Can Omega 3 fatty acids in late pregnancy reduce the risk of asthma development in children?

On June 16th and June 20th I wrote about asthma treatment and prevention and mentioned the apparent benefits of long chain omega 3 fatty acids (from fish oils). 

Recently published research(1) adds weight to the evidence for the benefits of fish oil supplementation in asthma prevention.  The study suggests that pregnant women who take fish oil supplements in the final trimester of their pregnancy could well be helping to reduce the risk of asthma development in their children.  The trial involved 533 women in their 30th week of pregnancy.  266 were given fish oil capsules (providing 2.7g omega 3 fatty acids) daily, 133 were given olive oil capsules and 131 were given capsules containing no oil.  The women took the capsules until delivery.  The scientists then assessed the children at age 16.  

The children of women who took the fish oil had a hugely reduced risk of developing asthma.  The risk (hazard rate) of asthma development in these children was reduced by 63% and the risk of allergic asthma was reduced by 87%. 

The authors conclude: “our results support that increasing n–3 PUFAs [fish oils] in late pregnancy may carry an important prophylactic [preventative] potential in relation to offspring asthma”.  Professor Sjurdur F Olsen, lead study author also notes “These are results from a relatively small trial and therefore it is most important that our results are confirmed by other trials before we change any dietary recommendations for pregnant women.”

As mentioned in the previous asthma posts, omega 3 fatty acids seem to have their positive effects for asthma prevention via their action on the immune system.  In the final trimester of pregnancy the developing foetus has a greater need for omega 3 fatty acids for brain development.  It may be that this is a critical time for the overall health effects of omega 3 fatty acids.

The study was carried out as part of a much larger ongoing research project, called the Early Nutrition Programming Project (EARNEST), funded by the European Commission to investigate the effects of early nutrition on later health outcomes.   It is a 5 year research programme (due to end in 2010) bringing together a multi-disciplinary team of scientists from 38 institutions in 16 European countries.  The project hopes to gain a better understanding of how nutritional conditions in early life, either pre- or postnatally can affect life-long health.  As part of the EARNEST project is the establishment of an Early Nutrition programming Academy (ENA).  The aims of the academy, among others, are to foster nutrition research and its standards, in particular as it relates to nutrition in women of childbearing age, infants and children.  It is a great step on the path to understanding the importance of early nutrition better!

If you are pregnant, or planning a pregnancy, and do not regularly eat oily fish you may wish to discuss the idea of taking a fish oil (long chain omega 3 fatty acid) supplement with your doctor or midwife.  Vegetarians and vegans have the option of taking a flaxseed (sometimes called linseed) oil supplement, this is a shorter chain omega 3 fatty acid which, if taken in large enough doses, can be converted by the body into the longer chain form.


(1)Olsen SF et al.  2008.  Fish oil intake compared with olive oil intake in late pregnancy and asthma in the offspring: 16 y of registry-based follow-up from a randomized controlled trial.  Am J Clin Nutr.  88: 167-175.

Written by Ani Kowal