Just stumbled across this, here in Oz we had the A2 milk come up on the shelves a few years back, I just ignored it thinking it was just another variant of fortified fat adjusted milk, but it turns out it is a distinction in the type of Caesin protein between A1 & A2.
Now I may get some terms wrong, but if you look through the links you can follow your own trail.
Basically about 8,000 years ago there was a mutation in cattle that resulted in a change in one of the Caesin proteins in milk, the mutation resulted in the A1 variation, Holstein, Freisen, typical black & white dairy cows and which most european and western dairy cattle have, the A2 is found in sheep, goats, traditional cattle through Africa & Asia and the Guernsey & Jersey breeds.
It is just a fine distinction of the Beta Caesin which is a 209 amino acid chain protein and there is a substitution at position 67 where the A1 variant has Histadine and the A2 variant has Proline, this results in the A1 breaking down at this point much more readily than the A2 to make a 7 amino acid peptide called beta casomorphin 7 (BCM7), which can through a compromised gut lining enter the blood stream, cross the blood brain barrier and attach to the opiod receptors, having a similar effect to opiates, it also appears that Gliadin from Gluten has the same type of process and effect.
There is new research coming on line linking the A1 beta caesin to a variety of conditions from, heart disease, autoimmune to SIDS & schizophrenia, Health organisations are in denial as most of their countries have large A1 dairy herds, but I think there is a slow silent changeover occuring, you know gotta sell the old stock before the new comes on line.
As you may assume I'm also into the Paleo thing and as with MS their always seemed to be some corrolation between Dairy and ill health, but there was always anomolies to deflect the argument, this may be what explains some of these contradictions.
The guy who wrote the book Devil in the Milk, Woodford is credited with breaking this story, shows a graph that indicates consumption of A1 milk is directly proportional to heart disease, unlike Ancel Keys who proposed the saturated fat consumption and heart disease hypothesis in the 50's, who drew the line he liked then only plotted the countries that sat on his line and has probably taken the great leap backwards in health through the "low fat health protocol".
The French Paradox is common in Paleo circles, high saturated fat intake and low heart disease, the pun was they drink red wine, so if you have a Cholesterol problem, ask your doctor to prescribe red wine rather than Statin medication. Well it turns out they also consume a lot of dairy, but most of their dairy is from Guernsey or Jersey cattle, both A2 varients. They also appear to have lower rates of MS, according to the last link with all the countries rates. Now the Islands of Guernsey and Jersey of the french coast, but actually Brittish also have lower rates of MS than the rest of the UK, not hard to guess what dairy breeds they run.
There is also a lattitude difference in favour of this of course, but another look on that map in the link says the MS rate in Germany is 149/100,000 vs 80 in France, overall there is only 5° latitude difference, which doesn't look like enough for nearly double the rate, but the german dairy herd is 60% holstein (A1) vs France majority A2 varieties. now you ask about sunshine and vitamin D, well yes France is better of in both of these, but theres more.
Take a look at Spain vs US, same latitude, similar UV but spain has vitamin D levels just over half of what US levels are, so worse MS, no, less than half 59 to 135, dairy in spain has historically been sheep and goat dominated, which are both A2.
By no means a comprehensive analysis, but it does seem to fit the bill, be interesting to see where this one goes from here.
Coeliac Disease is being more refered to now as the iceberg, where only the intestinal manifestation 10% is above the surface and the 90% of other gluten sensitivities are just coming to light, all in the same realm as caesin, is milk another iceberg with just lactose intolerance being above the surface, so like we've all been told make sure yough have a good breaqkfast of milk & cereal and you'll be unsinkable like the Titanic.
Here's some links:http://naturalbias.com/a1-beta-casein-t ... your-milk/http://arunsmusings.blogspot.com.au/201 ... asein.htmlhttp://keithwoodford.wordpress.com/2011 ... -syndrome/http://paleohacks.com/questions/84111/a ... z2LIykUJ9Rhttp://undergroundwellness.com/devil-in ... lk-part-1/http://www.healthline.com/health/multip ... /vitamin-d