A1 Beta Casein

There are rumors of the danger of cow's milk.  Further googling reveals the culprit is possibly one of the versions of milk proteins -  A1 beta casein - which is produced in varying amounts by different breeds of cows.  (The safe form supposedly is A2 beta casein.)  A digestion product of A1 beta casein (and not A2) is beta casomorphin, BCM7, which is an opioid and an oxidant that can damage low density lipoproteins (LDL), and "opioids have an effect on immune function which is a possible reason why A1 beta casein and BCM7 are so closely associated with autoimmune disorders."   (We are also told that "BCM7 is too large to be absorbed through a healthy intestinal lining", so you have to apparently have some intestinal problem for BCM7 to act.)

A1 Beta Casein: The Devil in Your Milk.

A2 Dairy Products of Australia Beta Casein web-site.

The first link claims:

A1 beta casein is only produced by cattle belonging to the Bos taurus subspecies which predominately exist in the western hemisphere. The Guernsey breed tends to produce about 10% of their beta casein as A1, the Jersey breed tends to produce about 35%, and the Ayrshire, Holstein, and Freisian breeds tend to produce 50% or more. Goats don’t produce A1 beta casein which makes their milk and the dairy products derived from it an excellent alternative.

 Milk from Indian cows may be lacking A1 Beta Casein.  The second link has a scientific citation

" For instance, a recent study on the beta-casein allele frequency in indigenous Indian cattle (Bos indicus) and river buffalo breeds (618 animals of 15 zebu cattle breeds and 231 buffaloes of 8 river buffalo breeds) reported 99 to 100% presence of the A2/A2 genotype in its indigenous cow (0.987) and buffalo (1.00) breeds (11). The same study also reported an absence of the A1/A1 genotype, thus in Indigenous Indian cow and buffalo breeds, nearly all animals are homozygous for the A2 beta-casein allele. 

While who knows what is true, if it is true, look at the possible implications.  In India, a milk-heavy diet will not contribute to heart disease, Type-1 diabetes, autism and schizophrenia (in all of which A1 beta casein is supposedly implicated).  So the vegetarian Indian milk-heavy diet might cross over to the US of A, where it can no longer work.

Or, assuming that at some point, (e.g, the China Study), milk and specifically casein, was implicated in various diseases studied in the West, but the A1/A2 beta casein difference was not noted, milk alarmism might wrongly influence diets in India.

Also think about what a big mistake trying to cross European and Indian cattle would be for India, unless the European cattle were screened for A1 beta casein.

From the A2 Dairy Products site: (DM-1 = Type 1 diabetes mellitus)

 Figure 2: Correlation of A1 beta-casein per capita (excluding cheese) in grams/day and new cases of DM-1 in 0 to 14-year olds between 1990-94 (r=0.92, 95% CI: 0.72-0.97) (p<0.0001). Dotted lines are the 95% confidence limits of the regression line [adapted from reference (13)].

PS: Here is the counter-argument: (PDF)

Scientific Report of the European Food Safety Authority (2009).

Based on the present review of available scientific literature, a cause-effect relationship between the oral intake of BCM7 or related peptides and aetiology or course of any suggested non-communicable diseases cannot be established. Consequently, a formal EFSA risk assessment of food-derived peptides is not recommended.