The jury is still out on whether cow's milk given to a newborn can cause type 1 (insulin-dependent) diabetes, commonly known as juvenile diabetes. However, evidence may be mounting that connects the two.
According to a study reported in the June 26, 1999, issue of Science News, Finnish researchers studying children prone to diabetes from birth found that babies receiving formula that includes cow's milk were more likely later to develop the immune reactions associated with type 1 diabetes than babies who were given a substitute formula.
The results of the study were reported to the American Diabetes Association at its 59th annual Scientific Sessions in San Diego in 1999.
Scientists observed 173 babies, who had someone in the family with type 1 diabetes, until the age of eight months. As part of the research, half of the babies received a formula containing milk, while the other half received a formula in which the cow's milk proteins had been broken into fragments called peptides. Because the formulas tasted and smelled the same, neither the researchers nor the parents knew which formula the infants received.
Outi Vaarala, an immunologist at the University of Helsinki, explained that an infant's immune system generally ignores cow's milk proteins that have been digested, but contact with one intact protein in cow's milk, called bovine insulin, can set type 1 diabetes in motion. The immune system would attack pancreas islet cells that make human insulin, which resembles bovine insulin, and would begin producing antibodies.
When the study group of infants reached age two years of age, 10 of the 89 children who received the cow's milk formula formed antibodies associated with type 1 diabetes; only three of the 84 babies who received the treated milk showed the antibodies, said Dr. Hans K. Akerblom, a pediatrician at the University of Helsinki.
Hans-Michael Dosch, an immunologist at the Hospital for Sick Children in Toronto, explained that these autoimmune antibodies are created by immune B cells and appear to dispose of damaged pancreatic islet cells. The antibodies indicate that bovine insulin might be spurring an immune system T-cell reaction against the child's own islet cells.
Suvi M. Virtanen, a nutritional epidemiologist at Finland's University of Tampere, said research has determined that a baby has a 4-in-10 chance of contracting type 1 diabetes within the next decade if the child has one type of autoantibody to insulin. The more types of these autoantibodies to insulin, the greater the risk of type 1 diabetes development, said Virtanen. In this study, three of the 10 children in the cow's milk group with diabetes-related antibodies showed one type of such antibody and the rest had two or more.