Early Infant Feeding and Type 1 Diabetes

Does the early introduction of cows milk to the infant's diet increase the risk of developing Type 1 diabetes? In Type 1 diabetes the beta cells of the pancreas no longer produce insulin. Along with inheriting a genetic predisposition to the disease, environmental factors such as the introduction of  food antigens which affect immune regulation, may also play a role. The association between introducing cows milk during the infant's first year of life and the development of Type 1 diabetes was investigated in a large population study undertaken in Helski, Finland (1).

Between 1994-1995, 6209 healthy term infants born in hospital participated in the study. These same infants were also participants in a study looking at supplementary feeds and the development of cows milk allergy. While in hospital mothers were encouraged to breast feed. Those infants who required supplementary milk feeds were randomized into groups to receive either cows milk infant formula (CMF) (1.5% protein and whey:casein 60:40) or extensively hydrolysed whey based formula (EHF) or pooled pasteurized  breast milk (PBM). All supplementary feeds given in hospital were recorded. When discharged from hospital mothers were again encouraged to continue breast feeding but asked to give CMF if supplementary feeds were needed. Mothers recorded the amount and type of infant formula given during the first 8 weeks. Mothers were asked about the liquid and solid foods given to their infant at ages 6 months and 12 months. When the children were 11-12 years old the national diabetes registry was consulted to find out how many children in the study had Type 1 diabetes.

In hospital 13.3% of infants were exclusively breast fed, 28.8% received CMF, 28% received EHF and 29.9% pooled breast milk. At the end of the study in  August 2006, 45 children had Type 1 diabetes - 9 in the CMF group, 12 in the EHF group, 16 in the PBM group and 8 who were exclusively breast fed. No association was found between developing Type 1 diabetes and receiving supplementary cows milk feeds or breast milk while in hospital. However fewer children who received cows milk based formula in hospital developed diabetes compared to those that didn't, but this difference disappeared by the end of the study. Those who had breast milk or pooled breast milk in hospital had diabetes in the same proportion as those fed CMF or EHF. Length of breast feeding, introduction of cereals and other solid foods was similar among those who developed Type 1 diabetes and those that didn't. Infants introduced to regular daily feeds of cows milk formula were at lower risk than those introduced later.

The advantage of this study is that the exact amounts of supplementary cows milk feeds given to infants in hospital are known. This is important as many infants are given small amounts of formula while in hospital and then exclusively or partially breast fed when home.

The study shows that very early exposure to cows milk in the general population of infants did not increase the risk of developing Type 1 diabetes. The early stimulation of the immune system by cows milk may confer some protective benefits. However, this may not be the case with infants known to be genetically at risk of diabetes, as the interaction of genes and environmental food antigens may produce an immune response with a differing outcome.

Reference:

1. Savilahti E, Saarinen KM. Early infant feeding and type 1 diabetes. Eur J Nutr. Published on line 5th March 2009 DOI 10.1007/s00394-009-008-z