Study: Peanut Consumption While Pregnant Reduces Child's Allergy Risk

Did your mother abstain from the gooey goodness of peanut butter while pregnant with you? If you're now allergic, a new study suggests that might be part of the reason why. According to the study, published in the JAMA Pediatrics journal, the more nuts a woman consumed while pregnant, the less likely her child was to have an allergy. Which makes a fair bit of sense, even to those of us who were humanities majors in college. Apparently, the incidence of peanut — or tree nut — allergies has more than tripled in children from 1997 to 2010.

About 1.4 percent of kids are allergic to some combination of almonds, Brazil nuts, cashews, hazelnuts, pecans, pistachios, macadamias, and walnuts. They're one of the most common allergies around, and, because reactions are often so severe, living with a nut allergy means having to take extra precautions. About 40 percent of allergic kids have had a near life-threatening reaction. (Who amongst us hasn't been on a plane when an announcement suddenly comes on, asking us not to consume nut products lest the person in the next row have a severe reaction mid-flight?)

But apparently, this new study comes after years of contradictory advice:

In 2000, the American Academy of Pediatrics advised pregnant women to avoid peanuts and tree nuts while pregnant or nursing, to avoid exposing infants, and to keep kids away from nuts until age 3. The pediatric academy reversed this advice in 2008, telling women there was no need to avoid nuts during pregnancy or early childhood.

Whoops. Looks like that might be directly linked to the rise in allergies, since women who reported eating nuts more than five times a week were 69 percent less likely to have an allergic child than women who ate nuts once a month or less. Though the researchers say that their study doesn't prove a cause-and-effect relationship — meaning women shouldn't start guzzling peanuts as a preventative measure — nuts are perfectly safe for non-allergic women to consume during pregnancy. Allergic women, on the other hand, are probably better off avoiding nuts:

The exception was children of women who themselves had a history of nut allergies. In those cases, when women ate nuts five or more times a week during pregnancy, their children had about two and a half times the risk of nut allergies compared to the kids of allergic mothers who avoided nuts during pregnancy.

"The take-home message is that the previous concerns or fears of the ingestion of nuts during pregnancy causing subsequent peanut or nut allergy is really unfounded," said Michael Young, a senior author of the study and an attending physician at Boston Children's Hospital.

And, since there's nothing that says childhood quite as well as a peanut butter and jelly sandwich, but the high prevalence of peanut allergies means that lots of kids are stuck with PB-less PB&Js or — worse! — have to substitute the iconic spread with almond butter or the like.