It is widely believed, although not proven, that early feeding of infants with cow milk-based diets may increase the risk of developing Type 1 diabetes, in genetically predisposed individuals. 1 Hence, delayed exposure to standard infant formula is being tried for diabetes prevention. 2 In this comment we propose that early feeding of 'diabetogenic' diets, which contain complex mixtures of animal and plant proteins, may be protective rather than detrimental. This view is based on feeding experiments in diabetes prone BB rats. In this animal model, the feeding of standard mixed protein diets with milk, soy, and wheat from weaning causes destructive insulitis and diabetes while hypo-allergenic diets containing hydrolysed proteins do not. 3 However, one of us observed that oral dosing of the diabetogenic diets in the first week of life significantly suppressed diabetes development. How do we explain this surprising finding? One contributing factor may be neonatal tolerance. This phenomenon has recently been described as reflecting the preferential induction of a Th2-type immune response. The resulting Th2 biased memory to dietary antigens may prevent the induction of diabetogenic Th1 cells 6 in response to diets fed after weaning. An even more important aspect may be that feeding of foreign proteins during the first week of life occurs under the protective umbrella of high doses of breast milk. The latter contains immune mediators such as TGFb which are thought to prevent undue immune responses in the suckling infant's gut and improve immune tolerance. In conclusion, early exposure of the infant's immune system to foreign, potentially hazardous antigens, may be beneficial, provided the encounter occurs under tolerogenic conditions. Such early education of the immune system may be important for the establishment of stable self-tolerance mechanisms.