Know Your Milk Protein
The Differences Among the Types of Milk Protein

by Scott Kolasinski

Protein is composed of chains of amino acids. There are twenty-two amino acids. When various forms of amino acids come together, they form protein. Therefore, different forms of protein contain different concentrations of amino acids. The primary source of dietary nitrogen (an essential element) for the body comes from these amino acids, usually in the form of meat, fish, eggs, dairy, soy and/or various nuts.

Of these, milk proteins have been extensively studied in the literature because of their many benefits of stimulating muscle production (such as in strength athletes), muscle retention (such as the elderly), muscle immuno-enhancing effects (AIDS and cancer patients), and beneficial changes in body composition (such as fat loss in overweight people).

Many of these milk proteins are now sold in nutrition stores to help the population with their goals, however, there are so many forms of milk protein available, that a consumer may get easily confused among them and wonder why would an individual want one product versus another. This article will help answer this question.

Milk Protein Concentrate and Milk Protein Isolate

Milk protein concentrate (MPC) and milk protein isolate (MPI) both contain the two primary proteins of milk called casein and whey (the liquid proteins). Concentrates and isolates are very similar, except isolates differ from the concentrates in that isolates possess a high protein content with almost no lactose content. However, because of the greater filtration, MPI may lack in subfractions (i.e. the molecular components) compared to MPC.

Undenatured proteins (i.e. less processed proteins) retain their original bioactive properties. The bioactive properties or subfractions, are what make each protein unique. Therefore, the greater the bioactive properties in the final product, the better the product for obtaining the health benefits of the subfractions.

The beauty of MPC and MPI is that because they contain both casein and whey (explained below), they contain the benefits of both of these proteins, but in lesser concentration as opposed to taking a purified bolus of whey or casein. MPC and MPI have interchangeable uses, but because of MPI’s solubility and greater protein content, milk protein isolate would be the preferred protein for people seeking to add high-protein, low-carbohydrate and/or low-lactose foods to their lifestyle.

This does not mean that MPI is superior to MPC. It depends on an individual’s goals. For example, because of an MPC’s greater fat content (low as it already is), it contains various subfractions. Studies suggest these compounds can improve immunity and intestinal health that both athletes and "normal" people may find beneficial. Thus, young and old, active or inactive, we all can benefit from a product containing some milk protein concentrate/isolate.

Whey Protein

Making up the liquid portion of the cheese-making process is whey. Whey's popularity has increased dramatically in recent years because of how cheap it is to manufacture and because of advances in processing technology.

Whey contains an impressive and complex array of subfractions. These subfractions include b-lactoglobulin, a-lactalbumin, immunoglobulins (IgGs), glycomacropeptides, bovine serum albumin and minor, smaller proteins such as lactoperoxidases, lysozyme and lactoferrin. Also, whey protein is a great source of branched chain amino acids (BCAA). BCAA’s are ideal for recovery from exercise. I know, this is a lot of "big-worded" scientific jargon, but protein manufacturers list a number of these subfractions on their ingredient labels to try to impress upon us. Do not be fooled by these potentially impressive lists of subfractions that are used as marketing tools. The above subfractions of whey are in all whey protein products. More of one or the other subfraction may be added to make a product more unique, but there needs research supporting the addition of whatever subfraction is added.

The following is a description of the development of whey protein powders as they have evolved over the past decade in purity.

Whey Protein Concentrate

Whey protein concentrates (WPC) are products derived from whey from which the water, minerals and lactose have been removed. In this form, whey is not of much benefit to athletes, but with gentle low-temperature processing and filtration, this liquid can be stripped of most of its lactose, fat, cholesterol and water to yield concentrated whey powders containing anywhere from 34 to 89% protein. Also, this low temperature and low acid condition ensures that 90-96% of this protein is undenatured thus containing many active peptide subfractions. Most of the health benefits of MPC are derived from whey.

It is important to note that there are significant price and nutritional value differences between the various whey protein concentrate supplements on the market. A WPC containing 34% protein may cost up to 80% less than better quality whey protein concentrates with protein contents of 77% or higher. The process of protein concentration calls for the use of various separation techniques such as diafiltration, ultrafiltration, electrodialysis and ion-exchange technologies.

Whey Protein Isolates (WPIs): Crude, or sweet dairy whey, can also be "isolated" via a process called cross flow microfiltration (CFM) or ion exchange (IE) filtration to produce whey powders that are virtually fat, carbohydrate (lactose) and cholesterol free. By definition, WPIs contain >90% protein by dry weight. On today’s market, you will find there are a few products that derive all of their protein content from WPIs, but WPIs are most often used in conjunction with WPC and/or other proteins to boost the overall protein content of a supplement.

Many people often ask which isolation process creates a better form of whey protein isolate. The following is a brief overview of the processes and the potential benefits each has to offer.

Ion Exchange (IE) is a process that separates proteins on the basis of their electrical charge. Ion exchange requires the use of various solvents to create an attractive charge on the proteins. Once charged, these proteins migrate toward oppositely charged resin beads in a reaction vessel. The protein can be later removed from the resin beads by reversing the charge to result in a highly purified WPI. Ion-exchange whey protein isolates contain more than 90% protein content with minimal lactose and no fat. This offers an advantage over whey concentrates in terms of pure protein content.
Although the ion-exchange process sounds pretty fancy, there are serious drawbacks to this method. Due to the nature of the ion-exchange process, the most valuable and health promoting components are selectively depleted. Though the protein content is increased, many of the most important subfractions are lost or greatly reduced, resulting in a denatured protein.

The pros of an ion-exchange whey is for those who simply want the very highest protein contents per gram, but the cons are that the higher protein content comes at cost; a loss of many of the subfractions unique to whey and more expensive than WPC. Is this acceptable? You be the judge.

Cross Flow Microfiltration (CFM) was developed to prevent the problems seen with IE proteins. CFM is a process that uses natural non-chemical ceramic filters to separate whey proteins from a variety of undesirables (i.e. fat, cholesterol, lactose, etc.). Advantages to this process include minimal protein denaturation, preserved protein subfractions and a higher calcium and lower sodium profile.

The only drawback of CFM is the price. One of the reasons for the high price is because the first company that developed the process patented the technology and now controls the price. It is a bit higher than making aWPC or IE whey isolate, but there is a better concentration of protein that offers all of the benefits of whey.

So, to sum up the take home message on the two filtration methods:
Cross Flow Microfiltration - Good

Ion-Exchange – OK at best.

Casein

Casein makes up approximately 75-80% of cow’s milk protein. Though not currently "en vogue" with many athletes (due, in large part, to the success of whey proteins), casein is easily assimilated by the body and a complete protein, a protein containing all the essential amino acids in amounts adequate for human use.

When casein enters and mixes with stomach acid, it creates a gel or paste-like substance, thus, slowing its absorption into the bloodstream and giving satiety. This results in a trickling of amino acids into the bloodstream. Because casein has this slow delivery of nutrients and decreased hunger, casein is the protein of choice in the pharmaceutical and food industries where it is used in baby formulas, enteral nutrition products, and meal replacement products.

Summary

Milk proteins contain casein and whey. However, various forms of whey protein have been developed via filtration methods because of the greater number of beneficial subfractions found in whey versus casein. As such, both casein and whey have their own benefits. Therefore, in terms of health benefits, both are beneficial for improving overall health.
Next month, I will describe a protein debate (which is better, casein, or whey?) and let you know what the research has to say. In this way, you will be able to conclude which, when, how and if these proteins should be supplemented to your lifestyle to enhance your personal fitness goals.

Until next time…