Early exposure to egg, peanut could reduce allergies

Early exposure to common allergens could reduce the risk of children developing an allergy to the foods, a new study has found.

In the largest analysis of evidence on the effect of feeding allergenic foods to babies, scientists from Imperial College London analysed data from 146 studies involving more than 200,000 children.

The results suggest that feeding children egg between the ages of four and six months may reduce their risk of developing egg allergy, while feeding peanut between the ages of four and eleven months may reduce the risk of a child developing peanut allergy.

The team also analysed milk, fish (including shellfish), tree nuts (such as almonds) and wheat, but didn’t find enough evidence to show introducing these foods at a young age reduces allergy risk.

Dr Robert Boyle, lead author of the research from the Department of Medicine at Imperial, said: “Until now we have not been advising parents to give these foods to young babies, and have even advised parents to delay giving allergenic foods such as egg, peanut, fish and wheat to their infant.”

“The number of children diagnosed with food allergies is thought to be on the rise,” added Dr Vanessa Garcia-Larsen, a co-author on the study from the National Heart and Lung Institute at Imperial. “There are indications that food allergies in children have become much more common over the last 30 years.”

She added that the reasons behind this rise are still unclear — doctors may be better at recognising food allergy, or there may be environmental factors involved.

In the meta-analysis, the team initially analysed 16,289 research papers on allergies and other immune system problems. Out of these, 146 were used for data analysis of when to feed babies allergenic foods such as egg, peanut, wheat and fish.

The results showed that children who started eating egg between the ages of four and six months had a 40% reduced risk of egg allergy compared to children who tried egg later in life.

Children who ate peanut between the ages of four and eleven months had a 70% reduced peanut allergy risk compared to children who ate the food at a later stage. However, the authors cautioned that these percentages are estimates based on a small number of studies.

Five studies (involving 1915 children) were used to estimate reduced risk of egg allergy and two studies (involving 1550 children) were used to estimate reduced risk of peanut allergy. Therefore these figures may change when more studies are completed.

Commenting on the findings, the UK Food Standards Agency said: “Imperial College London has produced a high-quality review. The government is considering these important findings as part of its review of complementary feeding for infants to ensure its advice reflects the best available evidence.”

The study was funded by the UK Food Standards Agency and supported by the Imperial NIHR Biomedical Research Centre, and the MRC-Asthma UK Centre in Allergic Mechanisms of Asthma.

The research has been published in the Journal of the American Medical Association.

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