The report contends that the guidelines fall short by failing to take into account the variation in individuals who could be consuming too much of particularly risky species. The groups urge both the Food and Drug Administration, which regulates commercially sold fish, and the Environmental Protection Agency, which regulates freshwater sport fish, to expand the list of off-limit fish. They also want the agencies to recommend smaller amounts of certain other fish, promote safe fish choices and update the mercury sampling data. Fish provide important health benefits to the developing fetus, and pregnant women should be encouraged to eat fish with consistently low methylmercury levels. Methylmercury, the harmful form, can cross the placenta and enter a growing fetus' brain within hours after the mother consumes food containing methylmercury, scientists say.
Mercury blocks the natural formation and migration of nerve cells and slows the growth of the brain.
Representatives of the FDA did not comment directly on the report, but said its own risk analysis considers variations in exposures to mercury through a seafood diet. The agency is seeking more data on at least 10 species, and intends to vigorously educate the public about risks and benefits of fish, they said. In January, the FDA issued new advisories warning women to limit fish consumption during pregnancy to avoid exposing fetuses to methylmercury. Pregnant and nursing mothers and young children should not eat any shark, swordfish, tilefish or king mackerel, the FDA said. The agency recommends limiting all other species to 12 ounces a week.