Fishy Info
How safe is tuna?
By Sam Roe and Michael Hawthorne, December 13, 2005.
Source: Chicago Tribune online
A Tribune investigation shows the tuna industry has failed to adequately warn consumers about the risks of eating canned tuna, while federal regulators have been reluctant to include the fish in their mercury advisories--at times amid heavy lobbying by industry.
When the Food and Drug Administration updated its mercury warning last year, it arbitrarily classified canned light tuna as low in mercury to "keep market share at a reasonable level," one agency official told an FDA advisory panel, according to transcripts of the meeting.
The government has recommended that children and pregnant women eat canned light tuna because it generally contains less mercury than canned albacore does. Yet industry officials acknowledged in interviews that tens of millions of cans of light tuna sold each year are made with a species that on average contains just as much mercury as albacore.
Making choices about canned tuna based on mercury risk is complicated because not all tuna species contain the same amount of the toxic metal, which can harm children's developing brains and cause neurological problems in adults.
- Albacore tuna is a big fish and therefore tends to have higher mercury levels. The government has warned young children and pregnant women to limit how much albacore they eat.
- There are no warnings for light tuna, because most of it is made with skipjack, a relatively small species with lower levels of mercury.
- But some canned light tuna comes from another species: yellowfin. While the mercury content of yellowfin varies, industry testing found the average to be equal to that of albacore.
About 15 percent of canned light tuna is made with yellowfin, the industry acknowledged. Each year, roughly 180 million cans of yellowfin are sold in the U.S. All of these cans are sold as "light tuna," and only about half are labeled as "yellowfin," "gourmet" or other wording that might signal to shoppers that the fish inside is likely high in mercury.
Industry leaders met privately with FDA officials five times in late 2000 when the agency was crafting its mercury warning, FDA records show. During one meeting, the U.S. Tuna Foundation argued that if consumers were warned about tuna, the market for canned tuna would shrink about 20 percent, the U.S. tuna fleet would default on loans, and the seafood industry could face numerous class action lawsuits "at substantial cost and adverse publicity," a copy of the industry presentation shows.
In the end, the FDA rewrote the draft and released the final version of the warning to the public in January 2001. It recommended that at-risk groups not eat shark, swordfish, king mackerel and tilefish. Tuna was not mentioned.
A month later, the FDA issued a statement explaining the warning. It said canned tuna was not included because consumers did not eat enough to cause a significant risk. Yet the federal government's own data showed canned tuna was then the nation's No.1 consumed seafood.
Among those calling for improved warnings about mercury in tuna is the American Medical Association, which adopted a policy last year that physicians should help make their patients more aware of the potential risks. The group also urged the FDA to consider "requiring that fish consumption advisories and results related to mercury testing be posted where fish, including canned tuna, are sold."
Last year, the state of California sued the nation's big three tuna producers, demanding they place warnings on cans of albacore and light tuna or post signs in grocery aisles to inform state residents that the products contain mercury. The state alleges the firms are violating a state law requiring business to warn people before exposing them to carcinogens or reproductive toxins. The case is continuing.
Tastes Like Chicken
Tuna Facts from an American canned tuna company.
Source: Chicken of the Sea.
How does methylmercury enter our food?
Mercury finds its way into the food chain primarily through fish.
Ocean Fish: Mercury finds it way into seafood from naturally occurring mercury found in oceanic underwater volcanoes. Ocean-going species swim in deep oceans far from human industrial sources of mercury.
Freshwater Fish: Freshwater fish Mercury enters freshwater species from natural sources as well as from anthropogenic (man-made) sources such as air pollutants (thanks to rain) deposited into rivers and lakes.
In the water, bacteria transform the mercury into methylmercury, a process called methylation. Larger, migratory species, such as shark and swordfish, absorb methylmercury from the water and ingest it when eating algae and other smaller species of fish. In the deep ocean, it would take thousands of years for anthropogenic mercury to reach the bottom sediment, be methylated and rise through the food chain.
Are Americans at risk for methylmercury poisoning from eating fish?
No. Only a very small number of pregnant women and women of childbearing age who may become pregnant who eat exceedingly large quantities of predator fish (shark, swordfish, tilefish and king mackerel) need to be aware of certain concerns. The FDA says that it is all right to eat other fish, "as long as you select a variety of fish while you are pregnant or may become pregnant, you can safely enjoy eating them as part of a healthful diet. You can safely eat 12 ounces per week of cooked fish."
"You can choose shellfish, canned fish, smaller ocean fish or farm-raised fish - just pick a variety of different species."
A Different Point of View
Mercury in Fish
Source: The World's Healthiest Foods.
Should I be concerned about mercury in fish and what fish are safe to eat?
All health experts agree that fish is an excellent source of lean protein accompanied by heart-healthy omega-3 fats, and many health organizations, such as the American Heart Association, recommend eating fish two or three times each week.
On the other hand, the FDA has issued a caution for pregnant or breastfeeding women and women of child-bearing age to avoid consumption of swordfish, king mackerel, shark and tilefish, and to limit consumption of fresh or frozen tuna steaks due to the high levels of mercury that have been found in these fish.
Human pollution is the problem, not natural occurrence of mercury
Although mercury is a naturally occurring heavy metal, both in the environment and in the body, its natural occurrence is miniscule and insignificant. Mercury has only become a problem in our environment and in our health because human activities, like the manufacturing of mercury batteries, thermometers, and mercury-containing fluorescent lights, have liberated mercury from ground ores and thrown it into the category of hazardous waste.
Mercury from discarded mercury-containing products has leeched its way from landfills and hazardous waste sites into our soil and water, and all of us now harbor bits of mercury from this process. For example, the Centers for Disease control in Atlanta, Georgia report that 8% of all women of childbearing age in the U.S. now have mercury levels in their bodies that exceed governmental guidelines.
How much mercury is safe?
The safety of eating mercury-contaminated fish is controversial because “safe” really depends on who is trying to stay safe and what they are trying to stay safe from. A very unhealthy person, perhaps in the hospital from weakness and poor nourishment, can withstand very little toxic exposure, including mercury-contaminated fish. An extremely healthy person, full of vitality, and optimally nourished, with good nutrient supplies and a strong ability to get rid of toxins, can definitely eat mercury-contaminated fish and remain healthy.
How much could such a person eat? Here the answer hinges on what the person is trying to stay safe from. An athlete facing endurance training might not want to deplete his or her nutrient supplies at all, and might not want to ask his or her body to engage in any unnecessary detoxification of mercury. In this case, the choice might be to avoid any mercury-contaminated fish. A well-nourished, healthy person just wanting to stay generally healthy, i.e., stay safe from premature aging or premature onset of chronic disease, might choose to eat canned tuna once or twice a week.
While it’s very different to measure amounts of mercury in the body than in the fish, the point here is that many organizations are moving in the direction of stricter standards when it comes to mercury levels, and for this reason, we at the World’s Healthiest Foods like the Canadian standard of 500 ppb better than the U.S. FDA standard of 1,000 ppb (or 1 ppm).
Fish to avoid
A draft advisory from the Food and Drug Administration and the Environmental Protection Agency containing new proposed guidelines on fish consumption was circulated at a meeting of the FDA's Food Advisory Committee December 10, 2003, in Washington, D.C. Recent FDA testing has indicated that canned albacore, known as white tuna, contains almost three times as much mercury as canned "light" tuna. The proposed advisory stated that although mercury levels in tuna vary, tuna steaks and canned albacore generally contain higher levels of mercury than canned light tuna. In the spring of 2004, the FDA issued recommendation that pregnant and nursing women, women of childbearing age and children limit their consumption of canned albacore tuna and tuna steaks to no more than 6 ounces per week and light tuna to no more than 12 ounces per week.
While albacore is a biological type of tuna, "light" tuna may be biologically classified as skipjack, bluefin, yellowfin, and tongol. All types except tongol may be labeled "chunk light" or "solid light", while tongol may only be labeled "chunk light". Our recommendation: when you choose to eat tuna, either purchase canned light tuna or if buying canned albacore, purchase it from a reputable supplier who has had the mercury levels tested by an independent lab.
We still recommend choosing which oily fish you consume wisely. Tuna, unless tested and found to be uncontaminated, and farmed salmon, which have been identified as having some of the highest levels of PCBs found anywhere in the world, should be avoided.
Most Highly Recommended Fish to Eat
The mercury content of other types of fish will vary with the species. Some varieties recommended by the Environmental Working Group and the U.S. Public Interest Group include wild Pacific salmon, flounder, haddock, shrimp, farm-raised trout and catfish; there was no mercury detected in these fish.
Freshwater Fish and Fish Caught by Family or Friends
Freshwater fish may also be contaminated with mercury, either from natural or industrial sources. For freshwater fish caught by family or friends, check with your state and local health departments for current advisories regarding mercury, or call toll-free 1-888-SAFEFOOD.
Tuna-Related Links
Commercial Tuna Websites
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