Mercury Health Hazards

Many of my patients love fish just like I do. It’s a good source of protein, heart-healthy Omega-3 fat, and delicious! Living in an area surrounded by water, fresh fish is abundant. However, I would like to share with you one major pitfall of eating fish too often: mercury (Hg) levels.

So far, there have been no reported cases of mercury poisoning from eating fish in the United States. Concern about that happening, however, has grown in the last 10 years. Although most fish in the US is safe to eat, many states issue health advisories limiting the consumption of certain types of fish.

As I like to tell my patients, seafood is safe to enjoy. The keywords are avoidance of some fish and moderation with others.

Let me explain how mercury gets into our food and who is at risk. I’ll also give you some tips on what you can do to prevent mercury from becoming a toxic problem.

How does Mercury get to our environment?

Mercury gets into our air from burning coal, wood, or oil. Rain and/or snow wash it onto the ground, our pastures, our oceans, lakes, rivers, and streams. It can also get into water from Hg-containing medical engineering waste that might be dumped into oceans or lakes.

In water, mercury is converted to the highly toxic compound methylmercury, which is easily absorbed by fish through their gills or from the marine life they eat. The cooking process does not remove it, so every time we eat fish or shellfish we can get traces of mercury.

As a physician, I am concerned about the potential chronic exposure of my patients to dietary mercury that is stored in the tissues. Research shows that most people are exposed to mercury by eating fish. However, the amount of Hg you eat depends on the fish you eat and where it comes from.

Who is at risk?

Although everyone—men, women, children—of all ages are at risk of dietary mercury toxicity, women (especially pregnant women) and newborns are at the highest risk. In a recent study, 10% of American women were found to be only 1/10th away from toxic Hg levels.

By eating tuna even twice a week, a woman may have too high levels of mercury stored in her tissues before becoming pregnant. Mercury can pass to the newborn and cause severe neurological damage and even death of the fetus.

Breastfeeding children may also be exposed through breast milk. Young children are also at higher risk because their brain and nervous systems are not fully developed until around age 11. They should not eat more than 12 ounces of low-mercury fish per week.

Do all fish have the same risk of mercury?

The short answer to this question is No. Certain lake fish like largemouth bass and walleye, the fish at the top of the food chain, can have levels of mercury (and other toxins) a million times higher! higher than those of the water! If you enjoy sport fishing, be aware that these types of lake fish can have a high amount of toxins.

The longer answer to this question is yes, possibly. Almost all fish and shellfish contain some mercury, and light to moderate consumption of fish should not be a health concern. As I tell my patients, your risk of Hg toxicity increases with the amount and type of fish you eat on a regular basis.

Here’s what the US EPA and the National Resources Defense Council (NRDC) recommend people do to reduce mercury exposure from eating fish:

•Avoid shark, king mackerel, swordfish, tilefish, grouper, marlin, orange roughy, lake bass, and walleye, which have the highest Hg levels.

•Limit albacore yellowfin tuna to 18 ounces per month; contains more Hg than light tuna.

•Limit saltwater bass, croaker, halibut, bluefin tuna, sea trout, and Maine lobster to 18 ounces per month. These have moderate Hg levels.

•Limit carp, mahi-mahi, crab, snapper, perch, cod, and monkfish to 24 oz. per month. These have lower Hg levels.

•Shrimp, sardines, canned light tuna, wild Alaskan salmon, pollock, whitefish and catfish, sablefish: these have the lowest Hg levels. You can enjoy up to 12 ounces a week.

*Visit the NDRC website for a more complete list and their mercury calculator for a personal recommendation using the fish you like and how much to eat, at http://www.nrdc.org

What else can I do about mercury exposure?

The good news is that although Hg is stored in body tissues, it is also released. You can clear it from your body in about 6 to 12 months if:

• Faster: Avoid eating fish that contain mercury entirely.

• Slower: Limit your fish/shellfish intake to the lower Hg levels listed above.

Here are some other naturally-based suggestions to help keep you free from toxic levels of mercury:

•Drink adequate amounts of water each day to flush toxins from your body tissues. Half of its weight should be consumed every day. If you weigh 200 pounds, drink 100 ounces of water.

•Avoid high fructose corn syrup: two recent studies suggest it may contain Hg.

•Avoid vaccines or contact lens solutions that contain thimerosal; this is a preservative derived from mercury.

•Dental amalgam fillings: If you have old mercury amalgam fillings, replace them with newer, tooth-colored mercury-free compounds. Your teeth will look great and you will be free from the source of mercury.

•Add some fermented foods to your diet – things like yogurt, kefir, sauerkraut, help flush toxins out of your body by creating good gut bacteria.

•Adequate amounts of vitamin C and E: helps prevent the harmful effects of mercury.

•Add some natural chelators to your diet, such as garlic, selenium, cilantro, and chlorella. These substances bind to toxins such as mercury and remove them from the body.

•Adequate fiber intake: It is important for good health and the reduction of mercury accumulation levels.

•If you have old mercury thermometers, replace them with digital thermometers. Be sure to dispose of old Hg thermometers and toxic waste like old paint.

• Energy saving light bulbs – or CFLs, contain minute amounts of Hg. If they break, open windows for 15 minutes to disperse vapors. Keep children and pets away to avoid inhaling or spreading dust. DO NOT vacuum as this will disperse dust. Wear rubber gloves and cover your nose and mouth to be safe and avoid inhaling dust. The tape or a damp cloth will help pick up the particles. The used ones should also be disposed of as toxic waste.

Mercury exposure is something we all need to avoid in our diet and in our environment as much as possible. It can have very damaging effects on our brain and kidneys and cause a whole list of symptoms and conditions including depression, fertility problems, and even Alzheimer’s disease.

However, with some common sense, following the guidelines listed here, we can still enjoy eating the seafood we love so much without worrying about toxicity.