Should peanuts be the latest food added to the "do not eat" list for moms-to-be? Maybe, according to preliminary research that found allergic infants at increased risk for peanut allergies if their mothers had ingested peanuts during pregnancy. Published online October 29, 2010, in the Journal of Allergy and Clinical Immunology, the study examined more than 500 infants in the US between 3 and 15 months old who likely had a milk or egg allergy but no known peanut allergy. Researchers note that more than a quarter displayed a strong reaction in a peanut "sensitivity" test, but children whose mothers had consumed peanuts during pregnancy were nearly three times as likely to show a potential indicator for the allergy.
Researchers also note that the more peanuts a woman reported eating while pregnant, the greater her infant's risk of a positive test. Consuming peanuts while breastfeeding, however, did not appear to significantly affect the test result.
In 2000, the American Academy of Pediatrics recommended that women whose infants were at increased risk of allergies based upon family history consider avoiding peanut products while pregnant and breastfeeding. However, the recommendation was withdrawn in 2008 due to limited scientific evidence to support it.
Just can't part with your peanut butter? The study's authors admit their findings are still inconclusive—and other research has drawn very different conclusions about peanuts and pregnancy. For example, a UK study comparing Israeli and British children found that prevalence of peanut allergy was far lower in Israel , yet Israeli children consume peanut from a very early age in the form of a peanut candy, and their mothers do not avoid peanut while pregnant.
"So we've had studies that sort of line up on both sides of the fence and we still don't have a definitive answer, and what this study tells us is that the jury is still out," says Dr. Susan Waserman, professor of medicine in the division of clinical immunology and allergy at McMaster University in Canada, in an interview with CTV News. Dr. Waserman was not involved in the study.