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. In fact, the American diet is far too low in omega-3s, making tuna one of the few foods we eat that give us this vital nutrient.
Tuna is very good for you!
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. Mercury, even at low 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 our diet because people eat so much of it.
The Mercury in Tuna Dilemma
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.
Warnings About Eating Tuna
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.
Low Mercury Tuna Fish
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 (which is certainly an option many people take), what is a conscious seafood lover to do?
Young tuna fish have far 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 low 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, 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, low-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 like the Marine Stewardship Council,
- 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 sushi-grade tuna medallions and canned tuna in BPA free cans! They carry minimal-mercury tuna, salmon and other seafood, too. Available online.
Safe Catch – has the lowest tested levels of mercury of any brand of tuna, and meets Consumer Reports “Low Mercury” criteria set for pregnant and nursing women and young children. Safe-Catch is also the only tuna endorsed by the American Pregnancy Association. BPA-free cans and Marine Stewardship Council certified. Available at better grocery stores, Costco and online.
This Tuna Poke recipe is a great way to get the most taste and nutrition from your sushi-grade, low mercury tuna:
Ahi Tuna Poke Bowl (Maguro Butsu)
- 14 oz. sushi-grade tuna, line-caught, skinned
- 1 bunch mustard greens, or cress (optional)
- 4 tsp. wasabi paste, or the same amount of wasabi power mixed with 2 tsp. purified water
- 4 Tbsp. coconut aminos, or nama shoyu
- 8 spring onions, or scallions, green part only, finely chopped
- 4 shiso leaves, cut into thin slivers, lengthwise
- sesame seeds, toasted (optional)
- 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 coconut aminos or 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. Garnish with sesame seeds, if using.
- Serve immediately and enjoy!