Human milk and host defence: immediate and long-term effects.

Convincing studies demonstrate significant protection during breastfeeding against diarrhoea, respiratory tract infections, otitis media, bacteraemia, bacterial meningitis, botulism, urinary tract infections and necrotizing enterocolitis. There is also good evidence for enhanced protection for years after the termination of breastfeeding against Haemophilus influenzae type b infections, otitis media, diarrhoea, respiratory tract infections and wheezing bronchitis. In some reports breastfeeding has also improved vaccine responses. Several studies show that milk may actively stimulate the immune system of the offspring via transfer of anti-idiotypic antibodies and lymphocytes. This may explain why breastfeeding diminishes the risk of developing coeliac disease. Some investigations suggest that there may also be a similar effect on allergic diseases and autoimmune diseases, as well as inflammatory bowel diseases and certain tumours. This needs to be confirmed.