What are you really eating?

Yesterday’s conversation about toxic sunscreen got me thinking about just how easily a few chemicals can turn something good into something bad.

In fact, these days, we can’t even trust kale to be healthy. This disease-fighting crucifer has managed to become a hazard to your health, thanks to industrial pesticides and weed killers.

And it’s not just fruits and vegetables that have suffered the effects of our increasingly toxic world. Really, the entire food supply is compromised… which is why it’s so important to do your homework before you shop.

Because as a new study on fish shows, you may not be getting the disease prevention that you’re paying for. In fact, you could be doing your body actual harm.

Pollutants steal fish’s superpowers

First, a little context: The effects of fish consumption on diabetes risk are still inconclusive. (At least, according to published research. The case is closed as far as I’m concerned… but I’ll get back to that in a moment.)

Some studies show that eating a lot of fatty fish is protective, and lowers the risk of type-2 diabetes—as you would expect. Meanwhile, others have shown a neutral effect, or suggest that it actually raises risk.

This has, of course, resulted in a great deal of unnecessary handwringing where dietary recommendations are concerned. But luckily, a team of Swedish researchers used some common sense and did what any reasonable scientists would do: They looked for an explanation behind these inconsistent results.

Specifically, they designed a study that would separate the effects of fatty fish on diabetes from the effects of the range of pollutants you might encounter in those fish. (And frankly, why no one has bothered to do this before is a complete mystery to me.)

Nearly 500 people who went on to develop type-2 diabetes participated in this study—compared with an equal number of healthy controls. Subjects reported on their fish intake and other lifestyle factors. But they also provided blood samples—two of them, ten years apart—which researchers analyzed for biomarkers to verify levels of fish consumption.

They also measured for a variety of environmental toxins—including persistent organic pollutants (POPs), dioxins, dichlorodiphenyltrichloroethane (DDT), and polychlorinated biphenyl (PCB). All of which are commonly found in farm-raised fish in particular (but also in fatty fish, like herring or salmon, that are caught in polluted waters). All of which raise type 2 diabetes risk.

And here’s what researchers found: Fish consumption on the whole has a neutral effect on diabetes. But when they screened out environmental pollutants, they found a very clear protective effect against the disease.

In other words, the toxins present in your fatty fish completely erase its benefits. But a clean, fresh catch is still a bona fide superfood.

Do your homework

If this isn’t proof that the quality of the food you eat matters, I don’t know what is. This is exactly why I continue to emphasize the importance of buying organic, free-range, humanely-raised animal products.

It’s been a while since I covered the basics of fish selection specifically, though. So let’s dive right in…

For starters, opting for wild-caught fish rather than farmed is key. I’ve personally witnessed fish farms where the fish are kept in putrid-looking water and given food that contains who knows how many toxins.

But avoiding larger fish like bluefish, king mackerel, grouper, sea bass, shark, swordfish, marlin, orange roughy, and tilefish—which contain high levels of mercury—is essential, too. Albacore, yellowfin, and ahi tuna can also be loaded with mercury. (Canned, light chunk tuna is considered OK if you limit your consumption to six or fewer servings per month.)

Seafood with the least mercury includes:

  • Anchovies
  • Crab
  • Crawfish
  • Flounder
  • Hake
  • Oysters
  • Perch
  • Salmon
  • Sardines
  • Scallops
  • Shrimp
  • Sole
  • Squid
  • Tilapia
  • Trout
  • Whitefish

I also recommend eating the freshest fish you can find. If you’re buying fish at a market or a store, there are a few guidelines you can use to help you purchase the freshest catch:

  • Buy fish whole. Check to make sure the eyes are clear and not cloudy, and that the gills are bright. If you don’t want to go to the bother of cooking a whole fish, ask the folks behind the counter to filet it for you.
  • The fish or filets should be firm to the touch and have an iridescent sheen.
  • Ask to smell the fish. If it has a “fishy” smell, that’s a clue it’s not fresh.

Ultimately, a little due diligence will ensure that you’re getting the most nutrition possible out of your fish… and none of the bad stuff. For an up-to-date list of the best seafood choices, you can’t go wrong by checking in frequently with Monterey Bay Aquarium’s Seafood Watch.


“Fatty fish without environmental pollutants protect against type 2 diabetes.” Science Daily, 06/19/2019. (sciencedaily.com/releases/2019/06/190619111245.htm)