Here’s one really easy way to lower your baby’s risk of developing childhood asthma

A tuna melt or fish tacos isn’t exactly the most popular food craving during pregnancy. So a recent study out of University of Waterloo and Copenhagen Prospective Studies on Asthma in Childhood offers welcome news for fish haters: Taking omega-3 fatty acid supplements during the third trimester can reduce the risk of childhood asthma by almost one-third.

According to the Asthma Society of Canada, at least 13 percent of kids in Canada are affected. Along with genetics and environmental factors, pregnancy diet plays a key role in the risk of developing asthma. And this study, published in the New England Journal of Medicine, suggests low-intakes of omega-3 in Western diets may be partly to blame.

In the study, researchers analyzed the blood of 695 Danish women for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)—omega-3 fatty acids found in cold water fish that regulate the immune system—at 24 weeks’ gestation and one week after delivery. The participating kids were then monitored until age five, the age at which asthma symptoms can be identified. During their third trimester, half of the women were given prescriptions for 2.4 grams of long-chain omega 3 supplements (the other half received a placebo). The women who were prescribed the supplements reduced their children’s risk of asthma by 31 per cent. It was even more beneficial for the women who started off with low levels of EPA and DHA, reducing the risk of their kids developing asthma by 54 percent.

To analyze the blood levels of those important fatty acids, the Danish researchers reached out to the University of Waterloo, which is one of the few laboratories in the world equipped to run such tests.

“Denmark has a whole spectrum of people who eat high, moderate and low amounts of omega-3, whereas in Canada we have a whole bunch of people who hardly eat any omega-3,” says Ken Stark, one of the researchers who worked on the blood analysis at University of Waterloo. While Stark says that there’s a small population in Canada’s coastal regions that does consume a significant amount of omega-3, Denmark takes in considerably more because of their surrounding oceans and long history of seafood consumption. That’s what made Denmark the perfect country for this study, says Stark. “It’s a neat population because you can start to see where the benefit of omega-3 kicks in. You have people who are eating it regularly and people who aren’t, so it helps answer how much we should be eating. In Canada it would be tricky to find that cut off.”

If you want to increase your omega-3 intake before taking supplements in the third trimester, fish is a great source “but you have to be careful about the species and the potential for mercury contamination,” says lead researcher Ken Stark, who recommends fish that’s lower on the food chain, like sardines or smelts. You can just as easily find supplements at your local drugstore; Stark suggests taking 0.5 grams a day.

Read more: What’s in your newborn’s gut influences asthma Is it safe to eat canned tuna during pregnancy? Prenatal vitamins will make your kid smarter, says new study