Soon after he turned thirty, professional BASE jumper Jeb Corliss stood on the edge of a cliff, ready to jump, and sensed nothing. He jumped anyway: "I had a nasty malfunction and almost got killed and my heart rate never changed," he says. "I remember landing and thinking, 'How can I almost die and not even be scared at all? Something's wrong.'" The lack of adrenaline was one thing. For the past year, Corliss also felt fatigued and slept more than usual.
He went to see a doctor and was diagnosed with mercury poisoning. This was unsurprising considering he worked out roughly four hours a day and ate packaged tuna for breakfast, lunch, and dinner. It was the only low-fat, muscle-building protein he never got tired of eating, even though it was loaded with mercury. "I deserved to be poisoned," he says.
Evidence suggests that as many as 90,000 people live with mercury poisoning without knowing it. Long-term exposure to mercury, which almost exclusively comes from eating fish, wears down cells and can contribute to chronic health conditions such as heart disease. Symptoms can be vague and hard to pin down — like Corliss' lack of adrenaline. They also include weight loss, hair loss, and muscular weakness; sufferers can feel tired, weak, and dizzy, imparied vision, hearing, speech, increased sensitivity to light, and clumsiness. If you have a number of these symptoms, doctors can order a simple test that measures concentrations in the bloodstream. The treatment is equally straightforward: Stop eating fish. Once diagnosed, it will take your body about two months to rid itself of the toxin.
Jeremy Pivens might be the most famous recent case of mercury poisoning — when he found himself in the hospital during his Broadway run of David Mamet's "Speed-the-Plow," and was maligned by the press for it (calling it the "sushi defense.") Hospitalization is fairly rare from mercury poisoning. More common, as Rich Gelfond, the founder of the IMAX cinema technology, found is having difficulties diagnosing the disease. When he began to feel off-kilter and had trouble walking across the street, he went for repeat neurological tests until, months later, one neurologist asked about his diet and tested him for mercury. His levels were extremely high. Gelfond was so frustrated by the lack of treatment options that he's since started a fund at the State University of New York-Stony Brook dedicated to mercury research.
Awareness of the problem is rising. This past October, the issue came to the international stage when the U.N. signed a treaty to curb widespread release of mercury into the atmosphere, primarily from coal- and oil-fired power plants and its use in gold mining — the first treaty ever to recognize a single chemical's detrimental effects on human health. The debate about the safe limit for mercury, however, remains wrapped up in controversy. On Tuesday, for instance, the U.S. Supreme Court agreed to hear an industry challenge to Environmental Protection Agency's limits on the emission of mercury.
Few nutritionists say to do away with fish altogether if you don't have mercury poisoning. The fatty acids in fish lower risks for chronic diseases such as heart disease, cancer, and arthritis. You should, however, try to eat smaller, younger fish, like anchovies, sardines, and mackerel, which tend to accumulate less mercury because they've spent less time in the sea and don't prey on smaller fish, further concentrating the mercury in their fat.
"It might sound counterintuitive, but the most affordable fish have the least amount of mercury," says Andy Sharpless, CEO of Oceana and coauthor of The Perfect Protein. The vast majority of men who eat fish once or twice a week will primarily benefit, but, as Michael Gochfeld at the Robert Wood Johnson Medical School point out, the upside usually does not continue beyond two fishmeals a week. "People who eat fish every day are at risk," he says. If you're eating sushior swordfish steaks three times a week, even if you're asymptomatic, ask your doctor for a blood test.
How to Avoid Mercury in Seafood
1. Choose your canned fish wisely: Albacore ("white") tuna typically has more mercury than canned light tuna. Troll-caught tuna, like the kind you find in a can from Wild Planet, will have more consistently low mercury levels because the fishing method tends to have smaller catch than long-line fishing. An even safer bet: Canned sardines.
2. Don't eat predators. Shark, swordfish, king mackerel, or tilefish are all near the top of the food chain. They also contain some of the highest levels of mercury of fish we eat.
3. Eat anchovies. These short-lived fish are all but devoid of mercury. They also happen to be one of the most omega- and calcium-rich species on the planet
4. Choose smaller fish. Avoid the temptation to pick the biggest fish at the market — smaller is likely younger, had less time to accumulate mercury, and is healthier.