What is the main protein in Milk?

The following guide will answer the query “What is the main protein in Milk?”. In addition, the article will address other important topics such as milk composition, their nutritional relevance, sources of milk proteins, and recipes for using dairy products in your meals.

What is the main protein in Milk?

The main protein in Milk is casein, comprising approximately 80 % of all proteins. The rest of proteins (the other 20 %) are grouped in the Whey proteins obtained from the serum (1,2).

What are the types and functions of Milk Proteins?

There are two main types of milk proteins, the casein (about 80 % of all proteins) and the whey proteins (the remaining 20 %). Whey protein contains other types of proteins, such as lactalbumin and lactoglobulin (1,2). In the following paragraphs, you can find the main functions of both casein and Whey.

What is the main function of Casein?

The main function of milk’s casein is to form different products, such as cheese and yogurt, after casein’s coagulation using enzymes or acidifying the milk. Moreover, you can find casein as an ingredient in different products such as breads, ice creams, beverages, desserts, among others (1,2). 

The casein is used in those products because it has good emulsifying properties (it could mix water and oil), it has “thickener” properties, so it could improve the texture of your products or maintain them homogeneous during the storage (1,2).

What is the main function of Whey proteins?

The main function of Whey proteins is to improve the nutritional value of food products. It is obtained from the serum after casein’s coagulation (1,2). 

Usually, serum’s sugars and salts are partially removed from the whey to obtain more than 25 % protein (3). Whey protein is normally added to reduced-fat foods to improve its texture and protein content.

What is the Nutritional quality of Milk Proteins?

The milk’s proteins are considered as high quality proteins. Milk proteins contain all essential amino acids and have high bioavailability, this latter means that your organism can completely digest, absorb, and use those proteins (4,5).

According to different sources (4), milk’s proteins can give you all essential amino acids. Actually, a single cup of milk (240 mL) could provide you with around 30 – 50 % of your daily essential amino acids requirements.

What are the Health Benefits of Milk Proteins?

The health benefits of consuming milk proteins are related to its nutritional quality (4-8), for example:

  • Children can enhance their growth (height) and muscle development
  • The vitamins (thiamine, riboflavin, niacin, folate, vitamin A, vitamin D, vitamins B6 and B12) and minerals (iron, zinc, calcium) in milk could strengthen your immune system, making you more resistant to get ill
  • The amino acids of milk’s protein could help to synthesize antioxidant and immunological molecules in your body

What are the Potential Health Risks of Milk Proteins?

There are potential health risks of milk proteins; since proteins can react with your immune system, there is a chance, especially in children, to have allergic reactions to milk’s proteins (4). In this case, a physician should determine if you have a milk’s protein allergy, and he or she should give you the correct treatment.

Another potential health risk is lactose intolerance, in this case, your organism is not able to digest lactose (the principal sugar in milk) and it may produce inflammation, stomachache, and diarrhea (4).

 Even if you consume milk proteins alone (or isolate), lactose could be present in very little concentrations, but that will be sufficient to make you feel bad (4).

Where can you find Milk Proteins?

There are several products where you may find and consume milk proteins; obviously milk is the main source to obtain milk proteins, but you can also consume cheeses, yogurts, and milk-based fermented beverages (9).

You can do a lot of interesting meals with milk, cheese, and yogurts. In this USDA website, you can find smoothies, soups, and dips; all of them look incredible!

What is the Milk Composition?

The bovine milk is composed mainly of water (85-87 %). The remaining components are proteins (3.5-3.8 %), carbohydrates (4.5-4.8 %), ashes (<1 %) and fats, which vary in different types of milk because milk is standardized to maintain a certain content of fat (1,2).

You may have noticed that there is whole milk, semi-skimmed milk, and skimmed milk. These three have different amounts of fat, for instance, whole milk has approximately 3.5-3.7 % fat, while semi-skimmed milk and skimmed milk have 1 and 0.1 % fat (2,5).

Besides all those nutrients, milk also has very important minerals and vitamins. It contains calcium which is a mineral mostly known for its role in bone development; another essential mineral in milk is zinc, it helps for your muscles and immune system development, and it is also an antioxidant! (4,6,7). 

Regarding vitamins, milk contains vitamin A, group B vitamins, and vitamin D, all these vitamins have a key role in the improvement of your immune system (4,8).


The following guide solved the query “What is the main protein in Milk?”. In addition, the article addressed other important topics such as milk composition, their nutritional relevance, sources of milk proteins, and recipes for using dairy products in your meals.


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