Principally, protein is protein....it delivers 4kcal of energy per gram, it’s comprised of amino acids and is the main structural component of muscle. However, protein is derived from a variety of sources including meat, egg, milk and soya, and less dense sources such as pea, hemp and brown rice. Despite the plethora of protein derivatives, protein is ultimately broken down to amino acid building blocks which are used to either repair and build muscle, metabolised for energy or used in cellular processes in the form of enzymes, cell replication (needed for growth and development) and the clean-up of waste products in the body.
Some sources of protein deliver more ‘essential amino acids’ compared to others e.g. a single egg contains all of the essential amino acids in one serving, whereas a portion of peas will deliver several ‘non-essential amino acids’ but will always leave your body short of some essential amino acids. The key to avoiding any amino acid deficiency is to consume a healthy balanced diet consisting of all the major food groups i.e. starchy carbohydrates, milk and dairy, fruit and veg and meat, fish, eggs and beans (protein sources) (NHS Choices, 2012).
However, when observing an intense training routine it is not always easy for people to consume adequate amounts of the abovementioned foodstuffs to satisfy their protein requirements. Consequently, people turn to readily absorbed high quality liquid protein, in the form of protein shakes to make up for this potential deficit (British Dietetic Association, 2011).
(NB: See our blog for our article on how to calculate your protein requirements)
Types of Protein Supplement
So fundamentally, protein is protein, but it has its subtle differences in the way it works, the way it is sourced, and the way it is delivered to the consumer market. Protein supplements are mainly derived from milk, egg, soya, pea, hemp and wheat, but the two most common forms are milk based whey and casein...think back to ‘little Miss Muffet’s curds and whey’ and you have the raw basis of this protein supplement. Whey protein then undergoes a number of processes to form a whey protein concentrate, whey protein isolate, or a whey protein hydrolysate, all of which deliver whey protein to some degree. The difference between these forms of protein depends on the level of processing they undergo. In the protein supplement world, the more processing a supplement undergoes, the purer the protein.
Whey Protein Concentrate
Whey protein concentrate receives the least processing and consequently contains some fat and carbohydrate (lactose). Typically this form of whey contains 70-85% protein relative to weight. Whey concentrate is the cheapest protein on the market but will provide the body with high quality, high biological value (easily absorbed) amino acids (Llewellyn, 2009).
Whey Protein Isolate
Whey isolate is the most popular protein on the market and in my opinion, for good reason too. It is the purest form of protein available and undergoes several membrane filtrations/ ion exchanges to produce a protein that is free from fat and carbohydrate, delivering 90% protein relative to weight. The biological value is as good if not better than whey concentrate, and the filtration process retains many of the key amino acids. Taste is generally better than whey concentrate because of the plainness of the powder emphasising the flavours that are added to it (Llewellyn, 2009; Kreider, Wilborb, Campbell, 2008).
Whey Protein Hydrolysate
Whey Hydrolysate is the most highly processed protein on the market; it is no better in terms of quality compared to whey isolate but has been pre- digested to form what’s known as a semi-elemental supplement designed to aid digestion and absorption. A pre-digested protein means there is a marked increase in the absorption rate. Similarly to whey isolate, hydrolysate delivers 90% protein relative to weight, and next to no fat or carbohydrate. The downside is that the branch chain amino acid content is slightly lower compared to concentrate and isolate due to the extent of processing it receives. Hydolysate is usually only added to protein shakes to make up the difference and is not generally consumed as a standalone supplement (Llewellyn, 2009; Kreider, Wilborb, Campbell, 2008).
Casein accounts for 80% of the protein found in cow’s milk, it is lumpy (micellar) in its raw form whereas whey is liquid. Like whey protein, casein contains essential, non-essential and branched chain amino acids (BCAA), but the overall BCAA content is lower than whey. The key factor that has embedded casein proteins position in the market is its slow digestion and absorption rate (up to 7 hours for complete absorption); this slower absorption is largely attributed to the micelles that are characteristic of casein. When purchasing Casein we recommend opting for ‘micellar casein’ due to the undenatured protein (undamaged protein) allowing for maximal absorption and utilisation. Like whey isolate, micellar undergoes a stringent filtration process which protects the micelles and protein integrity. Micellar casein can be as high as 92% protein relative to weight, with very low fat and carbohydrate levels. Casein mixes relatively poorly due to its micellar content, and for this reason it is often added to whey protein blends for its slow digestive properties and enhanced mixability (Llewellyn, 2009).
British Dietetic Association, (2011). Food fact Sheet. Sport. Retrieved June 26, 2012, from http://www.bda.uk.com/foodfacts/sportsfoodfacts.pdf
Kreider, R, B., Wilborb, C, D., Campbell, B., Almada, A, L., Collins, R., Cooke, M et al, (2010). ISSN exercise & Sport Nutrition Review: Research & Recommendations. Journal of the international society of sports nutrition. 7: 1550-2783.
Llewellyn, W, (2009). Sport Supplement Reference Guide. Conjugated-Linoleic Acid (CLA). Military trail: Molecular Nutrition LLC of Jupiter.
Nature Education, (2011). Protein Function. Retrieved June 26, 2012, from http://www.nature.com/scitable/topicpage/protein-function-14123348
NHS Choices, (2012). NHS Choices, you’re health, you’re choices. The eatwell plate. Retrieved June 26, 2012, from http://www.google.com/imgres?hl=en&biw=1422&bih=1036&tbm=isch&tbnid=wA7ZXiS3_wzD6M:&imgrefurl=http://www.nhs.uk/Livewell/Goodfood/Pages/eatwell-plate.aspx&docid=bWoVDhGoJGtMpM&imgurl=http://www.nhs.uk/Livewell/Goodfood/PublishingImages/eatwell%252520plate%252520377%252520sized.jpg&w=377&h=282&ei=WdnpT6-bLIbRhAelxZiPDQ&zoom=1