The Truth About the Seafood You Love

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Frozen seafood in fornt of restaurant - close up view ** Note: Soft Focus at 100%, best at smaller sizes

Omega-3 fatty acids are good for you, but contaminants aren’t.
Which seafood types are safest?

Those healthy omega-3 fatty acids can potentially help you reduce your risk of heart disease, stroke, cancer, and Alzheimer’s disease. They may also help improve cognitive development in infants and young children.

But then there are the contaminants. Mercury, PCBs, dioxins, and antibiotic residues can cause developmental problems, nerve problems, and antibiotic resistance, and have been linked to cancer and immune effects.

Considering we may be exposed to both healthy nutrients and unhealthy contaminants, how are we to choose which fish to eat?

Two General Recommendations

We can start by following two general recommendations:

  • Choose American seafood.
  • a variety of seafood types.

Why American? Recent studies have reported the following:

  • American seafood is generally well-managed.
  • Other countries may have different standards, sometimes employing drugs in raising fish that are banned in the U.S.
  • Most overseas fish farms are not inspected by U.S. officials.
  • Tests on foreign seafood have been disturbing, showing high percentages of toxic drugs, while tests on U.S. seafood show it to be free of these contaminants.
  • Other tests have shown that many of China’s fish farms are situated in areas where water, air, and soil are contaminated by industrial contaminants and vehicle exhaust.
  • Seafood that is often farmed in other countries—namely shrimp, crab, basa, eel, and tilapia—most often exceed drug residue limits.

Why a variety? The most popular seafoods in America are tuna, shrimp, and salmon. Tuna is a common source of mercury. Shrimp is overfarmed in Asian countries, and is linked with human rights abuses. Salmon, though healthy from wild sources, has been linked to contaminants and overuse of resources as a farmed fish.

Eating a variety of seafood helps support a well-rounded fish population, while exposing us to reduced levels of contaminants. Choosing oysters, mussels, clams, and the like supports healthy aquaculture, and provides healthy omega-3 fatty acids to your diet.

1. Tilapia

One of the most popular types of seafood in the U.S., tilapia mostly comes from China and some other Asian countries, though we do raise some here. It is a source of omega-3 fatty acids (though not as high as some other fatty fish), and is low in mercury.

There are some questions about farmed tilapia, though. A 2008 study found it contained large amounts of “arachidonic acid,” an omega-6 fatty acid that, when consumed often, may increase risk of chronic inflammation. This is likely only in people who consume a lot of omega-6 fatty acids, though, which often occurs on the standard western diet.

Best choice: Tilapia in moderation is good for you. It contains as much omega-3 as mahi-mahi and lobster, and it’s low in fat. Don’t eat it every day, but feel free to enjoy it once a week or so, as you wish. Studies have shown that Chinese aquaculture often uses animal feces as fish food. Check the label to see where your fish comes from, and choose American or Canadian.

2. Salmon

Salmon is considered one of the healthiest types of fish we can eat. It is a great source of omega-3 fatty acids, proteins, and amino acids, and gives us a good dose of vitamin B, vitamin D, selenium, phosphorus, and other nutrients. It’s also low in mercury.

The major concerns with salmon are the potential contaminants. So far, studies have shown that wild-caught salmon has fewer than farmed salmon. A 2004 analysis of about 500 samples of farmed salmon from five countries found that most were polluted with PCBs (polychlorinated biphenyls, man-made chemicals now banned in the U.S.) and dioxins. Levels were high enough that experts advised people to eat farmed salmon no more than once a month.

Since the news broke about this test, the industry has been working to clean up farmed salmon. So far, we don’t know how well they’re doing. We have only one Norwegian study showing that levels of these contaminants fell by half from 2004 to 2011.

Best choice: For now, wild-caught salmon is best. A good alternative may be farmed salmon from the U.S., Canada, or Chile, which all tested lowest for contaminants in the 2004 study. For the lowest risk, choose Alaskan wild-caught.

3. Shrimp

What’s the most popular seafood in the U.S.? Shrimp. By far. It’s low in mercury, has modest levels of omega-3 fatty acids, and is a good source of vitamin D, vitamin B3, zinc, protein, and healthy carotenoids. It’s also a great source of selenium, which has shown in studies to help reduce risk of cancer.

The concern is that most of our shrimp comes from overseas. Farmed shrimp from Asia and Ecuador have been shown in tests to contain traces of antibiotics that are banned from food in the U.S. Farmed shrimp from other countries, like China, India, and Mexico, are on the FDA’s watch list for illegal drug residues.

Other studies have found that imported frozen shrimp is often contaminated with bacteria like salmonella, MRSA, and E. coli. (Wild-caught shrimp from the U.S. and Argentina had the lowest levels.)

Best choice: Wild-caught shrimp or U.S. farmed shrimp. Look for farmed shrimp labeled Naturland, Aquaculture Stewardship Council, or Whole Foods Market Responsibly Farmed.

4. Tuna

Poor tuna. It always gets a bad rap because of the mercury contamination concerns.

Tuna is actually really good for you. It contains a unique form of selenium that is not only a good source of the nutrient for us, but has also been found in studies to bind with mercury compounds, potentially lowering our risk for mercury-related health problems.

Studies have also found that tuna can impart unique health benefits onto the human body. Those who ate canned tuna and oily fish like salmon more than twice a week had a reduced risk of atrial fibrillation.

Tuna is also a great source of omega-3 fatty acids, vitamin B, protein, and phosphorus.

But of course, there is the mercury. Recent research from the University of Michigan found that mercury levels in yellowfin tuna (also called ahi tuna) caught in the Pacific Ocean have increased nearly four percent every year since 1998.

This, apparently as a result of the mercury levels in the upper levels of the ocean having risen threefold since the industrial revolution.

Canned tuna, as well, is known to be contaminated with mercury. Albacore averages 40 mcg per four ounces, while canned light averages 13 mcg per four ounces. The FDA states that up to 7 micrograms per 22 pounds of (your) weight is safe per week. That’s about 50 mcg per week for a 150-pound person.

Best choice: Keep the tuna food chain in mind: bigger fish contain more mercury. Tuna highest in mercury include bluefin, ahi, and bigeye. Choose U.S. or British Columbia albacore, which is usually caught when it’s younger before mercury levels have had time to accumulate. (It’s also typically caught with more ocean-friendly methods like pole & line and trolling.) Look for those from Heritage Foods USA, Pacific Fleet, Wild Planet, MaryLu Seafoods, and Wild Pacific Seafood.

Note: “Chunk-light” tuna is actually a blend of different species and often includes meat from high-mercury bigeye tuna. Many also contain “skipjack,” a widely fished tuna species that’s caught with controversial methods that trap other fish as well, including sharks, rays, and sea turtles. Look for brands caught without using “Fish-Aggregation Devices (FADs),” which result in large amounts of bycatch.

5. Trout

This is one fish that can be safely bought farmed. It’s a great source of omega-3 fatty acids, high in protein, low in fat, and supplies your body with vitamin B (nearly a full day’s allowance), phosphorus and selenium.

The other good news—studies have found that farmed trout is low in mercury and PCBs—so low that health experts have named it safe for children and pregnant women to consume twice a week. Farmed trout is also considered ecologically responsible. Inland tanks and ponds eliminate the danger of farmed species mingling with wild ones.

Today’s farmed trout is considered even safer than wild trout, which has been over-fished and has tested high in PCBs in some areas.

Best choice: Rainbow trout farmed in the U.S. Removing the skin from wild trout can help reduce exposure to contaminants.

How do you make safe seafood choices? Please share any tips you have with our readers.

* * *

“Could your seafood contain toxic chemicals?” Today, 2013,

Paul Greenberg, “Three Simple Rules for Eating Seafood,” New York Times, June 13, 2015,

“The truth about tilapia,” Fox News, April 9, 2014,

“Fish for the Best,” Nutrition Action, April 2015.

Jeffery A. Foran, et al., “Risk-Based Consumption Advice for Farmed Atlantic and Wild Pacific Salmon Contaminated with Dioxins and Dioxin-Like Compounds,” Environmental Health Perspect. May 2005; 113(5):552-556,

Gina Kolata, “Farmed Salmon Have More Contaminants than Wild Ones, Study Finds,” New York Times, January 9, 2004,

Cathy Siegner, “Consumer Reports: Tests Find 60 Percent of Frozen Shrimp Contaminated with Bacteria,” Food Safety News, April 24, 2015,

“Tuna,” WH Foods,

Paul E. Drevnick, et al., “Increase in mercury in Pacific yellowfin tuna,” Environmental Toxicology and Chemistry, April 2015; 34(4):931-934,

Carl H. Lamborg, et al., “A global ocean inventory of anthropogenic mercury based on water column measurements,” Nature, August 7, 2014; 512:65-68,

Zhang X, et al., “Effects of skin removal on contaminant levels in salmon and trout filets,” Sci Total Environ, January 15, 2013; 443: 218-25,

Colleen M. Story

Colleen M. Story

Colleen M. Story, a northwest-based writer, editor, and ghostwriter, has been creating non-fiction materials for individuals, corporations, and commercial magazines for over 17 years. She specializes in the health and wellness field, where she writes and ghostwrites books, e-books, blogs, magazine articles, and more.

Colleen is the founder of Writing and Wellness. Her fantasy novel, “Rise of the Sidenah,” was released with Jupiter Gardens Press in September 2015. Her literary novel, “Loreena’s Gift,” is forthcoming in spring 2016 from Dzanc Books. She lives in Idaho.

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