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What is A2 Milk?

September 06, 2016 by NCSF 0 comments

A2 milk is currently marketed as a heathier choice over “regular milk”. It is purported to provide explicit benefits including easier digestion for those who are lactose intolerant and reduced risk for several disorders. But what is the difference between these products and are the claims actually true? It all comes down to the breed of the cow from which the milk came from, and consequently the type of casein protein(s) found in the product. Casein is the predominant form of protein in milk (constitutes about 80%), and there are several types. One type is beta-casein which exists in at least 13 different forms; the most common include:

Scientists believe the difference in casein content in milk from different breeds originated as a mutation that occurred between 5,000-10,000 years ago as cattle were being taken north into Europe. While African and Asian cattle continue to produce only A2 beta-casein today, the A1 version of the protein is common among cattle in the western world. Today “regular milk” most commonly consumed in the US contains both A1 and A2 beta-casein, while A2 milk contains solely A2 beta-casein. A2 milk is produced and marketed by the A2 Milk CompanyTM which was founded in New Zealand in 2000. It is primarily sold in Australia, New Zealand, China, some regions of the United States and the United Kingdom.

Interestingly, A1 and A2 beta-casein only differ by one amino acid. But that amino acid, found in A1 milk, results in the release of a specific peptide chain known as beta-casomorphin-7 (BCM-7) during digestion in the stomach. A few research groups have concluded BCM-7 to negatively affect the digestive system. Some studies seem to indicate that A1 beta-casein can be harmful among certain individuals, but findings within research starting as early as the 1980s have varied greatly. Its precise health relevance remains somewhat unclear even though research has been conducted to examine the relationship between A1 vs A2 milk and diabetes, heart disease, sudden infant death syndrome (SIDS), autism, digestive disorders and other issues.

Select scientific evidence summary:

Interestingly, a 2009 European Food Safety Authority (EFSA) review of scientific literature available at that time found there was insufficient evidence to prove that bioactive peptides in A1 milk have any negative effect on health or digestion. As part of their evaluation, the EFSA looked at the laboratory studies that have been done up to that point on BCM-7. They found that most were performed on animals and the BCM-7 was not administered orally, the way humans are exposed to it, but rather via injection into the peritoneal cavity, spinal cord or brain. This made the research unfavorable for understanding how BCM-7 might affect humans. On the other hand, a 2016 independent study published in the Nutrition Journal (prominently detailed on the A2 Milk CompanyTM website) showed A1 milk to be associated with increased gastrointestinal inflammation, higher levels of digestive discomfort, delayed fecal transit time in the intestines and decreased cognitive processing speed and accuracy following ingestion when compared with A2 milk. The authors of this study concluded that some common symptoms associated with lactose intolerance may stem from the inflammation that A1 milk triggers, and this can be avoided by consuming milk containing only the A2 type of beta-casein.

So what is the take-home message from the vast quantity of available information on the subject? It appears that the A1-A2 milk debate is still unsettled - much like some people’s stomachs after consuming cow’s milk. A few studies indicate A1 beta-casein may have adverse effects among certain individuals, but the total evidence at this time is too weak for any conclusive determinations.


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