For years, pregnant women were advised to avoid eating peanuts and tree nuts because these foods can be highly allergenic. The theory was that early exposure to such allergens could increase a child’s risk of developing a nut allergy. This theory was so widely believed that back in 2000 the American Academy of Pediatrics (AAP) endorsed these recommendations, even though there was a lack of supporting research. But just last week, a study was published showing that women (who don’t have a nut allergy) do not need to avoid nuts during pregnancy – in fact, pregnant women who ate more nuts had children with a lower nut allergy risk.
This paper actually came out after the AAP took back their suggestion of avoiding nuts during pregnancy (which happened in 2008). Why did they change their advice before the recent paper’s publication? Although an extensive study hadn’t been conducted previously, from 1997 to 2007 there was an observed increase in the number of nut allergy cases in the U.S. – in fact, the number of cases tripled. This brought about a reexamination of the anti-nut policies.
The recently published paper examined 10,907 children born from 1990 to 1994 whose mothers had reported their diet during, or around, their pregnancy. In 2006, these children were examined for having possible food allergies. The researchers found the following:
“The incidence of [peanut or tree nut] allergy in the offspring was significantly lower among children of the … nonallergic mothers who consumed more [peanuts or tree nuts] in their peripregnancy diet (≥5 times vs. <1 time per month: odds ratio = 0.31…)”
The researchers concluded by saying that:
“[The] study supports the hypothesis that early allergen exposure increases tolerance and lowers risk of childhood food allergy.”
For more information on general recommendations for preventing allergies in babies and small children, check out PubMed Health’s fact sheet on this topic.
This paper helps to emphasize the importance of actually investigating and testing a theory, even (and maybe particularly) if it’s a long-held and widely believed one.
For further reading:
- A. Lindsay Frazier et al.’s article “Prospective Study of Peripregnancy Consumption of Peanuts or Tree Nuts by Mothers and the Risk of Peanut or Tree Nut Allergy in Their Offspring” in the journal JAMA Pediatrics
- ScienceDaily’s article “Peanut and Tree Nut Allergy Incidence Lower Among Children Whose Mothers Ate Them During Pregnancy, Study Finds”
- PubMed Health’s “Fact Sheet: Preventing Allergies in Babies and Small Children“
- Teisha J. Rowland’s book Biology Bytes: Digestible Essays on Stem Cells and Modern Medicine
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