Introductory Overview of Whey Protein Usage
October 20, 2013 Admin 0
When discussing the subject of high protein diets, the question of protein sources usually comes into question. For some time, and before specialized proteins were available, whole eggs and later egg whites were the usual addition to the diet. Although milk was considered a reasonable protein source, it was not always relied on, as carbohydrate and fat contents prevented its consumption in large amounts. Even when skimmed milk was available, the lactose content prevented it from being a desirable way to increase your protein content for many.
Half a litre of skimmed milk contains about 17 grams of protein and that protein is approximately 80% casein and 20% whey. Casein (as calcium caseinate) was the original milk protein powder commercially available as a food supplement and was marketed and sold by sports supplement firms.
The product differed very little from caseinate products which were used in general food manufacture. Coffee whitener, dessert stabilisers and thickeners were often caseinate based, and very similar to casein based protein products aimed at bodybuilders and athletes. The supplements were often sweetened with sugar and had vitamin and mineral mixes added to them (referred to in marketing terms as ‘added value’).
When early protein supplements were formulated, they were often combined with skim or whole milk powders produced by simple spray drying techniques. This increased their lactose content in a similar way to consuming milk itself. As most early products were recommended to be mixed in milk, the resulting beverage was nothing short of a lactose-fest. The casein based protein powders available in the 1960’s are likely to differ considerably from protein products than contain casein in the present day, mostly because it is cheaper to produce casein in a pure form, simply by acidifying milk to the isoelectric point at pH 4/6 using lactic acid. Although the subject of a future article, high tech casein products based round casein micelles are produced in this manner and have little in common with early caseinate protein powders from a nutritional standpoint.
Besides the drawbacks mentioned, casein based protein powders show extreme hydrophobicity and are extremely difficult to mix into a palatable solution. It is this insolubility though that has spawned many a study to show how casein is a relatively slow absorbing protein compared to whey, and therefore has a different set of nutritional properties in comparison, most of which show benefit in certain circumstances. Whey and casein not only possess differing absorption rates, but largely differing amino acid profiles.
Whey protein is also known to stimulate insulin release in a manner which casein cannot. A high content of the branched-chain amino acid, leucine allows it to acquiesce a highly anabolic protein synthesis effect. The remarkable effect of leucine is in fact two fold : whilst leucine increases insulin secretion from the islets of Langerhans, the insulin released promotes protein uptake in muscle tissue. At first glance this is an ideal situation. The consumption of whey protein with its rich leucine content and the subsequent shuttling effect of insulin is aminoacidemic (an abundance of amino acids in the blood stream). Aminoacidemia aids in one aspect of the requirement for muscle hypertrophy and recovery after physical exercise, that of myofibrillar protein synthesis and increasing anabolic intramuscular signalling responses.
For these reasons, whey is the protein of choice after completion of resistance exercise such as weight training. Once any type of training is undertaken, whey protein is often used for its rapid absorption and assimilation properties. We already discussed how casein is a relatively slow digesting protein and would be of lesser value in a situation like this (but not without value as our later article will discuss). One mistake, often made is the consumption of whey protein di propia after exercise.
Once muscle breakdown has occurred via resistance exercise, two things have to be taken into account, increasing protein synthesis and decreasing protein breakdown. The most benefit would be garnered from catering for both the increase in protein synthesis whilst reducing protein breakdown. Whilst we know whey protein has an insulinogenic effect, it would not have enough effect on the reduction of protein breakdown on its own. To achieve a greater balance between these two issues, whey protein should be consumed with a carbohydrate matrix which maximises the protein sparing effect and likewise increase insulin response.
In this instance, consuming whey protein alone, a slower assimilating protein or carbohydrates on their own, would all avoid solving the issue of increasing protein uptake whilst decreasing protein breakdown. A successful post workout drink would therefore contain carbohydrates of a favourable glycaemic index and a generous amount of whey protein. To throw a small spanner in the works of the whey conundrum, whey proteins can also differ considerably, just like caseins. Whilst not the subject of this rather general overview, whey concentrate, whey isolate, cross flowing, micro filtrating and peptides are all terms you may hear or read when whey is discussed. To begin using whey as a supplement, starting with a reputable brand is paramount. We will discuss the merits of the particular types and blends of whey, along with the types and benefits of casein, in a later article.
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