Omega-3s, mercury, overfishing, oh my! There are so many factors to consider when choosing which seafood you should eat. We’ve done the research for you and narrowed it down to the best and worst seafood to eat!

What is bad about eating fish?

We have all heard that fish is healthy– it is a great source of quality protein and anti-inflammatory omega-3 fatty acids. However, not all fish are nutritionally equal. Some fish are less healthy because they have high concentrations of toxins accumulated from polluted waters or unsanitary fish farms. Plus, if you are concerned about the environmental impact of your food, many fishing practices are damaging to the environment.

Which pollutants do you need to be wary of in fish?

Pollutants mostly come as runoff from agriculture and manufacturing plants. Fish living in polluted water absorb it through their gills and in their food. Larger fish tend to have higher concentrations of toxins than smaller fish because they live longer, storing more toxins in their bodies as they grow.

♦ Mercury

Mercury poisons the kidneys and nervous system and can interfere with brain development, so pregnant women (or those trying to conceive) and children need to be especially careful. The NRDC writes:

“Eating contaminated fish is the number one cause of mercury exposure in America. Mercury is spewed into the air from coal-burning power plants and factories. That pollution can travel halfway around the world and then settle into lakes, rivers, and oceans, where it is absorbed or ingested by small organisms and then starts working its way up the food chain, its concentration rising with each step. Big predatory fish, like sharks or tuna, can have especially high concentrations in their bodies.”

Mercury can build up in the body over long periods of time, and eventually can cause symptoms like:

skin rashes
mood swings
memory loss
muscle weakness
mental disturbances
and more

♦ Polychlorinated biphenyls (PCBs)

PCBs were used as coolants and lubricants in electrical manufacturing. While the manufacturing of PCBs was stopped in the United States in 1977, PCBs do not break down easily, so they built up in bodies of water. The majority of people’s exposure to PCBs comes from food, especially from bottom-feeding fish and fish at the top of the food chain. Fish from the Great Lakes and Mississippi River are some of the places likely to have fish that contain PCBs. You should also research other water sources, especially if going fishing yourself, to see if there are any advisories about water contamination. The U.S. Environmental Protection Agency tests water, monitors fish contamination, and releases advisories; the EPA website is a good place to begin your research about specific fish and bodies of water.

♦ Industrial and agricultural pollutants (POPs)

A new study from the April 15, 2016 issue of Science Advances show that persistent organic pollutants (POPs) accumulate in fish and can interfere with P-gp, a protein that plays a role in cell detoxification. “[P-gp,] A protein found in cells of nearly all plants and animals… acts as the cell’s bouncer by expelling foreign chemicals from the body.” P-gp typically helps move toxic substances out of the cell, but all of the POPs tested in this study interfered with the protein’s cell protection mechanism. “The POP binds to the protein in a similar way as chemotherapeutics and other drugs [which are usually cleared from the cell thanks in part to P-gp], but instead of being transported out of the cell, the bound POP ultimately inhibits the protein’s ability to perform its defense function.” Learn more about POPs, their widespread effects, and the measures being taken to monitor and reduce their global presence at the EPA website.

Which are the best fish to eat?

The best fish to eat will depend on your main concern in regards to fish– Do you prioritize environmental impact? Freshness? Purity (fewest pollutants)?

Of course, ideally we’d only eat fish that meet all of those criteria. In writing our list of the best fish, we took all of these qualities into consideration, so the fish recommended here are both low in toxicity and environmentally friendly. Fresh fish is not always accessible, especially if you do not live near a clean natural water source, so sometimes the fish that is best for your body and the planet may only be available frozen or canned.

Here are the 4 healthiest fish (which are also some of the most environmentally friendly fish):

♦Herring (Atlantic and Pacific)

Herring are smaller fish (though not as small as anchovies or sardines), which means fewer contaminants stored in their fat. They are low in mercury, high in omega-3s, and are “OK” in terms of environmental impact (according to the Environmental Defense Fund).

♦Wild Alaskan Salmon

The Alaskan salmon fishery is extremely well-managed. The environmental impact of their fishing practices is minimal and 5 of the salmon species fished in Alaska have been certified by the MSC as sustainable. Wild caught salmon is also low in toxins, high in healthy omega-3 fats, and delicious! It is an excellent choice for a fish to consume frequently.

♦Sardines (Pacific, U.S. and Canada)

Sardines are low in mercury, high in omega-3s, and a sustainable food source; they are one of the best choices for seafood. Pacific sardines from from marine fisheries, not fish farms, and are caught with purse seines, hook-and-lines, and trawls. They are also small fish (which means less toxins stored in their fat) with quick reproductive cycles, so they are resilient even when fished relatively heavily.

♦Farmed Trout

U.S.A. Farmed Rainbow Trout is a relatively sustainable and safe fish to consume. The EDF gives it a “Best” in the Eco-rating and says it’s low in mercury. Plus, for us Southerners, trout can be a local selection!

Which fish should I avoid?

Chilean Sea Bass
Conch (wild)
Crab (Russia)
King Mackerel
Mahi Mahi (Costa Rica, Guatemala, Peru)
Octopus: Common (Portugal and Spain trawl, Mexico)
Orange Roughy
Pompano (imported)
Farmed Atlantic Salmon
- PCBs in farmed salmon
- Wild-caught salmon have a better omega-3 to omega-6 fatty acid ratio and fewer contaminants than farmed salmon
- Salmon farming can be detrimental to the environment — but luckily, some groups are working to make it a more responsible, sustainable practice
- When it comes down to it, farmed salmon is still a relatively healthy food. If the choice is between eating farmed salmon and never eating fish at all, still choose to eat farmed salmon occasionally.
Shark
Squid (China, India, & Thailand)
Swordfish (imported longline)
Tilefish
Tuna (imported Albacore, Bluefin, Yellowfin)
- Tuna has moderate to high levels of mercury
- Some tuna is better than others for your body and the environment. If you are going to have tuna, make sure you look over the EDF’s ratings for tuna caught in different places and with different fishing methods. For example, if they are caught with pole-and-line fishing, albacore tuna from the U.S. and Canada, yellowfin from the U.S. Atlantic, and yellowfin from the western central Pacific are environmentally friendly choices.

Other Seafood Considerations:

There are plenty of seafood choices that are somewhere in the middle on the health and sustainability fronts. The best thing you can do is be your own food detective. Research the issues surrounding the food you eat, pay attention to where it comes from, and ask questions at the fish counter. The following resources are very helpful!

Photo by Elapied

Sources:

http://www.seafoodwatch.org/-/m/sfw/pdf/guides/mba-seafoodwatch-southeast-guide.pdf?la=en

http://www.huffingtonpost.com/eatingwell/healthy-fish_b_1387875.html

http://health.usnews.com/health-news/diet-fitness/slideshows/best-fish

http://seafood.edf.org/common-questions-about-contaminants-seafood

https://www.nrdc.org/stories/mercury-guide

http://advances.sciencemag.org/content/2/4/e1600001.full

https://scripps.ucsd.edu/news/pollutants-fish-inhibit-humans-natural-defense-system