Casein protein – is it worth using?

Casein is the fraction of milk proteins that separates from whey, forming a curd during the cheese-making process. Casein is one of the proteins with the highest biological value, as it has an exemplary amino acid profile, i.e. a composition of amino acids that ensures optimal protein synthesis in our body.

1. Anabolic activity
2. Where does the controversy come from?
3. Casomorphin versus morphine
4. How should this problem be interpreted?
5. Casein reigns supreme

Anabolic activity

Protein synthesis is one of the most important metabolic processes, maintaining high physical fitness and health of our body. Studies have shown that casein is most likely the dietary protein with the highest overall anabolic activity, i.e. the ability to stimulate protein synthesis (including muscle building) in the human body.

Where does the controversy come from?

So-called casein is actually a mixture of several proteins from the casein group. Caseins account for almost 80% of the proteins present in cow's milk. The casein class includes four different subtypes: α-s1-casein, α-s2-casein, κ-casein and β-casein (beta casein), which is one of the most abundant subtypes, accounting for about 30% of the total casein mass in cow's milk.

And it is beta casein that is the source of problems and misunderstandings, which many readers have undoubtedly heard about. In this article, I will try to assess how real and how imaginary the problem is.

The crux of the problem

Genetic characterisation of dairy cows has shown that there are 13 genetic variants of beta-casein, among which variants A1 and A2 are dominant, being the most common in dairy cattle breeds worldwide. The difference between the two genetic forms concerns a single mutation resulting in the replacement of one amino acid at position 67 of the beta-casein protein chain; in variant A1, histidine replaces proline, which remains unchanged in variant A2. This mutation is believed to be the result of cattle selection for increased milk production.

The presence of histidine in the A1 variant of beta-casein allows human gastrointestinal enzymes to cleave it, resulting in the release of the beta-casomorphin-7 (BCM-7) peptide during digestion, which does not occur in the A2 variant due to the presence of proline. Therefore, the consumption of milk and dairy products from other dairy animals, such as sheep or goats, which only have the A2 beta-casein variant, does not result in the release of BMC-7 in the digestive tract.

Casomorphin versus morphine

As it turns out, BCM-7 is a peptide capable of binding to opioid receptors located in the central nervous system and the human digestive tract, which means that, in theory, it works in the same way as morphine, hence its name – casomorphin. Therefore, BCM-7 can potentially affect the physiology of the digestive tract, as well as other structures of the body, such as the nervous, cardiovascular, endocrine and immune systems.

Indeed, studies have shown a correlation between A1 casein consumption and health problems such as lactose intolerance, autism, type 1 diabetes, cardiovascular disease, sudden infant death syndrome and chronic constipation in children.

How should this problem be interpreted?

However, the above-mentioned health problems are associated with the inhibition of DPP-IV enzyme activity, disruption of the intestinal microflora and increased intestinal barrier permeability, resulting in relatively high concentrations of BCM-7 peptide in the digestive tract and bloodstream, and the appearance of undesirable symptoms of its excessive activity.

Casein reigns supreme

People with the above-mentioned conditions usually know that they should only consume dairy products free of A1 casein, i.e. mainly goat's and sheep's milk, which improves their health. On the other hand, people without these problems can probably consume common dairy products at will. And given the current state of research on casein, perhaps they should even be encouraged to do so...

As it turns out, consuming casein may play a significant role in protecting our digestive tract against cancer and maintaining proper cholesterol levels and healthy teeth.

Sources:

• https://vetdergikafkas.org/uploads/pdf/pdf_KVFD_2514.pdf
• https://www.mdpi.com/2304-8158/12/17/3151).
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3407276/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5149046/