Mercury in Fish and Shellfish: A Guide to Safe Consumption for Pregnant Women and Children

Creator: Doctronic
Published: 2023-05-17

Key Takeaways

Mercury accumulates in predatory fish like shark, swordfish, king mackerel, and tilefish at levels 10-20 times higher than smaller fish, making them unsafe during pregnancy and breastfeeding.
Pregnant and breastfeeding women can safely consume 12 ounces weekly (2-3 servings) of low-mercury options including shrimp, salmon, pollock, and canned light tuna—but should avoid albacore tuna which contains 3 times more mercury.
Children ages 1-11 require smaller portions at 8 ounces per week maximum, with serving sizes adjusted by age: 1 ounce per serving for ages 1-3, and 2-3 ounces for ages 4-11.
Mercury remains in your bloodstream for 12-18 months after consumption, so women planning pregnancy should begin following safe seafood guidelines at least one year before trying to conceive.
Methylmercury crosses both the placental barrier and blood-brain barrier, potentially causing permanent neurological damage including delayed language development, attention deficits, and reduced IQ in exposed children.

Fish and shellfish are an important part of a healthy diet, providing high-quality protein, essential nutrients, and omega-3 fatty acids. These nutrients are crucial for heart health and the proper growth and development of children. However, nearly all fish and shellfish contain traces of mercury, which can be harmful to an unborn baby or young child's developing nervous system if consumed in high amounts.

The risks from mercury in fish and shellfish depend on the amount eaten and the levels of mercury present. To help you make informed decisions about including fish and shellfish in your diet, the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) have issued the following guidelines:

1. Avoid High-Mercury Fish

Do not eat shark, swordfish, king mackerel, or tilefish, as these fish contain high levels of mercury.

2. Follow Recommended Serving Sizes

Pregnant or breastfeeding women: Eat up to 12 ounces (2 average meals) per week of a variety of low-mercury fish and shellfish.
Children aged 1-11 years: Eat up to 8 ounces per week of low-mercury fish and shellfish.

Some of the most commonly eaten low-mercury fish include shrimp, canned light tuna, salmon, pollock, and catfish. Albacore ("white") tuna has more mercury than canned light tuna, so limit your intake to 4 ounces per week if you are pregnant or breastfeeding.

3. Check Local Advisories

If you catch fish from local lakes, rivers, or coastal areas, check with your local health department for advisories about the safety of these fish. If no advice is available, eat up to 6 ounces (one average meal) per week of locally caught fish, and avoid consuming any other fish that week.

Mercury in Fish and Shellfish: A Guide to Safe Consumption for Pregnant Women and Children

Frequently Asked Questions

What is methylmercury, and how does it accumulate in fish?

Methylmercury is a form of mercury that can be harmful to your unborn baby and young child. It accumulates in fish as they feed in waters where mercury has been deposited from natural sources or industrial pollution. Larger, older fish tend to have higher levels of methylmercury.

Should I be concerned about methylmercury if I'm not pregnant?

If you regularly eat fish high in methylmercury, it can accumulate in your bloodstream over time. It may take over a year for levels to drop significantly, so people trying to become pregnant should also avoid high-mercury fish.

What if I eat more than the recommended amount of fish in a week?

One week's consumption does not significantly change the level of methylmercury in your body. If you eat a lot of fish one week, you can cut back for the next week or two to maintain the recommended average intake.

For more information about the safety of fish and shellfish, visit the FDA's food safety website, the EPA's fish advisory website, or contact your local health department.

The Bottom Line

Choose low-mercury seafood like salmon and shrimp while strictly avoiding shark, swordfish, king mackerel, and tilefish during pregnancy and early childhood. Stick to 12 ounces weekly for pregnant women and 8 ounces for young children to gain omega-3 benefits without mercury risks. If you need personalized guidance about safe seafood choices during pregnancy, Doctronic can provide tailored recommendations.