Among the unique qualities of Guernsey Milk is the presence
of the protein Beta-Casein A2 in the milk of approximately 96%
of Guernseys as opposed to most other European breeds which carry
a predominance of Beta-Casein A1. Guernsey cows can test A1/A1
or A1/A2 but the vast majority are A2/A2 cows.
Professor Keith Woodford has raised the global profile of
the potential benefits of A2 milk through his book 'Devil in
the Milk'. This very well researched book brought public attention
to a possible link between milk containing A1 beta-casein and
a range of serious illnesses, including heart disease, Type 1
diabetes, autism and schizophrenia.
The latest edition of Guernsey World (see home page) includes
two papers on this subject. 'Polymorphism of bovine beta-casein
and its potential effect on human health' is a very clearly written
paper by three Polish scientists. The European Food Safety Authority
produced a report, 'Review of the potential health impact of
ß-casomorphins and related peptides' (summary only published
in GW) in which it found that 'a cause-effect relationship between
the oral intake of BCM7 or related peptides and aetiology or
cause of any suggested non-communicable diseases cannot be established.'
However, the argument most strongly advanced by the proponents
of the benefits of A2 Milk is not that A1 Milk causes these illnesses
but rather that A1 milk is digested in a different way to A2
resulting in the release of a peptide or protein fragment called
Beta-Casomorphin-7 (BCM7). If this gets through the gut and into
the blood of genetically susceptible people it can have a detrimental
effect by exacerbating underlying problems.
There is an ongoing debate about how compelling the present
evidence is, but anecdotal evidence suggests that some people
who thought that they were lactose intolerant may be intolerant
to A1 milk through the release of BCM7. There is further anecdotal
evidence that some autistic people benefit from A2 milk. Unfortunately
most of the trials carried out so far have failed to meet strict
scientific standards, notably the double-blind discipline. However,
the International Journal Peptides recently published
a paper by Kost NV et al. (see link to this paper below) who
were able to isolate BCM7 in the blood of children that were
fed formula milk. They also discovered that some of the children
excreted BCM7 quite quickly while others did not. The children
who failed to excrete it rapidly tended to exhibit delayed development.
Specifically, the paper compared 37 breastfed babies with 53
fed with formula containing cow's milk. The researchers found
only one case of developmental delay in the breast-fed group
compared with 16 in the other group. More research is needed
but this seems to be a significant development.
Currently the largest volume of A2 milk sales is in Australia
where over10 million litres were sold in the last reported year
of trading by the A2 Corporation. Other countries have small
internal markets for A2 milk and some Guernsey herds are benefiting
from specific sales.
It may be many years before sufficient evidence of an acceptable
scientific standard is available to confirm or discredit the
A1/A2 hypothesis, mainly because of the scale, expense and difficulty
of conducting meaningful trials, but many respected scientists
are of the opinion that such research is merited. In the meantime
consumers have a choice, they can switch to A2 milk if they find
that it helps them. Guernsey breeders too have a choice. If they
think that A2 could be important to their future profitability
they can switch to using only A2/A2 bulls. WL Feb. 2010
