Late introduction of eggs can make children vulnerable to egg allergy, it has been shown.
The world-first study by the University of Melbourne and Murdoch Childrens Research Institute found babies given egg after 12 months of age were up to five times more likely to develop egg allergy as they grew older than infants introduced to egg at four to six months of age.
Lead authors A/Professor Katie Allen and Jennifer Koplin said the study added to growing evidence showing early introduction of allergenic foods could be the best way to protect children against allergies.
"Until recently, Australian and international guidelines recommended that infants with a family history of allergy delay introducing allergenic foods such as egg, peanut and nuts until up to two to three years of age," Ms Koplin said.
"Our study suggests that babies who ingest these foods at an earlier age may be less likely to develop food allergies as they grow older. It seems that early introduction of egg may protect against egg allergy, while delaying its introduction may put the child at increased risk of developing an allergy."
The study, published online today by the Journal of Allergy and Clinical Immunology, involved more than 2500 Victorian infants to assess whether timing of egg introduction was associated with increased or decreased risk of egg allergy.
Egg allergy is the most common food allergy in infants and toddlers and can result in hives, vomiting, diarrhoea and, in some circumstances, anaphylaxis.
Infants who were introduced to egg after 12 months of age had triple the risk of egg allergy at 14-18 months of age than those given egg at four to six months of age, irrespective of whether they had a family history of allergy.
Giving babies cooked egg (boiled, scrambled, fried or poached) proved more protective against allergy than egg in the baked form (cakes, biscuits and similar products). Of babies aged four to six months who were introduced to cooked egg, just 5.6 per cent developed egg allergy compared with 27.6 per cent of those introduced to cooked egg after 12 months.
The study found no link between egg allergy and the duration of breastfeeding or timing of introduction of first solids. A/Professor Allen said further research was needed to determine if the study findings could also be true for other allergenic foods.
"Confirmation that early introduction is protective for other allergenic foods may help better inform parents in the future and could have the potential to reverse the epidemic of childhood food allergy," A/Professor Allen said.
"Food allergies often develop in early childhood and can have a significant impact on quality of life for the child and their family.
"Although children normally outgrow egg allergy, they remain at increased risk of related conditions such as asthma and allergic rhinitis in later life, as well as other food allergies such as peanut and tree nut allergy which persist into adult life."
The research forms part of a wider study led by Professor Allen at the Murdoch Childrens Research Institute to track food allergy prevalence and causes among Victorian infants. A/Professor Katie Allen is a leading allergy researcher at the Murdoch Childrens Research Institute and a paediatrician at The Royal Children's Hospital. Jennifer Koplin is a PhD scholar at University of Melbourne based at the Murdoch Childrens Research Institute