When you get to the fish counter, you've got some decisions to make.
A lot has changed since we last talked about farm-raised versus wild-caught fish, so let's check in on the latest research.
Nutrition Diva is hosted by Monica Reinagel. A transcript is available at Simplecast.
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Welcome to the Nutrition Diva podcast. I’m your host Monica Reinagel. As you know, a lot of our episodes are triggered by questions from listeners, including this one. Lindsey recently wrote in to say:
“I was at my local grocer the other day debating wether to buy farm-raised Atlantic or wild-caught salmon. Being a fan, I immediately went to your episode archives and found the answer to my question there, but then noticed the episode was from 2014! I know nutrition science changes a lot and was wondering if there are any updates on the differences between farm raised and wild caught fish.”
One advantage to having 15 years worth of archives is that there aren’t a whole lot of food or nutrition topics that we haven’t talked about. But, Lindsey’s right to wonder whether things have changed in ten years. So, here’s an updated answer to the question of whether to buy farmed or wild-caught fish.
Obviously, there are lots of good reasons to include fish or other seafood in your diet on a regular basis. Eating at least two servings of fish or shellfish per week appears to reduce the risk of heart disease, delay the onset of Alzheimer's and dementia, and (if you're pregnant) make your baby smarter and healthier. It may even offer some protective benefits against depression.
However, as Lindsey discovered, when you get to the fish counter, you've got some decisions to make. In particular: should you buy wild-caught or farm-raised fish? Many assume that wild-caught fish must be a lot better for you because it's more "natural." But is this necessarily the case? And what about environmental issues and sustainability?
Over the past 50 years, the global demand for fish and seafood has quadrupled, driven in part by things like population growth and rising incomes, as well as the perceived health benefits of eating fish and the desire to eat less meat from cows, pigs, and chicken.
All of this increased demand has led, in turn, to massive increases in the harvesting of wild seafood, as well as an explosion in fish farming (or, aquaculture). And there are concerns about the sustainability and environmental impacts of both industries. So what’s a responsible consumer to do? Which is the better (or less bad) option?
Although efforts to promote more sustainable fishing practices and responsible aquaculture have been gaining traction in the decade since my original answer to this question, it’s still impossible to make a blanket recommendation. Choosing between wild-caught and farm-raised fish depends on what kind of fish you're buying, as well as where and how it is fished (or farmed), and other considerations, such as your budget.
But let’s take a look at some of the issues that you might consider, starting with nutrition. The nutritional differences between wild and farmed fish are not as great as you might think. By and large, both farmed and wild-caught versions of the same type of fish will deliver similar nutritional value.
The nutritional composition of wild fish is actually going to be a bit more variable, because it is dependent on their natural surroundings and food sources, which will vary from location to location and season to season.
The nutrient composition of farmed fish will also vary, depending on the feed formulation used and other factors, such as exposure to sunlight. But, unlike wild-caught fish, the nutritional value of the finished product is much more under the producer’s control.
One of the main reasons we recommend eating fish, of course, is that they are a uniquely potent source for long-chain omega-3 fatty acids. And here, farmed fish often have the advantage. Today's farmed Atlantic salmon provide significantly more omega-3 fats than wild-caught Atlantic salmon, for example.
This was not always the case. In the earlier days of aquaculture, farmed salmon was significantly lower in omega-3 than wild fish due to the food they were being fed. But once this was identified as an issue, the industry quickly responded, modifying the diet to enhance omega-3 content of the finished product.
The color of the flesh is not a reliable guide to omega-3 content, by the way. Atlantic salmon (whether fished or farmed) is a pale orange, while Sockeye is dark red. The paler Atlantic salmon provide more omega-3.
In terms of contaminants such as PFAs (aka “forever chemicals”), the biggest danger, ironically, may come from fish that consumers catch themselves, and not commercially caught or raised fish that you’re likely to find in grocery stores.
But, again, it is impossible to generalize. The level of forever chemicals that you might be exposed to depends less on whether the fish is farmed or wild-caught and more on the specific type of fish and where it came from.
The other contaminant that most people worry about with fish is mercury. Again, the amount of mercury depends mostly on the type of fish. The fish that present the biggest concern (swordfish, king mackerel, tilefish, shark, and tuna) are all wild-caught. The most common farm-raised fish (catfish, tilapia, and salmon) all have low or very low mercury levels.
What about antibiotics or hormones? Are fish farmers dumping drugs and other chemicals into the ponds to maximize harvests? Here in the U.S., regulations strictly prohibit the use of hormones or antibiotics in order to promote growth in farmed fish. (This is not necessarily the case in other countries.)
Aside from possible impacts on human health, there are also concerns about the environmental impact and sustainability of the huge increase in fish consumption. However, these are just as likely to apply to wild as to farmed fish. Wild-caught fish are sometimes harvested using practices that do a lot of collateral damage to the ecosystem and other fish. Fish-farming practices, on the other hand, can pollute the water and threaten local flora and fauna. Once again, it depends a lot on who is doing the fishing and/or farming.
Here in the U.S., for example, the National Oceanic and Atmospheric Administration regulates wild-catch fishing, setting and enforcing standards that protect the marine environment and fish populations. Fish farming operations in the U.S. are also strictly regulated. Any water that is discharged into the environment, for example, must be as clean or cleaner than it was when it came in.
Unfortunately, this is not the case everywhere. Farm-raised fish now constitutes 50% of the global food fish supply (and 90% of U.S. consumption), but the U.S. only produces a tiny fraction of that. And what we do produce is often more expensive than farmed fish imported from areas of the world with laxer regulations.
As much as I like to keep things simple for you, I'm afraid there's no easy answer to this one. There are a lot of factors to weigh: nutrition, safety, sustainability, and cost. And the outcome will be different depending on what kind of fish you're talking about and where it comes from.
The best resource I know for keeping it all straight is still the Seafood Watch program at the Monterey Bay Aquarium. You can search their website by type of fish, learn what the issues are, and get recommendations for best choices and better alternatives. They do an amazing job of keeping up with constantly-evolving industry practices and environmental issues all over the world and offer downloadable and digital guides.
One big thing has changed since my original episode. At the time, it was widely believed that farm-raised fish were genetically-modified, but that was an urban legend. Back in 2014, there were no genetically modified fish for sale in the U.S. At least, not as food. You could (and still can) buy genetically modified fish for your tropical fish tank that glow in the dark, thanks to some genes borrowed from iridescent coral.
Earlier this year, however, the FDA approved the first genetically modified salmon for human consumption. The AquAdvantage salmon, related to the Atlantic salmon, has been genetically engineered to grow faster. The FDA has determined that the genetic modifications used cause no harm or damage to the salmon itself, and that the resulting fish is biologically and nutritionally indistinguishable from regular salmon and safe for consumption.
The FDA also assessed the impact of this fish on the environment, including the possibility that the engineered salmon could escape the farm and interact with wild populations, and found this risk to be negligible.
Personally, I don’t have any concern about consuming genetically modified salmon. However, if you do, rest assured that all genetically engineered food products must be labeled as such. So, if you want to avoid AquAdvantage salmon, you can keep an eye out for it.
This is Monica Reinagel, the Nutrition Diva. If you have a nutrition question you'd like me to answer, you can email me at nutrition@quickanddirtytips.com. You can also leave me a message at 443-961-6206.
If your question is more on the subject of habits and behavior change, please check out my other podcast, the Change Academy, where we talk about how to convert our good intentions into sustainable healthy habits. You’ll find it wherever you listen.
Nutrition Diva is a Quick and Dirty Tips podcast and is supported by a fantastic team, which includes our Director of podcasts, Adam Cecil, audio engineer Nathan Semmes, Davina Tomlin runs our marketing and publicity, Holly Hutchings is our Digital Operations Specialist and Morgan Christianson is our Podcast Operations and Advertising Specialist.
Thanks for listening!