Expectant moms who go nuts boost child asthma risk

Pregnant women who eat nuts or nut products like peanut butter daily raise the risk their children will develop asthma by 50 percent, Dutch researchers said on Tuesday.

The study also showed that moderate amounts did not seem to have an effect, meaning it is too soon to say whether pregnant women should give up nuts because they contain many important nutrients and healthy fats a developing foetus needs, they said.

"We were the first to find these strong effects on asthma symptoms," said Saskia Willers, an epidemiologist at Utrecht University, who led the study linking nuts with asthma.

"But until we are certain we don't want to restrict them from the diet. So it is important that other studies replicate the findings," she said.

Asthma is an inflammatory disease causing wheezing, coughing and laboured breathing that can be life threatening. In some countries as many as 30 percent of children develop the condition, according to the World Health Organisation.

Scientists do not exactly know why some children develop asthma, although some believe that allergies can trigger the disease that causes a narrowing of the bronchial tubes.

Nuts and seafood are known to contain allergens that cause food allergies but the Dutch team only found a link between peanuts and asthma, Willers said.

In their study, more than 4,000 pregnant women completed a dietary questionnaire that asked whether they consumed vegetables, fresh fruit, fish, eggs, milk, milk products, nuts and nut products rarely, regularly or daily.

The researchers, who published their findings in the American Journal of Respiratory and Critical Care Medicine, then assessed the children's diets and looked to see who had developed asthma over an eight-year period.

Children whose mothers ate as little as one peanut butter sandwich a day had a far higher risk of asthma, Willers said in a telephone interview.

"If you eat moderately, it is probably not a problem," she said. "It is only if you eat nuts or nut products on a daily basis."

The study did not find a mechanism but Willers said peanut allergens may be crossing the placenta and sensitizing a foetus, making a child more prone to the disease.

The researchers also found a small benefit from eating fruit daily, and reported that the link between asthma and nuts remained after factoring for the child's diet, Willers added.