“Seafood Has Few Downsides”
Health experts often advise: “Eat more fish.” The American Heart Association recommends eating fish at least two times per week as part of a healthy diet. As a lean, readily available protein, fish is widely considered a healthy food choice that billions of people around the world rely on for nutrition. Seafood, which includes fish and shellfish, offers health benefits for the general population—including pregnant women and those who are breastfeeding, according to the 2015-2020 Dietary Guidelines for Americans. In addition to protein, fish provides healthy omega-3 fatty acids, vitamins B12, and E, plus iron, selenium, zinc, and iodine. Fish are also good sources of vitamin D and phosphorus. The guidelines note that eating about 8 ounces of seafood per week is linked to fewer cardiac deaths among people with and without pre-existing cardiovascular disease, based on scientific evidence. However, fish has also been the subject of public health advisories, due to the presence of contaminants that can be harmful to health. Seafood is the main source of human exposure to methylmercury, a powerful neurotoxin. In the United States, 82% of population-wide exposure to methylmercury comes from eating marine seafood and nearly 40% is from fresh and canned tuna. When ingested at high levels, this heavy metal can cause nerve damage in otherwise healthy adults, young children, and during fetal development. The fish with the highest mercury levels include king mackerel, marlin, shark, swordfish, bigeye tuna, and tilefish. The 2015-2020 Dietary Guidelines recommend that pregnant women eat 8 to 12 ounces of fish (the kind with lower mercury levels) per week and that adults, in general, eat at least 8 ounces per week.