Eating fish during pregnancy could be beneficial after all, say researchers from the University of Rochester Medical Center who voyaged to the Seychelles to study the benefits of nutrients found in fish and the risk associated with mercury exposure.
Over three decades, more than 1500 mothers and their children were observed, with results indicating that eating fish in as many as 12 meals per week does not lead to defects in the developing fetus.
Mercury makes way into the world's oceans both naturally and as a result of man-made constructs such as coal plants.
Compounds in fish such as polyunsaturated fatty acids (PUFA) could counteract the damage that mercury causes in the brain, according to the study, which was published in the American Journal of Clinical Nutrition.
"These findings show no overall association between prenatal exposure to mercury through fish consumption and neurodevelopmental outcomes," says Edwin van Wijngaarden, Ph.D., and associate professor in the University of Rochester Department of Public Health Sciences and a co-author of the study.
"It is also becoming increasingly clear that the benefits of fish consumption may outweigh, or even mask, any potentially adverse effects of mercury."
Participating women were tested for the amount of prenatal mercury exposure while they were pregnant and the research team used hair samples to gather their data.
At 20 months of age, the mothers allowed their babies to undergo a battery of tests to assess their motor and communication skills as well as their behaviour, with researchers concluding that mercury exposure did not correlate with low test scores.
The researchers also tested the women for the presence of PUFA during their pregnancies and concluded that children whose mothers had high levels of n3 - also known as omega-3 - fatty acids found in fish performed particularly well on tests.
These n3 fatty acids have anti-inflammatory properties, according to the researchers, whereas similar ones like the n6 - omega-6 - fatty acids found in meats and oils are known to promote inflammation.
According to the researchers, inflammation is the vehicle by which mercury inflicts damage, which explains why the anti-inflammatory fatty acids lead to favourable results.
"These findings indicate that there may be an optimal balance between the different inflammatory properties of fatty acids that promote foetal development and that these mechanisms warrant further study," says senior author Philip Davidson, PhD, a professor emeritus at U of R.
The Seychelles, an archipelago of 115 islands in the Indian Ocean off Southeast Africa, were selected for the study because the approximately 89 000 residents consume 10 times more fish than the populations of the US and Europe.