No Increased Risk of Food Allergies for Premature Children

The Journal of Allergy and Clinical Immunology, always a major source of the latest news on studies of dairy and other food allergies, carried the report of a study whose objective was "To determine whether premature or low-birth-weight children have an increased risk of developing food allergy compared with term or normal-birth-weight children."

The risk of developing food allergy in premature or low-birth-weight children by JJ Liem, Al Kozyrskyj, SI Huq, and AB Becker. J Allergy Clin Immunol. 2007 May;119(5):1203-9. Epub 2007 Mar 26

An article on the study by Stephen Daniells in FoodNavigator.com quoted the lead author as saying:

"To the best of our knowledge, this population-based study is the first to examine prematurity or low birth weight and the risk of developing food allergy."

"Our data suggest that no association exists between gestational age and birth weight with the development of IgE-mediated food allergies. As a result, the theory that an immature gut mucosa results in increased permeability to large-molecular-weight proteins and predisposes the baby to early sensitization needs to be questioned," he added.

This contradicts the findings of previous studies, which appeared to find that "immature gastrointestinal tracts as found in premature babies result in an increased uptake of food antigens."

The researchers analysed 13,980 children were born in 1995 and living in the province of Manitoba, and of these, 592 children were found to have food allergy. When the data was analysed with respect to birth weight and maturity, no association with food allergy was observed.

"Prematurity and low birth weight are not associated with a change in risk for development of food allergy in childhood," said the researchers.

The researchers did find that food allergy was associated with a maternal history of asthma and food allergy, however.

"The theory is that at a young age (ie. less than 3 years), an immature and permeable gastrointestinal tract will result in increased antigen uptake. Thus, highly allergenic foods may be absorbed more easily, increasing the risk for sensitization," said Liem.

"However, our large, population-based epidemiologic study does not support [this]. A possible mechanism preventing sensitization might be the development of immunologic tolerance to orally ingested allergens in premature infants.

"Such tolerance might result from interaction of high antigen concentration with the immature immune system of the preterm infant," he said.

"These data prompt us to ask whether it may be possible that introducing highly allergenic proteins (such as peanut) early in life would tolerise (as opposed to sensitise) a child to that particular antigen?" said the researchers.

They called for carefully designed and monitored studies to identify the best approach to the introduction of foods for infants and young children.

Newsfood.com put it more directly:

The researchers argued that weaning policies that advocate the avoidance of potential food allergens, such as gluten, lactose, peanuts and shellfish, may not be necessary. Indeed the paper went as far as to argue for deliberate introduction of potential food allergens into the diet of young children in order to stimulate tolerance, a suggestion that will need careful consideration, and to be backed by additional research.

Note that this was also suggested by the results of an earlier report, summarized in Desensitizing Food Allergies Possible in New Study