by James J. Galligan, Ph.D., Associate Chair,
Department of Pharmacology and Toxicology

The recent earthquake and tsunami in Japan has caused severe destruction and has damaged a nuclear power plant.  This poses the danger of release of radioactive materials into the atmosphere and subsequent exposure to the people living near the damaged plant.  You may have heard on the continuous news coverage of this catastrophe that medical personnel are providing potassium iodine to people at risk for radiation exposure.

Why is potassium iodine useful for protection against radiation toxicity?  To answer this question we first need to discuss the thyroid gland.  The thyroid gland produces thyroid hormone which is released into the circulation to regulate metabolism of cells throughout the body.  Cellular metabolism generates body heat and energy utilization.  Thyroid hormone contains iodide and without iodide there is not thyroid hormone and this disrupts normal cell metabolism.  Normally iodine comes from dietary sources (including iodized salt) and this is sufficient to maintain normal thyroid function.  One of the toxic substances released from a damaged nuclear reactor is radioactive iodine.  When people breathe in radioactive iodine contaminated air, they are giving themselves a dose of this toxic substance.  Radioactive iodine accumulates in high concentrations in the thyroid gland and the radiation can then damage the thyroid or cause thyroid cancer.  IOSAT Photo

Interestingly, radioactive iodine is used to treat thyroid cancer as the radiation will kill off the tumor cells and iodine accumulates in the thyroid gland.  Anyway, people who are at risk will be protected against accumulation of radioactive iodine in the thyroid gland by potassium iodine supplements.  Potassium iodine fills up the thyroid stores of iodine leaving no room for radioactive iodine to accumulate.  Because potassium iodine is safe and non-toxic, there is no risk to using this preventative treatment.

Let’s hope that there is a quick and uneventful resolution to the current nuclear danger in Japan.  In the meantime, supplements of potassium iodine will help reduce the long term risks of exposure to any leaking radiation.