Setting the Record Straight on Farmed Fish

fish market

Both tilapia (the fastest growing and most widely farmed fish on the planet) and catfish have low concentrations of omega-3 fatty acids and very high ratios of omega-6 to omega-3 fatty acids. In particular, tilapia and catfish contained much higher levels of the pro-inflammatory omega-6, AA, than the anti-inflammatory omega-3, EPA. This was and still is very concerning to me because these fish are so inexpensive and those who were eating fish for their heart health and couldn’t afford more expensive wild fish were settling for a fish that had an undesirable fatty acid profile.

Let me be clear here: Some farmed fish are very rich in beneficial long-chain omega-3 fatty acids, so I’m not in any way against farmed fish. Some have lower omega-3 content, but still plenty to be a significant health advantage. And others have an unhealthy omega profile. How can this be?

Because growing healthy fish, with all the benefits we need from those omega-3s, hinges on understanding the science of omega-3s and where they come from. So let me tell you what we know now about farmed vs. wild fish that may change your mind on the matter.

Should we farm fish?

We must. Our population is forecast to exceed nine billion by 2050, and up to 80 percent of the planet’s wild fishery is already severely overfished and struggling to survive.

Additionally, half of all fish consumed in 2011 were farmed, yet the wild fishery has continued to deteriorate. Why?

Well, one of the most popular fish in the US is salmon, whose main natural diet is smaller “feeder” fish. For decades, fish farmers have fed their salmon fish meal and fish oil from enormous catches of feeder fish. That omega-3-rich diet is why salmon has the omega-3-rich profile we need in our diet.

Fish farming has grown every year since 1970, so the oceans’ feeder fish (which are eaten by other wild fish, too) are also severely overfished. We’re killing small fish to grow big fish, and accelerating the demise of both.

Farmers inadvertently added another problem: the demise of the quality of farmed fish. To reduce costs, they started diluting (sometimes completely replacing) expensive fish oil with comparatively cheap soybean and corn oils. The fish grew okay, but their omega-3 levels plunged by an average 30 to 50 percent, while their pro-inflammatory omega-6 levels went up. The average omega-3-to-omega-6 ratio in farmed fish went from greater than 5-to-1 in 2002 (which is terrific) to 1-to-1 in 2013 (decent, but not great).

Are any farmed fish good to buy?

Yes, but we must choose wisely.

All fish are a fine source of protein, but not all are good sources of long-chain omega-3 fatty acids. For that, we need oily, cold-water species such as salmon or mackerel.

If you’re a fan of tilapia or catfish, you probably prefer a lighter, more delicate texture that doesn’t taste “fishy.” That’s fine, but those fish are not going to give you significant levels of long-chain omega-3s. I always tell audiences in my talks that, “if your fish looks like chicken, smells like chicken and taste like chicken, then it’s nutrient content is more like chicken than fish.”

To further muddy the waters, non-oily, warm-water fish often are raised in ponds, fed by dumping manure from grain-fed land animals into the water, where an algal biofilm known as periphyton helps the fish convert the waste into fish food. It’s ingenious, but the lipid profile is not good.

We also have to consider safety issues. The US, which ranks 13th in farmed-seafood production, is among the countries that impose strict regulations on fish farms to protect the environment and the health value and safety of the fish. However, the world’s top three farmed-seafood producers (and big exporters to the US) are China, India, and Vietnam.

Of the 10 species of seafood considered omega-3-rich and safe by the USDA, only two are significantly farmed here at home:

  • Atlantic salmon (farmed in Maine and Washington; also imported from Canada, Chile, and Europe)
  • Pacific oysters (farmed in Washington)

The rest from that list—anchovies, Atlantic and Pacific cod, lingcod, sablefish, herring, Pacific mackerel, and sardines—are wild caught.

How do we know if farmed seafood is safe and a good source of omega-3s?

  1. Make sure it’s an oily, cold-water fish such as salmon or trout, or Pacific oysters.
  2. Check the source country. If it’s not clearly marked, ask the store’s seafood manager. Seafood farmed in the US or Canada is what I’m personally most comfortable with. I’m a dedicated consumer of US-raised Atlantic salmon, which I eat at least every other day, because it’s good for me and for our country’s economy. Seafood imported from other countries is tested for general safety before it’s allowed in, but it’s not routinely tested for omega-3 levels. Fish fed cheap vegetable oils can look terrific, but still be very low in omega-3s.

A Sea Change on the Horizon?

A few biochemistry labs are working with special seed oils that have high levels of advanced omega-3 fatty acids, to feed farmed fish. One such seed oil is from an invasive weed called Echium, which contains stearidonic acid—an omega-3 that’s special because it‘s more easily converted into the desired long-chain omega-3s (DHA and EPA). I love the idea of using an invasive weed for good, rather than killing it with herbicides.

In a recent study, Atlantic salmon were fed a diet with 100 percent fish oil, 100 percent echium oil, 100 percent canola oil, or a 50-50 mixture of echium and canola. All four diets resulted in big, healthy-looking fish, but the 100 percent echium oil group had the same high DHA and EPA profile as the 100 percent fish oil group, at a ratio of about 4 omega-3s to 1 omega-6. This is an avenue of research that could give us a land-based way to feed farmed fish that won’t ruin their omega-3 fatty acid profile, or ours. Good for the fish, us, the oceans, and our country.

The bottom line is that we all must work together to make fish farming work so that we can feed this planet, and so that our health and that of our ecosystem can be strong and resilient again. While we wait for science to provide the industry with better options, we still have the ability to choose farmed fish that’s trustworthy for our table.

About Author

Brian Matthews

Brian Matthews is the President of Gene Smart and the leader of our Gene Smart team. His mission is to provide supplements to help you control your inflammation, your weight, and your life, based on the latest scientific information.


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