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Hazardous Levels of Mercury in Sushi

tuna, sushi, mercury, toxic fish, raw fish, mercury levels, fishRecent laboratory tests in New York found so much mercury in tuna sushi that two or three pieces a week at some restaurants could be a health hazard.

Eight out of the 44 pieces of sushi purchased by the New York Times for testing had mercury levels so high that the FDA could take legal action to remove the fish from the market.

Although all the samples were obtained in New York City, experts believe similar results would also be observed elsewhere.

While the FDA and EPA have warned children and pregnant women against consumption of canned tuna, fresh tuna was not included in the advisory. However, the tuna sushi in The New York Times sample contained far more mercury than is typically found in canned tuna.

The scientists who performed the analysis said they were "frankly surprised" by the results, and that they had run the tests several times to make sure there was no mistake.

Dr. Mercola's Comments:

Not too long ago I stated that one exception to the rule of not eating fish was sushi bars where you can order the fish raw, because it tends to diminish some of the toxicity.

However, recent testing of sushi bars show that sushi does appear to be equally contaminated with mercury, and in some cases worse than other fish. As one restaurant owner explained, they tend to buy larger, “better quality” fish, which in turn contains much larger concentrations of mercury due to their size.

However, the variable that still remains untested is if the mercury and other contaminants are as toxic if you consume the fish raw. In other words, does cooking it change the nature of the food to transfer its toxicity to you? To the best of my knowledge those studies have not been done.

If you like to practice the precautionary principle then it would be best to avoid it.  Personally I avoid tuna, whether raw or cooked. 

Extreme levels of mercury in tuna are not isolated to New York. I recently wrote an article where I used my own hometown of Chicago as an example where tuna sushi samples were found to contain very high amounts of mercury as well.

The Chicago tuna sushi samples came from ten high-rated Chicago sushi restaurants, and:

  • 70 percent exceeded the Illinois Environmental Protection agency’s (IEPA) special advisory threshold for methylmercury. At that level, women of childbearing age and children are advised to eat no more than one serving per month

  • 14 percent had a concentration higher than 0.730 ppm – a level that no women or children should ever consume

  • 10 percent of the tuna samples were unsafe for all consumers, because they contained mercury levels above 1.0 ppm, which is the legal action limit for fish sold in the U.S. 

Pregnant? Take Fish Off Your Menu   

Mercury is easily transferred to your child while in the womb. If you have high levels of mercury in your system, from eating a lot of fish, for instance, you could be putting your baby at risk. 

Studies have shown that the level of mercury in the umbilical cord blood of newborns is 1.7 times higher than the mercury level in their mother's blood.

Eating fish just two or more times a week has been found to raise mercury levels seven times beyond those in women who had not eaten any fish for a month, according to the CDC. With this in mind, if you are pregnant or planning to become pregnant, please avoid eating fish unless you can verify, via lab testing, that it does not contain mercury.  

The irony is, if it weren't for the increasing risk of contamination by substances such as mercury, melamine, and untreated fecal water, fish really would be the optimal food source for omega-3 

Animal-based omega-3 fats are absolutely vital for the complete development of your baby’s brain during pregnancy and the first two years of life. In fact, omega-3 fat, especially DHA (docosahexaenoic acid), is so essential to a child's development that if you -- and therefore your child -- are deficient in it, your child's nervous system and immune system may never fully develop, and it can cause a lifetime of unexplained emotional, learning, and immune system disorders. 

Time to Face Facts – Virtually All Fish is Now Toxic 

Also keep in mind that tuna, whether canned or raw sushi-style, is not the only kind of fish that contains alarming levels of mercury and other toxins. The issue of severely contaminated fish products has been in the news for years, and it’s not getting any better. Other examples include: 

2002Whale liver, commonly eaten in Japan, was found to contain more than 1,970 micrograms of mercury per gram of liver. At that concentration, an adult eating just 0.15 grams of liver (that’s equal to 3 percent of one teaspoon, folks!) would exceed the weekly mercury intake considered safe by the World Health Organization.

2003 -- Farmed salmon, which is being eaten in increasing amounts by millions of Americans, were found to contain high levels of dangerous PCBs. One study found concentrations of PCBs were 16 times higher than those of wild, ocean-fished salmon.

2003 -- According to FDA data, albacore (white) canned tuna was found to contain three times more mercury than chunk light (0.353 ppm vs. 0.118 ppm). Independent testing by the Mercury Policy Project found that the average mercury concentration in albacore canned tuna was even higher than that, with most samples exceeding 0.5 ppm.

2005 -- 68 percent of swordfish samples tested were above the FDA Action Level of 1 ppm mercury. The average mercury concentration found was 1.38 ppm, 38 percent higher than the FDA Action Level.

2007 -- "The Madison Declaration on Mercury Pollution" published in March 2007 declared a general world-wide warning to the public to be careful about how much and which fish you eat, stating that increasing mercury concentrations are now being found in a number of fish-eating wildlife species in remote areas of the planet.

Safe Alternatives Still Exist

I still believe there is a safe and effective way to get all the health benefits of omega-3, without any of the risks of mercury, simply by either:

  • Smaller fish are far less likely to be contaminated, so sardines and other tiny fish would likely be relatively toxin free.
  • Eating only clean, pure fish, such as Vital Choice Alaskan salmon, which I have had tested on numerous occasions and I know is mercury free
  • Take a high-quality omega-3 supplement, like krill oil or  fish oil

If you insist on eating typical, store-bought fish, however, and want to know more about the extent of your mercury exposure, I urge you, for the sake of your health and that of your family, to check out the online mercury calculator at

For a more comprehensive report on fish recommendations and dangers, please review my previous report on this topic.

+ Sources and References
  • International Herald Tribune January 22, 2008