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Not All Proteins Are Created Equal, Part I
By Lucho Crisalle RD
Believe it or not, all proteins are NOT created equal! Since this subject is pretty extensive, we have broken this article up into three parts. Part I addresses the different qualities and benefits of protein; Part II addresses Soy Protein specifically (its controversial shortfalls and benefits); and Part III addresses the best time to use each protein source.
Section of a protein structure showing serine and alanine residues linked together by peptide bonds. Carbons are shown in white and hydrogens are omitted for clarity.
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Ask any bodybuilder about protein, and they will say, "Whey is King." Unfortunately, that is about as far as most people's knowledge about protein goes, and most athletes and fitness enthusiasts, have no idea why whey is the best source of protein or that there are differing qualities and benefits from different types of whey protein.
The major players in the field of protein are
(in ascending order of quality)
Soy Protein,
Casein,
Whey Protein Concentrates (WPC),
Whey Protein Isolates (WPI),
and Hydrolyzed Whey Protein (HWP).
Being that soy is the only vegetable protein mentioned, and since it is quite controversial, we will discuss it separately in Part II. We will start by defining casein and the differing types of whey.
So, What is the Difference?
Casein
There are differing qualities of proteins that can be derived from milk; these are
casein and whey. Whey is the liquid left over during the cheese making process after
the casein in milk is converted into curds. The lowest quality and least expensive
form of protein is Caseinate, and can be found in the form of Calcium Caseinate, as
well as many other variations such as Potassium Caesinate, etc. As the name implies,
it comes from "casein" before it is converted into curds.
A 1997 study titled "Slow and Fast Dietary Proteins Differently Modulate Postprandial
Protein Accretion" published in the National Academy of Sciences journal indicated casein may be anticatabolic because it prevents protein breakdown. Because of its larger molecules, casein is digested slower than whey protein and maintains elevated amino acid levels in the blood for a longer period of time.
There are many benefits in maintaining elevated amino acid levels in blood as this has been
shown to diminish muscle breakdown (catabolism) as well as having an anabolic effect.
If your body is trying to repair muscle tissue, it needs amino acids in the bloodstream to be able to do so. It would be hard for a builder to build you a house with no materials; the same holds true for muscle repair and growth: they cannot take place without the presence of adequate amounts of amino acids in our bloodstream.
Although casein is the lowest priced and least refined of the proteins derived from milk,
it is a bit higher in glutamine, tyrosine, threonine, and arginine content than whey protein.
That is why a good refined whey protein supplement (such as an Isolate, or Hydrolysate)
will usually have these amino acids added to it. Casein also moves slower through the
digestive tract, which may allow for better absorption of amino acids and growth factors
as well as making it a better meal replacement protein due to its longer and slower transit time (which translates to longer satiety or a feeling of being full). By using casein as a meal replacement protein, we are less likely to experience hunger than if we use a protein supplement with a faster gastric emptying time (one that leaves the stomach more quickly).
The benefit of slower digestion and transit time is that it is thought that slower transit time may allow for a higher absorption of certain components that may not be absorbed from proteins that go through the proximal bowel at a faster rate. Therefore, casein is the best choice to use when our schedule does not allow us to have normal food. Still, normal food would be more beneficial as it takes much longer to leave the stomach and maintains our blood glucose levels better controlled than a "liquid lunch" since the "liquid lunch" does not require much work from the stomach in the form of digestion.
High quality food should be our first choice for breakfast, lunch, and dinner. If your schedule does not allow the "luxury" of setting aside enough time to prepare or purchase an adequate meal, casein is the best choice for a meal replacement if long term satiety is the goal. Possibly the biggest benefit of using a high quality casein protein supplement is its potential in functional properties being researched in hospitalized patients, infants and animals, such as immune enhancing and antiviral properties.
The enzyme hexokinase is shown as a
simple ball-and-stick molecular model.
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Whey protein concentrate (WPC)
Whey protein concentrate (WPC) is the next step up from caseinate and it comes from the liquid left over during the cheese making process (whey). In its raw form whey contains lactose, fat, salt, and other proteins. Originally all whey protein was made from whey sources left over from the manufacturing of cheese. If supplement manufacturers use this lower quality source of raw materials, harsh acids have been used to separate whey from casein resulting in a lower quality whey protein supplement.
Now there are companies that make whey and casein specifically for supplement manufacturers by extracting it from whole milk for the sole purpose of creating higher quality supplements, making the quality of whey protein today superior to the ones previously available.
There are many different processes designed to separate or filter the valuable fractions of protein found in whey. These range from microfiltration, ultrafiltration, nanofiltration, reverse osmosis filtration, dynamic membrane filtration, ion exchange, as well as many others that are being tested to yield the best product that contains as many of the beneficial health promoting portions of whey while leaving the impurities out.
These beneficial fractions include alpha-lactalbumin, beta-lactoglobulin, glycomacropeptides (GMP), lactoferrin, lactoperoxidase, immunoglobulins, lysozymes, and many more being studied to determine their role in health benefits. Whey protein derived from ultrafiltration is referred to as Whey Protein Concentrate (WPC). The ultrafiltration process does not remove any fat or denatured protein from the whey. For the WPC to be considered high quality, special processing prior to the ultrafiltration is necessary to remove the majority of the fat present in whey as well as separating out denatured protein and casein particles left over from the cheese making process if the raw material (whey) was acquired secondary to the processing of cheese.
WPC's can yield a product ranging from 20% up to 85% protein. They could be 20% protein and 85% fat and lactose, which is usually the case when not specified in a product. If the concentrate consists mostly of protein, it usually states so in the label; if it consists mostly of fat and lactose, your intestines will let you know with gas and bloating.
The way to tell if your WPC is high quality (highest percent protein as opposed to lactose and fat) is by looking at the label and calculating the percentage of protein compared to the total weight of the serving size. As an example, if your protein serving size is 23.5g and it yields 20g of protein per serving, the easy math is 20 ÷ 23.5 = .8510 x 100 = 85.10% which means your protein serving contains 85.10% protein.
Keep in mind that flavoring agents, sweeteners, gums, and even fiber in some supplements take up some of the volume of the total serving weight. This formula is to be used only with WPC supplements or any other supplement that consists of only protein as a way of determining the percentage yield of protein per serving. This formula is NOT to be used with Meal Replacement Powders (MRP's) as these contain fat and carbohydrates in "meal-like-quantities" and would show the protein yield to be very low as it is being compared to the entire serving.
Because of the many benefits of the differing types of protein that we will cover in this article, most protein supplement manufacturers "blend" or combine proteins for specific purposes ranging from slow gastric emptying time for meal replacement purposes, or quick emptying time for post workout recovery. It is these different blends that can also make a product superior or low quality, depending on the differing qualities and quantities of the proteins used in their blends. The protein yield formula described above CAN and SHOULD be used in single source as well as multi source proteins as long as they DO NOT contain a considerable amount of carbohydrates, fats, fiber, creatine, etc., as these other components will cause the formula to yield a lower and less desired protein per serving value or number. High quality supplements will use WPC with at least 80% protein content.
If the manufacturer is trying to reduce cost, they will use a product yielding a lower percentage of protein, meaning that more fat and lactose will be found in the product. This is easy to determine even without doing the math as these products tend to give you gas and cause bloating due to the lactose and fat content.
© 2007 Lucho Crisalle, RD, internationally recognized expert in nutrition created the
What Works! Ezine. Go to
www.exerciseandnutritionworks.com to get your copy of our
FREE REPORT "The Truth About FAT LOSS And The Way To A Leaner You - REVEALED!
Lucho Crisalle BS, RD brings 19 years of experience as a nutrition and fitness expert to
ENW Inc. He holds a Bachelor's Degree in Food Science and Human Nutrition and Dietetics
with a minor in Exercise and Sports Sciences from The University of Florida, Gainesville.
Lucho is credited with developing world class custom nutrition programs for Americas'
top CEOs, multi-million dollar health clubs, and enterprising fitness professionals.
Not All Proteins Are Created Equal, Part II
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