Would You Like Mercury With Your Sushi?
I consider myself an open-minded person. So just because a group attacks drunk-driving laws and anti-smoking regulations, just because it opposes replacing the junk food in school cafeterias and vending machines with healthy snacks, just because it opposed reducing the blood-alcohol level that constitutes the legal definition of drunk, and just because it calls concerns about obesity “hype,” do I dismiss its defense of mercury in tuna fish?
Of course not.
So when the Center for Consumer Freedom sent me (and probably scores of other reporters) a press release slamming yesterday’s New York Times story chronicling the high mercury levels the newspaper found in tuna sushi served in New York City restaurants and sold in upscale stores, I didn’t reflexively think, “oh, this is the group jump-started with a pile of money from a tobacco giant.” I didn’t think, “this is the group whose leader promised said tobacco company, Philip Morris, ‘to unite the restaurant and hospitality industries in a campaign to defend their consumers and marketing programs against attacks from anti-smoking, anti-drinking, anti-meat, etc. activists.’” I didn’t automatically recall the Washington Post editorial citing “documents showing that Coca-Cola, Wendy's, Tyson Foods, Cargill and Outback Steakhouse are among [founder Rick] Berman's largest donors.” I didn’t automatically recall that Berman had, as the Post reported, “accused Mothers Against Drunk Driving a. . . of ‘junk science, intimidation tactics, and even threats of violence to push their radical agenda.’” (I found those references only later.)
No, when the Center for Consumer Freedom demanded “a complete retraction” from the Times, calling their story “a completely irresponsible piece of ‘science’ journalism,” I looked into its accusations. What I found:
*The Center claims that the Food and Drug Administration’s “Action Level” for methylmercury, the form that poses the health threat, “includes a generous ten-fold safety cushion.” Implication: even though the sushi the Times tested exceeded the Action Level, don't worry.
No. The Action Level was established in the 1970s. It does not define a “safe” level of mercury. (Methylmercury can damage the brain, especially in fetuses and young children, putting them at risk for attention problems and poor language, visual-spatial, memory and coordination skills, as well as lower IQ.) The Action Level is a completely different kind of limit with the purpose of defining a mercury level—greater than 1 part per million--that makes fish “adulterated” under the law. “Adulterated” means FDA can immediately remove the food from the market. That's why it’s called an Action Level. The concept of a safety margin is incompatible with the legal concept and purpose of an Action Level.
In fact, FDA originally set the level at 0.5 ppm. But it was sued by the U.S. fishing industry, which argued that the economic impacts of that limit would be devastating. A judge agreed with the industry, and FDA had to raise the level to 1 ppm. The actual basis for the current level of 1 ppm is therefore avoiding economic impacts on the fishing industry, not safety.
More crucial, there is no single “safe” level of mercury in fish. But the Environmental Protection Agency’s reference dose, which is not a concentration like ppm but an amount of mercury consumed daily, is 0.1 micrograms per kilogram of body weight per day. That is presumably safe.
By this measure, a woman who weighs 60 kg (about 130 pounds) can consume 42 micrograms of mercury per week (0.1 ug/kg/day x 60 kg x 7 days) without exceeding the “presumably safe” dose. If she eats 4 ounces (120 grams) of fish four times a week, and the fish contains on average 0.1 ppm mercury (which would be low, given the mercury content of most fish on the market; the Times analysis found levels of .5, .6, .8 . . .up to 1.4 ppm), she would exceed the dose, getting 48 ug of mercury in a week. If she ate 16 ounces of swordfish, averaging 1 ppm, in a week, she’d ingest 480 ug of mercury, or more than 11 times what the EPA considers a red flag.
*The Center for Consumer Freedom also claims that “by definition, it’s not possible for anyone to exceed a reference dose with a single week’s worth of exposure.”
Someone needs to go back to 4th grade math. A single can of albacore tuna exceeds the weekly reference dose for a 60-kg woman (180 g x 0.36 ppm = 65 ug of mercury, and the allowed dose is 42 ug.)
*The Center for Consumer Freedom also claims that you’d have to exceed the allowed dose by 10-fold every day for your entire life to be at risk.
More nonsense. The greatest risk is to the developing fetus. We are not talking about cancer risk (which is often calculated in terms of lifetime risk and exposure.) The window during which a spike of exposure could be harmful to the developing brain might be as small as a few days, weeks at most.
All too often, people trying to balance the risks of mercury against the benefits of fish give up. Somehow we have let the tuna industry get away with claiming that if you worry about mercury you’ll lose out on the heart benefits of fish. More nonsense. A new analysis, “Hold the Mercury: How Consumers Can Avoid Mercury When Buying Fish,” by the ocean conservation group Oceana suggests lots of low-mercury fish. Tuna ain't one of them. Ocean finds that the 23 fresh tuna samples bought at grocery stores, mostly yellowfin and ahi tuna, had an average mercury content of 0.68 parts per million, in line with what the Times found. Tuna sushi tested even higher, with an average mercury content of 0.86 parts per million. One in three samples of tuna sushi was above the FDA’s action level of 1 ppm, with half the samples testing at 0.92 ppm. Says Oceana, “The mercury levels in our tuna samples were comparable to that of fish that FDA advises women of childbearing age and children to avoid.”
Oceana has asked major grocery chains to post the FDA’s mercury advisory at seafood counters, noting which species are high in mercury and which are okay. Whole Foods, Wild Oats, Trader Joe’s, Albertson’s and Safeway have; Oceana is still negotiating with Costco, Publix and A&P.
[The Center for Consumer Freedom's response.]