You may have seen the headlines after the article was published in JAMA Pediatrics on pregnant mothers and peanut and tree nut consumption:
“Eating Peanuts While Pregnant Cuts Child’s Risk of Allergy”
“Eating Peanuts While Pregnant Lowers Allergy Risk”
With the significant rise in peanut and other food allergies in the United States there is no surprise that expectant mothers are concerned about how their diet may affect the development of allergies in their unborn child. Unfortunately, the guidelines keep changing and the result is a great deal of confusion. The study itself provides useful information. The popular media headlines are not so helpful and may be misleading.
The study conducted by Dr. Michael Young, an associate 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 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. However, children of mothers who were allegic to peanuts or tree nuts did not have a significantly lower risk the study found.
What the study showed was that pregnant woman need not avoid eating peanuts and tree nuts which reverses a recommendation that was very common up until a few years ago. What it does not show is that “eating peanuts while pregnant cuts child’s risk of allergy” as the headlines tout. In a follow-up interview with WebMD, Dr. Young states that “our findings do not demonstrate a cause-and-effect relationship between women eating nuts during pregnancy and lower allergy risk for their children. Our results are not strong enough to make dietary recommendations for pregnant women.”
There are other factors that might be causing the association between eating nuts and a lower incidence of nut allergic offspring. For example, the pregnant mother “nut eaters” also ate far more fruits and vegetables. Also, there is no data in the study on why the pregnant mothers who did not consume the higher quantities of nuts made the decision not to do so. Was the decisions strictly dietary selection or was it because eating peanuts or other tree nuts made them feel “uncomfortable” or “sleepy” or ‘flushed?” In other words, were the non-nut eaters sensitive or allergic to nuts themselves and therefore avoided eating them? If that was the case, then pregnant mothers eating more nuts would not help the potential allergies of their children and it might endanger their own health.
Bottom line is that most dietary restrictions for pregnant women are unneccessary. There is no reason for an expectant mother to stop eating nuts or having a peanut butter and jelly sandwich. However, much more research needs to be done to determine what is causing the increase in food allergies.