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Protein has become synonymous with resistance training. Traditionally protein powders were used as a method of increasing the daily protein intake of strength training athletes. Milk and egg proteins were the basis of those chalky, bad tasting products that were associated with bodybuilding and the early 1980's. However whey protein fractions have revolutionised the benefits of protein powders and made them appropriate for daily use in many dietary programs.
Whey protein has a number of benefits over other proteins (1,2):
" high bioavailability- it absorbs rapidly decreasing stress on digestive enzymes
" It is high in branch chain amino acids which are excellent for muscle tissue repair
" Glutamine rich providing anti catabolic protection and anti oxidant benefits
" A highly concentrated protein source, that is very low fat
" It enhances production of glutathione a powerful anti oxidant
" Approximately 10% immunoglobulin protein which supports the immune system
" It is lower in lactose and sodium than other dairy proteins
However the benefits of whey protein fractions have been misrepresented within the industry. Many companies make claims about the superiority of their whey protein. The biological value (b.v) of a company's whey product is an excellent example of fictitious claims used to sell a product. Next time you read the promotional material for protein products you should be aware that biological value is an outdated measure of protein quality. It was originally designed as a percentage, representing the protein's ability to support nitrogen retention. Egg albumin was given a 100% rating. However filtered whey protein proved to be a better protein source for improving nitrogen retention and then values of greater than 100 were assigned. Supplement companies use these figures as a means for promoting whey as a superior protein. As filtration of whey increased the 'purity' of the whey the b.v increased and was then used as a tool to compare protein effeciency in building muscle (ref about bv required).
Much hype has surrounded the use of whey proteins and many supplement companies promote false science in an effort to improve sales. The process behind the manufacture of whey protein fractions should clear up many of the misconceptions behind whey protein.
When milk is separated for the production of dairy products, including cheese and yoghurt, whey is the liquid by-product of this process. The next step in purification is to filter out the fat and milk sugars (lactose), leaving a concentrated whey protein. The level of filtering determines the level of protein in the final product. For example whey protein concentrate can be as low as 30% protein or as high as 80%.
It is vital that this process occurs in a heat stable, cold temperature environment, such as in cross flow micro filtration. High heat levels will cause protein chains to denature. High percentage protein, whey protein concentrate (wpc80) is an excellent, cost efficient source of protein, which is an extremely high grade when compared to normal dairy protein (such as casein).
Whey protein concentrate can be filtered to a greater degree producing a whey protein isolate. An incredibly pure protein fraction, whey protein isolate provides significant advantages over other protein sources. Including negligible levels of fat and carbohydrate. The other major advantage is absorbability (3). Whey protein isolates are composed primarily of short chain proteins - di and tri peptides as well as amino acids. These short chain peptides require less digestion than longer chain proteins such as those in meat or less pure dairy proteins. This means that the protein reaches your muscle tissue much faster than normal food (4).
Dipeptides are bonds of two amino acids and tripeptides are bonds of three
amino acids. A protein is anything above a chain of 50 amino acids
(polypeptide). Proteins can be hundreds or thousands of amino acids bound
together. The body breaks these down with digestive enzymes. The amino acids
are then used by the body in millions of processes including the repair of muscle
tissue. The process required for muscle growth. (ref would be handy)
Another method of purification is to hydrolyse the whey fractions by treating them with an enzyme process to produce smaller whey peptides. Similar to isolate, hydrolysed whey consists of small di and tri peptides that are rapidly digested, with some longer chain peptides remaining. Unfortunately hydrolysation causes the whey to taste quite bitter and is therefore seldom used to the extent of whey isolates or concentrates. However it is a useful addition to a blended protein that mixes whey peptides providing a spectrum of short and medium chain peptides for rapid absorption.
(ref required on process of manufacture for whey conc,hydrol,iso)
Put simply, micro filtered whey protein is described as a superior form of protein because it is a highly concentrated protein source, which rapidly supplies amino acids to the muscle cell and is lower in fat than any other source of protein (5). For this reason supplement company's base they're leading protein supplements on whey protein fractions. The more filtered the fraction (isolate), the purer the protein and the greater the cost.
With a healthy dose of cynicism you may wish to address some of the promotional material that has influenced your views on which protein powder you select. When perusing the material it is important to remember that most of the recent developments in protein technology have been made by the manufacturers of dairy products, not sport supplement companies. The dairy industry supplies the majority of raw ingredients for protein powders. Contrary to what certain companies will have you believe the raw ingredients were not discovered or produced by the supplement companies. Most companies use contract food manufacturers to put together the raw ingredients, or in some cases, the larger companies own their own manufacturing facilities (I don't mean companies using a tub in the basement).
Research into protein metabolism is increasing, however you must be careful to examine the research yourself as it is regularly used as a means of legitimisation by supplement companies. An excellent example of this is a famous study by Boirie et al in 1997. The findings showed that 30grams of whey resulted in a 68% response for protein stimulus versus 43gm of casein, which produced a 31% response (7). You may recall the advertisements for whey protein saying 'new studies prove whey is 119% more anabolic than casein'. Statistics can be manipulated to support many claims. This is demonstrated by a rival companies claims that the same study showed whey protein is not as potent at inducing muscle growth because the rise in amino acids from whey was so quick that the amino acids were oxidised by the liver as an energy source. Therefore these aminos were not active at muscle cell site for tissue repair. Therefore slower proteins such as casein are required to maintain a defence against catabolism, promoting muscle growth.
Who to believe? There is not enough evidence to suggest one protein fits all. Examining protein intake and its effect on muscle mass has not been clearly researched using advanced strength trainers. Much of the research and resulting hypothesis involve a small leap of faith.
Now that a few of the myths about protein powders have been addressed it is appropriate to understand how, when and which protein supplement to use. As discussed in the article on increasing lean muscle tissue, we can only digest a limited amount of protein per serve (25 - 35 g). Therefore regular protein rich meals must be consumed throughout the course of the day. In many cases a meal replacement product may be used to substitute food at those moments in the day when you are unable to prepare healthy food. However you may require a lower calorie alternative or be specifically requiring a fast acting protein source. This is when whey protein becomes the outstanding choice.
Whey protein is prescribed as a post resistance-training supplement, when the bodies need for protein is increased (5). Whey fractions digest rapidly and cause a significant anabolic effect, however the shorter chain peptides of protein isolates and hydrolysates have little anti catabolic effect. The high branch chain amino acid and glutamine content of whey is beneficial in decreasing muscle breakdown, however a slower absorbing protein such as casein and food proteins (i.e. chicken/ fish) provide a slower absorption of protein, leading to a lower, but longer duration rise in amino acids. This provides ongoing protection against muscle tissue breakdown.
Therefore examining the data to date and witnessing the first hand results of many international standard athletes we have concluded; whey is best when you require rapid absorption, low fat and low lactose. It is normally convenient and adds total protein to your diet with minimal side effects (stomach disorder, bloating). So use whey fractions when you need fast acting proteins such as after periods of fasting, when you wake in the morning and immediately post training (6). However it is only one of the protein sources at your disposal. Whole food is often more taste satisfying and is better suited to your main meals. If you require a complete meal replacement snack where the time of absorption is not as important as immediately post workout, casein, soy and egg can be useful additions to your diet and are cheaper sources of protein (7) (refer to article on meal replacement).
Next time you choose a protein supplement you may understand a little more about exactly what is in your product. Be critical, read the labels and question the claims of the manufacturer. Think carefully about who is promoting the product and whether the benefits of the product are perhaps a little far fetched. If a company has discovered a secret ingredient why have you not heard more about it and what evidence is their of the results? Excuse the skepticism, but the supplement industry is full of new wonder products with short life spans!
1. Kelly, G.S. Sports Nutrition: A Review of Selected Nutritional Supplements For Bodybuilders and Strength Athletes, Alt Med Review, 1997;Vol 2, (3): 184-201
2. Fiat AM, Migliore-Samour D, Jolles P, et al. Biologically active peptides from milk proteins with emphasis on two examples concerning antithrombotic and immunomodulating activities. J Dairy Sci 1993; 76:301-310
3. Poullain MG, et al. Effect of whey proteins, their oligopeptide hydrolysates and free form amino acid mixtures on growth and nitrogen retention in fed and starved rats. J Parenteral and Enteral Nutr 1989; 13:382-386
4. Defronzo, R.A. Differential responsiveness of protein synthesis and degredation to amino acid availability in humans. Diabetes.1996; 45:393
5. Fryhbeck, G. Protein Metabolism: Slow and fast proteins. Nature 1998; 391:843
6. Pacy, PJ. Nitrogen homeostasis in man: the diurnalrespons of protein synthesis and
Degradation and amino acid oxidation to diets with increasing protein intakes. Clin Sci 1994; 86:103
7. Boirie, Y. Dietary protein quality influences postprandial protein utilization.
Reprod Nutr Dev. 1997; 37:337