Everything you needed to know about protein

Protein supplements have undergone a drastic revolution over the past ten years. Ten years ago they didn't have good taste, didn't mix well, didn't digest well, and were generally being consumed only by bodybuilders or hardcore athletes. Today there are great tasting protein powders, and they're being used by virtually everyone, including grandparents just looking to stay fit and healthy.

A few questions are routinely asked when it comes to protein supplementation, like what different kinds are available, what are the differences between various types, should more than one kind be used, and if there are certain situations where consumption of one kind would be more beneficial than another.

Some insight into milk proteins is a good starting point for understanding more.

Milk proteins fall into two general categories: casein and whey. In general, milk protein is 80% casein and 20% whey. Milk protein isolate can be made by centrifuging (high speed spinning) milk to separate the fat from the protein content, then adjusting the pH (measure of acidity) to the isoelectric point (pH where the overall charge on the sample is 0) of casein (typically a pH of 4.6), which causes the casein portion to become insoluble and precipitate (solidify) out of solution.

The whey portion remains soluble (liquid) and thus can be separated from the casein portion. This is not the end of the story however. Several modifications can be made to casein and whey.

Whey Proteins

Whey Protein Concentrate (WPC)
(Digested Quickly, Contain Lactose)

WPC is made using the soluble portion of isolated milk protein by refining it and further purifying it. WPC contains between 70-80% protein per weight and contains all of the active biofractions of whey including the alpha and beta-lactalbumins, immunoglobulins (IgGs), glycomacropeptides, bovine serum albumin (BSA) and minor peptides such as lactoperoxidases, lysozyme and lactoferrin.

Each of the sub fractions found in whey has its own unique biological properties. Some of these properties include anti-carcinogenic effects, pro-immune effects, and positive effects on the health of the digestive system.

Pros:

It contains a large amount of branched chain amino acids (BCAA's) relative to other kinds of proteins and it is quickly digested which causes a rapid spike in plasma amino acid levels, causing a greater increase in protein synthesis than other types of proteins.

It is also very well absorbed and receives a near perfect score on the biological value scale, which measures how well a protein is absorbed. It also contains all the previously mentioned biofractions, so you get all of their pro-health benefits.

Cons:

It is rapidly digested and causes a large spike in plasma amino acid levels, which means it will clear out of someone's system quickly (about 3 hours) and will not keep plasma amino acid levels elevated as long as other proteins. WPC may be difficult for some people to digest since it contains lactose.

Additionally, some people are allergic to the bioactive fractions in WPC and can have small to severe reactions to them. Most people afflicted with an allergy to one of the biofractions experience diarrhea, vomiting, nausea, or stomach ache after ingestion. These allergies are nothing to be overly worried about, but one should be mindful of them so if they do experience these symptoms they know what caused them.

Whey Protein Isolate (WPI)
(Digested Quickly, Higher Cost, Less Lactose)

WPI is made similarly to WPC except WPI undergoes an additional step of purification. In general there are two different ways to make WPI. One way is to use an ion-exchange column. A second way is to pass it through a series of filters.

Ion-exchange tends to increase the percentage of protein in the end product, but it also removes many of the bioactive fractions of whey that have positive benefits, and increases the content of Beta-lactalbumin, the most allergic sub-fraction in whey.

On the other hand, using a filtering process such as cross flow microfiltration, ultra filtration, micro filtration, reverse osmosis, dynamic membrane filtration, ion exchange chromatography, electro-ultrafiltration, radial flow chromatography, or nano filtration tends to purify the sample while still preserving many of the bioactive fractions in whey. These purification processes remove virtually all of the lactose and fat and what remains is generally as much as 90-96% protein.

Pros:

A greater percentage of the actual protein powder is pure protein with less fat, lactose, and carbohydrates than with WPC. WPI also tends to be more easily digested than WPC because it has less lactose. It also causes a rapid spike in amino acid levels like WPC.

Cons:

If ion-exchange is used to purify the powder, some of the bio-active sub fractions of whey are lost. Additionally, WPI is significantly more costly than WPC. WPI also tends to become foamy when mixed. It also has the downfall of a relatively fast clearance time, like WPC.

Hydrolyzed Whey Protein (HWP)
(Digested quickly, Higher cost, Less appealing taste)

HWP is made by exposing the whey fraction to enzymes, which "chop up" proteins to form shorter peptides.

Pros:

It is very quickly and easily digested and will rarely cause allergic reactions. It contains a greater percentage of protein, and also causes a rapid spike in amino acid levels (like WPC & WPI).

Cons:

It tastes terrible (terrible as in having to hold your nose to drink it). It costs more (than WPC or WPI), and contains few bioactive sub fractions. It also has the downfall of having a relatively fast clearance time (like WPC & WPI).

Casein Proteins

Calcium Caseinate
(Slower Digestion)

Calcium Caseinate is produced using the insoluble portion of milk protein and taking it through another chemical reaction to purify it.

Pros:

It gels in the stomach during digestion causing a slow, sustained increase in plasma amino acid levels, which can remain elevated for up to 7 hours longer than the increases caused by whey. Since the plasma amino acid levels remain elevated for a longer period of time, casein is also more anti-catabolic than whey due to suppressing skeletal muscle protein breakdown to a greater degree. Calcium caseinate is also much less expensive (compared to micellar casein).

Cons:

It only produces about half the increase in protein synthesis as what whey does, and is therefore not as anabolic. Casein also has a reduced concentration of BCAA's compared to whey and is not as bioavailable as whey. Calcium Caseinate is inferior to micellar Casein because it is denatured during processing.

Micellar Casein
(Slower Digestion, Higher Cost)

Micellar Casein is produced without the use of chemicals by separating the soluble whey portion of Milk Protein Isolate/Concentrate from the insoluble casein portion.

Pros:

It has all the same anti-catabolic benefits of calcium caseinate and is not denatured during processing.

Cons:

Like calcium caseinate, it is not as anabolic or bioavailable as whey and it is also more expensive than calcium caseinate.

Other Proteins

Egg White Protein
(Lactose-Free, Less Appealing Taste)

Egg White Protein is usually produced by drying egg whites into a powder.

Pros:

It has no lactose, fat, or cholesterol and has a good blend of amino acids. In fact it is nearly perfect in terms of fitting the amino acid requirements for humans, and it's more bioavailable than casein protein. In addition, it contains many vitamins and minerals and is relatively affordable.

Cons:

It's not quite as bioavailable (fewer amino acids absorbed into the bloodstream) as whey protein and is more expensive (than WPC). It does not cause as large of an increase in protein synthesis as whey protein does. In general it doesn't taste as good as the milk proteins.

Soy Protein Concentrate (SPC)

Soy Protein Concentrate can be produced a number of ways by taking defatted soy flour or flakes and either exposing them to acid wash, alcoholic extraction, or other methods of filtration. In all cases the end result is removal of much of the carbohydrate content and having about 70% protein per weight.

Pros:

It contains the complete spectrum of amino acids and is a good protein source for people who don't consume animal products. SPC contains isoflavones, which may have some health promoting benefits as anti-oxidants and anti-carcinogenics. SPC is also high in many vitamins and minerals.

Cons:

It has a relatively low concentration of BCAA's and is less bioavailable than milk or egg proteins. SPC is higher in carbohydrates than any of the other aforementioned protein sources. Isoflavones & phytoestrogens in soy may actually have a negative impact on breast cancer in post-menopausal women.

Soy Protein Isolate (SPI)

Is produced by further purifying soy protein concentrate to yield around 90% protein per weight.

Pros:

It has the benefits of SPC but has a greater percentage of protein and has fewer carbohydrates than SPC. SPI also has less isoflavones and phytoestrogens than SPC and may be a better choice for post-menopausal women.

Cons:

It contains less isoflavones than SPC and it is more expensive than it. It is also relatively low in BCAA's and less bioavailable than the aforementioned proteins.

Conclusion

Probably the most important thing to remember from all of this information is to take in enough total protein over the course of a day. The minimum for hard training athletes is around 1.2g/kg per day (the upper beneficial limit is generally somewhere between 2.2-2.8g/kg per day).

In order to utilize protein supplements to their maximum benefit, it is probably important to keep a few things in mind.

Fast acting proteins (like whey) are going to work best at times when protein synthesis is depressed and quick synthesis is needed (by spiking it). These times include post workout and upon awakening.

Slow acting proteins (like casein) work best when going long periods of time (>4 hours) between meals. Taking a casein supplement before sleep is a good way to help prevent protein synthesis from dropping as much during sleep.

A protein blend containing whey, casein, egg, and possibly soy may be best for other times of the day (for a meal replacement). Including whey assures the benefits of a fast acting protein, while casein will be slower digesting to help keep plasma amino acid levels and protein synthesis elevated for a greater duration of time.

Adding egg to the mixture provides the advantage of having a good blend of amino acids. Soy can be added if one wants the health benefits of anti-oxidants, or can be left out by those who don't want to spend the extra money or by post-menopausal women who may be sensitive to the isoflavones and phytoestrogens in soy.

Using the cheaper sources of protein (WPC, calcium caseinate, SPC) will save money, and for the most part, they are just as effective as their higher priced counterparts (WPI, micellar casein, SPI). Those with digestive disorders however, may want to spend the extra money for WPI, micellar casein, and SPI, which are easier to digest.

In conclusion, protein powders are an easy way to ensure adequate protein consumption each day. What type of supplement used depends on time of day, situation, budget, and digestive tendencies.