Fish Oil-Derived Fatty Acid Supplementation in Pregnancy Reduces Offspring Risk of Developing Wheeze and Asthma

Key Takeaway: One in five children is affected by asthma and wheezing disorders in Westernized countries. New research suggests that the pulmonary health of children worldwide could likely be improved with the increased intake of n-3 long-chain polyunsaturated fatty acid supplementation during mothers’ third trimesters of pregnancy.

Low n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) intake may contribute to the increased incidence of wheeze and asthma. The incidence of wheezing disorders has doubled in recent decades in Westernized countries. Currently, 1 in 5 children are afflicted with this disorder1. These changes have been concomitant with an increase in n-6 polyunsaturated fatty acid intake from vegetable oil consumption and a decrease in the intake of n-3 polyunsaturated fatty acids2, particularly the long-chain polyunsaturated fatty acids (LCPUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), derived primarily from cold water fish. Epidemiologic studies have observed that a n-3 deficient diet during pregnancy increased the risk of asthma and wheezing disorders in their offspring3.

A recent report4 of a double-blind, placebo-controlled clinical trial has found that supplementation with n-3 LCPUFA in the third trimester of pregnancy reduced the absolute risk of wheeze and asthma, as well as lower respiratory tract infections in their offspring. In this study, conducted in Denmark, 736 pregnant women in the 24th week of pregnancy were randomly assigned to receive 2.4 g per day of n-3 LCPUFA (55%EPA and 37% DHA) or placebo until 1 week after delivery. This level of LCPUFA intake was 10 times the normal daily intake in Denmark, and 20 times that in other countries, including the U.S. and Canada. Follow up of the children continued until they were 5 to 7 years old. Diary cards were completed each day by the mothers for the purpose of monitoring lung-related symptoms – cough, wheeze, infections of the lower respiratory tract and trouble breathing.  After age 3, persistent wheeze was called asthma.

The Danish investigators found that n-3 LCPUFA supplementation in the last trimester of pregnancy caused a significant 31% reduced risk of persistent wheeze or asthma in the children. In children of mothers who had low (lowest tertile) blood EPA and DHA, the effect of supplementation was greater leading to a significant 54% reduction in risk of persistent wheeze or asthma in their offspring. These positive changes in the risk of persistent wheeze or asthma due to third trimester fatty acid supplementation remained the same in children up to 7 years old.

The findings of this study are interesting because it suggests that the pulmonary health of a large number of children worldwide could likely be improved if their mothers increase their n-3 LCPUFA intake during the third trimester of pregnancy.

1. Mallol J. et al. 2010. International prevalence of recurrent wheezing during the first year of life: variability, treatment patterns and use of health resources. Thorax 65:1004-1009.
2. Blasbalg TL. 2011. Changes in consumption of omega-3 and omega-6 fatty acids in the United States during the 20th century. American Journal of Clinical Nutrition 93:950-962.
3. Blümer N, Renz H. Consumption of omega3-fatty acids during perinatal life: role in immuno-modulation and allergy prevention. J Perinat Med 2007; 35: Suppl 1:S12-8.
4. Bisgaard H. et al. 2016.  Fish oil-derived fatty acids in pregnancy and wheeze and asthma in offspring. New England Journal of Medicine  375:2530-38.