Eating Nuts in Pregnancy May Lower Risk of Common Food Allergy

Children born to mothers who ate nuts during pregnancy were less likely to develop peanut or tree nut allergies, according to a study published by JAMA Pediatrics.

The study, conducted by researchers at the Dana-Farber Children's Cancer Center in Boston, looked at 8205 children born to mothers who reported their diet during or shortly before or after their pregnancy as part of the ongoing Nurses’ Health Study II. Among the children, the researchers identified 308 cases of food allergies, including 140 children with peanut and nut allergies.

"Our study showed increased peanut consumption by pregnant mothers who weren't nut allergic was associated with lower risk of peanut allergy in their offspring," said the study's senior author Michael Young, MD, of Boston Children's Division of Allergy and Immunology, in a news release. "Assuming she isn't allergic to peanuts, there's no reason for a woman to avoid peanuts during pregnancy."

Researchers found that children whose nonallergic mothers had the highest peanut and tree nut consumption (consisting of 5 times a week or more) had the lowest risk of having a nut allergy. This lower risk of nut allergy was not observed among children born to mothers who had a peanut or tree nut allergy.

"Our study supports the hypothesis that early allergen exposure increases the likelihood of tolerance and thereby lowers the risk of childhood food allergy. Additional prospective studies are needed to replicate this finding," the study concluded. "In the meantime, our data support the recent decisions to rescind recommendations that all mothers avoid P/TN during pregnancy and breastfeeding."

The data, however, did not show a cause and effect relationship, meaning there was no proof that eating more peanuts during pregnancy will prevent a peanut allergy in children. Still, the link reported in the study supports the hypothesis that early allergen exposure increases tolerance and reduces risk of childhood food allergy, Young said.

Ruchi Gupta, MD, MPH, of the Northwestern University Feinberg School of Medicine, agreed in a related editorial published by JAMA that the study supports the guidelines that women not restrict their nut intake during pregnancy.

"Although the dietary surveys were not specific for the actual dates of pregnancy, these findings support recent recommendations that woman should not restrict their diets during pregnancy,” Gupta wrote. “Certainly, women who are allergic to nuts should continue avoiding nuts."

Pertinent Points:
- Children of mothers who ate nuts during pregnancy were less likely to develop peanut or tree nut allergies.
- Pregnant women with a nut allergy should continue to avoid peanuts or tree nuts.
- The study, which used data tracking the diets of pregnant women and comparing it with the number of children who had an identified nut allergy, did not establish a cause and effect relationship between pregnancy nut consumption and preventing an allergy.