I received several questions about whether my recommendations for fish consumption (one pound of cold-water, fatty fish per week) had changed since the Fukushima disaster. You may have seen reports in the media about the discovery of radioactive isotopes (cesium-134 and cesium-137) in Pacific bluefin tuna that migrated from Japan to California waters. (1) This was covered by more than a thousand newspapers worldwide and several thousand internet, television and radio outlets.
Unfortunately, despite statements by the authors of the original research and other authorities to the contrary, these media reports led to widespread belief that fish on the Pacific coast of the U.S. now contain harmful levels of radioactive chemicals. Several people have told me that they’re no longer eating seafood themselves or serving it to their children because of this information.
While it’s natural and appropriate to be concerned about radiation, in this case the concern is unfounded. A recent peer-reviewed study published in the Proceedings of the National Academy of Sciences evaluated the health risks of consuming Pacific bluefin tuna after the Fukushima event and found the following: (2)
- A typical restaurant-sized portion of Pacific bluefin tuna (200 grams, or 7 ounces) contains about 5% of the radiation you would get from eating one uncontaminated banana and absorbing it’s naturally occurring radiation. All foods on the planet contain radiation. Like every other toxin, it’s the dose of radiation (rather than its simple presence) that determines whether it’s toxic to humans.
- Levels of naturally occurring radioactive isotopes (polonium-210 and potassium-40) in bluefin tuna are greater by orders of magnitude than levels of radioactive isotopes from Fukushima contamination (cesium-134 and cesium-137). In fact, levels of polonium-210 were 600 times higher than cesium. This suggests that the additional radiation (in the form of cesium) from Fukushima is insignificant from a health perspective.
- Even at very high intakes (3/4 of a pound of contaminated bluefin tuna a day) for an entire year, you’d still receive only 12% of the dose of radiation you’re exposed to during one cross-country flight from LA to New York.
- Assuming the very high levels of fish consumption above, the excess relative risk of fatal cancer would be only 2 additional cases per 10 million similarly exposed people. And there’s reason to believe that number is no more than chance. Statistically significant elevations in cancer risk are only observed at doses of radiation that are 25,000 times higher than what you’d be exposed to by eating 3/4 of a pound of bluefin tuna per day.
- Some bottom-feeding fish right off the coast of Japan contain much higher levels of radiation (i.e. >250 times more cesium) than those found in Pacific bluefin tuna. Even if you consumed 1/3 of a pound per day of this highly contaminated fish, you’d still be below the international dose limit for radiation exposure from food.
Finally, according to Dr. Robert Emery at at the University of Texas Health Science Center at Houston says you’d need to eat 2.5 to 4 tons of tuna in a year to get a dose of cesium-137 that exceeds health limits. (3) That’s 14 to 22 pounds of tuna a day.
To date, I haven’t seen any credible evidence suggesting that there’s even a minuscule risk from eating fish caught in the Pacific ocean. If you read an article on the internet or elsewhere claiming that Fukushima radiation in seafood is causing problems, check to see if it includes references to studies published in peer-reviewed journals by independent researchers. If it doesn’t, I’d advise a healthy dose of skepticism.
My recommendations for seafood consumption haven’t changed. If there’s any risk you should be concerned about when it comes to fish, it’s the risk of not eating enough!