Gassy, bloated, and achy tummies after drinking milk often lead consumers to believe they’re lactose intolerant. This can sometimes lead to people giving up on the wholesome nutrition dairy can provide and may even lead people to (gasp!) buy alternative “milks” that aren’t milk at all. While some people may indeed have difficulty in digesting lactose, what’s wrenching some people's gut may be something else entirely. The type of beta-casein protein.
The Casein Cousins
Humans have been loving dairy for about as long as there’s been civilization. Often stored as cheese or various fermented forms like kefir and yogurts before refrigeration. When humans traveled north to Europe and took their dairy friends with them, something happened. A mutation in the type of protein they produced. The older milk protein is A2, while the mutated protein became known eventually as A1.
Most conventional dairy involves a mix of both kinds of proteins. Unless the package says A2/A2, you can be sure some of their cows carry the A1 genetics. (Probably most of them, as it’s the most predominate genetic makeup in cows in the United States.)
What's the Big Deal? (The Simple Version)
The simple version is that the kind of milk humans produce is A2 protein. It’s what our bodies are used to digesting from the very start of life. A1 protein breaks down in the body differently, releasing a peptide that can cause adverse reactions in many people, especially with digestion. But there’s also a correlation between that peptide and many, mostly inflammatory and neurological, diseases.
The Nerdy Version
To understand where the problem lies with the two beta-caseins, we have to look at the protein chain of amino acids. Each cow carries two copies of the gene that writes the beta-casein code. This means a cow can be A1/A1, A1/A2, or A2/A2. It’s through genetic testing that farmers and companies can know if they have solely A2/A2 cows producing their milk and certain older breeds are more likely to be A2/A2 over others.
Where the difference shows in the amino acids is at position 67. A2 protein chains have a proline amino acid in that space while A1 protein chains have a histidine amino acid there. At that position another chain branches off that is a peptide called beta-casomorphin-7 or BCM-7. This is the real problem bit.
Digestive enzymes that cut up proteins work their magic at exactly position 67. But how they interact with them changes because what lies in position 67 is different. Those enzymes cut the A1 protein at position 67 because histidine amino acid breaks easier, releasing the attached BCM-7. However, since A2 protein has proline amino acid in that spot, those digestive enzymes can’t break it at position 67, meaning the BCM-7 doesn’t go free into the milk.
The Problem Child: BCM-7
What makes the peptide BCM-7 such a problem? It’s a powerful opiate that can have some unhappy effects on humans and animals alike. This exogenous opioid interacts with the brainstem, and internal organs, especially the digestive system.
BCM-7 has been linked to neurological problems, including schizophrenic and autistic changes. It has been found in various studies that injecting animals with it can cause Type-1 diabetes and provoke an immune response in the body.
Correlations have shown that populations who consistently drink A1 milk see more cases of auto-immune disease, heart disease, type-1 diabetes, autism, and schizophrenia. Some of this is because BCM-7 causes inflammation in blood vessels. It also selectively binds to epithelial cells in mucous membranes, causing an increase in mucus.
Loving Your Tummy
Loving your tummy begins with making sure you get good nutrition and keeping things that irritate it out of the diet. People are catching on and more and more people who thought they could never have milk again are discovering A2/A2 milk doesn’t cause the discomfort conventional milk, with mixed beta-caseins, does.
It’s all about going back to our roots. To the milk, cheese, and yogurt our ancestors evolved around. Milk is a natural, complete nutritional food that humans have enjoyed for thousands of years, providing essential nutrients that other ultra-processed beverages (looking at you plant “milks”) can’t offer.