Pregnant and nursing women are told to avoid eating too much seafood so as to avoid exposing the child to mercury. However, a new study suggests that eating a lot of fish may not actually cause any harm to the child. In fact, it might actually help the fetus from having developmental issues in the future.

The research spanned three decades in Seychelles, a series of islands in the Indian Ocean, where pregnant women were consuming 12 servings of fish a week on average. No adverse effects or developmental problems were discovered, despite the fact they consume fish at a much higher rate than American families.

“These findings show no overall association between prenatal exposure to mercury through fish consumption and neurodevelopmental outcomes,” said Edwin van Wijngaarden, Ph.D., co-author of the study and associate professor in the University of Rochester Department of Public Health Sciences, in a statement. “It is also becoming increasingly clear that the benefits of fish consumption may outweigh, or even mask, any potentially adverse effects of mercury.”

The study followed over 1,500 mothers and their children. At 20 months, the children were given a variety of tests to measure the development of their communication and motor skills. The mothers were tested during their pregnancy to determine their mercury levels. The researchers found no correlation between mercury and low test scores, results that matched the group’s earlier studies.

Researchers previously believed that the adverse effects of fish consumption competed with the positive effects. The positive effects were thought to just edge out the negative effects. However, the new research indicates a much more complex relationship. Compounds present in fish, namely polyunsaturated fatty acids, may counteract the damage mercury causes to the developing brain.

“This research provided us the opportunity to study the role of polyunsaturated fatty acids on development and their potential to augment or counteract the toxic properties of mercury,” said Sean Strain, Ph.D., lead author of the study and professor of Human Nutrition at the Ulster University in Northern Ireland. “The findings indicate that the type of fatty acids a mother consumes during pregnancy may make a difference in terms of their child’s future neurological development.”

Mercury is found in the environment both naturally and as a result of human activities such as processing fossil fuels. Much of it ends up in the world’s oceans and consequently fish contain trace amounts. The researchers note that there is a confirmed link between mercury and developmental problems.

Current Food and Drug Administration guidelines suggest pregnant women limit their fish consumption to two meals a week. Currently, the guidelines for fish consumption are under review to reflect new nutritional information.