Supplementation with omega-3s during pregnancy

Summary

• 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 disorder^1. 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. 

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