Nutty Diet in Pregnancy: Asthma Risk?

Study Shows Eating Nuts Daily During Pregnancy May Up Kids' Risk of Asthma

Reviewed by Louise Chang, MD on July 14, 2008

July 15, 2008 (New York) -- Pregnant women who eat nuts or nut products such as peanut butter every day during pregnancy may increase their offspring's chances of developing asthma by nearly 50%, compared with women who rarely or never consume nut products during pregnancy.

The increased risk is evident for the child's first eight years, according to a new study in the July issue of the American Journal of Respiratory and Critical Care Medicine.

"Daily versus rare consumption of nut products -- which we assumed was largely peanut butter -- was consistently and positively associated with childhood asthma symptoms, including wheeze, dyspnea [shortness of breath], doctor diagnosed asthma and asthma-associated steroid use," conclude the study researchers, who were led by Saskia M. Willers, MSc, an epidemiologist at Utrecht University, the Netherlands.

The researchers caution that more study is needed to confirm these findings before issuing any recommendations regarding pregnant women and eating nut products. Exactly how eating peanut butter or nut products daily during pregnancy may affect offspring's risk of developing asthma is unclear. But the researchers speculate that maternal factors may influence the development of the airways and immune system of the developing fetus.

So what's a mom-to-be to do?

Don't panic and make any dramatic changes in your diet based on this study, stresses Neil Schachter, MD, medical director of respiratory care at Mount Sinai Medical Center in New York City.

"It's not like if you have a peanut butter sandwich once or twice a week while you are pregnant that you are doing your child harm," he tells WebMD. "It's a very interesting study and something to take into account, but it's just one study and we need a confirmatory study to show this is a real finding."

His best advice? "Until the verdict is in, it's probably a good idea not to eat peanut products all the time during pregnancy."

Manju Monga, MD, the Berel Held Professor and the division director of maternal-fetal medicine at the University of Texas Health Sciences Center in Houston, agrees.

"Moderation is key and there are good nutritional benefits from eating peanut butter that should not be discounted based on one study," she tells WebMD. "It is highly unusual to find someone who eats nuts or nut products every single day during their pregnancy. And this is the only group of women who had an increased risk of their children developing asthma."

The new study looked at close to 4,000 expectant mothers who completed a dietary questionnaire that asked how often they consumed vegetables, fresh fruit, fish, eggs, milk, milk products, nuts, and nut products during the last month. The researchers also tracked their children's diets at 2 years of age; their asthma and allergy symptoms were assessed yearly until they turned 8. The final analysis included data on 2,832 children and their mothers. Six percent of the mothers in the study consumed nuts or nut products daily.

Women who consumed nuts and nut products daily during pregnancy were more likely to have children with wheezing, shortness of breath, use steroids for asthma, and have symptoms of asthma, than were children of moms who rarely consumed nuts or nut products while pregnancy. Most study participants reported rare or regular intake (which according to the definition of the study included up to six times per week) of nuts or nut products. There was no increased risk of asthma in the children of moms in that group, the study showed.

Show Sources


Willers S.M. American Journal of Respiratory and Critical Care Medicine, July 2008; vol 177: pp 1-8.

Neil Schachter, MD, medical director of respiratory care, Mount Sinai Medical Center, New York City

Manju Monga, MD, Berel Held Professor and the division director of maternal-fetal medicine at the University of Texas Health Sciences Center, Houston.

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