Mark Tallon

THE GREAT Protein Debate: Casein vs.Whey

By Mark J. Tallon, B.Sc., M.Sc., CBiol., MBiol., CSCS

Discover the Best Source of Protein to Optimize Your Performance!

You know your body needs protein for recovery, growth, and optimum performance. So you head for your local health-food store to buy a protein supplement...seems like an easy task, right? Once in the store, though, you're confronted by shelves of weight gainers, meal-replacement powders, and a host of protein sources like soy, casein, and whey. So how do you make the right decision for the most scientifically credible, cost-effective protein source?

Whey has been shown time and time again to be second to none when it comes to improving recovery, immune function, and athletic performance. You've heard that before, I'm sure. So why are we still talking about whey? Is there anything new to add? Well, yes. You see, over recent months, there has been a wealth of new information about the beneficial effects of whey and protein in general, as well as newly released data that indicates a better method to optimize its use.

1 | Optimal Performance and Protein Intake

Long gone are the caveman views that it's only the strength and bodybuilding community interested in supplementing their protein intake. Protein is now recognized as an important food source for every active exerciser; unfortunately, many nutritional advisors are still behind the times.

This appears to be due to their difficulty making a distinction between dietary needs to offset nutritional deficiency vs. dietary needs to enhance performance. These two goals require two very different approaches. What many nutritionists and dieticians fail to realize is that when advising athletes on protein intake, a clinical deficiency in consumption might lead to a loss in muscle mass and recovery; however, correction of that deficiency will not necessarily lead to optimal performance.

The way I see it, every athlete we work with wants one thing from supplementation "Maximization of Performance," and every exerciser seeks to "improve body composition." So will going above the recommended intake for deficiency prevention increase your recovery, adaptation, and most importantly, your performance?

2 | What Research Says About Protein Intake

Lemon, et al., studied different protein intakes and compared nitrogen balance between the groups. Nitrogen balance indicates if enough protein has been taken to allow muscle growth and recovery rather than breakdown; i.e., more protein is available than can be used. The data shows us that endurance athletes need around 1.2 to 1.4 g/kg of bodyweight to achieve a positive balance (see Fig. 1). Similar data has shown strength athletes have a maximum need of 1.8 g/kg.

You may be surprised to know that although we have data recommending up to 1.8 g/kg, at present, the recommended RDA for protein intake is only 0.8 g/kg bodyweight. Just another example of need verses optimization. One of the most important rationales behind a higher protein intake for those of us involved in exercise is that of supporting the recovery process from intense training: if you don't have an adequate dietary intake, you will suffer the consequences in recovery. In essence, this brief overview indicates that without optimizing your nutrition, there will be inadequate recovery from year-round training sessions, and you will see only MINIMAL progress in your adaptation to intense RESISTANCE or ENDURANCE training sessions.

3 | Whey Protein Isolates: Next Millennium Nutrition

About 20% of all proteins available in milk take the form of whey—the other being casein, which makes up 80%. Once considered a waste product and discarded into ponds, whey protein research over the past decade has begun to describe unique beneficial properties not seen in other protein sources.

Fig. 1 Adapted from Tarnopolsky, M.A., et al., "Evaluation of Protein Requirements for Strength Trained Athletes," J Appl Physiol 73 (1992) : 1986-1995.

Lemon, P.W.R., et al., "Protein Requirements and Muscle Mass/Strength Changes During Intensive Training in Novice Bodybuilders," J Appl Physiol 73 (1992) : 767-77.

Most whey proteins for sale today are whey hydrolysates. These hydrolysates are obtained from larger whey proteins enzymically broken down into smaller pieces for one reason and one reason only: to enhance absorption.

The GI (gastro-intestinal system) prefers hydrolysed proteins as they are more easily absorbed into the bloodstream than whole protein sources, meaning they get delivered rapidly to where they are needed most—your muscles. Because of its increased bioavailability, whey protein absorption is about twice as fast as intact/whole proteins, so it's considered a far superior form of protein supplementation for athletes. But what makes WHEY the best of the rest?

4 | Why Is Whey #1?

The best way of attacking this is to compare it to its nearest competition—casein. Both are high-quality protein sources, yet they have two main differences.

1) Their amino acid composition.
2) Their bioavailability.

Simply put, the amino acids from whey move through the GI into your bloodstream and therefore your muscles much quicker than casein, which means casein delays the delivery of amino acids to your muscle! However, this is not always the most advantageous of properties as far as nutritional optimization is concerned. Let's investigate...

This difference means that there is a rapid up-regulation of protein synthesis using whey proteins, which is ideal for use after exercise when protein needs are at their greatest. The elevation of those essentially needed amino acids from whey ingestion are elevated for five hours and then return to normal but do not influence protein breakdown.

Casein elevates blood amino acid concentrations for seven hours and decreases protein breakdown but stimulates synthesis to a much smaller degree than whey (see Fig. 2). As we know, the balance between breakdown and synthesis is what allows muscle growth and recovery.

So what this data means is much of their effectiveness is an issue of the rate that these proteins can break down rather than a direct comparison of their innate amino acid composition. Dangin, et al., compared directly slow digesting casein to a faster digesting casein source and similarly with whey. At the end of the seven-hour period, the slow protein (whether casein or whey) led to greater protein balance (more synthesis than breakdown).

In essence, we are still awaiting a direct training study comparing casein and whey with the same breakdown periods. Then we can truly assess them head to head. Until then, we must look at the studies separately to demonstrate which is better. A better alternative, however, may be to use a mixture of both supplements within your diet. The alternative may be in the use of a chemically modified form of whey that can break down over a period similar to casein. But this is not currently available.

On a final note: casein is not very palatable in a high dosages and is difficult to mix unless you fancy a milkshake with the consistency of cement, so I suggest any mixture you consume contain no more than ten grams of casein per serving!

Fig. 2 Adapted from Boirie, Y., et al., "Slow and Fast Dietary Proteins Differently Modulate Post-Prandial Protein Accretion," Proc Natl Acad Sci 94 (1997) : 14930-5.

5 | Protein Pulsing: Timing Matters

The most valuable information we are likely to provide you with in this article is how best to incorporate whey and similar proteins into your current nutrition plan.

A talk at the 2003 ACSM conference described possibly the most effective way to optimize protein use based on the concept that any intake above 1.8 kg confers no additional advantage to protein synthesis. I suggest this concept is best described as "Protein Pulsing" due to the pulsitile nature of protein release using this method.

Let me explain... When researchers assess the effectiveness of a protein for synthesis and protein balance, they use nitrogen balance as one marker, but they also use the measurement of an enzyme that controls the rate of branched chain amino acid oxidation.

Its activity is elevated when we increase our protein intake or increase our exercise level. In Figures 3 and 4, the shaded area represents a period where this oxidation activity decreases between meals. What this suggests is that the protein delivery to the muscle is no longer above that needed to synthesize new muscle proteins, so its activity decreases as a mechanism to spare protein sources (decreased oxidation).

Fig. 3 Protein uptake following a common dietary intake (three meals a day).

Fig. 4 Improved protein uptake with the dietary intake modified to five meals a day, similar to that recommended by Real SOLUTIONS (for resistance athletes).

If diet were optimal, we would have a constant plateau indicating a positive protein intake. When comparing a standard meal program (Fig. 3) against typical Real SOLUTIONS recommended meal guidelines (Fig. 4), there are far shorter periods where protein intake is not optimized (as indicated by the shaded areas). The reason for this is simple: we PULSE the intake of protein far more regularly, in essence increasing the delivery of amino acids to the muscles. In simple terms, the more frequent the protein intake, the better the uptake and delivery to the working muscle. (The data above is based on a 70-kg [154 lbs] man and a 1.8 g/kg intake [126 g of protein]: that's 25 g per meal if five meals are consumed or 42 g per meal if three meals are consumed.)

The best application of this data is in the indication of how we should use whey and casein; i.e., for those of you who desire a greater anabolic (muscle-building) response, which may include increased muscle mass, using a greater percentage of casein is recommended due to its slower release rate. For those of you who desire optimum recovery and to maintain muscle mass, whey is definitely the better protein source. It therefore makes sense due to the different effects whey and casein have on digestion and amino acid release that we apply this RATIONALE to our advantage in a simple plan. (See the sidebar "Your 3-Step Plan to Whey Better Protein Balance!")

Your 3-Step Plan to Whey Better Protein Balance

1) After Training

After training, the body is grasping for essential nutrients to rebuild those damaged muscle fibers and branched chain amino acid oxidation is elevated, so without a quick dietary supply, oxidation may continue to breakdown muscles. So the quicker we can deliver these essential peptides, the better. Whey protein would be the best form of protein just for this at 25 g per serving. (It may be taken in two doses to enhance recovery—one dose before training and one immediately after.)

2) During the Day

Throughout the day, your protein source can be maintained with consumption of whole foods, including lean meats, fish, and eggs. For those of you who train more than once a day, further supplemental whey protein may be needed as whole foods tend to take longer to break down, and large amounts of undigested foods in the stomach during training can be detrimental.

3) Prior to Sleep

Although sleep and bedtime are seen as synonymous with recovery and recuperation, the eight to ten hours of sleep are also a time of fasting. Over this time, you want to provide your body with the essential materials for muscle building and recovery. This could be achieved with either pure casein or a combination of whey and casein, delivering a constant stream of vital amino acids and peptides over a longer time. Indeed, recent studies have shown a significant benefit using a combination of whey and casein on lifting capacity. Based on this data, I suggest a final meal of the day composed of around 21 g of whey and four grams of casein.

The Final WORD on WHEY!

Well, we have covered most of the pertinent issues related to whey protein and your performance along with aspects of recovery and food timing.

Surely, you can now see why whey is the clear champion of proteins. It's cost effective and a high-quality source of protein that's easy to mix and absorb, making it perfect for your post-training meal. Due to the much better processing methods in the manufacture of whey, it is low in sugars, fat, and calories, so it's a great way to maintain muscle mass while on a calorie-restricted diet. In essence, whey has proved itself to be a versatile anti-catabolic (anti-muscle-wasting) protein source that is great for recovery and great for performance, yet combining it with casein may enhance its already compellingly effects.

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