Got A2 Milk? By Debbie Bowman On Staff Nutritionist for Edible Island Whole Foods Market

December 3, 2016 Debbie Bowman

Have you ever heard of A2 milk?  A few months ago I hadn’t, but fortunately I read a book that mentioned A2 milk.  I was intrigued enough to purchase and read another book devoted to the subject, The Devil In The Milk - Illness, Health and the Politics of A1 and A2 Milk, by Keith Woodford.  


So what exactly is A2 milk?  To properly explain this we need to start with the basics of what comprises the milk we drink.  Milk is about 85% water. The remaining 15% is made up of fat or cream, whey, and milk solids. The milk solid part is composed of many different components but It is the protein part of the solid we’re interested in. One of these proteins is called beta casein. 


Beta casein is a chain of 229 amino acids with proline at number 67 of the amino acid chain – at least the proline is there in some cows. The cows with proline at number 67 are called A2 cows and are the older breeds of cows (e.g. Most Jerseys, Guernseys, Brown Swiss, Normandes, Asian and African cows). A few thousand years ago, a mutation occurred in this 67th slot, converting the proline to histidine. Cows that have histidine at number 67 are called A1 cows and include breeds such as Holstein, Friesian, Ayrshire and British Shorthorn. Interestingly, Holsteins have been used to improve milk production in many countries, including North America, and as a result, it is now established that A1 cows produce the majority of the milk we drink. More specifically, the A1 gene appears to be more prevalent in herds that have been pressured to maximize milk production, such as changes in their feed, population density and exposure to bovine growth hormone and antibiotics.  Sadly, it seems that A2 milk was the variety to which humans originally adapted, with the A1 variant a more recent product of modern agricultural practices and pressures.


Why does A1 or A2 matter?  To explain this we need to get a little scientific, so here goes:  Remember, beta casein is a chain of 229 amino acids with either proline or histidine at the 67th slot.  When proline is the amino acid at number 67 the bonds around that amino acid are strong.  When histidine is the amino acid at the 67th slot the bonds are weak.  The problem is that when one digests A1 milk the histidine bond breaks resulting is a peptide of seven amino acids called betacasomorphin-7 (BCM7).  Now here’s the important part.  BCM7 is a is a very powerful opiate (narcotic) with a structure similar to morphine that has some undesirable effects on animals and humans. Upon digestion, BCM7 can enter the blood stream where it interacts with the internal organs and even the brain, especially when fed to infants or those with ulcers or leaky gut.  Epidemiological studies have implicated BCM7 in heart disease, Type 1 diabetes, autism and schizophrenia.  Animal studies have singled out BCM7 to create inflammatory reactions in the small intestines.  It also changes hormonal function, as well as affects the nervous and immune system.   BCM7 will cause brain fog, poor thinking, as well as problems with sleep. These neurologic issues may also be a factor in the concerns with schizophrenia and autism.


It’s important to note here that there is still much controversy surrounding the question of A1 and A2 milk.  Although there are many studies that implicate A1 milk in human disease, there are no double blind and randomized human studies that can prove a correlation.  That’s a pity, but the reality is that it’s very difficult to conduct such trials.  However, if common sense were to prevail it would seem prudent to adopt changes if there were enough statistically relevant data pointing to the possibility that BCM7 is damaging.  And there is.   


Besides being free of BCM7, it’s possible that A2 milk could be a healthy dietary choice for people who are lactose or dairy intolerant.  (If you have any life-threatening inflammatory/allergic issues, please consult with your doctor before trying any other form of milk.) A recent study in China compared the effects of A1 and A2 milk in 45 people with dairy intolerance. There was a significant reduction in both symptoms and inflammatory markers with the ingestion of A2 milk. It’s interesting to note that these benefits were seen in both lactose tolerant and lactose intolerant participants–suggesting that some of the symptoms routinely attributed to lactose intolerance may actually relate to BCM7. Though small, this study was of high quality, both randomized and double-blinded.


So how can you find A2 milk?  Unfortunately, in most of North America true A2 milk is not readily available.  However, there are some close alternatives, namely milk made from breeds that are more likely to be A2 cows - Guernsey, for example.  (Guernsey cows are 96% A2 but Jersey cows, depending on the herd, are less reliably A2 -  with only a 60% A2 in some cases.)  Goat and sheep milk are 100% A2.  (Dairy products that are mostly fat, such as butter, are fine to consume for most, regardless of A1 or A2 status.) Happy Planet is making an organic milk sourced only from grass fed Guernsey and Jersey cows.  Even though Happy Planet does not market their milk as pure A2 it is less likely that milk from these cows will produce the possibly dangerous opioid BCM7.  You can find milk from Happy Planet Creamery in the dairy aisle at Edible Island Whole Foods Market.  



To learn more about A2 milk visit