There seems little doubt that coeliac disease is getting more common in some countries, and no-one knows why. Early feeding practices are an obvious area to investigate. In Sweden, there was a sudden surge in coeliac diagnoses in the 1980s–90s which was blamed on giving gluten very early, and some research done then suggested that deliberately ‘priming’ the infant by giving small amounts at age 4–6 months could actually prevent the disease developing. Official weaning advice since then has tended to reflect this.

Co-incidentally, two European studies set out to test …