Peanut allergy is one of the most common allergies in the United States, afflicting up to 1.5 million Americans and killing about 100 people a year.
To prevent an allergy from developing, doctors have recommended that small children and nursing mothers avoid peanuts.
But recent studies questioned if early exposure limited the allergy or increased the risk, perhaps explaining a rise in allergies.
The latest study, published in The Journal of Allergy and Clinical Immunology, found that early exposure might provoke tolerance.
The authors examined two populations of genetically similar children, more than 8,000 in all. In one group, most ate peanuts by 9 months; those in the other had little or no early exposure. The scientists found the unexposed children were six times as likely to develop the allergy.
Dr. Robert A. Wood, a pediatric immunology expert at Johns Hopkins, said the research was intriguing but not final, and parents should be cautious.
Some children may be genetically destined to be allergic. Parents should be on the lookout for infants who show allergies to other things or have a family history of allergy.
Source: The New York Times