Junkfood Science: Fishy sushi scares

January 25, 2008

Fishy sushi scares

We now have a national newspaper create a news story, then report it as news, incorrectly — and, incredibly, that is considered professional journalism.

New York Times bought tuna from twenty stores and select restaurants and had them all tested for mercury levels. What did it find?

All of the tuna it tested being sold commercially in New York had mercury levels nearly ten times below the lowest amount that has been shown might ever pose a danger to the most sensitive population (babies and children) with a lifetime of daily exposure.

Good news, reassuring news, helpful news. There is no evidence of anything to fear.

But that was not what the paper’s health reporter or editors reported this week. Instead, the paper put a different spin on the findings. In a story quoting well-known mercury activists, it headlined its sushi series with “High Mercury Levels Are Found in Tuna Sushi.”

The newspaper had samples of tuna tested by Dr. Michael Gochfeld of the environmental and occupational medicine department at Robert Wood Johnson Medical School, who also treats patients with mercury poisoning and is the former chair of the NJ Mercury Task Force. According to the paper, they found “so much mercury [in most of the samples] that a regular diet of six pieces a week would exceed the levels considered acceptable by the Environmental Protection Agency.”

The NY Times failed to mention what it meant by “high,” or put the science into factual context for readers. Even the highest mercury levels the Times found were far below what the FDA or EPA have identified as a level where potential health risk might begin: called the benchmark dose.

The benchmark dose is the lowest dose considered safe from any effect over a lifetime of daily exposure in the most sensitive population of children, explained Dr. Joseph Jacobson, of Wayne State University and a member of the National Academy of Sciences’ Committee on Methylmercury.

The FDA and EPA then add an arbitrary ten-fold safety cushion to that, to arrive at a “reference dose” — that’s the 1 part per million which the FDA uses for regulatory reporting (called its “Action Level”). That safety cushion is not a threshold where any possible risk begins; but that's what the Times incorrectly reported and used for its definition of "high."

The EPA does not determine or regulate safe levels of mercury in commercial seafood for human consumption, the FDA does. The EPA issues environmental fishing advisories for the small portion of recreational fishing. To minimize consumer confusion, however, they did jointly issue fish consumption advisories.

The Times found mercury levels in the tuna samples of 0.1 to 1.4 parts per million — all far below any potential risk. The levels were a tiny fraction within the regulatory safety cushion. And the results were not surprising. The FDA, which tests methylmercury levels in commercially-sold seafood, has found similar ranges and found that the 25 most popularly-eaten fish average methylmercury levels of 0.12 ppm.

The Times proceeded to warn of the risks for women who might become pregnant and children. It failed to mention that according to the U.S. Centers for Disease Control and Prevention’s National Health and Nutrition Examination Survey (NHANES), not a single woman of childbearing age or child in the United States has mercury levels anywhere close to unsafe levels.

In fact, it’s impossible for American women to eat enough fish to put their newborns at risk, according to the U.S. Department of Agriculture’s Human Nutrition Information Services. It analyzed the diets of American women of childbearing years using several available dietary surveys and factored in endless possibilities — such as heavy fish consumption, eating fish varieties with the highest methylmercury levels, repeatedly eating the same fish, and the amounts of methylmercury in a range of commercial fish samples. After 100,000 iterations, they found it was inconceivable for a mother to eat so much purchased fish she’d put her baby anywhere near harm’s way. Dr. James Heimbach, former associate administrator with the HNIS, reported at the FDA Methylmercury scientific meetings that American women “simply are not exposed to levels of methylmercury that would place the newborn children at risk.”

The Times also failed to mention any of the research of the world’s foremost experts on methylmercury and health — even though it has been widely reported and internationally recognized. For more than 30 years, researchers at the University of Rochester Medical Center, in Rochester, New York, have closely followed populations eating large amounts of fish, including Samoans, Peruvians and residents of the Seychelles, and found no associated adverse effects in adults or children. The most careful and exhaustive, double-blind, longitudinal methylmercury exposure study ever conducted on expectant mothers and children was done on the people of Seychelles. These people have the highest per capita consumption of fish in the world, typically 12 fish meals each week, the same types of fish Americans eat. Even though the Seychelles children get 10 to 20 times more methylmercury than U.S. children, the researchers have tested them for more than 14 years now (using multiple global tests and over 57 endpoints for neurocognitive, language, memory, motor, perceptual-motor, and behavioral functions) and found no detectable adverse effects.

As the FDA’s scientific experts concluded after reviewing the evidence, even among populations eating many times more fish than Americans eat, scientists have found no credible evidence of neurotoxicity, or anything remotely resembling brain damage, retardation or learning disabilities or other health concerns.

In fact, there has never been a case of an American eating so much fish as to be harmful. The only cases in the scientific literature of mercury poisoning from fish and subsequent neurological problems — a fact confirmed by Dr. Thomas Clarkson, a toxicologist at the University of Rochester School of Medicine — were the result of an industrial mercury spill in Minamata Bay, Japan in the 1950s, which resulted in fish with methylmercury levels 40 to 1,000 times higher than the fish Americans, and most people around the globe, eat. These tragic poisonings first pointed out that at extremely high exposures, mercury was a neurotoxin and might affect the developing fetus.

But poisonings from a rare toxic spill is much different from the amounts of methylmercury that have always naturally been in fish and in human bodies. Methylmercury — an organic compound produced by methane-generating bacteria deep in bodies of water as they ingest inorganic mercury — is nothing new. And despite all of the recent scares, the amounts we’re exposed to have been dropping for centuries. While a physiological basis for the neurodevelopmental effects of toxic levels from mercury poisoning is understandable, there is no biological basis why our natural, low-level exposures would pose any risks, according to Dr. Gary J. Myers, M.D., another methylmercury expert at the University of Rochester Medical Center.

The Times published an accompanying piece describing the findings of Dr. Jane Hightower in San Francisco, whose controversial work has been with women complaining of vague symptoms of fatigue, thinning hair, aches and trouble concentrating and who believe they are being poisoned. She tested their hair or blood and found some with those same “high” levels. After eliminating fish from their diet, the women — described as “high end consumers” — said their symptoms went away. [Evidence not of the effects of mercury, but of nocebo and placebo.]

But the Times failed to mention the conflicts of interests of the people quoted in their story, all of whom were with environmental groups lobbying against mercury, as the National Fisheries Institute noted. In a public statement about the Time’s “poorly-sourced sensational article,” it said it “presents a distorted report on sushi and seafood that is at odds with widely accepted science.”

One of the restaurants that the Times singled out for having “high” mercury levels was Nobu, owned by Drew Nieporent and Robert De Niro, and considered one of the finest Japanese restaurants in New York. Chef Nobu Matsuhisa’s creations are considered works of art and widely praised by celebrities from Madonna, Giorgio Armani, Bill Clinton, Andrea Agassi, Robin Williams, Cindy Crawford, Leonardo DiCaprio to Kate Winslet, who described them so good they are “quite simply heaven on earth and sex on a plate.” The Times failed to mention that Nobu has been in the crosshairs of environmental groups for selling seafood these groups oppose. Or was Nobu’s mention not a coincidence, either?

In the end, however, the Times series has been largely ignored by the media and it has not been widely disseminated by reputable publications and news outlets, much to their credit.

Even the largest consumers of tuna in the world — the Japanese, who consumed 610,000 tons just in 2004 — were unimpressed by the Times stories. Coming from the site of those tragic poisonings during the 1950s, these residents understand that real toxicology risks come in the dose. The Japanese government doesn’t consider these levels, that occur naturally in nearly all fish, to be a health concern and doesn’t set limits on mercury content in tuna. Teruo Tagaki, chief of the product safety office of Japan’s Fisheries Agency, said that “the newspaper is exaggerating the risk.” He told Bloomberg in Tokyo about the 2005 study by Japan’s Food Safety Commission that found ingesting as much as 100 micrograms of mercury each week presented no risk to health for a person weighing 50 kilograms.

It appears some Times readers bought this week’s hoax, however, with truly worried comments on their forums. A few television stations and newspapers also picked up the Times mercury story, even embellishing it further by claiming the FDA was behind it and was going to take legal action to ban tuna sushi, and that the levels found were what “the FDA considers so high that the food is legally adulterated.”

Did the Times actually believe readers would buy their made-up news scare? Or did they believe it themselves? It is difficult to imagine that national-scale professional journalists don’t understand the basics of fact checking and balanced reporting, or the basics of sound science and health (like the dose makes the poison). Or was it all a perverse joke on readers? That’s what it appears reading a side piece that was clearly satire, with an imaginary debate with the presidential candidates.

Whatever their motives, making up a news story, needlessly scaring readers, and failing to give readers the full story is not professional journalism. Not even close.

So, if you paused before heading to your favorite sushi or seafood restaurant, or began to wonder what is safe to eat during Lent, it pays to remember to be skeptical of scary things in the news.

The only thing anyone need concern themselves with is proper - sushi bar - etiquette. And, how you can possibly taste all of the delicious sashimi there is to enjoy.

© 2008 Sandy Szwarc

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