Given the vast amount of benefits from seafood, we need to be eating more of it. Seafood is the primary source of the active form of omega-3 fatty acids (EPA and DHA) that appear to prevent heart disease, boost brain and immune health, and help fight inflammatory diseases like arthritis and irritable bowel syndrome. But mercury levels and harmful fishing practices make navigating the waters to find the best seafood difficult. So the question that remains is this: how can we take advantage of the seafood’s potent nutritional content without building up toxins in the body and while protecting our precious waters?
A good rule of thumb to follow is the bigger the fish, the more mercury. So eat smaller fish that don’t have a lifespan long enough to build up mercury, like tilapia, sardines, anchovies, clams, mussels, and oysters. Fish sold as steaks, for example, are often big fish. If a fish can’t fit on a platter whole, it’s probably high in mercury. Some of the lowest mercury seafoods include shrimps, salmon, catfish, and pollock , all of which are small. Yet it takes a mighty large platter to fit a whole tuna, since yellowfin, bigeye, and bluefin tuna often exceed 100 pounds. Over one-third of the U.S. population’s mercury comes from canned tuna.
Sustainable fishing practices are essential to help keep a supply of healthy seafood. Harmful fishing practices often leave the ocean’s precious habitat demolished by a bottom trawler or a dredge net. Some species, like coral, need centuries to grow back! Tons of fish are killed unnecessarily and tossed out with certain fishing methods. Even dolphins, sea turtles, seals, whales and seabirds are regularly accidentally caught and killed. The United Nations Food and Agriculture Organization estimate that one in four animals caught in fishing gear dies as unwanted catch.
When certain types of fish are caught faster than they can reproduce, they can become harder to find and eventually unavailable forever. Slow growing fish like Chilean sea bass and orange roughy, for example, are particularly vulnerable to overfishing. Some fish farms are great and even help the situation. American and Canadian shellfish farms may actually improve water quality, but many fish farms are overcrowded and pollute the water. The fish become diseased which spreads to wild fish. So it’s critical to ask your store or market’s seafood about their seafood sourcing policy. Also, don’t hesitate to buy frozen seafood as it’s frozen soon after being caught, but make sure it’s sustainable. Look for eco-labeling from the MSC, the GAA, Global-GAP, or others to know which farms to trust.
Check out Monterey Bay Aquarium Seafood Watch The Super Green List to obtain the best seafood choices that provide high omega-3s, are low in mercury, and sustainable. The list is updated as these seafood options change.
The Best of the Best:
- Atlantic Mackerel (purse seine from Canada and the U.S.)
- Freshwater Coho Salmon (farmed in tank systems, from the U.S.)
- Pacific Sardines (wild-caught)
- Salmon (wild-caught, from Alaska)
- Salmon, Canned (wild-caught, from Alaska)
Other Healthy “Best Choices”
- Albacore Tuna (troll- or pole-caught, from the U.S. or British Columbia)
- Sablefish/Black Cod (from Alaska and Canadian Pacific)
As long as seafood is low in toxins like mercury and caught in a sustainable way, it is still nutritious without being super high in Omega-3 fatty acids. Seafood is also a good source of protein, vitamins A, B12, D and E, iodine, selenium, calcium, zinc and iron. Many of these nutrients tend to be low in our diet, making seafood important to our health even if it’s lower in omega-3s.
Selenium, for instance, is highly bioavailable in fish. An equal dose of selenium can substantially reduce the detrimental effects of toxic levels of mercury. So it’s possible that concerns of methylmercury accumulation in some fish populations may be offset by selenium. Selenium can help prevent disease on a cellular level, which is probably why selenium seems to help protect men from prostate cancer. Selenium also helps the thyroid and supports healthy immune function.
Sustainable, Low Mercury Seafood Choices
- Crab (Domestic)
- Croaker (Atlantic)
- Perch (Ocean)
- Shad (American)
- Sole (Pacific)
- Squid (Calamari)
- Trout (Freshwater)
Avoid bluefin tuna, wild sturgeon, all species of shark, orange roughy, skates and rays, most Chilean sea bass, most Atlantic halibut, and most marlin. If you want specific information about the safety of fish from local lakes, rivers, and coastal areas, check EPA’s handy map.
Take May’s Healthy Challenge and eat more low mercury, sustainable seafood to take advantage of the incredible omega-3 fatty acids and all the other nutrients that are hard to eat enough of in our diet!