Soy Vs. Whey Vs. Casein Protein Shakes

There are many different protein shakes on the market. Some come with flashy names like “Nitro-Tech” and “Isopure” while others opt for more direct names like “Muscle Milk” or simply “100% Whey.” No matter what the name, or how flashy the label and advertising are, the base of the product is protein. This protein can come from different sources. Three of the popular choices are soy, whey, and casein. Many shakes combine the proteins for the best absorption and long term amino acid release.

Let’s take a look at each of these three proteins and what they have to offer. Starting with soy, we find a protein that is complete (containing all the essential amino acids) and available in abundance. This protein is extracted from the soybean. It is processed to produce a soy protein isolate. This is a highly digestible source of amino acids for building muscle. The benefit of soy protein is the low fat, cholesterol, and calorie content. Vegans find this protein useful because it is a plant based protein and provides the complete array of amino acids. Soy protein can be gritty and some users complain of a little after taste.

Casein Protein

Casein is found in cow’s milk, and makes up 80% of the protein in milk. This is the curd that results when milk is left to sour. This is the most commonly used protein in the food industry. Casein itself is not readily dissolved in water so the salts, caseinates, are more often found in the ingredient lists of foods and supplements. Calcium caseinate is the most commonly used caseinate in foods and supplements. It is a smooth protein and breaks down slowly in the digestive tract. It coagulates in the stomach which results in a slower digestion and a feeling of fullness. Unfortunately, this is also the reason for the uncomfortable gas and bloating sometimes associated with protein shakes.

Whey Protein

Whey protein is the other 20% of milk protein. It is a natural by-product of cheese making. In its raw form it contains fats, lactose, and other milk products. Most whey is processed to produce whey protein concentrates and whey protein isolates which are very protein rich. Whey protein is made up of very high-biological-value proteins. The two main proteins in whey are beta-lactoglobulin and alpha-lactoglobulin, which account for almost 80% of the total whey protein. Also found in whey, in smaller amounts, are immunoglobulins IgG, glycomacropeptides, bovine serum albumin, lactoferrin, lactoperoxidase and lysozyme.

Whey protein isolates can be prepared several different ways. The ion-exchange method produces isolates that are high in protein but low in glycomacropeptides, lactoferrin, lactoperoxidase and some bioactive peptides. Microfiltration, or ultrafiltration, isolates have a higher content of glycomacropeptides, lactoferrin, lactoperoxidase and the bioactive peptides, but less bovine serum albumin. Cross-flow microfiltration produces an undenatured protein with greater than 90% protein and it retains the natural sub-fractions with no fat or lactose. There are three main forms of whey protein. Hydrolyzed Whey Protein Isolates (HWPI) are very easily digested, but it is expensive to process and leaves a very bitter aftertaste that cannot be covered by sweeteners or flavoring. Whey Protein Isolate (WPI) is also easily digested, but it has a much better flavor than HWPI. It is made using cross-flow microfiltration which also means it is virtually fat- and lactose-free. The last group is Whey Protein Concentrates (WPC) which is the least expensive form, but it has a wide variance of protein content, is not as readily digested, and may contain a larger amount of fat, carbohydrates, and lactose.

Soy Protein

Soy protein is a great choice for the person looking to add complete proteins without animal sources. It also has other health benefits found in soy. Casein is a cheaper protein, that breaks down slower, so there is a sustained release of amino acids. This is a good choice for a night time protein supplement. Whey, especially WPI, is a good choice for someone looking to get no fat, lactose free, protein that can be absorbed quickly into the system, especially after a workout. Each protein has its benefits, and its drawbacks. Give each type a try, or find a supplement that incorporates each in its formula.  Looking to choose a dirnk with the right type of protein for you?  Check out the best protein shakes.