Mercury in the Flu Vaccine? What to be Nervous About (or Not)

Like cell phones and Starbucks, mercury is everywhere. It's the silvery liquid in old thermometers, it's in rocks and soil, in dental fillings, and in the air. And, lately, it's in the news: Mercury in swine flu vaccines! Mercury in fish!

Don't hit the panic button. Mercury exposure is serious. It can cause neurological and muscular damage in adults and kids, and especially in babies still in the womb. But there are some serious Internet myths about it, too. Keep yourself healthy with these truths:

Myth: There are high amounts of mercury in the swine flu and seasonal flu vaccines.
Truth: Multiple-dose vials of these vaccines do contain the mercury-based preservative thimerosal. But the amount is tiny. A single dose delivers about 28 micrograms of mercury, same as a small tuna sandwich. And while the tuna has methyl mercury, the type that accumulates in your bloodstream and has been linked to nervous-system damage, the type in thimerosal is ethyl mercury, which, studies suggest, is eliminated from your body relatively swiftly.

Yes, the swine flu shot has thimerosal, but thimerosal has been removed from virtually all other vaccines for kids under the age of 6 and for many vaccines given to older kids and adults, too. If you're still concerned about it, some thimerosal-free versions of both vaccines will be available this fall and winter in single-dose vials, prefilled syringes, or "mist" versions that are inhaled instead of injected. But if you can't find one, go with the regular thimerosal-containing type. Don't die while trying to avoid a tuna sandwich's worth of mercury.

Myth: Since there's mercury in some fish, it's better to avoid all fish.
Truth: Fish are the top source of mercury in the human diet. But not all fish are bad. Your body needs the heart-healthy omega-3 fatty acids found in some fish (and if you're pregnant or nursing, your growing baby needs 'em, too -- omega-3s help build better brains). Instead of cutting out all fish, aim for two weekly servings of salmon or trout, which are low in mercury, as is canned light tuna (in contrast, albacore's got three times more mercury), pollock, and even fish sticks -- and cut out higher-mercury types like shark, swordfish, king mackerel, and tilefish (some environmental groups add wild striped bass, bluefish, blue fin tuna, and marlin to that list). Have varieties like orange roughy, Chilean sea bass, and blue crab only once or twice a month. By the way, it isn't just the fish fat that's healthy -- it's the fish protein as well. The good news is that the fatty fish high in omega-3s, like salmon, are generally lower in mercury because they eat microscopic sea creatures like zooplankton; in contrast, lean predatory fish that munch on smaller fish (which already have mercury building up in their bodies) tend to accumulate more mercury that then gets passed along to you.

Myth: Breathing the air near coal-fired power plants makes you a walking mercury dump.
Truth: Mercury released from power-plant smokestacks is inorganic mercury, the least toxic type. It's a public health issue not because of direct inhalation but because it wafts through the atmosphere and settles in waterways around the globe, where it undergoes chemical changes that allow it to move up the food chain right to your dinner plate (it accumulates in some of the fish you eat). A new U.S. Geological Survey report found trace levels or higher in every fish caught in 300 streams, large and small -- even from creeks along the coasts of North Carolina, South Carolina, Georgia, Florida and Louisiana. Other research has found mercury in fish that live deep in the ocean and in remote streams in Canada and Alaska. What's important: If you fish and then eat what you catch, be sure to keep up with local fish advisories about mercury and other toxins (find U.S. advisories at http://www.epa.gov/waterscience/fish/; in Canada contact the provincial or territorial government to find out about any local advisories).

Myth: Silver fillings release toxic mercury into your mouth.
Truth: Amalgam fillings do contain minute amounts of mercury, but once they're in, little mercury vapor is released. The big risk is not having them placed in a well-ventilated dentist's office and not using a dam in your mouth while you're having the work done (that same precaution needs to be taken for composite fillings).