BLOG

No nutrient has been utilized more for building lean muscle and transforming the physique than protein. In fact, it is the single most important nutritional component in the muscle-building equation. That is why it's vitally important for any bodybuilder or other athlete to know the facts regarding protein, and why certain types are better than others. That's also why the product development team at ProSource is providing this comprehensive overview of the latest scientific findings surrounding protein, important detailed information regarding different types of protein, how they are produced and which one is best suited for each objective. Several of the most relevant forms of protein will be defined and discussed relative to their respective advantages and disadvantages.

The intent is for you to use this guide to better understand how to maximize the muscle-building results of your training program with optimal protein supplementation. In addition to comparing all of the common forms of protein, distinctions will be made between concentrates, isolates and hydrolysates, as well as specialty extracts that have recently been developed, which have shown to provide significant benefits with regard to muscle synthesis. Finally, a rating from 0 to 10, with 10 as the absolute best, will be assigned to each form of protein to simplify decision-making regarding what protein you should consider.

All Things Protein
Adequate protein is critically important for many aspects of health. But for athletes who train to maximize muscle mass and minimize body fat, like bodybuilders, the need for adequate protein at necessary times cannot be overstated. Intense exercise training both challenges and damages muscles, which increases the body's requirement for protein. When protein (as well as carbohydrates and fats) is provided in optimal amounts, the rate at which the body can recover from the workout and build more muscle is sharply increased [1, 2].
When choosing your protein supplement, it is important to clearly understand several key things about your body and how it handles the protein you ingest. The ultimate goal of this guide is to provide the most detailed assay on our industry's most relevant protein sources so everyone, from top competitive bodybuilders to the weekend warriors, can gain from this report, as it should prove to be invaluable toward your bodybuilding efforts.

FIRST, proteins are made up of amino acids, which can be put into groups based on how easy it is for your body to produce them. Amino acids that your body makes in large amounts are called nonessential amino acids because it is not essential for you to get them from your diet. On the other hand, amino acids that your body cannot make at all are called essential amino acids because it is essential you get them in adequate amounts from the food or supplements you consume. Lastly, some amino acids are produced in good amounts by our body but under times of stress (like when you are ill or when you are training heavily) the body does not produce enough of them. These are called conditionally essential amino acids.

SECOND, proteins are commonly classified as complete or incomplete proteins. A complete protein is any protein source that provides both adequate amounts and ratios of the essential amino acids to facilitate the rebuilding of various proteins found throughout our body. Consequently, an incomplete protein is any protein source that does not provide either adequate amounts or ratios of the essential amino acids to support cellular protein growth. How do I know if a protein is complete or not? If your source of protein is derived from an animal it is considered a complete protein source. Examples then include beef, pork, fish, egg, milk (or dairy products), and poultry such as chicken, turkey or game fowl. Proteins derived from plants are incomplete, with soy being the only noteworthy exception as recent high quality isolate versions of soy protein may be considered complete [3].

THIRD, muscle cells have been shown by research to absolutely require essential amino acids to reach maximal rates of synthesis or growth, and resistance exercise requires even further increases [4, 5]. It is becoming abundantly clear that the essential amino acid, leucine, in particular, plays a critical role in stimulating muscle protein synthesis and scientists continue to examine and explore the extent of this bioactivity [6, 7]. This point is so important that a dedicated section on leucine is provided later in this guide.

FOURTH, research has determined that the optimal dose of essential amino acids to maximize muscle protein synthesis is approximately 10 to 12 grams [1, 8-10]. Increased levels of muscle protein synthesis can remain for 2 to 3 hours after their ingestion, whereby another dose of amino acids is needed to favorably shift the cellular balance between protein growth and protein breakdown [11]. Additionally, research tells us that when the levels of amino acids decrease outside of the muscle cell, that protein synthesis will decrease [12]. Therefore, one of the most important dosing strategies is to pattern your eating and supplementation to deliver around 10 to 12 grams of essential amino acids every 3 hours or so, if at all possible.

FIFTH, a few recent studies shed some light on the question of how much protein to consume in one setting. The first study provided graded intakes of powdered essential amino acids in 0, 5, 10 or 20-gram doses to either young or older men and found that 10 grams of essential amino acids was the ideal dose [10]. Another study compared muscle protein synthesis changes in younger men after they ingested either 0, 10, 20 or 40 grams of egg protein. The authors concluded that 20 grams of protein was the optimal amount. The 20-gram dose led to significantly greater levels of protein synthesis than the 5 or 10-gram dose and was equivalent to protein synthesis levels produced when a 40-gram dose was ingested [13]. The latest study used whey protein and also concluded that 20 grams of protein appeared to be an optimal dose. However, if you're an older man and the protein is consumed shortly after a resistance workout, a higher dose could be considered [14]. The biggest take-home message is that mega doses of protein are simply not needed and you are better served to provide a 20-25 gram dose more frequently throughout the day.

SIXTH, how you take your protein, either as one large dose or spread out over several small doses is commonly considered. This question was also recently addressed by researchers, who concluded that, while both patterns of ingestion increased muscle protein synthesis, a larger dose led to larger increases in amino acid levels in the blood, when compared to spreading that same dosage out over several hours. Two important messages stem from this work, and the first is to just get the protein inside you. Second, the authors felt that the bolus ingestion led to better changes because the dose of leucine provided was at, or closer to, required levels [15].

SEVENTH, the content of leucine within your protein is growing to be a more important factor seemingly each year. While the collective function of the essential amino acids is a key consideration, more and more research continues to tell us that the branched-chain amino acid content [16, 17] and in particular the leucine content of a protein source, may be as important of a consideration. As it stands, scientists feel that the leucine content alone can be responsible for impacting how much muscle mass can be gained due to leucine's central role in activating proteins responsible for muscle protein synthesis[18].


For example, when essential amino acid drinks containing different doses of leucine were given to healthy adults during a bout of cycling exercise, the drink with the higher content of leucine was responsible for greater improvements in muscle protein synthesis [19]. Even without the anabolic power of exercise, leucine-enriched meals given to older men have been shown to support increased rates of muscle protein synthesis [20]. The most convincing evidence, however, comes from a recent study, published in 2012, where multiple doses of whey protein, leucine and essential amino acids were provided both at rest and after a resistance exercise. A whey protein isolate was found to promote the longest increase of muscle protein synthesis, while even a small dose of protein (6.25 grams) with added leucine was still able to promote similar increases in blood levels of both the essential amino acids and leucine [21].

Clearly, the extreme importance of leucine in the bodybuilding equation has been well established in the scientific community, while the evidence still continues to mount. With that, the production of leucine-specific supplements, and protein products with added leucine, has been on the rise. Of these products, there is one in particular that has most every protein expert excited, simply because it does the best job possible in providing the most bioavailable potency of leucine. Word has been spreading fast about NytroWhey Ultra Elite, not only because it provides the most powerful compendium of premium protein content, but also because it contains Leuvon 590 (leucine bound leucine peptides). This highly bioactive peptide formula yields up to four times more leucine than other protein products. That is a pivotal difference. Furthermore, Nytro Whey Ultra Elite has taken full advantage of the recent development by Glanbia Nutritionals, a world leader in protein technology and development, by also providing two elite proteins (Provon and TherMAX) that, according to Glanbia research, delivers a final protein with not only the highest levels of bioactive leucine, but also superior amounts of hydrolysates that promote rapid incorporation of essential amino acids into your growing muscles.

Determining Protein Quality
A few standard methods are commonly used to discuss differences in the overall quality of proteins found in various food sources. As we discussed earlier, a complete protein is considered to be of higher quality due to its containing higher amounts of all of the essential amino acids. Chemical scores are also used to determine protein quality, whereby the amino acid content (especially the essential amino acid content) of any given protein is compared to a standard or reference protein (e.g., egg protein). If, for example, a protein contains 80% of the amount of one (or more) amino acid(s) in comparison to the reference protein, this protein source is given a score of 80. Proteins that contain all of the essential amino acids in amounts identical to (or greater) than the reference protein are subsequently assigned a chemical score of 100 (or higher). Thus, a higher chemical score infers a higher quality protein. Another method, net protein utilization, uses a similar concept that evaluates how much protein is utilized by the body per dose of protein being delivered. Therefore, any protein source that results in greater amounts of protein being utilized per gram is assigned a higher score, which suggests them to be of higher quality. The most commonly discussed and accepted method of determining protein quality is the protein digestibility corrected amino acid scores (PDCAAs). This method uses a formula to calculate a score that represents both the amino acid requirements of our body and their ability to digest the protein. The higher the PDCAA score, the better the protein. Table 1 provides both net protein utilization (NPU) values and PDCAA scores for different types of protein.

Leading Canadian scientists recently published a paper that identified a shortcoming relative to the PDCAA method, whereby no value can be greater than 1.00. In fact, they performed their own calculations and indicated that many forms of protein, including milk solids (1.21), casein (1.23), whey (1.21) and soy (1.04) would all have values above 1.00. This is an important point to consider as it brings to light subtle differences between various sources of protein that, along with other factors such as protein digestion rates, branched-chain amino acid content or other amino acids, may contribute to factors that dictate how much muscle can be gained if consumed as part of a heavy resistance training program. In other words, although the PDCAA method tells us clearly that proteins like whey, casein and soy are all high quality, assigning them the same score may be misleading, as the actual amino acid contents of these proteins are different, and as a result, have been shown to go on to impact how our body responds to resistance exercise and subsequently builds muscle [8].

In summary, several different types of protein exist, some of better quality than others. To optimize delivery of the needed amino acids as well as other valuable nutrients various sources of protein can provide, it is first recommended that people eat a wide variety of proteins from the foods found in their diet. Resistance training athletes and bodybuilders are recommended to consume a diet that contains around 1.2 to 1.6 grams of protein for every kilogram of body weight. For individuals weighing between 160 and 250 pounds (72 -- 114 kgs), this means they should be eating around 86 to 182 grams of protein each day [1]. Due to the vast amount of research surrounding sources of protein like whey and casein as well as the changes seen with exercising athletes, these proteins are the most commonly considered for athletes who train to improve not only their performance, but also both their muscle mass and body composition.

Production Methods and Techniques
All proteins may come from the same source, but how the original source of protein is prepared is very important. To help understand the concept, let's say we have a pail of protein produced from one batch of milk from one cow. You could even go so far as to assume that milk was produced on the same day and same time of day when the cow was eating the same diet, etc. From that large base of protein, three production processes are typically used (concentrate, isolate or hydrolysate) and can all be produced from the same vat of milk protein. A concentrate can have a large range of carbohydrate, protein and fat and by definition must be between 34 to 89% protein by weight. This means if 100 grams of a concentrate are produced, 34 to 89 grams must be protein for it to be called a concentrate. However, you must be aware that a company can put the word concentrate on its label and the final product could only be 35% protein by weight, which means that somewhere close to 65% of it will be carbohydrate and fat. Not good.

Let's look now at whey isolate, which, by definition, must be at least 90% protein by weight, which means that if 100 grams are produced, at least 90 grams of it must be protein for it to be called an isolate. As noted earlier, whey isolate provides the greatest content of pure protein, amino acids, leucine and other health promoting components, such as the vital glycomacropeptides. The key is quality, and the highest quality isolate in the industry today is Provon from Glanbia. This form is manufactured using state of the art Cross Flow Microfiltration (CFM) processing that yields the highest amount of pristine protein content possible. As a result, it is the highest quality whey isolate available. To find it, look no further than NytroWhey Ultra Elite. This powerful protein complex, also found in NytroWhey Original, offers the purest, highest quality whey isolate for optimum muscle growth.

Lastly, hydrolysate formulations are a relatively more recent form of protein that continues to gain in stature due to its greater absorption benefits. Hydrolysates can be produced from most sources of protein (whey, casein, soy, etc.) and can also be made from concentrates or isolates. A hydrolysate product can go through any one of a number of techniques to hydrolyze or partially break down the long peptide chains found in every protein we eat. Most often, hydrolysates are produced using either enzymes that specifically break apart certain proteins or acid mixtures that also naturally cleave bonds found within protein molecules. Hydrolysates continue to be popular for fitness and bodybuilding for a number of reasons. For starters, studies indicate that shorter chains of amino acids are rapidly digested and incorporated into the tissues of the body faster than any other form of protein. This rapid absorption is perfect for immediate assimilation, which benefits every bodybuilder seeking fast mass gain. It also is extremely beneficial for an athlete who needs to recover as rapidly as possible (maybe because they are training 2x in one day or they have another game or event tomorrow)[22]. The degree of hydrolysis is key. Proteins that can report higher degrees of hydrolysis and a greater abundance of very short peptide chains (2 to 5 amino acids long) are typically favored. Finally, research has suggested that hydrolysate versions may also reduce allergens, which may be important for certain individuals [23].


To ensure the greatest potency hydrolysate, it is best derived from an isolate rather than a concentrate, for the afore-mentioned reasons. That's why it is critical to look for a protein product like NytroWhey Ultra Elite that contains a hydrolylsate (TherMAX) produced from a whey protein isolate base (Provon) that 
delivers the highest degree of hydrolysis in the bodybuilding industry. Another important consideration here is the fact that TherMAX is derived from a proprietary enzymatic processing technique, not chemical, that not only yields optimum amounts of very small peptides but also produces a superior taste.

All in all, this combination lays the groundwork for a product to deliver not only high levels of critically important amino acids, but also makes them rapidly available to the muscle tissue so they can go to work immediately.

Protein Sources
Milk proteins are the predominant source of proteins used by bodybuilders for a number of reasons, but mainly because they are the highest quality and easily have the greatest amount of research performed on them. Briefly, whole milk is approximately 87% water and 13% solids. The solid proportion is comprised of many compounds, including proteins, fats, carbohydrates, vitamins, minerals, etc. Approximately 27% of the solid fraction is protein, with ash and other minerals (6%), fat (30%) and lactose (27%) comprising the remainder of the solid proportion. The protein proportion naturally found within milk is subsequently divided into approximately 80% casein protein and 20% whey protein.

Whey Protein
Whey protein is the liquid portion of milk produced as part of the cheese-making process via ultrafiltration, and is commonly formulated into either concentrate, isolate or hydrolysate versions. Whey protein is considered a complete protein and, according to many different rating scales, has the highest level of quality (see Table 1) [8, 9]. In addition to packing the most punch relative to amino acid content, whey proteins are very soluble and as a result are digested rapidly. The digestion rate of whey protein is a key point as studies have shown that the faster digestion rate of whey is responsible for the rapid increases in amino acid concentrations in the blood, which leads to rapid increases in muscle protein synthesis [24, 25].
 

Follow us on or for a chance to win this product!

Whey Protein Isolate
As highlighted in the previous paragraph, isolate versions of whey protein are considered to be of the highest quality available. Whey protein isolate has excellent levels of all of the important amino acids. It is easily digested, mixes well, absorbs quickly and has the most scientific support. Several studies have clearly shown that delivering a dose of whey protein isolate of about 20 grams every three hours or so is an extremely potent and effective means to maximally stimulate muscle protein synthesis. The most convincing of these studies provided whey protein isolate to young, active men who were experienced with resistance training. The first study reported that almost a two-fold greater increase in lean body mass occurred, in addition to greater increases in bench press strength, when compared to athletes who ingested carbohydrates [26]. This same research group later compared the changes in strength, muscle mass and body composition in two groups of young, healthy males who were already experienced with resistance training after one group ingested whey protein isolate and another group ingested a casein protein. When whey protein isolate was ingested, significantly greater increases in lean body mass and strength were found, when compared to the changes seen after casein ingestion [27].

Finally, a recent paper outlined the findings from nine different published studies that were at least eight weeks in duration which compared the resistance training adaptations seen after the subjects ingested either milk, whey protein, soy protein or carbohydrate. Collectively, this approach detailed the responses seen in close to 250 research subjects, which identified that whey protein ingestion was responsible for the greatest increase in lean mass, averaging slightly over an eight pound increase in muscle mass [8]. This paper and others [9, 28] strongly support the contention that whey protein isolate is the most effective protein supplement for a bodybuilder to ingest.

To produce a whey protein isolate, two additional filtering processes are typically used: ion-exchange or cross-flow microfiltration. Ion-exchange is a chemical process that produces a product high in amino acid content, but largely damages the biological activity of many important fractions found in the protein. On the other hand, cross-flow microfiltration yields a product with amino acid levels equal to or greater than that of ion-exchange, but does not damage any of the natural biological fractions found within whey proteins. In addition to the outstanding levels of protein, essential amino acids and leucine, whey protein isolate, more so than any other type of protein, contains a number of important bioactive fractions that are responsible for several important health effects. For example, whey protein has high concentrations of the amino acid cysteine, which is closely linked to antioxidant protein, making the cells stronger and more resistant to damaging free radicals [1, 8]. In addition to cysteine, whey isolate also contains a mixture of beta-lactoglobulin (~65%), alpha-lactalbumin (~25%), and serum albumin (~8%) along with a host of illness-preventing immunoglobulins. Collectively, these microfractions convey several additional health-promoting attributes, most importantly an ability to strengthen the immune system. For a number of reasons, these fractions are important to promote maximal health and depending on the type of filtering process that is used; both the content and biological activity of these fractions can be severely altered. Therefore, when deciding on a whey isolate protein, the majority of scientific thought considers Cross Flow Microfiltration (CFM) as superior to ion-exchange filtration.

Follow us on or for a chance to win this product!

Whey Protein Hydrolysate
Hydrolysate products are produced from intact protein sources such as whey protein and casein protein. A number of positive benefits that research has indicated may confer favorable muscle building results are derived from the hydrolyzing process. For starters, a number of studies indicate the smaller, shorter chains of amino acids produced in the hydrolysis process may enter the bloodstream directly, surrounding your muscle more rapidly and effectively, while avoiding first-pass extraction by other organs in the body, such as the liver and intestines [29, 30]. Particularly when the hydrolyzed protein product is produced from a high quality whey protein isolate, as is the case with NytroWhey Ultra Elite, this effect will make more amino acids available to stimulate muscle protein synthesis. As discussed above, a critical factor that drives increases in muscle protein synthesis is the amount of amino acids found right outside the muscle cell, and whey protein hydrolysates are extremely effective at stimulating these increases. Additionally, hydrolysate products stimulate rapid increases in the anabolic hormone insulin, which bodybuilders have known for years to be intimately involved in many aspects of growth and recovery [31].

It's important to understand that many different types of protein can be hydrolyzed, but just because one protein is hydrolyzed doesn't mean they are all the same. The degree of hydrolysis is an important factor that can impact some important characteristics from one protein to the next. Degree of hydrolysis is a determination of what extent the protein chain has been broken apart; more specifically it is often represented as a percentage of the peptides that are hydrolyzed all of the way down to peptide chains that are just two and three peptides in length. The greater the percentage the more complete the hydrolysis process, which subsequently will fully facilitate the positive attributes associated with a hydrolyzed protein.

As a point of comparison, many commercially available "hydrolyzed proteins" have a DH (degree of hydrolysis) of just 2 or 4 on the scale. An elite quality hydrolyzed protein like MyoZene from BioQuest has a DH many, many times that rate. All in all, any protein product which possesses a higher degree of hydrolysis will optimize the absorption and delivery of its constituent amino acids, while providing a sharp and rapid spike in insulin. This is a good thing.

To fully illustrate the positive impact of different types of protein, a recent scientific study compared the changes in muscle protein synthesis of soy protein isolate, micellar casein and a hydrolysate made from whey protein isolate both at rest and after a single bout of resistance training. When compared to soy protein isolate and micellar casein, whey protein hydrolysate was responsible for extremely sharp and rapid increases in the amount of essential amino acids found in the blood as well as the greatest increases in muscle protein synthesis [32]. More specifically, greater rates of muscle protein synthesis were found at rest without any influence of exercise, and when a single bout of resistance training was added. In fact, whey protein hydrolysate was actually several orders of magnitude more effective at increasing muscle protein synthesis when taken in the immediate period of time after completing a weight workout--the one-hour window of opportunity, if you will. In short, a hydrolysate produced from whey protein isolate works very well at rest on a non-workout day, but works even better when taken shortly after a workout. Similarly, a study completed by Cribb and colleagues compared the ability of a hydrolyzed whey protein isolate to stimulate changes in strength and body composition over the course of several weeks while completing a heavy resistance training workout. In this study, ingestion of a hydrolyzed whey protein isolate was responsible for greater increases in strength as well as greater improvements in both lean muscle mass as well as fat mass when compared to ingestion of a casein protein product [27].

Whey protein, whey protein isolate and whey protein hydrolysate have been summarized here first because they are the best for fast and potent delivery of amino acids and other growth factors. Premium quality isolate versions of whey protein, such as those found in NytroWhey and NytroWhey Ultra Elite, have the highest concentrations of essential amino acids, including leucine and the other branched-chain amino acids, while also taking advantage of ultra and cross-flow microfiltration that yields a product with exceptional bioactivity. No other protein product has as much support from the scientific community as whey protein isolate. Its ability to maximally stimulate muscle protein synthesis without exercise, and even higher levels when combined with resistance exercise, eventually goes on to produce greater increases in strength, muscle mass and body composition improvements.

In closing, any conversation regarding protein for bodybuilding and other fitness interests should start and end with a high quality whey protein isolate.

Follow us on or for a chance to win this product!

Micellar Casein
Micellar casein is another excellent protein, with some similarities to whey, but also differing dramatically in its bioactivity. Micellar casein is the thick or "curd" portion of milk produced as part of the cheese making process. When directly compared to other forms of protein, micellar casein has exceptionally high levels of the essential amino acids, including leucine. The most interesting aspect of micellar casein is its powerful anti-catabolic benefits stemming from its ability to digest slowly, which allows for higher, more balanced leucine levels over an extended period of time. Unlike whey protein, micellar casein protein is not soluble in the acidic environment of the stomach, which leads it to clump up and thus digest in a much slower fashion [24]. This digestive action is extremely favorable, and in fact, research studies using miceller casein over the last ten years continually show that it has a powerful ability to prevent the loss or breakdown of protein, while also still providing a robust ability to facilitate protein growth [25, 33]. The long, slow release and strong ability to prevent muscle loss and breakdown are the exact reasons why bodybuilders must consider a micellar casein protein product in their regimen. One that is just being released amid much acclaim is Ultimate Casein from BioQuest. This new product is striking in its purity, quality, efficacy and even delicious taste, so it would appear to be an excellent start.

Advances in modern membrane technology have permitted manufacturers to isolate native micellar casein from fresh skim milk. This native micellar form is a pure protein with an excellent amino acid profile absorbable over a long duration. Even when compared to whey, micellar casein is responsible for an improved balance of protein across the tissues of the body over time periods of up to seven hours [24, 25]. In summary, adding micellar casein to your daily regimen covers your growth and recovery efforts during long periods of time when you don't have ready access to regular sources of protein and amino acids (such as during sleeping). In fact, it is perfect for use before bedtime because of its unique ability to provide a steady supply of protein overnight.

A word of caution. Not all casein products contain micellar casein, and instead, incorporate sodium, potassium or calcium caseinates. Caseinates are made to improve and speed up the protein's ability to digest by changing its chemical properties. While good for some purposes, this is the exact opposite effect a bodybuilder or strength and power athlete should look for in a casein product. The value of micellar casein comes from its ability to digest slowly, not quickly, as we have whey isolate and hydrolysate for that. Moreover, all of the supportive scientific research conducted using casein, which has demonstrated its ability to digest slowly, was performed with micellar casein [24, 25]. Overall, micellar casein is an excellent source of protein that contains very good levels of all of the essential amino acids and offers a great complement to the faster absorbing isolates. But to get the benefits of slow digestion and prevention of protein breakdown, a product like Ultimate Casein that uses a superior form of micellar casein must be considered.

Follow us on or for a chance to win this product!

  Milk Protein
The FDA states that products containing milk protein concentrate (or isolate) should contain all of the proteins naturally found in milk, and moreover, these proteins should exist with the same ratios as those naturally found in milk. As mentioned before, bovine (cow) milk contains approximately 80% casein and 20% whey. Therefore, products containing milk protein concentrate or milk protein isolate are best considered as "blends" of whey and casein. As with casein and whey protein, concentrate and isolate versions of milk proteins can be produced and some people feel like you can get "the best of both worlds" by consuming a milk protein concentrate or milk protein isolate. Interestingly, limited research is available examining the impact of milk protein concentrates or isolates. However, when one considers the powerful outcomes for both whey and casein individually, a combination of the two does seem to be a solid concept. One available study did examine the impact of a blend of whey (40 grams) and casein (8 grams) in young,  healthy, active men, who resistance-trained four days per week while supplementing on exercise days over a 10-week period [34]. When changes in strength and body composition were compared to a carbohydrate placebo and another group containing mostly whey protein, the authors found that muscle-mass gains as well as maximal strength levels were greater when the blend of whey and casein was consumed [34]. Furthermore, a two-part study using fat-free milk compared the changes in amino acid levels and muscle protein synthesis to a soy-protein and carbohydrate-containing beverage. The fat-free milk was responsible for the greatest increase in amino acid and muscle protein synthesis levels in the short term [35] and when compared to the changes in fat-free mass after 12 weeks of resistance training and consuming either drink, the fat-free milk beverage was responsible for significantly greater increases in muscle fiber size and overall muscle mass [36]. Of course, it is important to note that this is in comparison to soy protein, not whey isolate or micellar casein.


Animal Proteins (beef, poultry and fish)
Proteins found in beef, poultry (chicken, turkey and game fowl) and fish are complete proteins that can also contain significant amounts of other healthful nutrients. While the overall protein and essential amino acid content of beef can be quite good, the content of some negative health nutrients, primarily cholesterol and saturated fat, should be a consideration, particularly if you have elevated levels of risk for cardiovascular disease. Similarly, poultry and fish are excellent sources of protein and when the type of meat (white vs. dark) is carefully considered as well as the preparation method (baked, grilled, fried) these are excellent lean sources of protein. Certain types of fish are particularly attractive as they can provide substantial amounts of healthy fats and nutrients that other forms of animal proteins typically fail to provide. It is widely recommended that daily intake of these proteins occur, but due to the need for proper storage and preparation the convenience and use of these types of proteins in and around your workout (to take advantage of effective nutrient timing) is challenging. For these reasons, animal proteins are commonly not considered as a protein source for an athlete to consume on the run or before or after a workout. Certainly, they should be a large part of your overall diet but just as certain, they are not as efficient as supplemental protein.


Egg
Proteins from egg whites are considered to be of high quality and are still used as the reference or standard protein for determination of NPU values (see table 1). Albumin, a key protein found in egg whites is also found in our blood and is used by the body to help carry various substances throughout the body and to minimize amino acids from being broken down so they can be used to later build proteins, like muscle protein. A recent study used egg protein in dosages ranging from 5 to 40 grams to determine the dose that optimizes muscle protein synthesis response. A 20-gram dose was determined to be the optimal dose of egg protein to maximize muscle protein synthesis [13]. For years, egg protein was considered one of the best protein sources, but higher production prices and associated challenges have led to a decrease in the use of egg protein in dietary supplements. Again, good in the diet, especially the whites, but not a substitute for supplemental whey and micellar casein protein products.



Soy
Soy protein is extracted from the soybean plant, and despite lacking or having low levels of methionine, soy is considered a good source of protein. Soy protein has excellent digestibility, making its constituent amino acids highly available to bodily tissues [3]. Soy proteins are available in isolate (>90%) and concentrate (>70%) versions, and thus are excellent sources of protein for vegetarians. Known more for potential health benefits rather than for bodybuilding, soy protein contains isoflavone glucasides, which may be linked to improvements in lipid and bone, while promoting possible reductions in the risk for heart disease and various cancers [37], but these results are not conclusive [38, 39]. The ability of long-term soy use to potentially impact the balance between estrogen and testosterone has resulted in soy protein being considered an inferior form of protein for athletes and bodybuilders. It is worth noting that recent studies have provided conflicting results regarding soy protein's ability to impact circulating levels of testosterone [40, 41].

Relative to exercise, a recent study had a small group of young, healthy, exercise-trained men consume a small dose (22.4 grams) of a soy protein isolate at rest and before a single bout of lower-body resistance exercise [32]. Drink ingestion resulted in significant increases in essential amino acid levels in the blood, with and without exercise. Additionally, synthetic rates of muscle protein synthesis were also found to increase when drink ingestion was combined with resistance exercise [32]. However, when these changes were compared to those seen in older men after 20 grams and 40 grams were ingested on separate occasions of both whey protein and soy protein, whey protein was responsible for greater increases in muscle protein synthesis, which the authors attributed mostly to the differences in leucine content [42].


Gelatin
Gelatin is produced from the collagen found oftentimes inside the hide and bones of both swine and bovine. Gelatin is known to contain protein, collagen and various amino acids and it is marketed as part of food products as well as bone and other dietary supplements. The overall protein quality of gelatin is extremely poor. Unfortunately, there are a number of products on the market, including a few protein bars that contain varying amounts of gelatin in lieu of quality protein.


Conclusion--Top 3 Proteins for Maximum Muscle-Building
As we now know, there are a number of key factors that exist regarding protein supplementation and maximizing the adaptation your body will make to adapt to stressful and challenging exercise. While a number of proteins are available on the market, the fact is, whey isolate, whey hydrolysate (preferably derived from whey isolate) and micellar casein are the proven and preferred Top 3 proteins in both the scientific and bodybuilding communities. This ranking should be prefaced by the fact that these proteins must be of the highest quality in order to ensure results beyond adequate and into the rarefied realm of maximum efficacy!

Ultra and Cross Flow Microfiltration whey isolate protein, as found in NytroWhey products, deliver the highest amounts of pristine, amino-rich protein, including leucine, and should be a strong consideration for any bodybuilder who wants to pack on muscle and improve their body composition. More recent advances in protein technology have led to the development of a superior hydrolysate protein that's derived from a whey isolate base and provides rapid absorption of essential aminos and other key growth factors, as found in NytroWhey Ultra Elite, which also yields the highest amounts of synthesizing leucine in the category. An additional important consideration involves doing all that you can to minimize the loss or breakdown of the muscle you do build, while also adding to your mass gains even while you sleep.  In this regard, research continues to demonstrate that micellar casein is the best protein for this effect and Ultimate Casein is our industry's most powerful available.

While an athlete's overall daily diet of various proteins (e.g., milk, egg, and animal proteins) provides a critical foundation of nutrition, the combination of a high quality whey protein isolate or hydrolysate product during and after your workout, with a micellar casein at night, is certain to result in the most effective delivery of critically important amino acids to successfully prime your muscles for rapid growth and optimum physique development.

---

Chad Kerksick, PhD, is an Assistant Professor of Exercise Science in the Health, Exercise and Sport Sciences department at the University of New Mexico. He teaches undergraduate and graduate courses in exercise physiology, biochemistry and nutrition. His research interests and expertise focus on studying the impact of exercise and nutrition interventions on health, performance and recovery.

References:
1. Campbell, B., et al., International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr, 2007. 4: p. 8.
2. Kreider, R.B., et al., ISSN exercise & sports nutrition review: research & recommendations. J Int Soc Sports Nutr, 2010. 7(1): p. 7.
3. Rodriguez, N. and W. Lunn, Proteins and Amino Acids The Repair Blocks Their Place in Growth and Recovery, in Nutrient Timing Metabolic Optimization for Health, Performance and Recovery, C. Kerksick, Editor 2011, CRC Press: Boca Raton, FL. p. 44-60.
4. Tipton, K.D., et al., Nonessential amino acids are not necessary to stimulate net muscle protein synthesis in healthy volunteers. J Nutr Biochem, 1999. 10(2): p. 89-95.
5. Volpi, E., et al., Essential amino acids are primarily responsible for the amino acid stimulation of muscle protein anabolism in healthy elderly adults. Am J Clin Nutr, 2003. 78(2): p. 250-8.
6. Fujita, S., et al., Nutrient signalling in the regulation of human muscle protein synthesis. The Journal of physiology, 2007. 582(Pt 2): p. 813-23.
7. Drummond, M.J., et al., Nutritional and contractile regulation of human skeletal muscle protein synthesis and mTORC1 signaling. J Appl Physiol, 2009. 106(4): p. 1374-84.
8. Phillips, S.M., J.E. Tang, and D.R. Moore, The role of milk- and soy-based protein in support of muscle protein synthesis and muscle protein accretion in young and elderly persons. J Am Coll Nutr, 2009. 28(4): p. 343-54.
9. Tang, J.E. and S.M. Phillips, Maximizing muscle protein anabolism: the role of protein quality. Curr Opin Clin Nutr Metab Care, 2009. 12(1): p. 66-71.
10. Cuthbertson, D., et al., Anabolic signaling deficits underlie amino acid resistance of wasting, aging muscle. FASEB J, 2005. 19(3): p. 422-4.
11. Bohe, J., et al., Latency and duration of stimulation of human muscle protein synthesis during continuous infusion of amino acids. J Physiol, 2001. 532(Pt 2): p. 575-9.
12. Bohe, J., et al., Human muscle protein synthesis is modulated by extracellular, not intramuscular amino acid availability: a dose-response study. J Physiol, 2003. 552(Pt 1): p. 315-24.
13. Moore, D.R., et al., Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. Am J Clin Nutr, 2009. 89(1): p. 161-8.
14. Yang, Y., et al., Resistance exercise enhances myofibrillar protein synthesis with graded intakes of whey protein in older men. The British journal of nutrition, 2012: p. 1-9.
15. West, D.W., et al., Rapid aminoacidemia enhances myofibrillar protein synthesis and anabolic intramuscular signaling responses after resistance exercise. Am J Clin Nutr, 2011. 94(3): p. 795-803.
16. Nair, K.S. and K.R. Short, Hormonal and signaling role of branched-chain amino acids. J Nutr, 2005. 135(6 Suppl): p. 1547S-52S.
17. Rennie, M.J., et al., Branched-chain amino acids as fuels and anabolic signals in human muscle. J Nutr, 2006. 136(1 Suppl): p. 264S-8S.
18. Kimball, S.R. and L.S. Jefferson, Signaling pathways and molecular mechanisms through which branched-chain amino acids mediate translational control of protein synthesis. The Journal of nutrition, 2006. 136(1 Suppl): p. 227S-31S.
19. Pasiakos, S.M., et al., Leucine-enriched essential amino acid supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis. The American journal of clinical nutrition, 2011. 94(3): p. 809-18.
20. Rieu, I., et al., Leucine supplementation improves muscle protein synthesis in elderly men independently of hyperaminoacidaemia. The Journal of physiology, 2006. 575(Pt 1): p. 305-15.
21. Churchward-Venne, T.A., et al., Supplementation of a suboptimal protein dose with leucine or essential amino acids: effects on myofibrillar protein synthesis at rest and following resistance exercise in men. The Journal of physiology, 2012.
22. Manninen, A.H., Protein hydrolysates in sports nutrition. Nutr Metab (Lond), 2009. 6: p. 38.
23. Schaafsma, G., Safety of protein hydrolysates, fractions thereof and bioactive peptides in human nutrition. Eur J Clin Nutr, 2009. 63(10): p. 1161-8.
24. Boirie, Y., et al., Slow and fast dietary proteins differently modulate postprandial protein accretion. Proc Natl Acad Sci U S A, 1997. 94(26): p. 14930-5.
25. Dangin, M., et al., The digestion rate of protein is an independent regulating factor of postprandial protein retention. Am J Physiol Endocrinol Metab, 2001. 280(2): p. E340-8.
26. Burke, D.G., et al., The effect of whey protein supplementation with and without creatine monohydrate combined with resistance training on lean tissue mass and muscle strength. Int J Sport Nutr Exerc Metab, 2001. 11(3): p. 349-64.
27. Cribb, P.J., et al., The effect of whey isolate and resistance training on strength, body composition, and plasma glutamine. Int J Sport Nutr Exerc Metab, 2006. 16(5): p. 494-509.
28. Hayes, A. and P.J. Cribb, Effect of whey protein isolate on strength, body composition and muscle hypertrophy during resistance training. Curr Opin Clin Nutr Metab Care, 2008. 11(1): p. 40-4.
29. Monchi, M. and A.A. Rerat, Comparison of net protein utilization of milk protein mild enzymatic hydrolysates and free amino acid mixtures with a close pattern in the rat. JPEN. Journal of parenteral and enteral nutrition, 1993. 17(4): p. 355-63.
30. Stoll, B. and D.G. Burrin, Measuring splanchnic amino acid metabolism in vivo using stable isotopic tracers. Journal of animal science, 2006. 84 Suppl: p. E60-72.
31. Manninen, A.H., Hyperinsulinaemia, hyperaminoacidaemia and post-exercise muscle anabolism: the search for the optimal recovery drink. British journal of sports medicine, 2006. 40(11): p. 900-5.
32. Tang, J.E., et al., Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men. J Appl Physiol, 2009. 107(3): p. 987-92.
33. Dangin, M., et al., Influence of the protein digestion rate on protein turnover in young and elderly subjects. J Nutr, 2002. 132(10): p. 3228S-33S.
34. Kerksick, C.M., et al., The effects of protein and amino acid supplementation on performance and training adaptations during ten weeks of resistance training. J Strength Cond Res, 2006. 20(3): p. 643-53.
35. Wilkinson, S.B., et al., Consumption of fluid skim milk promotes greater muscle protein accretion after resistance exercise than does consumption of an isonitrogenous and isoenergetic soy-protein beverage. Am J Clin Nutr, 2007. 85(4): p. 1031-40.
36. Hartman, J.W., et al., Consumption of fat-free fluid milk after resistance exercise promotes greater lean mass accretion than does consumption of soy or carbohydrate in young, novice, male weightlifters. Am J Clin Nutr, 2007. 86(2): p. 373-81.