The children of mothers who ate a lot of peanuts while pregnant may be at an increased risk of developing an allergy to the nut -- and the more peanuts the mothers ate, the greater the chances, a study found.
But it still is not yet clear if a mother's consumption of peanuts can actually cause the serious and potentially fatal allergy that appears to be on the rise, currently affecting about 1 percent of children.
Scott Sicherer of Mount Sinai School of Medicine in New York City and a team of colleagues at five locations across the United States studied more than 500 infants between 3 and 15 months old who likely had a milk or egg allergy but no known peanut allergy. Most had not yet tried to eat peanuts.
The study, published in the Journal of Allergy and Clinical Immunology, found that more than a quarter displayed a strong reaction in a peanut "sensitivity" test, with children of mothers who had consumed peanuts during pregnancy having nearly three times the odds of showing this potential indication of an allergy.
The more peanuts a woman ate while pregnant, the greater her child's chance of a positive test -- although consuming peanuts while breast-feeding did not appear to have a significant impact.
Sicherer and his team noted that the research did not show a clear cause and effect relationship, and that the children in the study only underwent blood tests for peanut sensitivity, which isn't the same as an allergy diagnosis.
His team is continuing to follow the children to determine what allergies might come and go.
The lack of clarity on the issue has left many women confused.
"I have had mothers say they ate a lot of peanut and think they caused a peanut allergy, and I have had other mothers say they avoided and wonder why their child has an allergy," Sicherer told Reuters Health in an email.
"I think that we unfortunately have to say that we do not yet know a certain answer. But the good part of that conclusion is that mothers should not necessarily have a guilty feeling about their past diet decisions."
Guidance on maternal peanut consumption has varied over the last decade.
The American Academy of Pediatrics issued a recommendation in 2000 that women consider avoiding peanuts during pregnancy and breastfeeding if one of the parents or a sibling had allergies, but withdrew it in 2008.