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Potassium Iodide & Radiation Exposure: What is my Best Protection?

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Author: Dr. Meghan Walker ND

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Potassium Iodide & Radiation Exposure: What is my Best Protection?

Since the time that oxygen first appeared on earth, living organisms have been exposed to radiation. The most recent tragedy in Japan however, has brought radiation exposure and protection to the forefront of conversations for much of the planet.

While the media is delivering coverage of Japan’s humanitarian and nuclear crisis, providing an appropriate context for global radiation exposure is important for assessing our risk. Radiation is measured using the unit sievert and quantifies the amount of radiation absorbed by human tissues. One sievert is equivalent to 1000 millisieverts (mSv). In physics, radiation is defined as energy or waves that travel through a medium or space and is divided into two distinct forms, ionizing and non-ionizing. Radiation such as radio and microwaves are thought to be relatively harmless, yet all forms of radiation have the potential to cause harm when exposure occurs at high levels.

Throughout the course of a year, the average person is exposed to radiation from a variety of sources, but together, these rarely exceed 3mSv. At the higher end of the exposure scale, a full-body CAT scan results in approximately 10mSv of radiation. In contrast a chest x-ray results in 0.02mSv, a mammogram 0.7mSv and a coast-to-coast flight, approximately 0.03mSv. 

It is estimated that the radiation levels immediately surrounding the damaged Fukushima Daiichi plant in Japan is approximately 400mSv. This dose is enough to cause radiation sickness within several hours. 

Averting Exposure

According to most experts, the risk for radiation exposure in North America is minimal. Even after the Chernobyl disaster, notable radiation exposure did not extend beyond 1500km.  In this case, North America and Japan are separated by more that 7000km of ocean. Despite the low level of risk, mechanisms for radiation protection have been widely circulated and it is important to distinguish fact from fiction.

Potassium Iodide: 

Potassium iodide is one of the most commonly cited mechanisms of protection, and for good reason. Iodine is an important element used by the body to make thyroid hormones. Most of the iodine in our bodies comes from the food we eat, but can also be absorbed through the lungs if the airborne quantity is sufficiently high. Following a radiological or nuclear event, radioactive iodine may be released into the air and then absorbed in the lungs. In this case, the radioactive iodine is rapidly taken up by the thyroid and disseminated through the body as thyroid hormone. When potassium iodine is given orally, the body will not need to use the radioactive iodine that it is receiving from exposure. In this sense, potassium iodide cannot prevent radioactive iodine from entering the body, but can protect the thyroid from radioactive uptake. 

Potassium iodide cannot reverse the health effects caused by radioactive iodine once damage to the thyroid has occurred, nor can it protect the body from radioactive elements other than radioactive iodine. Taking potassium iodide is not advised as a ‘just in case measure’ and should be taken under the direction of public health advisories or the direction of your primary health care provider. Taking any kind of iodine when it is not prescribed can cause permanent damage to the thyroid’s normal functioning.

Other Important Nutrients:

Vitamin C is a potent anti-oxidant and has long been shown to reduce the effects of radiation toxicity even at moderate doses. Vitamin E and Selenium are two additional nutrients that have both been shown to decrease tissue damage as a result of radiation exposure such as with cancer therapies. Selenium has the additional benefit of increasing glutathione production, an important component of detoxification. When taken together, vitamins E and C have additionally been shown to decrease radiation-induced mutations in DNA. All of these nutrients are present in a high quality multi-vitamin and should not be taken at higher doses unless advised by your health care professional. (BJR. 2004 77:97-99).

Miso soup: 

There is always a strong argument to keeping things simple. One study completed on doctors who worked in Hiroshima following the Second World War, found that those who consumed miso soup on a daily basis experienced few episodes of cancer as a result of radiation. (Hiroshima J Med Sci. 2001 Dec;50(4):83-6). As well as being a tasty addition to lunch, miso soup is loaded with anti-oxidants, iodine and healthy nutrients. Drink up.

While taking the initiative to protect your health is always encouraged, it is important to consider the context. If you have questions about radiation or appropriate supplementation, consult the guidance of someone qualified to provide strategic, sound advice.

Miso Soup Recipe:

Miso soup is really easy to prepare on your own. 

  • 4 cups of water
  • 3 tablespoons miso paste (available in yellow, white or red), the longer fermented, the better. (In the refrigerated sushi section of the grocery store). 
  • 1 package organic medium tofu, diced. 
  • 1 scallion or green onion, sliced to 1/2 inch pieces.
  • Keep (dried seaweed) crumbled or chopped. Alternatively, use 2.5 tsp dashi, a combination of kelp and dried fish (bonito).
Heat 4 cups of water to boiling, if using dashi, add now. Turn down heat to medium and stir in miso paste until dissolved. Place tofu, onion and kelp in soup. Gently heat for 2-3 minutes prior to eating. Once the miso is added, do not let the soup boil.  


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