Fishy Science

Background:  Environmental and animal-rights activists have disseminated bad science and needlessly stoked public fears about the healthfulness of eating seafood, in an effort to reduce fishing and fish consumption.  The U.S. Food and Drug Administration (FDA) and Environmental Protection Agency advise consumers that that “fish and shellfish are an important part of a healthy diet and can contribute to heart health and children’s proper growth and development.”

  • The Center for Science in the Public Interest (CSPI), Oceana, the Mercury Policy Project, and other activist groups have advocated for mercury warning labels at every grocery counter where fish is sold, despite the fact that the FDA has determined such government warnings would be misleading. And the California Supreme Court ruled in 2006 such warnings on cans of tuna would cause more public-health harm than good.
  • Trace levels of mercury in seafood have been blown widely out of proportion by the media and environmental activists. Consumer Reports drastically departed from widely accepted fish-consumption safety standards by advising that “pregnant women [should] avoid canned tuna entirely.”  Environmental Defense warns that babies and children “may suffer brain damage and learning disabilities” from trace amounts of mercury.
  • One of the researchers behind the mercury scare, Dr. Jane Hightower, said in the findings of her study that “because only mercury was tested in these individuals, other contaminants responsible for symptoms cannot be ruled out;” “Cause and effect regarding symptoms was not fully addressed in this study;” and “A comparative analysis for the purpose of controls is not available.” In other words, the researcher who told United Press International that “you shouldn’t have more than half a can of tuna a week” could not reasonably support that claim.

What’s the research behind the message?  Scientific research reveals that the actual threat of mercury contamination has been grossly inflated, and that the benefits of fish consumption far outweigh any risks associated with mercury contamination.

  • There are no scientifically documented cases of Americans developing mercury poisoning from eating commercially-bought fish. And Dr. Ashley Roman of the New York University Medical Center has told Reuters that “there has been no case of fetal mercury toxicity due to fish consumption reported in the United States.” The only fish-related documented cases in the medical literature are from Japan in the 1950s and 1960s, following a massive industrial spill of mercury into fishing waters.
  • A twelve-year study conducted in the Seychelles Islands found no negative health effects from exposure to mercury through heavy fish consumption. On average, people in the Seychelles eat between 12 and 14 fish meals every week, and the mercury levels measured in the island natives are higher than those measured in the United States. But the island participants suffered no ill effects from mercury in fish, and they received a significant health benefit from eating fish in the first place.
  • Studies published in 2005 in the American Journal of Preventive Medicine found that even eating small amounts of fish each week can result in a 17 percent lower risk of heart disease, a 12 percent lower risk of stroke, and (when eaten by pregnant women) a modest increase in children’s IQ. The Omega-3 fats found in fish can also protect against Alzheimer’s disease, arthritis, breast and prostate cancer, and many other conditions.
  • In February 2007 the esteemed British medical journal The Lancet published a groundbreaking study comparing nutrition data collected from more than 8,900 British mothers with the results from IQ, motor-skill, and other developmental tests performed on their children from the ages of 6 months to 8 years. The research, led by National Institutes of Health physician Dr. Joseph Hibbeln, concluded that “there is no evidence of neurodevelopmental risk from prenatal methylmercury exposure resulting solely from ocean fish consumption.”

What should I do about my fish intake?  Consumers should know that fish is an excellent source of omega-3 fatty acids and other key nutrients. The federal government advises that pregnant and breastfeeding women (and women who may become pregnant) avoid just four high-mercury species of fish (shark, tilefish, king mackerel, and swordfish). These species are not commonly eaten in America, and other consumers (e.g., men, post-menopausal women, teens) are not covered by this advisory.

  • The FDA builds a ten-fold cushion of safety into its mercury recommendations. That means a pregnant woman could eat five times as much tuna as the FDA says she can and still be protected from the risk of negative health impacts by a 200 percent buffer.
  • Overblown fish scares end up hurting the poorest Americans. Approximately 4.4 million U.S. households earning $30,000 or less completely eliminated their purchases of canned tuna between 2000 and 2006. During those years, women in those households gave birth to nearly 260,000 children. Canned tuna was the most affordable form of omega-3 fatty acids for the women in those households.  By eliminating tuna, they eliminated a valuable source of nutrients from their developing fetuses.
  • The U.S. government’s Institute of Medicine (a division of the National Academies of Science) warned in a major 2006 report that a “spillover effect” from one-size-fits-all fish warnings could deny most consumers the health benefits of seafood consumption.