Fish is a protein-rich food that is healthy for both children and adults. It contains a good type of fat (omega-3 fatty acids), as well as nutrients such as vitamin D. It also is low in saturated fat. At the same time, a lot of attention has focused on the contaminants that may be in fish and that could pose health risks.
One of the most widely discussed contaminants is mercury, which at high levels can be toxic. It gets into oceans, rivers, lakes, and ponds, and can end up in the fish we eat. Mercury in bodies of water like lakes and streams—some of it discharged from industrial plants—can be converted by bacteria into mercury compounds such as methylmercury. As a result, certain predatory fish (including shark and swordfish) can contain high quantities of mercury, which when consumed can have a serious negative effect on a young child’s developing nervous system.
Other environmental pollutants have been found in fish and other foods, including polychlorinated biphenyls (PCBs) and dioxins. Although PCBs are chemicals that were manufactured primarily for use as fire retardants and in electrical transformers, they were banned in the US in the late 1970s. However, they have remained in the environment in water, soil, and air, and have been found in fish. PCBs have been associated with thyroid problems, lowered IQ, and memory impairment in young children.
Dioxin is another pollutant that has been detected in fish. It is the byproduct of certain chemicals by incineration and can interfere with the developing nervous system and other organs, particularly when the exposure is long-term. Fortunately, PCBs and dioxins have decreased significantly in recent years.
You need to make an effort to reduce your child’s exposure to toxic substances in food. Government agencies are recommending that young children reduce their intake of certain fish that may contain high levels of mercury. Specifically, young children should not consume king mackerel, swordfish, shark, and tilefish. At the same time, other types of fish and shellfish are low in mercury, including canned light tuna, salmon, shrimp, cod, catfish, clams, flatfish, crab, scallops, and pollock, so these are much better choices for your child. Nevertheless, you should limit your child’s intake of even these safer selections to less than twelve ounces per week.
For information about the safety of fish and shellfish caught in your area, contact state and local health departments. The health department in your state also can provide any advisories issued about the presence of other toxins in fish in your area.