Peanut allergy could plummet by 77 percent if peanut products were added to all babies' diets at four to six months of age, according to new research led by the University of Southampton, Kings College London, and the National Institute for Health and Care Research (NIHR).
Peanut allergy has seen a three-fold increase in recent decades. It now affects around one in 50 children in the UK. However, there is increasing evidence that eating peanut products from an early age during infancy can reduce the risk of allergy and help reverse this trend.
Now, a study published in the Journal of Allergy and Clinical Immunology has gone even further to assess the best time to introduce the allergen into babies' diets, identifying a clear 'window of opportunity' between four and six months of age depending on the child's health.
The new analysis was led by Professor Graham Roberts, Professor in Paediatrics, Allergy and Respiratory Medicine at the University of Southampton and the NIHR Southampton Biomedical Research Centre, and Professor Gideon Lack at King's College London, with expertise from the Immune Tolerance Network (ITN) and National Institute of Allergy and Infectious Diseases (NIAID) in the USA.
Professor Graham Roberts said: "Over several decades, the deliberate avoidance of peanut has understandably led to parental fear of early introduction.
"This latest evidence shows that applying simple, low-cost, safe interventions to the whole population could be an effective preventive public health strategy that would deliver vast benefits for future generations."
Reducing risk
Most peanut allergies have already developed by the time a child turns one year of age. It is more common in children with severe eczema and egg allergy. Children of non-white ethnicity are also more likely to be affected.
The study used data drawn from the Enquiring About Tolerance (EAT) and Learning Early About Peanut Allergy (LEAP) randomised-controlled trials - both studies led by Professor Lack - plus the Peanut Allergy Sensitization observational study. These include children who are at high and others who are at low risk of developing peanut allergy.
The modelled approach showed it was best to introduce peanut products to babies at four to six months of age. For babies with eczema, four months is recommended. This should be in the form of smooth peanut butter or other peanut snacks suitable for babies – not whole or broken peanuts. The baby should also be developmentally ready to start solids.
Researchers advise mothers to breastfeed at least the first six months of their child's life, as well as introducing peanuts to their diet from four to six months.
Window of opportunity
Overall, the data found that introducing peanut products into all babies' diets by six months could reduce peanut allergy across the population by up to 77 percent. Waiting to introduce the peanut products until 12 months of age would lead to only a 33 percent reduction.
Professor Gideon Lack, from King's College London and Guy's and St Thomas' NHS Foundation Trust said: "The benefits of introducing peanut products into babies' diets decreases as they get older. This reflects the experience in Israel, a culture in which peanut products are commonly introduced early into the infant diet and peanut allergy is rare.
"There is a narrow window of opportunity to prevent an allergy from developing. Introducing peanut products at four to six months of age could substantially reduce the number of children developing peanut allergy."
Targeting the whole population
The research also showed that the greatest benefit can be achieved if the whole population is targeted. This is because most allergies occur in the many babies without any known risk factors. Targeting just babies with severe eczema would only reduce peanut allergy in the population by less than five percent.
The findings provide evidence for recommendations in recent North American and European allergy guidelines. These recommendations suggest the early introduction of peanut products for all infants, based on an extrapolation of previously published data from the LEAP and EAT studies conducted at King's College London.
The study, titled "Defining the window of opportunity and target populations to prevent peanut allergy" has recently been published in the Journal of Allergy and Clinical Immunology.
