In fact, the new study, which appears in the American Journal of Clinical Nutrition, suggests that the nutrients found in fish have properties that protect the brain from the potential toxic effects of the chemical.
Three decades of research in the Seychelles have consistently shown that high levels of fish consumption by pregnant mothers — an average of 12 meals per week — do not produce developmental problems in their children. Researchers have previously equated this phenomenon to a kind of biological horse race, with the developmental benefits of nutrients in fish outpacing the possible harmful effects of mercury also found in fish.
However, the new research indicates that this relation is far more complex and that compounds present in fish — specifically polyunsaturated fatty acids (PUFA) — may also actively counteract the damage that mercury causes in the brain.
“These findings show no overall association between prenatal exposure to mercury through fish consumption and neurodevelopmental outcomes,” said Edwin van Wijngaarden, PhD., 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.”
The new study comes as the U.S. Food and Drug Administration and international agencies are in the process of revisiting fish consumption advisories to better reflect the health benefits of nutrients found in fish. The FDA’s current guidance — which recommends that pregnant women limit their consumption of certain fish to twice a week — was established because of the known risk of high level mercury exposure on childhood development.
Mercury is found in the environment as a result of both natural and human (e.g. coal plant emissions) activity. Much of it ends up being deposited in the world’s oceans and, as a result, fish harbor the chemical in very small amounts.