Study rejects benefits of fish oil capsules

A University of Adelaide study has found no evidence that taking fish oil capsules during pregnancy can help reduce the risk of post-natal depression, contrary to international recommendations.

In an article published recently in the Journal of the American Medical Association, Professor Maria Makrides said a study of 2400 pregnant women in five Australian maternity hospitals between 2005 and 2009 supported this finding.

Professor Maria Makrides, who is Professor of Human Nutrition at the University of Adelaide and Deputy Director of the Women's and Children's Health Research Institute, said the results also contradicted existing recommendations that fish oil capsules taken in pregnancy help newborn babies' language and cognitive development.

In a five-year study led by Professor Makrides, half the women in the latter stages of pregnancy were given fish oil capsules and the other half vegetable oil capsules. There was no significant difference in either the incidence of post-natal depression or neuro-developmental outcomes of their children.

"These results show that recommendations to increase omega-3 fatty acids in pregnancy are being made without sound evidence," Professor Makrides said.

She said previous findings from the United States and Europe suggesting the benefits of fish and seafood during pregnancy were based on observational studies that could not separate the influence of social variables from the intake of fish and seafood.

"Despite the paucity of hard evidence, women are being recommended to increase their intake of fish oil fats in pregnancy and the nutritional supplement industry is successfully marketing products with fish oil, claiming they optimise brain function in both mother and infant.

"Before omega-3 supplementation in pregnancy becomes widespread, it is important to establish not only any benefits, but also any risks to mother or child," she said.

While depressive symptoms were more common among women with a previous or current diagnosis of depression, there was no difference between the control group and those taking fish oil capsules.

Similarly, 700 children from the study group who were assessed for cognitive and language development at 18 months of age showed no marked differences.

The study was funded by a $1.6 million National Health and Medical Research Centre (NHMRC) grant awarded to Professor Makrides in 2004.

Other University of Adelaide researchers involved in the study included Professor Bob Gibson from the School of Agriculture, Food and Wine, and Professor Philip Ryan and Lisa Yelland from the Discipline of Public Health.

Story by Candy Gibson