Use of potassium iodide in radiation exposure

Following the seismic events that damaged several nuclear reactors in Japan, many Americans are concerned about the possibility of exposure to radiation drifting across the Pacific Ocean with the prevailing winds. This has resulted in a buying frenzy of potassium iodide tablets, a known deterrent to certain effects of radiation on the body. In situations such as these, however, it is prudent to listen to experts monitoring radiation levels to learn the likelihood of being exposed and to understand what can and cannot be done in regard to radiation exposure.

What is potassium iodide (KI)? Potassium iodide is a salt form of iodine, whose primary function in the body is to help make thyroid hormone. Concentrated food sources of iodine include kelp (seaweed), shellfish, cow's milk, and eggs. Potassium iodide is often added to table salt to produce "iodized" salt, which serves primarily to provide a source of iodine for the body. Potassium iodide is available in tablet and liquid form. One form of potassium iodide called SSKI is used by people with emphysema as an expectorant to help loosen and break up mucus in the airways.

How does potassium iodide help with radiation exposure? With the release of gases following a nuclear accident such as occurred recently in Japan, radioactive iodine can enter the body through the lungs. Since the thyroid gland concentrates both radioactive as well as stable iodine, high levels of radiation can develop in the thyroid gland. Over time, this can lead to the development of thyroid cancer. Potassium iodide, if taken in time and at the proper dosage, can block the absorption of radioactive iodine by the thyroid and prevent cancer from occurring.

What potassium iodide does not do. There are a number of potentially damaging effects of radiation on the body. The development of thyroid cancer is only one of these. Potassium iodide provides protection only for the thyroid gland. Depending on the amount of radiation absorbed by the body, the type of radiation, the route of exposure, and the length of time a person was exposed, other adverse health effects range from skin reddening to acute radiation syndrome (ARS), which can result in death.

Is there any harm in taking potassium iodide? Potassium iodide should only be taken when the risk of exposure to radiation warrants its usage. In the case of a radiation emergency, the benefits of taking potassium iodide are believed to outweigh the risk. As with any other medication or supplement, however, adverse effects can occur with taking potassium iodide. Those people with a known allergy to iodine should not take potassium iodide. Additionally, anyone with an existing thyroid condition (Grave's disease, goiter, thyroiditis, etc.) should only take it under the guidance of a physician. Other side effects of potassium iodide include intestinal upset, rashes, and inflammation of the salivary glands.

Current recommendations. A few days ago, the U.S. Nuclear Regulatory Commission released the following statement, "Given the thousands of miles between the two countries, Hawaii, Alaska, the U.S. Territories and the U.S. West Coast are not expected to experience any harmful levels of radioactivity." With that in mind, most authorities believe that taking potassium iodide is unnecessary at this time.

Since the situation in Japan is still unfolding, we need to remain vigilant regarding the potential for radiation exposure. For more information on the effort by the U.S. government to monitor radiation levels and inform the general public, go to the Environmental Protection Agency's sites: Japan Nuclear Emergency:
Frequently Asked Questions or RadNet.

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