Fukushima and Radioactivity in Seafood

Image Credit: Photl. This image has been modified.

Fukushima Radiation & Seafood

With prevailing westerly winds over Japan, radioactive fallout from the Fukushima nuclear power plant tragedy was detected throughout North America at levels comparable to those seen 25 years earlier from Chernobyl, the only other category 7 nuclear event in history.

The highest levels of radioactive iodine in rain water were found in Boise, Idaho, and the highest levels in milk were found in San Francisco at levels ten times higher than the federal maximum allowed in drinking water. This is below that which would be expected to pose a direct threat to U.S. public health, but a controversial paper in the International Journal of Health Sciences suggested the radioactive plume from the nuclear meltdowns in Fukushima may be responsible for the subsequent bump in U.S. mortality — similar to what we saw after Chernobyl (see my 4-min video Fukushima and Radioactivity in Seafood for details). However, the authors themselves underscore that their research shows merely a correlation, and potential evidence of a causal link. They stress that more research is necessary.

Of all the radiation released, only a tiny fraction of the fallout reached U.S. shores—most was absorbed by the Pacific Ocean. What does that mean for seafood safety?

Researchers report unequivocal evidence that Pacific Bluefin tuna have transported Fukushima-derived radioactive fallout across the entire North Pacific Ocean. Tuna migrate from Japan to California and appear to have taken some radioactivity with them.

Unfortunately, more than just radiation from nuclear disasters enters our oceans. Our oceans have become humanity’s sewers; everything eventually flows down into the sea. This has implications for other aspects of seafood safety:

Even though there was a 10-fold spike in radioactive cesium levels in tuna, the researchers put it in context by noting that there were baseline levels of radioactivity in fish even before Fukushima, due to everything from thermonuclear weapons tests and sunken nuclear submarines to the radioactive elements found naturally in the earth’s crust.

The levels in seawater of radioactive polonium (the element used in the horrific assassination of Russian dissident Litvinenko) are miniscule, but it strongly bioaccumulates up the food chain into fish. Polonium is a by-product of uranium decay and is frequently cited as one of the reasons that tobacco is so carcinogenic. That was something the tobacco industry was well aware of and could have easily removed, but the process that could have removed the polonium affected the absorbability of nicotine. The loss of the nicotine “kick” sensation was found unacceptable by industry executives. So they kept the polonium in.

Cigarette manufacturers’ protection of stockholders over the public is not unique to that sector. More industry hijinks in:

The radioactive polonium in cigarettes has been speculatively blamed for the link between smoking and male infertility, but most of human exposure comes from diet—mainly fish and shellfish. And this was before Fukushima.

So what happens if we eat seafood? Researchers measured the increase in radioactive polonium levels in semen after a single seafood meal. It caused a 300 percent spike in radioactivity levels. Probably not enough to cause infertility—but that was just one meal. Whether the kind of dose you can get from eating seafood is high enough to damage sperm cells still needs to be established. Researchers calculate that may have to eat as much as a pound of seafood a month before we might realize the harmful effects of the radiation.

More on infertility in:

Interestingly, there’s 8 times more polonium in cooked shrimp than in raw. Researchers think it’s because most of the polonium is in the shrimps’ internal organs, which is released in to the boiling water and contaminates the muscle. Gutting crustaceans before cooking may therefore decrease radiation exposure.

The greatest radiation exposure risk, however, comes not from Fukushima fallout or the polonium naturally found in seafood, but from doctors. See my video, Cancer Risk from CT Scan Radiation. This was touched on in a recent New York Times op ed.

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 – 2015 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, From Table to Able, and Food as Medicine.


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

31 responses to “Fukushima Radiation & Seafood

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  1. I am a bit confused……does the Polonium occur naturally in tobacco leaf/plant or has the industry somehow bred tobacco over the years to have this?

      1. Interesting. It seems likely that organic tobacco/cigarettes would be exempt from this polonium issue (but not that from other tobacco health issues). Is man-made/grown tobacco the real problem, as far as the cancer goes? I’m not promoting organic tobacco but it does raise an interesting question and possibility.

        1. Any smoke inhalation is damaging to the respiratory tissue regardless of it’s makeup of being “natural” or “adulterated” (eg. damage to lungs of forest fire firefighters).

          That’s why there are known second-hand smoke (others smoke you inhale) and third hand smoke (the particles of smoke you smell on others) warnings. If you can smell it you have a smoke particle up your nose.

    1. Polonium is added to tobacco through fertilizers because it gives smokers that initial “zing” after lighting up. Polonium is also approximately 250,000 times more toxic than cyanide.

  2. Any cautionary signs that swimmers who spend considerable amounts of time in the California Pacific Ocean are exposing themselves – through the skin, or even from radiation airborne coming off the surface waters?

    Surfers spend upwards of 30 + hours a week, some more, out in the radiation containing Pacific.

      1. I don’t know but you raise an interesting possibility.

        At what point, I wonder, are people going to opt to stay out of the ocean in USA? I wonder if that is the future.

      1. Great cartoon! People like that are sick pigs. They want to die, and anything to speed it up is OK with me. They are ruining the air I breathe, and I would rather punch them in the face for assault. They should have to eat it or inject it, so it only hurts them. There is nothing more frustrating then walking outside in the clean air, breathing, then suddenly getting slammed with a toxic shot of cancer to my lungs. If I sprayed them with harmless pepper spray, or skunk extract, I would be arrested. Why not them?

      1. Wow! Your Cell phone?! That is dedication, and to that level I bow. (Just like the movie Wayne’s World–“I’m not worthy”)

  3. There is such a multitude of other health hazards and environmental problems with shrimp. Instead of trying to make it a smidgen less hazardous, why not opt instead for vegan seafood options (including shrimp), which are better for the animals, for our health, and for the environment? Recipes, products and more can be found on the Vegan Seafood Resources page of Fish Feel dot org.

  4. Another meatless, zero fat dinner consumed tonight.

    I have a patient who ingests 35 g of non-hydrolyzed whey protein powder with his breakfast, and I have not been able to answer whether this is harmful or beneficial for his health. He is otherwise on a strict plant-based diet. He uses this quantity of whey for intense resistance training and to increase the satiety of his breakfast. Would this much whey cause an IGF-1 spike? Would it be bad for his arterial health?

    Thanks for anyone who knows.


    1. My take on seaweed is…..don’t eat it.

      I suggest getting your leafy greens from land instead. If iodine is what you are after, indulge in pineapple and medjool dates and a mix of fresh veggies, and on a consistent basis.

      Think of all the junk that gets dumped in the ocean…and they can’t test for EVERYTHING.

  5. It pleases me to see that you recommend hair testing [once considered ‘quackery’] for mercury before females contemplate pregnancy. Considering mercury content in dietary fish as a Hg source is noteworthy. However, what your information about mercury does not take into consideration, and should, is this:

    1) Mercury from dental amalgams, which can keep depositing Hg into a female’s body, regardless of the type of or how little fish a female eats; and

    2) Mercury content in vaccines, especially in the current flu vaccination program that is recommended for pregnant women.

  6. from the blog post: “Researchers calculate that may have to eat as much as a pound of seafood a month before we might realize the harmful effects of the radiation.”

    I think that amount would be easily reached by many people. After all, haven’t popular/media “experts” been advising people to eat fish at least once a week. I think it would be easy for people to eat a quarter of a pound of fish a week – getting them easily to that pound a month.

    This is another a great example of how “moderation” kills. Who wouldn’t consider a single fish meal a week to be moderate? (Where “who” = anyone not educated by NutritionFacts and similar sources. :-) )

  7. I think this conversation is going down the wrong track with the cigarette discussion or CT scans. Radiation accumulates up the food chain and people are at the top. Polonium doesn’t go away the day after you eat it. Otherwise Alexander Litvenenko would still be with us. What is the half life of Polonium?
    And eating a pound of seafood in a month isn’t unusual for many people. It seems to me that human beings eating seafood from the Northern Hemisphere Pacific Ocean are accumulating dangersous radiation in their bodies.
    According to an artile in The Guardian in November 2013, polonium once injested doesn’t leave the body. A dose of a few milligrams can be fatal. http://www.theguardian.com/world/2013/nov/06/polonium-210-poison-alexander-litvinenko

  8. At first I thought “I don’t eat seafood”. (Which is the specific focus of this specific article, rather than the entire ecological disaster.) Then I realized that I do: seaweed.
    Dr. Greger, what is the danger in seaweed?

  9. A couple of us have asked about seaweed.
    That done, I don’t suppose ingesting Polonium would help us neither a borrower nor a lender be.

      1. Thank you. Yes, I had seen those videos and have been avoiding both hijiki and kelp.

        The problem for me (and any concerned eater!) is that many of the seaweed snacks are just labeled “seaweed”. (!) I have actually gotten on websites and corresponded with several companies, about *what* kind of seaweed they use.

        Stash teriyaki seaweed, so they say, is something like organic and conscientiously farmed in the ocean near Korea. Similar answers from others, I think Trader Joe’s. Big help there.

    1. What are the new results in 2017 now Dr Greger? Is there any new info on fish and seafood consumption . I’m avoiding the lot!
      Am I right in doing so???

      1. Thank you for asking about an update on this topic, Edd1. I didn’t see any updated videos by Dr. G. yet, but I will pass along this request. I did quick PubMed search and noticed there are a few 2015/2016 research studies and there appears to some controversy about fish safety today in the Japan area.

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