Women who eat nuts during pregnancy — and who aren’t allergic themselves — are less likely to have kids with nut allergies, a new study suggests.
Dr. Michael Young, an associate clinical professor of pediatrics at Harvard Medical School, and colleagues collected data on more than 8,200 children of mothers who took part in the Nurses’ Health Study II. The women had reported what they ate before, during and after their pregnancies.
About 300 of the children had food allergies. Of those, 140 were allergic to peanuts and tree nuts.
The researchers found that mothers who ate the most peanuts or tree nuts — five times a week or more — had the lowest risk of their child developing an allergy to these nuts.
Children of mothers who were allergic to peanuts or tree nuts, however, did not have a significantly lower risk, the study found.
The report was published online Dec. 23 in the journal JAMA Pediatrics.
The rate of U.S. children allergic to peanuts more than tripled from 0.4 percent in 1997 to 1.4 percent in 2010, according to background information included in the study. Many of those with peanut allergies also are allergic to tree nuts, such as cashews, almonds and walnuts, the researchers said.
“Food allergies have become epidemic,” said Dr. Ruchi Gupta, an associate professor of pediatrics at the Northwestern University Feinberg School of Medicine.
“Our own studies show that 8 percent of kids in the United States have a food allergy — that’s one in 13, about two in every classroom,” said Gupta, the author of an accompanying journal editorial.
Yet why this epidemic is happening remains a mystery, Gupta said. “We do not have any evidence as to what is causing this increase in food allergy,” she said. “It’s some kind of genetic and environmental link.”
The new findings do not demonstrate or prove a cause-and-effect relationship between women eating nuts during pregnancy and lower allergy risk in their children, Young said.
“The results of our study are not strong enough to make dietary recommendations for pregnant women,” he said.
Young said the findings do, however, add to the growing evidence that early introduction of foods increases the development of tolerance and reduces the risk of allergies.
“Our data should reassure pregnant women that they could eat nuts without causing the offspring to be allergic to nuts,” he said.
Read more: WebMD