protein is required for tissue repair, along with the maintenance of a positive nitrogen balance.
  
Okay enough of the biology, right? Let’s get down to the meat and potatoes of this article - should you use whey or casein protein and why?

Whey Protein - The Facts

You will see whey protein the most in the supplement stores. Whey is a component of cow’s milk and accounts for about 20% of its protein content. Interestingly, most whey is produced as the byproduct of cheese manufacturing. (Remember Little Miss Muffet?)

Whey protein includes all the essential amino acids (remember those?) and is especially high in branched-chain amino acids, which are key for muscle protein synthesis. Whey protein has more sulfur-containing amino acids than its counterpart, casein. Because of this trait, it has a slightly higher level of biological utilization than other proteins.

"Interestingly, most whey is produced as the byproduct of cheese manufacturing."

Whey is considered a fast protein source. It digests fairly quickly, which causes a rapid increase in amino acid levels in the body. After consuming whey protein, blood amino acid levels peak at around sixty to ninety minutes after ingestion. This peak is short lived and is not sustained past two to three hours.

When protein floods the body with amino acids in this way, some of the protein is oxidized or wasted as excess. Since whey protein is so quickly digested, this is the protein you want to use right after your training session. This is because your muscles have broken down from your workout, and since whey protein is so fast acting, it can aid in muscle repair by increasing muscle synthesis.

Reference: http://tinyurl.com/j77gyna