Fish supplements may reduce risk of asthma

Fish oil supplements taken in the third trimester of pregnancy could reduce the risk of children developing asthma.

A Danish team compared 500 pregnant women randomised to three different groups in the last 10 weeks of their pregnancy. One group received fish oil supplements, another, olive oil supplements and a third group, nothing.

The trial was comparing the effect of the three interventions on risk of pre-term birth and low birth weight. Those in the fish oil group extended the length of their pregnancies by an average of four days and the average birth weight of their babies by 100grams compared to the other mothers.

A follow up 16 years later traced all but three of the original 500 mothers and their offspring. Nineteen children had developed severe asthma but those whose mothers had taken fish oil supplements had a reduced risk of their child developing it than those who had taken olive oil.

Professor Sjurdur Olsen, lead author of the Statens Serum Institut in Denmark, said: 'Omega-3 fatty acids in fish oil may have modulatory effects on the immune system. It could also possibly be related to its effect on increasing pregnancy duration.'

The trial is published online in the American Journal of Clinical Nutrition.