By Chioma Umeha
A new study has linked low intake of omega-3 with
rise in childhood asthma. The researchers said that taking fish oil during the
third trimester of pregnancy could reduce a baby’s risk of developing asthma by
almost a third.
The study, published Thursday, in the New England
Journal of Medicine, was conducted by the Copenhagen Prospective Studies on
Asthma in Childhood (COPSAC) at the Copenhagen University Hospital, with
testing done at the University of Waterloo (UW).
“We have long suspected there was a link between
the anti-inflammatory properties of long-chain omega-3 fats, the low intakes of
omega-3 in Western diets and the rising rates of childhood asthma,” Hans
Bisgaard of COPSAC said in a release.
“This study proves that they are definitively and
significantly related.”
Fish oil and olive oil
For the five-year study, 736 pregnant women were
asked to take 2.4 grams of either fish oil or the placebo olive oil daily
starting at 24 weeks of gestation.
The study was a double-blind test, meaning neither
the researchers nor the women knew who was taking which supplement.
Researchers were able to follow up with 695
children for their first three years, and again when they were five years old.
The risk of asthma in the children whose mothers
took fish oil was 16.9 per cent compared to 23.7 per cent for the children of
mothers in the placebo group, the study found.
Asthma is a chronic inflammatory disease of the
airways that can cause a shortness of breath, coughing, wheezing and tightness
in the chest. Statistics Canada reported in 2010 that 8.5 per cent of the
population aged 12 and older has been diagnosed with asthma.
The Asthma Society of Canada reports it is most
common during childhood and affects at least 12 per cent of Canadian children
and is a major cause of hospitalization.
Asthma prevention
Long-chain omega-3 fatty acids, which include
eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are found in cold
water fish, the researchers said.
The study also involved testing the levels of EPA
and DHA in the pregnant women’s blood – testing that was led by Ken Stark,
Canada Research Chair in nutritional lipidomics and professor in the faculty of
applied health sciences at the University of Waterloo.
He also said that the testing was comprehensive
and thorough. The blood of the mothers was tested before, during and after they
took the supplements.
The tests they did were a rapid analytical
technique developed by Stark as a low-cost, quick alternative to traditional
tests. The lab at UW is one of the few labs in the world equipped to run them.
It was important to get it right because there
have been many studies on fish oil where researchers were not as thorough,
which has created confusion about whether fish oil is beneficial.
“The neat thing about this study is the quality,”
Stark said. “One of the key things was actually using that blood indication so
you really know who was taking it, who wasn’t taking it.”
The testing was able to show women with low blood
levels of EPA and DHA at the start of the study benefited the most from taking
fish oil – it reduced their children’s risk of developing asthma by 54 per
cent.
“The proportion of women with low EPA and DHA in
their blood is even higher in Canada and the United States as compared with
Denmark. So we would expect an even greater reduction in risk among North
American populations,” Stark said in a release.
