Americans eat nearly three pounds of tuna each every year (usually in cans), making it the nation’s second most popular seafood after shrimp. The government promotes it via school lunch programs, WIC (the federal food program for poor women and children), and even in the U.S. Department of Agriculture dietary recommendations.
Low in fat, high in protein, tuna contains Vitamins A & D and lots of omega-3 fatty acids that are thought to protect against heart disease and boost brain development early in life.
But because of emissions from power plants and garbage incinerators, tuna also absorbs significant amounts of methylmercury, a form of mercury that concentrates in the fatty tissues of big fish and humans. Fatal in high doses, mercury at lower levels has been linked to a host of health and developmental problems in babies and adults.
Tuna is not the highest-mercury fish we eat—that title belongs to swordfish and tilefish—but it is by far the largest source of mercury in the diet because people eat so much of it.
None of this is news to federal regulators. In 1970, a New York chemistry professor tested a can of tuna in his pantry and discovered that it contained significantly more mercury than what the FDA then considered safe. After running tests of its own, the agency recalled nearly 1 million cans of tuna. It also issued an “action level” under which fish with more than 0.5 parts per million (ppm) of methylmercury could be pulled from the market.
An action level is not a regulation. It doesn’t require anyone to do anything. Even so, the fishing industry found the new standard so intolerable that it sued the FDA. As a result, in 1979, the FDA doubled the level to 1 ppm, making it twice as high as what the U.S. Environmental Protection Agency (which issues mercury advisories for anglers) and the European Union consider safe. The action level in China is 0.3 ppm—more than three times more stringent than the FDA’s.
But tuna often exceeds even the weak US standard: In 2006, for instance, the group Defenders of Wildlife tested cans of tuna straight out of grocery stores and found that 1 in 20, particularly those imported from Latin America, had mercury above the FDA action level and could, in theory, be pulled from the shelves.
It was only after years of criticism from environmental groups and scientists that the FDA began to warn pregnant women about mercury. But, when the FDA failed to come through on tougher regulations to back up their warning, some states stepped up with more stringent warnings. Washington State, for example, warns that children under six should eat no more than half a can of albacore tuna a week.
Because of continued pressure from scientists, doctors, and environmental groups, in 2003, the FDA did revise the mercury advisory for several kinds of fish, but again it bent the science to accommodate the tuna industry’s interests so that canned light tuna would end up in the low mercury group “in order to keep the market share at a reasonable level.”
The current FDA advisory warns pregnant and nursing women to eat no more than 6 ounces of albacore, and no more than 12 ounces of chunk light tuna, per week.
The FDA recommends the same guidelines for children, with the vague suggestion that they eat “smaller portions.” A 44-pound preschooler who follows the FDA guideline would consume four times the mercury the EPA considers safe.
Because of mercury contamination, mainstream commercial brands of tuna should be eaten in extreme moderation, and probably avoided by pregnant and nursing women altogether.
Most of the world’s fisheries are contaminated with Mercury, PCBs and other human-made pollutants, and they are significantly over-fished. But farmed fish are pumped full of antibiotics and have their own grave environmental issues. So, unless you choose to abstain from eating fish altogether, what is a conscious consumer to do?
Young tuna fish have less methylmercury than any other tuna because they are caught before they grow large enough to accumulate a lot of mercury in their bodies. But not all “minimal-mercury” tuna is created equal: to be eco-friendly as well as low-mercury the tuna also needs to be pole, troll, or line-caught in the pristine waters of the North Pacific, and, ideally, certified as sustainably harvested.
Because of consumer demand, there are a few companies who have made it their business to supply eco-friendly, young, minimal-mercury tuna fish. Their products come at a premium because they:
- sustainably harvest selected tuna breeds with poles and lines instead of nets,
- monitor the percentage of their catch, often through third-party sustainable-fishery certifiers,
- rigorously test their products to ensure that their mercury levels fall well below EPA and FDA standards, and
- use BPA-free cans to package their product.
Here are some of those companies…
Vital Choice – offers Marine Stewardship Council-certified sashimi-grade tuna medallions and canned tuna in BPA free cans! At .08ppm, Vital Choice has the lowest average mercury level of any of the minimal-mercury tuna brands. Also carries minimal-mercury salmon and other seafood. Available online. (My favorite choice and an SFF sponsor, please visit them!)
Eco-Fish – offers canned tuna that carries the Seafood Safe label in BPA free cans. Available at better grocery stores.
Wild-Planet – offers troll-caught, minimal-mercury canned tuna. They are in assessment for Marine Stewardship Council certification. May use BPA in their cans. Available online.
Here’s a great way to get the most taste and nutrition from your sashimi-grade, minimal mercury tuna:
- 14 oz. very fresh, line-caught, sushi-grade tuna, skinned (where to find online)
- 1 carton mustard greens or cress (optional)
- 4 tsp. wasabi paste from a tube, or the same amount of wasabi power mixed with 2 tsp. pure, chlorine-free water
- 4 Tbsp. coconut aminos or nama shoyu (or if you can't do soy, liquify 1 tsp. sea salt (or to taste), 1 Tbsp. fresh portobello mushroom and 3-4 Tbsp. raw apple cider vinegar)
- 8 spring onions (scallions), green part only, finely chopped
- 4 shiso leaves, cut into thin slivers, lengthwise
- Cut the tuna into 3/4 inch cubes or 1/2 inch thick medallions.
- If using mustard and cress, arrange as a bed in four small serving bowls or plates.
- Just 5-10 minutes before serving, blend the wasabi paste with the nama shoyu in a bowl, then add the tuna and spring onions. Mix well and leave to marinate for 5 minutes.
- Divide among the bowls and add a few slivers of shiso leaves on top.
- Serve immediately and enjoy!
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