 The tight correlation among countries between the incidence of type 1 diabetes among children and cow milk consumption didn't account for Iceland. So you see studies like this, cow's milk consumption in children and adolescents was correlated with the incidence of type 1 diabetes, but only when they excluded the Icelandic data. Is it just genetics? Maybe yes and no. The people of Iceland are genetically similar to other Nordic countries, but their cows are not. Icelandic cattle have been isolated from interbreeding with other cattle breeds for over a thousand years. See, there are two main types of casein protein, A1 and A2, and Icelandic cattle are unusual in that they produce mostly A2 milk, and that may explain the lower incidence of type 1 diabetes in Iceland. See, A1 casein breaks down into casomorphin, because A2 casein doesn't. And casomorphin has opioid properties that may alter immune function, perhaps increasing susceptibility to infections that may themselves trigger type 1 diabetes. And that's the kind of milk you get with Holstein cows, the ones with the classic black and white pattern, which makes up about 95% of the US dairy herd and much of the global dairy herd. It got to a point where dairy boards began taking out patents on methods for selecting non-diabetogenic milk to avoid triggering type 1 diabetes. Certainly did restore that tight linear relationship between milk consumption and type 1 diabetes if you just looked at A1 casein consumption. But these so-called ecological or country-by-country studies really only serve to suggest possibilities that then need to be put to the test. So studies like this were designed where hundreds of siblings of type 1 diabetics were followed for about 10 years, and those that drank a lot of milk had about 5 times the risk of coming down with a disease too. By the mid-90s, more than a dozen such studies were done, and overall, they found that early cow's milk exposure appears to increase the risk of type 1 diabetes by about 50%. That was good enough for the American Academy of Pediatrics who decided that cow's milk protein may indeed be an important factor in the initiation of the process that destroys your insulin-producing cells. And so the avoidance of cow's milk protein may reduce or delay the onset of type 1 diabetes. Yet another reason to emphasize breast is best. For those at risk, they strongly encouraged the avoidance of products containing intact cow's milk protein as opposed to hydrolyzed formula, in which the milk proteins are all broken up into tiny pieces, which is used for kids with dairy allergies or could potentially make it less risky. I mean, you don't know until you put it to the test. Based on the population studies and meta-analyses of all those antibody studies, which suggested that cow's milk may serve as a trigger of type 1 diabetes, the next year a pilot study was initiated to see if babies at high genetic risk would be less likely to develop antibodies that then attack their own pancreas if they drank casing that was chopped up first. And here's the study. The hydrolyzed formula did seem to reduce the appearance of at least one autoimmune antibody, but not two or more, which is more predictive of the development of the disease. But that was enough for the investigators to embark on the ambitious trigger study, the trial to reduce incidence of diabetes and genetically at risk. A multinational randomized prospective trial involving randomizing thousands of newborns across 15 countries with expected completion in 2017. But in 2010 we got some preliminary data suggesting it may have helped, but didn't quite reach statistical significance, meaning basically there was a greater than 1 in 20 chance it could have just been a fluke, and indeed when the final autoimmune antibody results were published, the special hydrolyzed formula didn't seem to help at all. Now they did just look at a special group of children at high genetic risk with diabetes running in the family, whereas the great majority of children who get type 1 diabetes don't have any afflicted close relative. But perhaps most importantly, as the researchers themselves emphasized, their study wasn't designed to test whether cow's milk is or is not a trigger for the disease, just what effect the hydrolyzed casein formula might have. Maybe it's not the casein, maybe it's the bovine insulin. Insulin autoantibodies, antibodies, our body produces to attack our own insulin, and appears the first sign in pre-diabetic children. Because cow's milk contains bovine insulin, cow insulin, around the same time the other researchers were looking at a casein, this research team was following the development of insulin-binding antibodies in children fed with cow's milk formula. They found significantly more antibodies to bovine insulin in the cow's milk formula group compared to the exclusively breast-fed group, who may only have been exposed to a few cow proteins through their mom's breast milk if their mom drank the stuff. Furthermore, the bovine antibodies cross-reacted to human insulin, potentially being that caught in the crossfire cause that triggers at least some cases of type 1 diabetes. But you can't know for sure until, you guessed it, you put it to the test. Same as the other one, a randomized double-blind trial, but this time they tried a cow's milk formula from which the bovine insulin had been removed. And indeed, without the bovine insulin exposure, the children built up significantly fewer autoimmune antibodies. But what we don't yet know is if this will translate into fewer cases of diabetes. Stay tuned.