Frances Dale reports

A2 milk is about to be launched onto the British market by Robert Wisemen dairies, the UK's biggest fresh milk company – thereby re-igniting the storm of controversy which raged in Australian and New Zealand some five years ago about the supposed health benefits of A2 milk.

What is A2 milk?

The controversy centres on the protein/beta casein content of the milk – A1 versus A2. It appears that originally, thousands of years ago, the protein in all bovine milk was A2 – as was, and is, the protein in milks from Jersey and Guernsey cows, water buffalo, goats, many Indian breeds of cow, yaks, donkeys, camels etc. At some point, no one knows when, a mutation occurred which moved the amino acid at position 67 in the chain of 209 amino acids that make up beta-casein protein in milk.

In A2 beta-casein, the amino acid with which it is linked is proline (closely bonded with the amino acids at position 66 and 68), but, thanks to the mutation, in A1 beta-casein the amino acid at position 67 is histidine. This linkage can be more easily broken down, in the process of digestion, into a protein fragment known as BCM7 (beta-casomorphin-7) which behaves like an opiate. (This will be a familiar scenario to those who follow the gluten and dairy free diet advocated by Paul Shattock and the Autism Research Unit in Sunderland for the management of autistic spectrum conditions).

For more scientific details on these proteins see www.betacasein.org.

As a result of this mutation the bulk of European cows, Friesians, Holsteins etc, produce mainly A1 milk, only a few breeds such as Jerseys and Guernseys still producing predominantly A2 milk.

What is so good about A2 milk?

Supporters of A2 milk claim that it is less allergenic and that A1 milk and may be associated with serious health conditions such as heart disease, type 1 diabetes and autism. For a fairly succinct summary see this paper given by Professor Keith Woodward to a General Practitioners conference in Sydney in 2011. In this paper he refers to over 250 medical and scientific papers relating to casomorphins and their effect on human health.

(Professor Woodford – see his blog here – is professor of Farm Management and Agribusiness at Lincoln University in New Zealand and has written a book called 'Devil in Milk' about the health issues and industry politics for A2 milk.)

However, despite the relative wealth of material about BCM7 and its effects, there is, as yet, little research to show that A2 milk is 'healthier'. All other considerations aside, there has not been sufficient time since it appeared on the scene for any longitudinal studies on A2 milk. There are, however, a wealth of anecdotal reports on the success of A2 milk (often in the guise of camel, buffalo, yak, donkey etc milk) in resolving cow's milk intolerance, digestive problems and even some symptoms of autism. (For starters see reports on the FM site on camel's milk, donkeys' milk, buffalo milk, a long article on goat's milk and a report back in 2009 of the successful use of Guernsey cow's milk for autism.)

Not surprisingly, the European dairy industry, supplied almost entirely by A1 cows, has been less than enthusiastic about A2 milk and, equally unsurprisingly, EFSA (the European Safety Authority) has remained firmly on the fence. In 2009 they reviewed the 'available scientific literature on the possible health effects of beta-casein and related peptides in milk and other foods, such as autism, cardiovascular disease and type 1 diabetes' and decided that 'a cause and effect relationship is not established between the dietary intake of BCM7 (beta-casomorphin-7), related peptides or their possible protein precursors and noncommunicable diseases'.

Cow's milk intolerance and allergy

However, while the larger question of whether A1 milk and its related peptides are really responsible for coronary heart disease or type 1 diabetes (for those who are interested nutritionist Margaret Moss most definitely sees a link with CHD – see here) remain unanswered, it seems more than likely that it may be relevant in cases of food, and more specifically, cow's milk intolerance and possibly, even allergy.

It is becoming increasingly clear that allergy/intolerance is rarely to a whole protein but to individual molecules within that protein. (See the presentation by Dr Adriano Mori at the 2011 Allergy Research Foundation meeting.) It therefore seems perfectly reasonable that it could be the mutated beta-casein fraction in A1 milk that causes the problems for some of those who are allergic or intolerant to cow's milk, not beta-casein as such.

But, while experimenting with A2 milk if you are cow's milk intolerant could well bring benefits but will certainly not do you any harm, if you (or your child) are cow's milk allergic then you should treat it with very great caution. As yet, there is no evidence of the non-allergenicity of A2 milk, it is absolutely not recommended for those with cow's milk allergy. Even if it did not trigger a reaction, the possibilities for contamination and confusion are endless.

Lactose intolerance

Inevitably, some A2 supporters are also claiming that A2 milk is lactose free or will help to resolve lactose intolerance.

A2 milk is still milk and all mammals' milk contains lactose (sugar); lactose has nothing to do with the proteins in milk so changing the protein will in no way affect the lactose content of the milk. If you are lactose intolerant it means that you do not produce sufficient of the enzyme lactase to digest the milk and your production of lactase will not be affected by the milk's protein content.

However, it is possible that, if you have reacted badly to milk and have blamed it on a lactose intolerance, you could have been reacting to the A1 proteins and not to the lactose, in which case the A2 milk could be just what you need.

For a rather sparse UK A2 site got to www.a2milk.co.uk; for a rather more informative site go to www.a2milk.com.au; for supplies, watch your supermarket shelves....

First published in September 2012

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