ASK THE DOCTOR: The lowdown on mercury in fish
Swordfish is considered a high mercury fish, containing nine times as much mercury as low mercury fish.
By DR JIM MITTERANDO

Q - I am worried about recent reports of mercury in fish. Which fish can my family safely eat?

A - In an effort to balance the health benefits of seafood with concerns about potential hazards of mercury in fish, the government recently issued new guidelines for fish consumption in children and women of childbearing age.

Nearly all fish contains small amounts of mercury, which isn't a health concern for most people. However, unborn babies and young children are more susceptible to the harmful effects of mercury because the nervous system is still developing. With this in mind, the Food and Drug Administration and Environmental Protection Agency have taken a better-safe-than-sorry approach to mercury in fish. They designed guidelines to keep mercury consumption far below levels shown to cause harm. By following these conservative recommendations, parents can safely include fish as an important part of a healthy diet.

Women who may become pregnant, pregnant women, nursing mothers, and children 12 years and under can safely eat two meals per week of 6 ounces of cooked, ‘‘low mercury'' fish: cod, salmon, shrimp, flounder, canned chunk-light tuna, haddock, trout, pollock, squid, shellfish (except lobster) and catfish. Toddlers should eat smaller portions. Fish sticks and ‘‘fast-food'' sandwiches are commonly made from fish that are low in mercury.

The ‘‘medium mercury'' fish - striped bass, canned albacore (solid white) tuna, tuna steaks, halibut, lobster, bluefish, grouper - contain three times as much mercury as low mercury fish. One 6-ounce serving can be safely eaten once per week. In the United States, the EPA considers most fish caught in ponds or lakes to be ‘‘medium mercury.'' However, fresh-water fish in more industrial states, such as Massachusetts, may have higher levels of mercury that may not be safe because lakes tend to be more polluted and concentrated with industrial waste than the ocean. It is best to check either with local officials or check the Massachusetts Department of Public Health web site at www.state.ma.us/dph/ to determine the safety of local lakes for fish consumption.

The ‘‘high mercury'' fish - swordfish, shark, mackerel king and tilefish - contain nine times as much mercury as ‘‘low mercury fish.'' Children and women of childbearing age should not consume these fish.

All other adults can eat these higher mercury fish, in moderation, without health risks. It may be prudent for adults to limit their consumption of higher mercury fish to once per week and eat lower mercury containing fish most times.

The only cases of mercury poisoning from fish consumption occurred in Japan in the 1950s and 1960s during industrial accidents that polluted fishing waters with large amounts of mercury that far exceeded our local mercury levels. It is currently unknown if there are any long-term risks for adults consuming low levels of mercury in fish. The general consensus is that any potential, small risk from mercury is offset by its nutritional benefits.

The American Heart Association continues to recommend that adults should eat at least two servings of fish per week because of the cardiovascular benefits.

Unfortunately, the issue of mercury pollution that jeopardizes our health and food supply was not addressed in these guidelines. Obviously, further restrictions need to be established to limit industrial release of mercury from coal-burning power plants, etc. into the environment.

For further information, please refer to the FDA web site at www.cfsan.fda.gov/seafood1.html.

Dr. Jim Mitterando is a family doctor at Cohasset Family Practice and a staff member at South Shore Hospital in Weymouth.

Readers should send questions to: Ask the Doctor, The Patriot Ledger, P.O. Box 699159, Quincy, MA 02269-9159, or by E-mail to his attention at features@ledger.com.

Questions of general interest will be answered in this column. The information in this column is not intended to diagnose individual conditions, and individual replies are not possible. Readers should see their own doctors about specific problems.

Copyright 2004 The Patriot Ledger
Transmitted Tuesday, March 30, 2004