Eggs or peanuts in early infant diet may cut allergy risk

Introducing eggs or peanuts early into infants’ diet is associated with a lower risk of developing egg or peanut allergy, says a systematic review of the evidence published in JAMA.1

The review found “moderate certainty” evidence that introducing eggs to the infant diet at 4 to 6 months was associated with reduced egg allergy and that introducing peanuts at 4 to 11 months was associated with reduced peanut allergy when compared with later introduction of these foods.

Infant feeding guidelines have moved away from advising parents to delay introducing allergenic food, but most guidelines do not yet advise introducing such foods early.

Robert Boyle, of Imperial College London, and colleagues carried out the systematic review and meta-analysis for the UK Food Standards Agency, to inform guidance on UK infant feeding. They extracted data from 204 titles reporting 146 studies.

Evidence from five trials with 1915 participants showed that introducing eggs into the diet at 4 to 6 months was associated with reduced egg allergy when compared with later introduction (risk ratio 0.56 (95% confidence interval 0.36 to 0.87)). The absolute risk reduction in a population with a 5.4% incidence of egg allergy was 24 cases per 1000 population.

Evidence from two trials with a total of 1550 participants showed that early peanut introduction at 4 to 11 months was associated with reduced peanut allergy (0.29 (0.11 to 0.74)) when compared with later introduction. The absolute risk reduction in a population with a 2.5% incidence of peanut allergy was 18 cases per 1000 population.

However, the researchers found only low certainty evidence that introducing fish into the diet before age 6 to 12 months was associated with reduced allergic rhinitis and only very low certainty evidence that introducing fish before 6 to 9 months was associated with reduced allergic sensitisation. The study also found high certainty evidence that the timing of gluten introduction was not associated with a risk of celiac disease.

These findings should not automatically lead to recommendations to feed eggs and peanuts to all infants, the researchers noted. “The imprecise effect estimates, issues regarding indirectness, and inconclusive trial sequential analysis findings all need to be considered, together with a careful assessment of the safety and acceptability of early egg and peanut introduction in different populations,” they said.

In an accompanying editorial Matthew Greenhawt, of Children’s Hospital Colorado in Aurora, USA,2 said the analysis showed that changes to guidelines, now advising not to delay introduction of allergenic foods, were correct.

“Delay of introduction of these foods may be associated with some degree of potential harm, and early introduction of selected foods appears to have a well defined benefit,” he wrote.

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