Fish is Healthy but Here’s Why You Might Not Want to Order It at a Restaurant

Fish is Healthy but Here’s Why You Might Not Want to Order It at a Restaurant

(Last Updated On: April 13, 2019)

image of an appetizer with rare fried tuna and salmon on restaurant table

Fish enjoys somewhat of a health halo, thanks to the high omega-3 content of fish, particularly fatty fish, like salmon. So, you might feel a bit virtuous when you choose the fish entrée at a restaurant over a pasta dish or a steak. Yet that seafood entrée may not be as healthy as you think. Here’s why you should think twice before ordering fish at a restaurant or eating sushi at a sushi bar.

The Problem of Fish Fraud

Is fish you get at restaurants not what it seems? According to a study published by the environmental group Oceana, 33% of fish served in a sampling of restaurants is mislabeled, based on DNA testing. The researchers made this discovery after surveying almost 700 restaurants nationwide in twelve states. What does this mean? You might think you’re eating Chilean sea bass but may actually be munching on Antarctic toothfish. Yes, such a fish really exists! The most commonly mislabeled fish types were tuna and snapper – and it’s not just restaurants that are mislabeling fish but grocery stores and sushi bars as well.

Another issue is where the fish you’re ordering comes from. Think that it was caught locally from pristine bodies of water? Not likely. Nine out of ten fish available for purchase comes from foreign areas that often have less stringent safety standards. Why is this a problem? Mislabeled fish has potential health implications. Some fish, especially large species, accumulate high levels of mercury over a lifetime as well as other toxins that are harmful to health.

Why Mercury is a Problem

The type of mercury you get from seafood is called organic mercury to distinguish it from inorganic mercury, the type people are exposed to through industry. When you consume organic mercury in food, bacteria in your gut add a methyl group to mercury and the resulting methylmercury builds up in your body and affects the functioning of the immune system, lungs, kidneys, digestive tract, or nervous system.

Mercury exposure is particularly problematic for women who are pregnant. Health care professionals advise women who are pregnant not to consume fish high in mercury while pregnant and we should all avoid eating fish high in mercury more than one or two times per month. You might think you’re eating a fish low in mercury based on how it’s labeled and actually be eating another type of fish that’s higher in mercury and toxins.

Fish that are larger in size and higher in the food chain, like tuna, king mackerel, shark, tilefish, swordfish, usually contain higher levels of mercury than smaller fish, like sardines, shrimp, and anchovies. Wild-caught salmon, pollock, and catfish are other lower-mercury options.

Farm-Raised vs. Wild-Caught Fish

Another factor that determines the levels of toxin, like mercury, in seafood is whether fish is wild caught or raised on a farm. Farmed fish may contain higher levels of toxins, although they may also contain more omega-3s as they tend to be fattier. However, some farms feed fish actual fish oil while others use lower quality vegetable oil. The former fish, as you would expect, contain higher levels of omega-3s.

How can you avoid the all too pervasive problem of fish fraud? Know what questions to ask. Inquire as to where it came from and whether the fish you order at a restaurant or buy from a supermarket was wild or farm raised. If the price sounds too low, be suspicious. It may be priced low because it’s a cheaper form of fish. According to Larry Olmsted, author of Real Food, Fake Food, certain types of fish are almost always mislabeled. One example is red snapper.

If you’re trying to get more long-chain omega-3s in your diet, fish is the best source. So, fish that’s not contaminated with toxins or heavy metals has health benefits – but can you feel safe eating it? Groups are pushing for greater transparency for the benefit of the consumer. The hope is to set up a system that traces the fish from where it’s caught to the supermarket to ensure proper labeling. The European Union took such an approach and seafood fraud dropped by 14%. Until then, be alert for anything “fishy” when shopping for seafood or ordering it at a restaurant. Even better, don’t order seafood when you go out unless you’re familiar with the restaurant. The odds of mislabeling are simply too high.

Until then, consider taking a fish oil or long-chain omega-3 supplement. Fish oil, particularly pharmaceutical grade, doesn’t typically contain significant amounts of mercury or other toxins. Also, beware if you’re a fan of sushi. A parasite-related illness called anisakiasis that comes from eating raw fish contaminated with parasites is on the rise. Cooking fish to a temperature internally of at least 145 degrees F. kills that parasite, as does freezing for a minimum of three days.

The Bottom Line

Fish, theoretically, is a healthy option, high in protein and healthy fats, but they also harbor environmental chemicals and heavy metals. These unwanted toxins come from the increasingly polluted waterways that that seafood is harvested from. Fish can also carry other nasty surprises, such as parasites.

Yet, eating fish has perks that are almost too good to pass up. Some studies show that a diet higher in fish or fish oil is linked with a lower risk of sudden cardiac death. Plus, omega-3s have an anti-inflammatory effect and may modestly reduce blood pressure and the risk of developing a blood clot.  So, do a little snooping and ask lots of questions before biting into your next piece of fish, especially when ordering it from a restaurant. If you’re not sure about its origin, consider fish oil supplements after approval from your physician.


References: “Oceana Study Reveals Seafood Fraud Nationwide” “Seafood Fraud Is Literally Everywhere”
Scientific Reports 6, Article number: 21892 (2016)
World Health Organization. “Mercury and Health” “Parasites Could Be Lurking in Your Sushi”
WebMD. “Avoiding Mercury in Fish – Topic Overview”


Related Articles:

Seafood is High in Protein but Is It Safe to Eat?

2 thoughts on “Fish is Healthy but Here’s Why You Might Not Want to Order It at a Restaurant

  1. I think there is a typo.
    “The former fish, as you would expect, contain higher levels of omega-3s.”

    I believe should say “omega-6s”

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