The benefits of fish consumption during pre-natal development may offset the risks associated with mercury exposure, shows a study.

Nutrients found in fish have properties that protect the brain from the potential toxic effects of the chemical.

Compounds present in fish - specifically polyunsaturated fatty acids (PUFA) - may actively counteract the damage that mercury causes in the brain.

The type of fatty acids a mother consumes during pregnancy may make a difference in terms of their child's future neurological development.

"It is also becoming increasingly clear that the benefits of fish consumption may outweigh, or even mask, any potentially adverse effects of mercury," said Edwin van Wijngaarden, associate professor in University of Rochester in Britain.

Mercury is found in the environment as a result of both natural and human activity.

Much of it ends up being deposited in the world's oceans and, as a result, fish harbour the chemical in very small amounts.

"It appears that relationship between fish nutrients and mercury may be far more complex than previously appreciated," said Philip Davidson, principal investigator of the Seychelles Child Development Study.

The study appeared in the American Journal of Clinical Nutrition.