Radiation and Iodine
After the recent earthquake in Japan there have been concerns regarding radiation exposure and what preventative treatments are available in cases of exposure. Followup from the Chernobyl nuclear accident in 1986 found iodine deficiency to be linked to worse health outcomes, including higher incidence of thyroid cancer.
Potassium iodide has been recommended for the prevention and treatment of effects secondary to exposure to radiation, particularly radioactive iodine. The theory behind the suggested treatment is that if the iodine receptors in the thyroid do not have iodine molecules attached then radioactive iodine can latch onto receptors. By making sure iodine receptors are replete, the receptors are full and thus preventing radioactive iodine from being absorbed.
The World Health Organisation (WHO) recommended daily requirement of iodine is 150mcg, and in pregnancy 250mcg per day; the level of iodine intake beyond which no added health benefit is expected is 500mcg. The WHO dose recommended for treatment of those in the nuclear fallout zone is 130mg, or over 1000 times above the normal recommended maximum dose and only for those subjected to very high levels of radiation.