March 9, 2011

061 A1 & A2 Milk [3 May 2010]

I recently learned something interesting about milk. Keith Woodford in his 2007 book “Devil in the Milk: illness, health and the politics of A1 and A2 milk” explains the two types of cow milk based on the form of a protein called beta-casein. A single mutation in a European cow thousands of years ago resulted in a change to this protein which affects the milk we drink today.

Milk from African and Asian cattle breeds and some older European breeds such as Jersey and Guernsey contain A2 beta-casein. Newer European breeds including the Holstein produce milk containing A1 beta-casein. (Goats and sheep, by the way, produce A2 milk.) So what difference does this make?

The beta-casein in A1 milk releases, in digestion, a smaller protein called beta-casomorphin-7 (BCM-7) which is the “devil in the milk”. In his forward to Woodford’s book, Thomas Cowan MD writes that BCM-7 “…is the exact culprit in the myriad of symptoms [that he has observed in his patients who had problems with milk] …including joint and muscle pains, fatigue, digestive disturbances, and headaches”.

Woodford writes that BCM-7 selectively binds to the epithelial cells in mucus membranes and stimulates mucus secretion. (This may explain the persistent though often disputed belief that cow milk is “mucus forming”.) BCM-7 is also implicated in more serious health problems including: type 1 diabetes, ischemic heart disease, and neurological conditions such as autism and schizophrenia.

Woodford argues persuasively that much improvement in population health could be achieved by switching dairy production to A2 breeds. This process is quietly underway in New Zealand, where most of the research on A1-A2 milk has been done over the past decade, and A2 milk is widely available in Australia. There has been no such movement in the USA and Canada, and to date no acknowledgement of the problem. Dairy farmers can begin their own conversion by breeding with A2 semen. Meanwhile, if you are a farmer, you could buy yourself a Jersey cow and begin producing your own A2 milk. Raw milk is healthier for you anyway, but that’s a topic for a future column.

To read excerpts from Woodford’s book go to and search for “devil in the milk”. For more technical reports see which references more than 80 published studies on BCM-7 and its effects on health.

This article is intended for educational purposes only; for medical advice consult your licensed health practitioner.

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