Dutch scientists at Utrecht University studied the connection of nuts consumption with the risk of asthma. The study involved 4 000 pregnant women who were asked to fill in a dietary questionnaire that specified their eating habits during pregnancy. They were asked whether they ate vegetables, fresh fruit, fish, eggs, milk, milk products, as well as nuts and nut products and rarely, regularly or daily.
Over an eight-year period, the researchers followed up the children of the pregnant women who took part in the research to see who had developed asthma. The results of the study showed that those children whose mothers consumed at least one peanut putter sandwich daily were more likely to have asthma symptoms, including wheeze, dyspnea, doctor diagnosed asthma and asthma-associated steroid use.
Scientists also find little effect of daily fruit consumption during pregnancy on reducing the risk of asthma. They said that the association between nut products and asthma remained even after controlling for the child's diet. Authors say that some other factors might play the role and further study is needed.
Saskia Willers, an epidemiologist at Utrecht University and the leading author of the study said that eating nuts in moderate amounts might not affect the child, but consuming nuts and nut products daily might considerably increase the risk of developing asthma.
It is still not clear why some children develop asthma, but it was thought that certain allergens might contribute to the narrowing of the bronchial tubes, leading to asthma. Nuts and seafood are known to be among the allergen products and this might explain the link between daily consumption of nuts and asthma.
It is believed that peanut allergens may affect the unborn child, crossing the placental barrier during pregnancy.
Willers explained that scientists are uncertain whether nuts should be avoided during pregnancy as this product is known to be rich in nutrients and healthy fats that are good for the development of the fetus.
Asthma is a chronic condition affecting around 30 percent of children, according to the WHO data. Scientists do not know exactly what causes the diseases as it is associated with a great number of environmental and genetic factors.
The study was published in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.