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How much fish is safe to eat?

September 8, 2017 (Updated: August 3, 2021)
Lily Moran

Not long ago, our waters were filled with healthy, nutrition-rich fish—an amazing source of vital omega-3 fatty acids. But today, though our waters are still filled with fish, they’re also filled with toxins—and so, in turn, nearly every fish contains toxins as well. Sadly, it’s time to ban eating some fish, to limit consumption of others, and to protect yourself against this unhealthy mess.

The Environmental Protection Agency (EPA) recently reported on its study of more than 25,000 water samples, taken from nearly 2,000 U.S. waterways.

The bottom line?


More than half—55 percent—of the nation’s rivers and streams were rated “poor,” and so contaminated by mercury, unhealthy bacteria, and other toxins that they couldn’t “support healthy populations of aquatic life.”

Highlights—or should I say “lowlights”—of the study:

  • In some 13,000 miles of rivers, the native fish had unhealthy amounts of mercury
  • The Northeast and deep South took top “dishonors” as the worst regions, with an appalling 71 percent of rivers rated “poor”
  • In some areas, bacterial pollution “exceeds thresholds protective of human health”
  • All up, just 21 percent of rivers were rated “healthy communities.”

So much for a lazy, riverside afternoon catching tonight’s dinner. You might catch tomorrow’s diseases instead.

Why are there fish you can’t eat?

We have only one food chain. Everything that happens there affects everything else. One flawed link in the chain and down it all goes. A food-chain reaction.

Here’s a perfect example.

A major cause of this tragedy is phosphorus and nitrogen pollution that comes from fertilizer and wastewater run-off. These find their way from farms and plants into the local water system, where they contaminate the water and the fish. The waters empty finally into the sea. More pollution and contamination.

How ironic—producing more food on land produces poor food in the water.

What are the risks of eating fish?

The main and most worrisome pollutant is mercury, a byproduct of incinerators, chemical producers, and coal plants. It’s spewed up into the air, gets wind-blown in all directions, and eventually settles on land, waterways, and oceans—where it’s ingested by fish. Make no mistake, there is no such thing as healthy levels of mercury. Even trace amount can do tremendous harm.

There’s also seaborne radiation from the Fukushima meltdown, reported to have landed on U.S. and Canadian coasts in June 2013. Some say it’s harmless, some say it’s doomsday.

When I see recent reports of unprecedented die-off of marine creatures on the California coast, I tend to doubt the experts who tell us not to worry.

But the presence of mercury and other contaminants is only part of the problem. What makes them deadly is how they behave in your body.

Mercury’s partners in crime

There’s a class of pollutants called persistent organic pollutants (POPs), which includes insecticides, pesticides, fungicides, coolants, and flame retardants.

Persistence is their power. Unlike other toxins, they don’t enter the body, do their damage, and get chased out by the immune system and liver. They land in your body tissues—and stay there.

The problem is that, in a process called biomagnification, the toxins accumulate.

Here’s how it works to eventually give us big fish—that pose big threats.

You see, toxins work their way up from the bottom of the food chain. Even the tiniest microorganisms contain them. The smallest fish feed on them, and then they, too, carry a growing store of toxins, which bigger fish take on as they eat smaller fish. The bigger and older the fish, the bigger the toxin load—which increases our own toxin load with every bite.

What’s so bad about mercury and other POP toxins?

If you had to invent the most evil toxin, the one that would disrupt the most essential interactions in your body, you’d invent mercury.

There are good reasons why The World Health Organisation (WHO) calls mercury “One of the top ten chemicals or groups of chemicals of major public health concern.”

Some of those reasons are, and I quote the WHO report:

  • “Exposure to mercury—even small amounts—may cause serious health problems, and is a threat to the development of the child in utero and early in life.”
  • “Mercury may have toxic effects on the nervous, digestive and immune systems, and on lungs, kidneys, skin and eyes.”

I’ll add only that mercury is among the top contenders as contributing to the incidence of Alzheimer’s. You don’t want it anywhere near you.

To one degree or another, all POPs are linked to life-threatening outcomes. But from here to the end, I’ll confine remarks to just mercury, which:

  • Makes new strains of bacteria that can become antibiotic-resistant, aka “superbugs”
  • Impedes repair of damaged DNA
  • Kills the good bacteria in our digestive system, so we can’t absorb essential nutrients
  • Disrupts our cells’ ability to allow or prevent certain materials through our cell membranes
  • Deactivates vital minerals, including zinc, magnesium, calcium, and chromium
  • Disrupts enzymal activity necessary for every function in your body
  • Blocks neurotransmitters that communicate with the brain
  • Encourages the immune system to create an autoimmune response against the body
  • Interferes with hormone secretion and the function of the endocrine gland

When any of these disruptions strike, there’s a greatly increased risk of:

  • Reproductive problems
  • Candida and irritable bowel syndrome
  • Lupus
  • Cancer
  • Dementia
  • Depression
  • ADHD
  • Autism
  • Parkinson’s disease
  • Diabetes
  • Heart disease

Bottom line: If you’re a thermometer, no need to worry about mercury.

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The rest of us better watch out.

How to watch out, and for what?

Here’s my fish safety ranking list, with advisories based on what an adult male, or a woman not intending to be pregnant, can safely consume.

You’ll notice no farmed fish, though some experts claim some are OK.

There are too many horror stories about overcrowding, hormones and antibiotics in feed. Farmed fish have the same problems as Big Food’s beef and pork factories with the same awful results.

The fish marked * have been overfished. Limit your consumption, please. This fish contamination chart applies to fish caught and sold commercially, not those you catch yourself.

Low mercury—cleared for enjoying

  • Anchovies
  • Butterfish
  • Catfish
  • Clam
  • Crab (Domestic)
  • Crawfish/Crayfish
  • Croaker (Atlantic)
  • Flounder*
  • Haddock (Atlantic)*
  • Hake
  • Herring
  • Mackerel (N. Atlantic, Chub)
  • Mullet
  • Oyster
  • Perch (Ocean)
  • Plaice
  • Pollock
  • Salmon (Canned)**
  • Salmon (Fresh)**
  • Sardine
  • Scallop*
  • Shad (American)
  • Shrimp*
  • Sole (Pacific)
  • Squid (Calamari)
  • Tilapia
  • Trout (Freshwater)
  • Whitefish
  • Whiting

Moderate Mercury—6 servings or less per month

  • Bass (Striped, Black)
  • Carp
  • Cod (Alaskan)*
  • Croaker (White Pacific)
  • Halibut (Atlantic)*
  • Halibut (Pacific)
  • Jacksmelt (Silverside)
  • Lobster
  • Mahi Mahi
  • Monkfish*
  • Perch (Freshwater)
  • Sablefish
  • Skate*
  • Snapper*
  • Tuna (Canned chunk light)
  • Tuna (Skipjack)*
  • Weakfish (Sea Trout)

High Mercury—3 servings or less per month

  • Bluefish
  • Grouper*
  • Mackerel (Spanish, Gulf)
  • Sea Bass (Chilean)*
  • Tuna (Canned Albacore)
  • Tuna (Yellow fin)

Highest mercury—do not eat:

  • Mackerel (King)
  • Marlin*
  • Orange Roughy*
  • Shark*
  • Swordfish*
  • Tilefish*
  • Tuna (Bigeye, Ahi)

It’s tragic that our big fish are now health threats. When they’re wild and free, in clean waters, they’re among the most nutritious foods in the world.

The credit for that goes to one key nutrient.

Omega-3 saves us

If you had to invent the most powerful, versatile, health giver, you’d invent omega-3 essential fatty acids (EFA).

Emphasis here is on essential. You need EFAs to live. You can’t survive without them.

The trick is that unlike other life-sustaining nutrients, we can’t produce omega-3 ourselves. We can only get it from what we eat.

In this world overflowing with supplements for every condition, I choose omega-3 as one of only two supplements I insist all of my patients take—old, young, healthy, sick. That’s how important it is.

Omega-3 is a “team” of super-skillful EFAs:

  • Eicosapentaenoic acid (EPA) produces chemicals that help reduce inflammation and symptoms of depression
  • Docosahexaenoic acid (DHA) accounts for a high percentage of our brain weight, and is vitally important to normal brain development and function
  • Alpha-linolenic acid (ALA) helps produce EPA and DHA, and is used by our body for energy

Working together, the omega-3 team gets a lot done:

  • Reduces inflammation throughout the body
  • Improves heart health
  • Supports mental health
  • Reduces weight and waist size
  • Reduces liver fat
  • Prevents dementia
  • Promotes bone health

It’s a pity we can’t trust fish to provide adequate omega-3 anymore. But even when we enjoy fish, we never know how much omega-3 we’re getting. Amounts vary fish by fish, by portion size, etc.

So as I said, I recommend an omega-3 supplement to all my patients.


At least 1,000 mg/day (make sure your supplement says 1,000 mg of omega-3 and not just 1,000 mg of oil). Talk with your doctors before starting any supplement.

Chlorella unleashed

Even if you haven’t been eating a lot of fish, almost all of us have some mercury built up in our bodies. And the longer it’s been building up, the more threatening it is.

The good news? Not only can we get rid of it, we can safely eat many fish, even those with moderate mercury content, by putting a few defenses in place.

Chlorella is a freshwater algae that grabs toxins and drags them out of your body.

That includes mercury. If you take chlorella both before and after eating fish, it keeps mercury from settling into your system. Chlorella binds to it and away it goes.

Chlorella comes in tablet, powder, or extract form. There are different formulations, so talk with your doctor about what’s right for you.

Chlorella comes with loads of extra health bonuses. It’s used to:

  • Prevent cancer
  • Reduce radiation treatment side effects
  • Stimulate the immune system
  • Increase white blood cell counts (especially in people with HIV infection or cancer)
  • Slow the aging process

That’s good medicine.

I recommend 2 tabs in the morning, 2 at midday and 2 before dinner—essential if fish is on the menu.

Take good care.


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