Pregnant women, women trying to get pregnant and young children are advised by both the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) to avoid some types of fish due to high levels of methylmercury. Methylmercury is a compound formed when mercury from the air falls into streams and oceans. Mercury comes from many places in the environment including factories, burning of fossil fuels and disposal of mercury-containing products. Fish absorb the methylmercury when they feed in the water and it builds up in their tissues over time.
Why is meythlmercury a concern for pregnant women and young children? Research shows that for most people, consumption does not cause a health concern. In fact, fish and shellfish contain high quality protein and other essential nutrients, are low in saturated fat and contain omega-3 fatty acids. A well balanced diet that includes a variety of fish and shellfish can contribute to heart health and children's proper growth and development. Women and young children in particular should include fish or shellfish in their diets due to the many nutritional benefits. However, fish shown to have high levels of methylmercury should be avoided. High levels of mercury in the bloodstream of unborn babies and young children may harm the developing nervous system.
Methylmercury builds up in more in some types of fish and shellfish than others, depending on what the fish eat. Most fish and shellfish have traces of methylmercury. Larger fish that have lived longer have the highest levels of methylmercury because it has had more time to accumulate.
Large fish that pose the greatest risk are:
- king mackerel
Pregnant women, women trying to get pregnant and young children should avoid eating these fish. They can eat up to 12 ounces (2 average meals) a week of a variety of other fish and shellfish that are lower in mercury.
In addition, pregnant women, women trying to get pregnant and young children should be careful about the safety of fish caught by family and friends from local lakes, rivers and coastal areas. Always check local advisories first. If no advice is available, they should eat up to 6 ounces (one average meal) a week of fish caught from local waters, but not consume any other fish during the week.
Shrimp, canned light tuna, salmon, pollock and catfish are LOW in mercury. Albacore (“white”) tuna has more mercury than canned light tuna. If a pregnant woman or young child does eat albacore tuna, she or he can eat up to 6 ounces (one average meal) and choose another fish low in mercury for your second serving of the week.
For more information about the risks of mercury in fish and shellfish call the FDA's Food Information Hotline toll-free at 1-888-SAFEFOOD or visit FDA's Food Safety website. For more information about the safety of locally caught fish and shellfish, visit the Environmental Protection Agency's Fish Advisory website or contact your state or local health department.