Many of my patients love fish as do I. 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 an important pitfall of eating fish too often – mercury (Hg) levels.
As yet, no cases of mercury poisoning from eating fish have been reported in the United States. The concern for that occurring, however, has grown in the last 10 years. Although most U.S. fish are safe to eat many states issue health advisories limiting the consumption of certain types of fish.
As I like to tell my patients, you can enjoy fish and seafood safely. The key words are avoidance of some fish and moderation with others.
Let me explain to you how mercury gets into our food and who is at risk. I’ll also provide you with some tips on what you can do to prevent mercury from becoming a toxic problem.
How Does Mercury Get Into Our Environment?
Mercury gets into our air from the burning of coal, wood, or oil. Rain and/or snow wash it down into soil, grasses, our oceans, lakes, rivers, and streams. It can also get into water from Hg-containing medical engineering waste that might get dumped into the ocean or lakes.
In water, mercury then becomes the highly toxic compound methylmercury which is easily absorbed by fish through their gills or from the marine life they eat. The cooking process doesn’t get rid of it, so every time we eat fish or seafood we can get trace levels of mercury.
As a doctor, I’m concerned about my patients’ possible chronic exposure to dietary mercury as it stores in tissues. Research shows that most people are exposed to mercury from eating fish. However, the amount of Hg you take in depends on what fish you eat and where it comes from.
Who’s At Risk?
Although everyone, men, women, children, of all ages are at risk for dietary mercury toxicity, women (especially pregnant) and newborns are at highest risk. In a recent study, 10% of U.S. women were found to be just 1/10th away from toxic levels of Hg!
From eating tuna even twice a week, a woman can have too high levels of mercury stored in her tissues before she becomes pregnant. Mercury can pass to the newborn and cause serious neurological damage and even death of the fetus.
Breastfeeding children can also be exposed through mother’s 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 consume more than 12 ounces of low mercury level fish per week.
Are All Fish An Equal Mercury Risk?
The short answer to this question is No. Certain lake fish like large-mouth bass and walleye, top of the food chain fish, can have mercury (and other toxic) levels a million times higher than that in the water! If you like sport-fishing, be aware that these types of lake fish can be toxin-heavy.
The longer answer to this question is, yes, possibly. Nearly all fish and seafood 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 regularly.
Here’s what the US EPA and the National Resources Defense Council (NRDC) recommend people do to decrease mercury exposure from eating fish:
- Avoid shark, King mackerel, swordfish, tilefish, grouper, Marlin, orange roughy, Lake Bass, walleye – these have the highest levels of Hg.
- Limit white albacore tuna to 18 oz a month – it contains more Hg than light tuna.
- Limit saltwater bass, croaker, halibut, bluefin tuna, sea trout, Maine lobster to 18 oz a month. These have moderate levels of Hg.
- Limit Carp, Mahi-Mahi, crab, snapper, perch, cod, and monkish to 24 oz a month. These have lower levels of Hg.
- Shrimp, sardines, canned light tuna, wild Alaskan salmon, pollock, whitefish, and catfish, black cod – these have the lowest levels of Hg. You can enjoy up to 12 ounces a week.
*Please visit the NDRC’s website for a more complete list and their mercury calculator to get 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 does store in body tissues, it also gets released. You can clear it from your body in about 6-12 months if:
- Faster – You avoid eating fish that contain mercury completely.
- Slower – You limit your intake of fish/seafood to lowest-Hg levels noted above.
Here are some other natural-based suggestions to help keep you free of toxic mercury levels:
- Drink adequate amounts of water per day to flush toxins from your body tissues. Half your weight should be consumed every day. If you weigh 200 lbs, drink 100 oz of water.
- Avoid high fructose corn syrup – two recent studies suggest that it may contain Hg.
- Avoid vaccines or contact lens solution that contain thimerosal – this is a mercury-derived preservative.
- Dental amalgams – if you have old mercury amalgam fillings, replace them with newer, tooth-color mercury-free compounds. Your teeth will look great and you’ll be free of the mercury source.
- Add some fermented foods to your diet – things like yogurt, kefir, sauerkraut, help remove toxins from your body through creating good gut bacteria.
- Adequate amounts of Vitamin C and E – help prevent damaging effects of mercury.
- Add some natural chelators to your diet – things like garlic, selenium, cilantro, and chlorella. These substances bind to toxins like mercury and move them out of your body.
- Adequate fiber intake – is important to good health and lessening levels of mercury accumulation.
- If you have old mercury thermometers – switch them out for digital thermometers. Make sure you dispose of the old Hg thermometers as toxic waste like old paint.
- Energy efficient 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 scattering the dust. Do NOT vacuum as this will scatter the dust. Wear rubber gloves and cover your nose and mouth to be on the safe side to avoid inhaling any of its dust. Tape or a wet cloth will help pick up particles. Used ones should also be disposed of as toxic waste.
Mercury exposure is something we should all avoid in our diets and environment as much as possible. It can have very damaging effects on our brains and kidneys and cause a whole list of symptoms and conditions including depression, fertility problems, and even Alzheimer disease!
With some common sense, however, following the guidelines listed here, we can still enjoy eating the seafood we love so much without concern of toxicity!
Mark Rosenberg, M.D.
Natural Health News