Milk consists of carbohydrates, fat, vitamins, minerals – and protein. The milk protein is composed of two components, namely 80% casein and 20% whey protein. There is 3.4g of protein in milk, per 100g.

So while pure milk contains protein, special shakes with whey protein or casein provide protein in concentrated form and only contain small amounts of fat and carbohydrates. Protein is an indispensable part of sports nutrition because it has been proven to support muscle building and muscle maintenance and help maintain healthy bones.

Casein Protein

Casein accounts for the proportion in milk used to make cheese – hence the name that can be derived from the Latin word for cheese, causes. In cheese and curd, casein is responsible for the firm consistency. Casein protein has a high biological value, so the body can easily convert it into the body’s protein. Casein is digested very slowly, which can take up to eight hours in total. Casein, therefore, bears the names time-released protein and – because some athletes like to take it before going to bed to supply their body with amino acids overnight – night-time protein. Two forms of casein are common in sports nutrition:

  • Micellar casein
    Micellar casein is obtained by ultrafiltration. Here, the micellar casein separates from the other constituents utilizing a particle using a filter. The whey protein flows through the filter. This manufacturing process is very gentle and leaves the components of the proteins in their natural state.
  • Caseinate
    Caseinate is functionally modified casein, which means that it was produced by acid precipitation and subsequent neutralization by adding minerals such as calcium hydroxide or potassium hydroxide. The caseinate can then be separated from the other milk components using filtration and centrifugation. The combination with minerals results in calcium caseinate, for example. Caseinate is also slowly absorbed, but overall somewhat faster than micellar casein.

Whey Protein

Whey protein, more common among athletes under the English name whey protein, is the smaller fraction of milk protein. Whey protein has a higher biological value than casein and tops even that of whole ice cream. Whey protein is the classic among athletes. They like to take it before and after training, because the protein can be used very quickly by the body and is therefore directly available during the strenuous training phase or afterward. Whey protein is usually available as a protein powder in these three forms:

  • Whey Protein Concentrate
    Concentrate is the purest form of whey protein. It is obtained from sweet or sour whey by ultrafiltration. The concentrate has a protein content of 70 to 80%, but a comparatively high-fat content of about 3 to 4%. Whey Protein Isolate: Isolate is the highest quality form of whey protein because it is very pure. It is obtained using microfiltration, which ensures that the nutrients are retained. Whey Isolate has a protein content of up to 99% and very little fat.
  • Whey protein hydrolyzate
    Enzymes are used to produce hydrolyzate, which ensures that the proteins are already broken down into peptides – i.e., chains of amino acids – so that the body can use them more quickly. The whey protein’s specific forms differ, for example, about the production process and the associated components of the individual nutrients, taste, and price. However, all three types are rich in protein and thus support muscle building and muscle maintenance. In some protein powders, the individual variants are mixed to combine the respective advantages. In so-called multi-component proteins, different proteins are mixed to combine their advantages. A shake with casein and whey protein provides the body with excellent protein throughout the day: the casein slowly but steadily releases its amino acids to the collection, while the whey protein is used directly. In addition to milk protein, multi-component proteins often contain other protein sources, such as soy or eggs.

What to do if you have a Milk Protein Allergy or Lactose Intolerance?

A milk protein allergy is rather rare. Around 2% of children under the age of two are affected, but the allergy usually disappears with increasing age. With a milk protein allergy, the immune system reacts with antibodies to the protein. Milk and milk products should, therefore, be avoided. Depending on the severity of the allergy, however, milk from goats and sheep may not cause any problems. Other alternatives are herbal products such as soy or rice drink or yogurt made from coconut milk. Lactose intolerance is more common than an allergy to protein. More and more adults are responding to milk and dairy products with complaints. However, the problem with lactose intolerance is not the proteins, but the milk sugar they contain lactose. Depending on the severity of the lactose intolerance, whey proteins, for example, often contain little to no lactose, can be well tolerated.

Milk, and especially cow’s milk, is an essential foodstuff for most people. However, it poses a risk for allergy sufferers because, in addition to a swelling of the mouth or mucous membranes, it can cause diarrhea or worsen of neurodermatitis and, in rare cases, can even cause an allergic shock.

Besides, a cow’s milk allergy harbors the risk of other allergic diseases, such as atopic eczema or allergic asthma. “Adequate supply of milk producers, that is, the cows, with vitamin A could counteract this effect of possibly converting a harmless food protein into a milk allergen” explains first author Karin Hufnagl. However, it is questionable whether vitamin A’s positive impact in the study can also be achieved through food additives.

Artificially supplementing food with vitamins may not have the same effect as natural ingredients and is likely to result in an inadequate loading of the milk allergen. It is therefore necessary to supply the animals with a corresponding amount of vitamin A when they are kept or fed. This can be achieved, for example, by adding more green fodder. Corresponding follow-up studies still have to be carried out.

Karin Hufnagl

Protein Takeway:
protein in milk

Protein in milk can help build and maintain muscle mass. A protein powder can make it easier for you to meet your daily protein requirements. With its combination of whey protein with a lot of leucine and its casein content, the protein in milk ensures that your muscles are optimally cared for.


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