Nut Consumption Does Not Increase Childhood Asthma Risk

There is no evidence that consuming peanuts and tree nuts during pregnancy increases the risk of childhood asthma and allergies, a study suggests.

Children whose mothers consume peanuts and tree nuts during pregnancy appear to have a decreased risk of asthma, according to the results of a study published online on June 29, 2012, in the Journal of Allergy and Clinical Immunology. The study was based on an analysis of data on 61,908 mothers and their children from the Danish National Birth Cohort.

The researchers used food questionnaires that covered 4-week periods to assess the frequency of peanut and tree nut consumption by the mothers. The asthma status of children at 18 months of age was determined based on parental reports of childhood asthma diagnosis, wheeze symptoms, and recurrent wheeze. Asthma status at 7 years of age was determined based on asthma diagnosis by doctors as well as wheeze in the previous year and allergic rhinitis as a self-reported doctor’s diagnosis.

According to the food questionnaires, 61% of the mothers reported no peanut or tree nut intake during pregnancy, whereas 3% reported consuming peanuts at least once per week, and 9% reported consuming tree nuts at least once per week. The researchers’ results showed that children whose mothers consumed peanuts or tree nuts at least once per week during pregnancy were actually less likely to have asthma at 18 months of age. Compared with children whose mothers abstained from peanuts and tree nuts during pregnancy, the odds ratio (OR) for having asthma at this age was 0.79 for children whose mothers regularly consumed peanuts and 0.75 for those whose mothers regularly consumed tree nuts.

The researchers also found evidence of the benefits of maternal nut consumption for children at the age of 7. Compared with children whose mothers abstained from peanuts and tree nuts during pregnancy, children at this age whose mothers consumed peanuts at least once per week during pregnancy were less likely to have asthma (OR = 0.66) as were children whose mothers consumed tree nuts at least once per week during pregnancy (OR = 0.89). Children whose mothers consumed peanuts or tree nuts at least once a week during pregnancy were also less likely to have medication-related asthma at age 7, with an odds ratio of 0.83 for peanut consumption and 0.81 for tree nut consumption. Finally, the researchers found that children of mothers who regularly consumed tree nuts were less likely to have allergic rhinitis at age 7 (OR = 0.80), but they found no such association for maternal consumption of peanuts.

The researchers note that their findings indicate that there is no reason for women to avoid eating peanuts or tree nuts during pregnancy and that eating them regularly during pregnancy may actually confer a significant protective benefit on their children. They note, however, that their results were limited by the self-reporting of outcomes and exposure and the inability to assess risk for processed products or products containing nut residues such as peanut butter or cereals or candy bars. In addition, the study authors did not track maternal diet during lactation or early childhood diet.