A new milk is coming. It’s called A2 milk, a substitute for conventional milk. You ought to know about it. It launched in New Zealand twenty years ago, but it’s headed your way soon.

First off, did you even know there was an A1 and A2 milk?

 

Getting the names straight

Cow’s milk protein is called beta-casein. It comes, these days, in several “genetic variants”:

  • BC (beta-casein) A1, referred to as BCA1 or A1 milk.
  • BC (beta-casein) A2, referred to as BCA2 or A2 milk. (1)

When and how these variants came on the scene:

Approximately 800 years ago, cows produced milk that didn’t contain both BCA1 and BCA2. Cow’s milk from thousands of years ago, science says, produced only BCA2, so you could call it A2 milk. As a nutritional or medical practitioner or just plain anybody who buys any kind of milk, be it coconut or almond or goat or cow, you ought to know your milk A B C’s.

As animals were domesticated and bred for human use, a natural genetic mutation occurred in one of the 209 amino acids that make up the typical genetic profile of cow’s milk. This changed the physiologic personality of milk. In essence, this created a new milk. A milk that was not just A2, but which contained both A1 and A2. Yet the human gut, at least of some humans, may not yet be able to optimally handle this new dairy.

A mixture of A1 and A2 is the kind of milk most of us buy in the dairy section of most stores in today’s societies. In fact, the milk that most Europeans and most of the Western World has been consuming, actually contains more A1 than A2. So modern milk could accurately be called A1 milk.[2,3]

This means you have been buying and drinking basically A1 milk even if you didn’t realize it.

 

Milk Intolerances

One out for four people has trouble digesting milk. Some science is suggesting it might really be the fault of the A1 protein, which is much harder to digest for many people than the old natural A2 protein used to be.

A1 beta-casein has been proven to cause gut woes. A1 protein, some studies suggest, releases opioid beta-casomorphin (BCM-7) into the small intestine. This BCM-7 opioid has been linked to gut issues and has even been incriminated in making milk somewhat addictive.(4, 5) It’s an opioid-like molecule, so upon ingestion there is a bit of a “high” (more in some folks than others) that makes people want to consume more milk to keep the high going.

My old boyfriend in college at the University of Michigan (who went on to become the astrophysicist that invented and owned the first windmill farm in the US and also designed the water/lake/filtering system in Austin where I live) was incredibly addicted to milk. So much so, he kept the fridge by the end of our bed. That’s all the bedroom had. A bed. And a fridge.

 In the middle of the night if he wanted some “high” he could get up, reach over, and down some of the gallons of milk he consumed per day. Of course, he later realized milk was his allergic downfall. Eventually he gave it up to be healthy and well.

So, was Hans addicted to the opioid? Which comes from the A1 milk? Hmmm.

Issues from A1 milk include: impaired gastrointestinal functions, such as decreased intestinal contractions (the less your gut contracts, the longer your “transit time” and the more you are prone to constipation as well as other downstream health issues), intermittent constipation with diarrhea (Irritable Bowel Syndrome (IBS) type presentation) and lowered immune function secondary to suppressed white blood cell formation (lymphocyte proliferation). (6,7)

Studies linking A1 milk consumption to gut issues were, for a number of years, mainly performed on animals. Thus, the data, like Rodney Dangerfield, didn’t get much respect. Now, there’s emerging scientific links between A1 milk consumption and heightened risk for a number of gut diseases [8] as well as other health issues like type 1 diabetes [9] and even heart disease.[10]

Some researchers stretch this link to include mood and behavior disorders, such as autism and schizophrenia.[11]  I have personally seen, on a fairly regularly basis, a link with milk intolerances to diverse mood issues such as ADHD, depression and anxiety in clinical practice.

A new company trying to get A2 milk into the marketplace sponsored a lot of this research. So this research, once again like the ghost of Rodney Dangerfield, (I miss him a lot can you tell?) didn’t earn much respect until 2014! That’s when an independent study, not from the company selling A2 milk, reported a significant rise in “dangerous inflammatory markers” consistently occurring when mice were fed only A1 milk.[12]

Small clinical studies in lactose-intolerant humans link A1 milk to softer stools, multiple adverse gut symptoms, decreased cognitive performance, and markers of inflammation, all of which shout out loud that milk intolerances might have more personalities than we have thought.  These many symptoms overlap fairly well with issues linked to the very elusive irritable bowel syndrome complex. [13,14,15]

Some researchers question if some cases that we thought were due to lactose intolerance might actually be due to A1 milk protein intolerance, or a combination of intolerances; deficiency of the lactase enzyme that digests milk sugar, lactose along with issues with A1 milk. This is rather big dietary news!

A huge human study came on the scene. In 2017, a randomized, crossover trial of 600 Chinese adults showed significant improvement in gastrointestinal symptoms, like gut pain and bloating (again, IBS symptoms) 12 hours after consuming A2 milk. While, in comparison, there was an increase in painful and adverse symptoms after consumption of A1 only milk.[16,17,18]

Still some critics debunk all this. They claim this is a huge hype to get the public to buy A2 milk that’s coming to your grocery store momentarily.

Presently, not enough science explains what’s what. But that’s the unfolding of science. It dribbles out bit of this and that till we get the bigger picture. Or, we figure out who is trying to make money out of all this, and we see the light.

But I have a lot of patients that know they can’t consume lactose or dairy, and I look forward to seeing how they do with A2 milk.

I would love to know what you, your friends or your patients say when tried. Let me know at [email protected]

At least you now know what the heck A2 milk is and its backstory.

 

References

  1. J Food Sci Technol. 2018 May;55(5):1942-1947. doi: 10.1007/s13197-018-3088-z. Epub 2018 Mar 2. Use of urea-polyacrylamide electrophoresis for discrimination of A1 and A2 beta casein variants in raw cow’s milk.
  1. The A2 milk case: a critical review. Eur J Clin Nutr. 2005;59:623-631.
  2. Is A2 milk the game-changer for dairy intolerance? Today’s Dietitian. October 2017. Source Accessed July 29, 2018.
  1. Production of Cow’s Milk Free from Beta-Casein A1 and Its Application in the Manufacturing of Specialized Foods for Early Infant Nutrition. 2017 Jul 12;6(7). pii: E50. doi: 10.3390/foods6070050.
  2. An assessment of the addiction potential of the opioid associated with milk. J Dairy Sci. 1994 Mar;77(3):672-5.
  3. Is A2 milk the game-changer for dairy intolerance? Today’s Dietitian. October 2017. Accessed July 29, 2018.
  4. Effects of milk containing only A2 beta casein versus milk containing both A1 and A2 beta casein proteins on gastrointestinal physiology, symptoms of discomfort, and cognitive behavior of people with self-reported intolerance to traditional cows’ milk. Nutr J. 2016;15:35
  5. Systematic review of the gastrointestinal effects of A1 compared with A2 beta-casein. Adv Nutr. 2017;8:739-748
  6. A1 beta-casein milk protein and other environmental pre-disposing factors for type 1 diabetes. Nutr Diabetes. 2017;7:e274
  7. The A2 milk case: a critical review. Eur J Clin Nutr. 2005;59:623-631
  8. Health implications of milk containing beta-casein with the A2 genetic variant. Crit Rev Food Sci Nutr. 2006;46:93-100
  9. Comparative evaluation of cow beta-casein variants (A1/A2) consumption on Th2-mediated inflammatory response in mouse gut. Eur J Nutr. 2014;53:1039-1049
  10. Comparative effects of A1 versus A2 beta-casein on gastrointestinal measures: a blinded randomised cross-over pilot study. Eur J Clin Nutr. 2014;68:994-1000.
  11. Clinical evaluation of glutathione concentrations after consumption of milk containing different subtypes of beta-casein: results from a randomized, cross-over clinical trial. Nutr J. 2016;15:82
  12. Effects of milk containing only A2 beta casein versus milk containing both A1 and A2 beta casein proteins on gastrointestinal physiology, symptoms of discomfort, and cognitive behavior of people with self-reported intolerance to traditional cows’ milk. Nutr J. 2016;15:35.
  13. Effects of cow’s milk beta-casein variants on symptoms of milk intolerance in Chinese adults: a multicentre, randomised controlled study. Nutr J. 2017;16:72
  14. Comparative effects of A1 versus A2 beta-casein on gastrointestinal measures: a blinded randomised cross-over pilot study. Eur J Clin Nutr. 2014;68:994-1000.
  15. Clinical evaluation of glutathione concentrations after consumption of milk containing different subtypes of beta-casein: results from a randomized, cross-over clinical trial. Nutr J. 2016;15:82.