Delaying the introduction of eggs into babies’ diets seems to increase up to fivefold the chance infants will become allergic to the food.
The finding by Melbourne researchers is the reverse of the existing widespread belief that this practice reduces the risk.
The researchers found babies introduced to eggs between the ages of four and six months were 60 per cent less likely to react against eggs than those who first tried them at 10-12 months.
Those not given eggs until they were over 12 months old were 3.4 times more likely to develop egg allergy.
The protection appeared especially strong — just 20 per cent of the risk — for babies given eggs that had been boiled, scrambled, fried or poached, and less so for those given egg-containing baked foods such as cakes and biscuits.
Until last year, guidelines in Australia, the US and Britain recommended babies at high risk of developing food allergies because of a family history not be given eggs, peanuts and other allergenic foods until they were two or three years old.
Pediatrician Katie Allen, lead author of the new study, published online yesterday by the Journal of Allergy and Clinical Immunology, said although this advice was changed last year to say there was insufficient evidence that such foods should be avoided, the latest results suggested the guidelines could be modified further.
“The statement can now be revised to say that it (introducing such foods early) is likely to be protective,” Associate Professor Allen said.
Egg allergy is the most common food allergy in children.
Although most grow out of it, they remain at higher risk for allergy-related conditions such as asthma.
With colleagues from the Murdoch Children’s Research Institute and the University of Melbourne, Associate Professor Allen recruited 2589 infants aged 11 to 15 months from immunisation centres across Melbourne.
After giving birth to her daughter Alexandra, Kara Masters was told by nurses not to give her eggs in her first year or two. She participated in the study when indicative skin-prick tests at the age of six months suggested Alexandra had multiple food allergies.
During the study, Alexandra, now aged 15 months, came up in hives when given even tiny amounts of egg white to eat under closely supervised conditions.
She has since been able to eat cupcakes, and following discussions with the researchers her mother has been including eggs in foods such as bread, in the hope this will maximise the chances Alexandra will lose the allergy by the age of eight.
“I hope this will change the guidelines,” Ms Masters said.
“You want to do the best thing for your child, but if you’re getting different information it’s hard to know what the truth is.”