• coeliac disease
• breast feeding
• gluten

Coeliac disease is a multifactorial disorder developing as a result of a complex interplay between genetic and environmental factors.¹ HLA and non-HLA genes are involved, and gluten is obviously a critical environmental factor as the disease goes into remission when gluten is eliminated from the diet. The important case control study by Ivarsson et al concludes that feeding with breast milk when gluten is introduced in children under the age of two years protects against coeliac disease. Breast milk can therefore be considered an environmental factor for this disease as well.

Proving causality using epidemiology is demanding.² There may be both recognised and unrecognised confounding factors associated with breast feeding, which are not properly adjusted for. The authors controlled for one obvious factor—gluten intake. Introducing large amounts of gluten increased the risk of coeliac disease compared with small or medium amounts. Notwithstanding, multivariate analysis demonstrated that breast feeding at the time of gluten introduction in itself reduced the risk of coeliac disease. A plausible mechanism would strengthen the evidence for a causal relationship. What could then be the mechanisms for this protective effect?

The lactating mammary gland and the infant intestine is an immunological dyad.^3,4 Human milk contains defence factors such as secretory IgA antibodies, free secretory component, lysozyme, and lactoferrin which …