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Allison Bullen ate peanut butter by the scoopful while pregnant with her son Braxton, who's turning 3 in August.

The Huntsville, Ont., mother craved the taste, she says, and Braxton does now too - he has been served peanut butter on toast for breakfast nearly every day since he was 1.

But now Braxton is having trouble breathing.

"It hasn't been called asthma yet, but he does get a croup cough about twice a year," she said. "If this continues, when he is 5 he will be tested for asthma."

Researchers in the Netherlands might attribute that to his mother's nut consumption during her pregnancy.

A study conducted by researchers at Utrecht University found that expectant mothers who reported eating even a small amount of nuts or nut products every day during their pregnancy increased the risk of their child developing asthma by 50 per cent.

The study, featured in the July issue of the American Journal of Respiratory and Critical Care Medicine, asked about 4,000 pregnant women to track their eating habits by listing how often they ate vegetables, fresh fruit, fish, eggs, milk, milk products, nuts and nut products during the month before they gave birth.

Once the children were born, their diets were also followed until age 8, with special attention to any allergies or symptoms of asthma that might have developed.

The study found that children whose mothers reported eating nuts on a daily basis, compared with those whose mothers rarely - fewer than three times a month or never - consumed nut products while pregnant, were 50 per cent more likely to develop wheezing or other asthma-related symptoms.

"We were pretty surprised to see the adverse associations between daily versus rare nut product during pregnancy and symptoms of asthma in children because we haven't seen this in similar previous studies," study author Saskia Willers said in a statement.

However, she acknowledged that supplementary studies need to be done before women can be advised against eating nuts during pregnancy.

Sharon Dell, a pediatric respirologist at Toronto's Hospital for Sick Children, agreed there is not enough evidence in the study to make mothers skip the Skippy for good, but said the study will help pave the way for future links between pregnant women's diets and asthma.

"It is confirming what a lot of research has been telling us - exposures during pregnancy are important to the development of asthma," she said.

Allan Becker, head of Allergy and Clinical Immunology at the University of Manitoba, said the survey isn't enough to link nut ingestion with asthma. He also said Europeans don't eat as many nut products as North Americans do, which means the correlation between nuts and asthma could be much smaller here.

And while previous studies have also shown negative effects associated with a pregnant woman's daily diet of peanut munching, including a British study in the late 1990s that prompted the government to advise pregnant mothers against eating the legume, Andrée Gruslin, a maternal fetal medicine specialist at the Ottawa Hospital, said eating nuts is actually good for pregnant women.

"Although there may be a small correlation here, I think it'd be very important for pregnant women not to take this as 'you shouldn't eat nuts in pregnancy,' because nuts are very good for a pregnant woman's diet," she said.

Andrea Holwegner, a Calgary-based dietitian, said she would only tell expectant mothers to avoid nuts if there was a history of allergy in their families.

"It's kind of a blurred area and no one's taken a firm stance on what we should be doing," she said of the mixed research about the diets of pregnant women.

"If there's no allergy within your family I typically say I don't believe research is strong enough to suggest you need to do that."

Even if a firm correlation ever surfaces, Surrey, B.C., mother Christina Manke, due to deliver her fifth baby on July 27, said she will keep snacking on peanut butter.

"I love nuts, and sometimes it's all I can stand to eat," the 25-year-old said. "I get very sick when I'm pregnant so if I can keep nuts or peanut butter down, then that's what I will eat."

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