Dr Fox, what do you think about Guernsey milk and the theory that form of casein it contains is less intolerable to humans than the form of casein in Friesian and Holstein milk? (For the benefit of other MNers, who may not know what I am talking about, almost all dairy-farmed animals produce milk in which the beta-casein is predominantly A2, except for Friesian and Holstein cows, in which the beta-casein is predominantly A1. Virtually all commercial milk, and milk products, are from Friesian and Holstein cows. Guernsey milk contains 90% or more A2 beta casein. There are studies linking A1 beta casein with various chronic conditions, and demonstrating a reduction in these issues when dairy consumption is of A2 beta casein milk.)
"It is interesting to note that a factor in regular milk, BCM7, is released when A1 beta casein is digested. BCM7 is a strong opioid that can affect gut processes and mucus production ? causing some allergic or intolerance symptoms. BCM7 can also stimulate skin reactions and the release of histamine. A2 milk does not produce BCM7 on digestion."
on this website: www.naturaltherapypages.co.uk/article/beta_casein_intolerance (I would have liked to find a more mainstream source)
My brother was a typically sickly, snotty, asthma-y, weedy kid in the 60s and 70s. As an adult he realised that milk made him ill, and cut it out of his diet. He is now a farmer and has access to unhomogenised milk from a single herd of pure-bred Guernsey cows, and has discovered that he can safely drink their milk with no ill-effects, whereas 'conventional' milk still makes him ill.
I would also like to know whether, for someone with a dairy intolerance that is quality-of-life-affecting, rather than life-threatening, it is better to totally exclude dairy products or to consume them only in amounts that are small enough not to set off a reaction.
Thanks!