title: Taking the leap earlier: the timing of tolerance.
abstract: OBJECTIVE
  The paradigm for the primary prevention of peanut allergy was, until recently, strict avoidance of peanut during pregnancy, infancy, and early childhood. However, in countries that had these dietary guidelines, the prevalence of peanut allergy greatly increased in contrast to low prevalence rates of peanut allergy in countries where infant diets included peanut at an early age, suggesting the hypothesis that early introduction of peanut is superior to delayed introduction of peanut as a strategy for the primary prevention of food allergy. This review examines recent high-quality studies that support this hypothesis.
  
  
  RESULTS
  Publication of the Learning Early about Allergy to Peanut interventional trial showed that 17% of children avoiding peanut until 5 years of age developed peanut allergy compared with 3% of children who started eating peanut at ages of 4-11 months. Two birth cohort studies demonstrated that high maternal consumption of peanut during the pregnancy period reduced the risk of peanut allergy in offspring by 50-75%.
  
  
  CONCLUSIONS
  Recent studies indicate that early introduction of peanut enhances the development of tolerance to peanut, reducing the risk of childhood peanut allergy.
authors.affiliation: Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Young
mesh_terms: D010367:Arachis / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology*; D007223:Infant; D007227:Infant Nutritional Physiological Phenomena; D039382:Maternal Nutritional Physiological Phenomena; D021183:Peanut Hypersensitivity / Q000453:epidemiology / Q000276:immunology* / Q000517:prevention & control; D011247:Pregnancy; D015995:Prevalence; D011322:Primary Prevention / Q000379:methods*; D012306:Risk; D013997:Time Factors; D014481:United States / Q000453:epidemiology