Now the FDA and the Environmental Protection Agency are trying to clear up questions so more pregnant and breastfeeding women as well as children eat more fish.
They're recommending at least 8 ounces and up to 12 ounces per week of fish that are lower in mercury. Fish lower in mercury include shrimp, salmon, tilapia and cod, which are good sources of omega-three fatty acids. Canned tuna and even one serving of deep sea tuna, a week, would also be acceptable.
But health officials say pregnant women should avoid swordfish, tilefish, king mackerel and shark, which are high in mercury.
Consumer groups had been pushing for mercury content labels on fish, but the FDA decided not to require them.
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