Mothers who take fish oil supplements in late pregnancy could reduce the chance of their child developing asthma, a new study claims.

Currently in Ireland, around 20% of children are affected by asthma.

The findings also indicate that fish oil supplements lower the risk of pre-term delivery and increase the birth weight of babies.

Danish researchers traced the children born to mothers who took part in a trial conducted in 1990. In the original trial, more than 500 pregnant women were split into three groups for the last 10 weeks of their pregnancy. One group was given fish-oil supplements, another olive oil and the third no supplements.

The mothers who took fish oil increased the length of their pregnancies by an average of four days, and the average birth weight of their babies by about 100g.

The purpose of the trial was to see whether the effects of fish oil taken in very early life had any effect on the child’s risk of developing asthma as they grew up.

By the time they were 16 years old, 19 of the children had developed such severe asthma, that at some point they had to go to hospital. However overall, the risk of developing asthma was reduced in those whose mothers had been given fish oil supplements, compared to those whose mothers had been given olive oil supplements.

“There is strong evidence that the omega-3 fatty acids in fish oil may have modulating effects on the immune system. The reason fish oil might protect a foetus from developing asthma in later life could possibly also be related to its effect on increasing pregnancy duration,” suggested Prof Sjurdur F Olsen of Statens Serum Institut in Denmark.
 

Premature children have a higher risk of developing asthma and the omega 3 fatty acids found in fish oils could both reduce the risk of pre-term birth and the likelihood of a baby later becoming asthmatic through their effect on reducing inflammation.

“It may be that the period shortly before delivery is the critical window for these effects of omega 3 fatty acids,” said Prof Olsen.

However the researchers warned that the results are from a relatively small trial and must be confirmed by other studies before dietary recommendations for pregnant women are changed.

Source :  American Journal of Clinical Nutrition.