A recent Australian study has found that fish oil supplements taken during pregnancy might help prevent allergies in babies at high risk for them.

The study, published in the Journal of Allergy and Clinical Immunology, found that babies whose mothers took fish oil had weaker immune reactions to common allergy triggers and at one year of age showed signs of being less allergy-prone.

Anti-inflammatory properties
Scientists looked at whether fish oil capsules, rich in omega-3 fatty acids, might help prevent the development of allergies in babies born to women with a history of hay fever or asthma. Children with a family history of allergies are at increased risk of developing them.

The theory is that because omega-3 fatty acids have anti-inflammatory properties, they may affect the developing immune system in a way that makes it less prone to allergic reaction.

Greater amounts of omega-3 fats in cell membranes
Researchers had 98 pregnant women take either fish oil capsules or capsules containing olive oil. The women took four capsules per day from the 20th week of pregnancy until delivery. Analyzing cells taken from the babies' umbilical cord blood, scientists found greater amounts of omega-3 fats in the cell membranes of newborns whose mothers took fish-oil supplements. In addition, their immune cells tended to have a weaker reaction to allergy-producing substances like cat dander, compared with babies in the comparison group.

At the age of one year, infants whose mothers took fish oil were three times less likely to show sensitivity to egg during skin tests used to detect allergies. Babies in the fish-oil group were more likely to develop the allergic skin condition eczema, but among infants with eczema, those in the fish-oil group were much less likely to have a severe case.

Decline in dietary fish oils
According to the scientists, it's possible that the rise in allergic disease over the past few decades could be related, in part, to a decline in omega-3 fats in the Western diet. Fatty fish like salmon, tuna and sardines are a prime source of omega-3s; the fats are also found in certain vegetable sources, such as canola oil and flaxseed.

Pregnant women are advised against taking any medication or supplement unless the benefit is known to outweigh any potential risk to the fetus. Pregnant women should always consult their doctor before taking drugs or supplements.

Reference:

1. D. Y. M. Leung, et al., “Fish Oil Intervention to Prevent Infant Allergy,” Journal of Allergy and Clinical Immunology, 112: 6: 1020.