The scientists from Imperial College London conducted a systematic review and meta-analysis on behalf of the UK’s Food Standards Agency (FSA), looking at a total of 146 studies, including intervention trials and observational studies.
They found evidence that the timing of when certain allergenic foods are given to infants is associated with risk of allergic disease, but not risk of autoimmune disease (such as coeliac disease).
It found 'moderate-certainty' evidence that giving babies egg at the age of four to six months was associated with reduced egg allergies and introducing peanuts at the age of four to 11 months was associated with reduced peanut allergy compared with later introduction of these foods.
However, there was low-certainty evidence that fish introduction before age 6 to 12 months was associated with reduced allergic rhinitis and very low-certainty evidence that fish introduction before age 6 to 9 months was associated with reduced allergic sensitisation.
“These data conflict with previous recommendations to delay introduction of allergenic foods to the infant diet and suggest that current guidelines that do not advise early introduction of allergenic foods may need to be revised,” write the study authors.
An FSA spokesperson told FoodNavigator: “The government is considering these findings as part of its review of infant feeding advice to ensure our advice reflects the best available evidence."
It currently advises waiting until the baby is six months old before introducing commonly allergenic foods such as peanuts, nuts, seeds, egg, cows’ milk, soy, wheat (and other cereals that contain gluten such as rye and barley), fish and shellfish.
After six months parents can introduce them in very small amounts, one at a time, watching carefully for any symptoms of an allergic reaction.
“There is no evidence that waiting until your child is older will prevent them developing a food allergy,” the spokesperson added.
Spokesperson for the British Society for Immunology Dr Louisa James said the findings were encouraging and supported a growing consensus that the timing of food introduction can influence the natural history of food allergies.
“Unfortunately the number of reported studies that could be included in this analysis was small and there were important differences in the way each study was conducted. This means that, despite positive findings overall, additional evidence is now needed before any new specific recommendations on the timing of introduction of allergenic food can be made,” she added.
Graham Roberts, professor and honorary consultant paediatrician in paediatric allergy at the University of Southampton, said parents should be sure to bring their babies to an allergy clinic before introducing allergenic foods to their diet.
“If testing is negative, the paediatrician may recommend that you introduce peanut and egg into your baby’s diet.”
"Timing of allergenic food introduction to the infant diet and risk of allergic or autoimmune disease: a systematic review and meta-analysis"
First published online 20 September 2016, doi:10.1001/jama.2016.12623.
Authors: D. Ierodiakonou et al.