henry copeland:

Why the world is becoming more allergic to food - BBC News

But it is thought that eating trigger foods during weaning can lead to a healthy response and prevent the allergy developing, because the gut's immune system is prepared to tolerate bacteria and foreign substances, such as food. This was the basis for King's College London's LEAP Study, which showed about an 80% reduction in peanut allergy in five-year-old children who regularly ate peanut from the year they were born.
- www.bbc.com