While talking about the quality of animal protein sources at a recent nutrition workshop, we were asked an interesting question: “I know grass-fed is better than grain-fed for beef, but aren’t things a little more complicated with fish?” The answer is yes – the issue with choosing high quality fish goes far beyond wild-caught vs. farmed. In fact, we discussed a wide variety of factors that go into making healthy seafood choices in our Conscientious Omnivore – From the Sea post.
Turns out, however, that there are even more considerations when it comes to eating seafood. We recommend eating fish – particularly, cold-water fatty fish – in part because they’re a healthy, real-food source of Omega-3 fatty acids. But some of those fish may come with a penalty – high levels of toxic heavy metals (like mercury) that are decidedly unhealthy.
When choosing fish and shellfish, you are ideally considering three big-picture factors all at once: Seafood that is (a) healthy for you, the environment and the seafood populations, (b) provides a decent amount of Omega-3 fatty acids, and (c) is relatively low in mercury. Whew.
For us conscientious omnivores, this is no easy feat. Many fish meet one or two criteria, but not all three. For example, swordfish is rich in Omega-3 and has several “best choice” and “good alternatives” (per Seafood Watch), but contains the highest levels of mercury. Scallops are extremely low in mercury and are all either a “best choice” or “good alternative”, but you’d need to consume more than a pound to provide just 1 gram of EPA and DHA. Tricky, huh? But please, don’t abandon the idea of eating fish altogether. Today, we’re going to cross-reference a vast number of resources to help you arrive at the best-of-the-best, our “Seafood Trifecta”.
We’ve referenced our Conscientious Omnivore piece, and the Monterey Bay Seafood Watch guide, to help you arrive at “Best Choices” or “Good Alternatives” based on the health of the fish and their wild populations, what’s good for the environment, and what’s best for your health.
We then referenced the National Resources Defense Counsel and the FDA to determine fish and seafood with the lowest levels of mercury. Low levels of mercury are considered anyting testing less than 0.09 ppm (parts per million). Moderate levels are between 0.09 – 0.29 ppm. High levels of mercury test higher than 0.3 ppm.
Finally, we referenced several resources based on American Heart Association estimates and other independent sources detailing the amounts of Omega-3 content in different types of fish. (Note, exact amounts of Omega-3 in each type of fish will vary, and therefore are not detailed here.)
We then cross-referenced all of this information to arrive at our Seafood Trifecta recommendations below.
Whole9’s Seafood Trifecta
Highest levels of Omega-3 of any seafood (amounts will vary by type/portion size)
Lowest levels of mercury (0.022 ppm)
Best Choices and Good Alternatives:
- Salmon (market names: Chum, Keta, King, Pink, Red, Silver, Sockeye, Sake); Alaska; wild-caught
- Salmon (market names: Coho, Chum, Keta, King, Pink, Red, Silver, Sockeye, Sake); California, Oregon, Washington; wild-caught
- Salmon (market names: Coho, Sake, Silver); British Columbia; wild-caught
- Salmon (canned); wild-caught
Tip: Don’t overlook canned salmon! It’s the same great source of Omega-3 and still low in mercury. Buy brands that specify “wild-caught”.
High levels of Omega-3
Lowest levels of mercury (0.013 ppm)
- Pacific Sardines (market names: Iwashi, Pilchard, Sardine) U.S.; wild-caught
Tip: Fish lower on the food chain (like sardines) tend to have low levels of mercury. When mercury is deposited into the water, microorganisms help convert it to methylmercury, a highly toxic form of mercury. Small organisms and plants take up the mercury as they feed. As animals higher up the food chain eat those plants and organisms, they, too, take in methylmercury. The process continues, with levels of mercury increasing up the food chain.
High levels of Omega-3
Lowest levels of mercury (0.050 ppm)
- Atlantic Mackerel (market name: Boston Mackerel, Caballa, Common Mackerel, Saba); U.S., Canada; wild-caught
Tip: The EPA has issued Spanish and King Mackerel consumption advisories for women, men and children due to elevated mercury levels. Choose only the Atlantic version – the EPA says it’s safe to consume up to twice a week.
High levels of Omega-3
Lowest levels of mercury (0.084 ppm)
- Atlantic Herring (market names: Brit, Pilchard, Sardine, Sild, Sperling) U.S. Atlantic; wild-caught
Tip: In Europe and America, herring are often salted and smoked, or pickled. To make your own pickled herring, try this recipe, using coconut flour and your favorite saturated fat for frying.
Moderate levels of Omega-3 (based on serving size)
Lowest levels of mercury (0.017 ppm)
- All populations are curently thought to be healthy, therefore all are considered a “best choice”.
Tip: Most folks aren’t going to eat their weight in anchovies, but including them as a seasoning is a good way to get a little more Omega-3 in your diet. (It all adds up, right?) Anchovies work well to flavor tomato sauces, fish sauces, salad dressings, vegetables, chicken, and lamb. Capers and olives are also particularly good partners with anchovies. To remove some of the salt from anchovies, soak in cold water for 30 minutes, then drain and pat dry before using.
Sole or Flounder
Moderate levels of Omega-3
Lowest levels of mercury (0.056 ppm)
- Flounder (market name: Sole, Sanddab, Hirame); U.S. Pacific; wild-caught
- Summer Flounder (market name: Fluke, Hirame); U.S. Atlantic; wild-caught
- Pacific Sanddabs (market name: Melgrim, Mottled Sanddabs, Soft Flounder); U.S. Pacific; wild-caught
- Sole (market name: Flounder, Sanddab, Sole, Hirame); U.S. Pacific; wild-caught
Tip: Flounder is a lean, flaky fish with a mild sweet taste and firm texture. Being a lean fish, the best way to cook flounder is with wine, sauces and other liquids to help keep them from drying out. Try to avoid sauces or herbs that might overpower the delicate taste of flounder fish.
Tuna (canned, light)
Moderate levels of Omega-3
Moderate levels of mercury (0.128 ppm)
- Tuna, Skipjack – Canned (market name: Light) Worldwide; wild-caught
- Tuna, Tongol – Canned (market name: Light) Worldwide; wild-caught
- Tuna, Yellowfin – Canned (market name: Light) Worldwide; wild-caught
Tip: Only the canned “light” versions of tuna are outside of the high mercury range. Canned albacore is considered high in mercury, and should be consumed in moderation (no more than one can every 7-14 days, according to the FDA). Furthermore, tuna is a bit more complicated than other fish, as several varieties have “good choice” and “avoid” criteria based solely on the catch method. Refer to the Seafood Watch tuna guide for additional details.
The Seafood Summary
We encourage everyone to get your Omega-3 from natural, real food sources as often as possible. And it’s clear from our research that wild-caught Alaskan salmon is as close to a perfect seafood as you can get – high in Omega-3, low in mercury and with a number of “best choice” and “good alternatives”. We encourage everyone to eat more salmon while it’s fresh and in season, freeze some for winter, and consider wild-caught canned salmon as a good alternative.
For those of us who don’t get enough Omega-3 rich foods in our everyday diets, supplementing with a high quality fish oil (rich in Omega-3 fatty acids EPA and DHA) might be a good idea. Refer to our Fish Oil Calculator and Fish Oil FAQ for details.
Finally, accept the fact that it’s simply not possible to get the full C.V. of every fish you eat. Buying canned light tuna in the grocery store means you probably won’t ever know how the fish was caught, and whether that does, in fact, make it a good choice. So just do the best you can with the resources you have on hand – because that’s all we can ask of ourselves.
Questions, comments or delicious herring recipes? Share them in comments.
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