Type-1 diabetes is commonly called juvenile onset diabetes or insulin dependent diabetes. It is caused by the body’s loss of the ability to make insulin. This differs from type-2 diabetes, which is the kind of diabetes that occurs latter in life. Type-2 or adult onset diabetes is not characterized by a lack of the ability to produce insulin. It is caused by the body becoming insensitive to insulin.
A study appearing in the journal, Diabetes (2000;49:912-917) shows that there may be a connection between type-1 diabetes and milk consumption. They found that if a child had a sibling with type-1 diabetes, he or she was five times more likely to develop the disease if they drank more than a half-liter (a little more than a pint) of milk each day.
It is not clear why milk can trigger this response in the genetically susceptible. Perhaps one of the proteins in milk triggers an immune response that in turn creates an autoimmune attack on the pancreas—destroying the cells that produce insulin.