Whey vs Casein Protein – Benefits & Disadvantages

Jessica Lewis
November 2, 2016

Nutrients are for the body what electricity is for a TV or what gas is for a car: its primary fuel. Specialists make a clear distinction between the two nutrient classes, micronutrients and macronutrients, and assign them different roles in the human body’s structure. As the name suggests, the micronutrients are comprised of vitamins and minerals that are essential to the individual’s health when used in modest amounts. Macronutrients, on the other hand, are compulsory in the diet as the body feeds on and uses them to create and release energy.

There are 3 macronutrients, namely the proteins, carbohydrates and fats. They are equally important so people should integrate them in the everyday meals in relatively similar quantities. It is good to keep in mind some things about them: complex carbohydrates are better than the simple ones, unsaturated fats are the healthier counterpart of the saturated ones and the best protein sources are lean meat, unprocessed dairy products and plants.

As of late, people have started using various products to supplement the body with extra nutrients as to enhance its function. Body builders more notably are the ones who use and promote supplements, those rich in protein in particular. Judging by the way many of them look, it seems that protein-based body building supplements are rather efficient both for losing weight and gaining muscles. While there are many other products whose formulas are plant based (Garcinia Cambogia extract or Forskolin for example), a bodybuilder’s arsenal is mainly comprised of two primary animal proteins: whey and casein.

Both compounds naturally occur in milk, being its main proteins. Still, some differences between them might influence possible customers in buying one or the other.

Whey and Casein

What used to be regarded as a waste product of milk is nowadays one of the most appreciated muscle building supplements. Endurance athletes use it but bodybuilders are the ones to have made from whey the popular product that it is at the present moment.

casein_whey_300x300Whey is the liquid remaining after the milk has been curdled in order to obtain cheese. The cheese production requires either an edible acid or rennet (a complex of enzymes found in the stomach of newborn calves) to be added to the heated milk. Two products are the result of milk coagulation: curds or the milk solids and liquid whey. Afterward, whey is usually used to obtain ricotta or whey butter. Another thing various manufacturers do is neutralize the liquid with citric acid and concentrate its protein percentage down to 80 or even 90% which is quite common when integrated into body building supplements. The product is then warmed and dried, thus becoming whey protein powder. As many others milk products, whey contains lactose and should be avoided by people who show intolerance to the compound. Moreover, when included in foods as an additive, it can lead to a lactose percentage higher than what these patients can tolerate. Whey contains vitamins and minerals along with lactose and low-fat levels, albeit in minor amounts.

Casein is the main milk protein, being present in both animal milk and the human breast one in larger quantities than whey is. It has low water solubility and a texture similar to gel. Due to this aspect, casein has the property to form a clot when inside the stomach so many companies that produce muscle building supplements regard it as one of their favorites. If whey is a fast acting protein, casein digests and releases nutrients slower. Often times, the amino-acid release process can last for several hours. In terms of use, casein seems to be more prolific than whey. This is both due to its texture and the fact that it represents a larger percentage in milk’s total composition. Casein is currently integrated into the production of paint, glue or plastics, aside from being a primary component in the cheese making process.

In terms of protein supplementation, whey is the more traditional compound although present in a lower percentage than casein. Some users have confessed that whey protein is one of the most potent types of supplements available on the market. However, casein protein users might contradict them every day, as casein seems to be more efficient, judging by how it reacts inside the body.

Which of these two groups is more trustworthy? Is whey protein better than casein protein or the other way round? Chances are they are the most efficient when used together. But for now let us take a closer look at each of them.


Whey Protein

After milk coagulated and the liquid portion was separated from the curds, producers process it even more as to make better use of it. Whey is then concentrated, dried and integrated into various supplements’ formulas. If in its original form is has little protein amounts, by the time it is processed it becomes whey protein isolate, a compound with no less than 90% protein. This is the result of it being drained by water, lactose and cholesterol. Specialists deem the whey isolate as its purest and most concentrated form. Another variation is Hydrolysate which is comprised of predigested peptide molecules that can be more easily absorbed and metabolized. Whey hydrolysate is generally more appreciated and used by all groups of people. Firstly, because it lacks certain constituents found in whey isolate that can produce allergies in children or people who might show intolerance to some of them and secondly because it enhances the amino acid absorption and provides the body with micronutrients faster than other compounds do.

Probably the most important aspect about whey protein is that it contains all 9 essential amino acids the body cannot produce by itself and has to obtain them from food. Also, it is rich in branch-chained amino acids which are necessary for muscle protein synthesis. Whey is quickly digested and emptied from the stomach. After it reaches the intestines, it is absorbed by their walls and released into the blood stream. The process usually takes about 20 minutes. Soon afterward, its amino-acids trigger certain metabolic activities inside the body such as protein synthesis or oxidation. Solely from this perspective, whey looks rather promising, compared to other supplements.

In addition, numerous body builders have affirmed that branch-chained amino acids have the property to ease recovery after working out for extended periods. The statements do not have a personal aspect as they are backed by scientific evidence. Studies suggest whey has high antioxidant properties and can increase glutathione production. Glutathione is a tri-peptide found in plants, animals, fungi and bacteria. It acts as a very potent antioxidant by protecting them from damage due to oxidative stress. Glutathione has a similar manner of action when inside the human body as well. In addition, whey’s ability to be quickly digested makes it suitable for use after long sessions of intense training.

Depending on the degree of difficulty and the time attributed to them, workouts can exhaust and even break the muscle cells. Thus, by acting so fast, whey protein can interfere and fix the damage while providing relief from muscle pain. Regular whey protein consumption also supports high blood amino acids levels for longer than usual which are related to an enhanced protein synthesis. This latter process is linked to an increase in the muscle mass of individuals who consume it. Some studies point towards whey protein’s possible satiety-inducing properties in individuals that are emotional eaters. Specialists suggest this is due to the presence of the compound’s structure of the various amino acids involved in the control of pancreatic secretion. Others state that whey protein might interfere with ghrelin’s mechanism of action and even block it for short periods. Ghrelin is a hormone that induces appetite. By suppressing it, whey protein might be beneficial, aside from the muscle building process, in the weight loss one also. In a study where participants were given drinks containing various types of proteins such as whey, tuna or egg albumin, the individuals who consumed the whey protein ones registered a decrease in appetite. This led to the conclusion that it can be efficient when used in overweight or obese patients. However more evidence is needed as proteins, be they animal or vegetal, act mainly on the muscular system level.[2]

Casein Protein

Casein is milk’s essential protein. Cow milk is made of no less than 80% casein while the human breast milk can contain anywhere from 20 to 45%. Essential, non-essential or branch-chained amino acids, they can all be found in casein’s structure. Unlike whey, casein protein is rather incapable of being dissolved in water in its original form. However, once it makes contact with liquids it forms micelles, small structures with a gelatinous texture which allow for a better water solubility. Casein is slowly digested once it reaches the stomach due to this aspect. This way, its amino-acids benefit for a more steady release than in the case of other animal based proteins. If whey hydrolysate had a relatively fast absorption rate that allowed for elevated amino acid levels for shorter periods, casein protein seems to be more efficient.Studies show it can maintain them for up to 7 hours after consumption. As a comparison, casein protein might be to whey what complex carbohydrates are

Studies show it can maintain them for up to 7 hours after consumption. As a comparison, casein protein might be to whey what complex carbohydrates are to the simple carbohydrates: an overall better energy source. Casein protein is regarded as an anti-catabolic and seems to be the element that balances the protein synthesis process. Due to a faster absorption, whey causes a sudden increase in protein synthesis. Casein, on the other hand, does not have the same effect on the amino-acid levels but decreases protein breakdown more efficiently than whey does. Because of this, casein supplements might be a more viable option to other similar products currently on the market. Since casein’s mechanism of action is visibly a slower one than whey protein’s, casein supplements are not the best choice for a post-workout boost. For this reason, bodybuilders use it during the night time when the body enters a relaxation mode and muscle tissues can be more easily repaired. All in all, casein might seem like the more prolific milk protein. However, there are some concerns surrounding casein consumption one might want to take into consideration before using such supplements.

Like most animal products, milk is linked to the occurrence of several medical conditions as well. By being its main constituent, casein can be regarded as the main culprit for milk’s unfavorable status. While epidemiological studies show inconclusive results, experimental projects suggest casein plays a significant role in the development of prostate cancer cells. Also, milk products in general, might promote the proliferation of cancer cells in spite of doing so with healthy cells also. More studies are to be conducted in the near future as milk is one of the most consumed foods. Although regarded as an excellent source of micro and macro nutrients, milk might as well have a downside to it if improperly integrated into the daily diet.[3]

Whey versus Casein: Which one is Better?

Both protein sources have advantages as well as disadvantages. To claim that one is better than the other would be incorrect. Whey protein might act in a different manner than casein protein and interact with the body processes more actively as casein appears to be a more passive compound. Even so, if the information stated above managed to offer an overview of their mechanism of action, the reader can easily understand that whey and casein, rather than opposing, complete each other.

If whey is more active and offers the body a kick as to synthesize protein efficiently, casein is able to reduce protein breakdown. Likewise, if casein protein maintains high amino-acid levels for several hours, whey protein is the most reliable supplement after an intense workout.

In a study, the participants were split into 2 groups and asked to fast for ten hours. They were then given either whey protein supplements or casein protein ones. The results were the following:

  • Both groups registered high leucine levels after using the supplements; leucine is an amino acid that enhances the protein synthesis process and is currently integrated into numerous bodybuilding supplements
  • The whey group saw a more drastic increase; the effect wore off about 4 hours after consumption
  • The casein group’s levels were lower but they were more constant and declined only after 7 hours
  • Whey protein had little to no effect on protein degradation while casein influenced it but was rather ineffective in regards to protein synthesis

A similar research project suggested that protein based supplements are more reliable in terms of muscle building properties. The study’s participants, all untrained men, were asked to perform regular workouts for 14 consecutive weeks and were offered supplements before and after the training. The daily dose consisted of either 25 grams of carbohydrate or 25 grams of milk protein (casein and whey combined). Once the study concluded, researchers have stated that the protein group registered a major increase in muscle mass when compared to the carbohydrate group. This might be because proteins are the muscles’ primary fuel so their function is naturally enhanced more by amino-acids and less by carbohydrates.

All these facts lead to the final conclusion that whey and casein protein might have distinct functions but they benefit the body more when they are used together rather than separately. While it is true that whey supplements are more popular among body builders, casein seems to gain more fame as an increasing number of companies are willing to integrate it in their products. Itis good to address a doctor before using such supplements. Either way, people usually buy and try them even without a specialist’s advice as the majority of ingredients integrated into their formulas are deemed as safe. If tempted, one should always pick the higher-quality product as the cheap ones have a price tag in accordance with their efficacy rate.