How Safe Is Your Sushi?

Health Tips / How Safe Is Your Sushi?

There’s been some completely unnecessary bickering between conventional and integrative physicians the past few years over mercury, and to a lesser extent lead and other toxic metals like arsenic and cadmium. While everyone agrees that these substances are poisonous, they aren’t unanimous on the best ways to diagnose and treat toxic metal poisonings.

However, there’s complete agreement among doctors about the following:

  • Lead poisoning is dangerous, especially in young children, in whom it causes permanent brain damage. Lead-containing paint chips were once a sweet snack for kids who didn’t have enough to eat. Fortunately, with the elimination of lead-based paints in 1978, doctors don’t see much of this anymore.
  • Mercury, especially in the form of methyl mercury, is dangerous, especially if you’re a fetus, where brain damage is the main issue. This is the type of mercury found in fish and seafood. Long-term exposure in adults can cause a constellation of symptoms, including fatigue, confusion, and muscle weakness, and can be confused with early Alzheimer’s, multiple sclerosis, and amyotrophic lateral sclerosis (ALS, or Lou Gehrig’s disease)
  • Elemental mercury (liquid quicksilver) and mercury vapors from industrial exposure are also quite toxic.
  • The form of mercury used in vaccine preservatives (thiomersol) is now rarely used, and it’s worth noting this form has been deemed not toxic.

The major points of contention, often leading to unpleasant arguments among physicians, accusations of patient and insurance fraud, threats of de-licensure–I mean really nasty stuff—revolve around overdiagnosis and inappropriate overtreatment.

The easiest and most efficient way to diagnose excessive levels of both mercury and lead in the body is via blood and urine tests.


There are two other controversial tests that frequently come back with a positive result and lead to inappropriate and expensive treatment.

  • Hair analysis was quite popular a few years ago, but when researchers realized that the vast number of hair products people apply to their heads would confuse the results, they largely abandoned it. (Even with clean hair, the test is frequently inadequate. In a study from nearly 20 years ago, investigators sent clean hair samples from the same person to three different labs and got three completely different results.)
  • Urine testing after provoked chelation is something I’ve used and also abandoned. With this test, the patient takes a metal-removing agent called a chelator and urine is collected the next day. Since all of us have some amount of mercury in our bodies, the test result often seems positive when actually it’s not. After doing a lot of research on the value of provoked chelation, this test, too, has been pretty much abandoned simply because the false positives caused unnecessary patient anxiety and overtreatment.

Inappropriate overtreatment

Formerly when people were diagnosed with mercury toxicity, they could find themselves signing up for long-term intravenous chelation therapy, with or without the extraction of mercury-containing dental amalgams, spending tens of thousands of dollars on unproven treatments. These programs were once touted (and since disproved) as cures for both multiple sclerosis and autism.

Actually, if mercury excess is diagnosed oral chelating agents (such as DMPS, DMSA, and chlorella) are quite safe, to the extent that they’re sold without a doctor’s prescription. You may not even need these as the very best treatment is to trust your body’s own detoxifying systems and avoid additional mercury exposure. I rarely use DMPS or DMSA in my practice and neither do I subject patients to some of the incredibly complicated and emotionally overwrought mercury protocols I’ve seen online.

Simple treatment for mercury toxicity

Keeping it simple works well. Here are a couple of examples from my own archives and those of a fellow physician:

Case #1 A professional wine expert living in Paris was found to have mental changes and muscle twitching. He acknowledged a “sushi addiction,” eating it once or twice daily for years. His mercury levels were toxic, but he improved clinically and returned to his usual health with oral chelating agents and sushi avoidance.

Case #2 A semi-professional body builder had gotten it into his head that tuna would give him a competitive edge. Never doing anything by halves, he ate four (four!) cans of tuna a day for years. He read about mercury issues and requested testing. I expected him to set a record for toxicity, but to my surprise his blood and urine mercury levels were perfectly normal, as were the levels after provoked chelation (I was still doing this test at the time). Some people are blessed with really good detoxifying systems.

Case #3 A generally healthy 40-year-old man had some vague symptoms of fatigue. All routine tests were negative, but he was concerned about mercury because he ate sushi once a week. His levels were quite toxic, up there with the sommelier in Case #1. The levels returned to normal by avoiding sushi and by taking detoxifying antioxidants (glutathione, lipoic acid, n-acetyl cysteine) and a chelator from nature, chlorella.

A reasonably priced product that combines chelators with detoxifiers is Chelex by Xymogen.

So what should you do?

To date, except for the symptoms of mercury toxicity itself (mood changes, headaches, insomnia, muscle twitching, tremors, and weakness), mercury has not been linked to actually causing any specific illnesses, like Alzheimer’s, multiple sclerosis, or autism, but mercury poisoning can imitate the signs and symptoms of a wide variety of conditions.

Therefore, if you’re experiencing chronic and unexplained symptoms of any stripe and there’s a possibility of long-term mercury exposure, get tested. The blood and urine tests are simple and straightforward and can set your mind at ease.

Since most of us don’t live where there’s mercury in the air, and most mercury-containing thermometers and blood pressure cuffs are history, our exposure comes via fish and seafood. Here’s a list to consider, but remember that fish is otherwise quite healthful and complete avoidance is definitely not recommended. If you’re pregnant, that changes everything. You really want to eliminate the high and mid-range fish during your pregnancy.

Unless you’ve got a mouthful of old dental fillings and an otherwise unexplained high level of mercury, I’d leave the fillings alone. However, if you need new fillings and don’t want the mercury, just ask your dentist. She’ll be happy to comply.

Be well,
David Edelberg, MD