Not-so-healthy health food mucks up your body’s defenses

If you take your health seriously, you probably love fish. It’s arguably one of the healthiest foods on the planet and a great source of protein, omega-3 fatty acids and vitamin D.

But for all the wonderful reasons to love fish, there is also one good reason to proceed with caution at your next fish fry…

You’re probably well aware that fish contain environmental pollutants, like mercury (it’s not a huge secret that our oceans aren’t pristine). But a recent study suggests that these pollutants could be impacting your immune system in a dangerous way.

Research conducted by the Scripps Institution of Oceanography at the University of California- San Diego found that environmental pollutants in fish can actually prevent the body’s natural defense system from getting rid of toxins.

“When we eat contaminated fish, we could be reducing the effectiveness of this critical defense system in our bodies,” said Amro Hamdoun, an associate professor at Scripps and lead author of the study.

To gather their data, researchers studied something called P-gp in both mice and humans. P-gp is a protein found in the cells of most plants and animals that removes foreign chemicals from the body.

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Researchers analyzed how effectively P-gp was keeping the body toxin-free by focusing on the persistent organic pollutants (POPs) most commonly found in human blood and urine, as well as in the muscle tissues of wild-caught yellowfin tuna. These pollutants included old-school offenders like DDT and newer troublemakers like flame retardants.

It turns out, all of the pollutants researchers studied interfered with P-gp’s ability to expel harmful toxins from the body.

If you love fish but also love being vibrant and healthy, this is bad news. This means these pollutants are preventing your body’s immune system from doing its job and protecting your cells from potentially deadly diseases… like cancer.

However, there’s still hope out there for fish-lovers. Some fish are safer than others to eat, so selecting your seafood carefully could go a long way toward keeping your POP exposure down.

For example, farmed salmon tends to contain a lot of POPs, while wild-caught Alaskan salmon tends to contain much less. Other safe fish options include farm-raised arctic char, farm-raised rainbow trout and wild-caught pacific sardines. And, if your fish is on the small side, that also means less contaminants (that’s why krill oil is a better choice than fish oil, by the way), so steer clear of those big fat fish filets.

How you eat fish is important too. Exposure to pollutants can actually be reduced by 50 percent just by how you prepare and cook fish. Contaminants tend to collect in the skin and fat, so removing the skin and trimming away the back and belly fat is a wise idea if you want to experience the health benefits of fish without a heaping portion of immune-hampering pollutants. And grilling (be careful not to char!), boiling or baking fish is always a healthier choice then frying (another reason to steer clear of your local fish fry).

Jenny Smiechowski

By Jenny Smiechowski

Jenny Smiechowski is a Chicago-based freelance writer who specializes in health, nutrition and the environment. Her work has appeared in online and print publications like Chicagoland Gardening magazine, Organic Lifestyle Magazine, BetterLife Magazine,, and