Questions abound regarding the use of Potassium Iodide (chemical symbol “KI”) to protect the thyroid gland following Japan’s nuclear catastrophe. Many thousands of concerned citizens on the US west coast are rushing to vitamin stores and pharmacies in desperate search of KI. Hundreds of thousands of KI pills have been purchased online. While I am neither a radiation expert nor a toxicologist, I feel compelled to dispel some myths about KI.
First some background: During a nuclear accident, radioactive isotopes can be released into the air. Radioactive iodine #131 is among the most well known but certainly not the only harmful isotope. KI is given under emergency conditions with the goal of preventively loading the body’s tissues. The thyroid is the main target of this protective action because it’s the body’s main concentrator of iodine. The thyroid uses iodine to build hormones that regulate body temperature, metabolism and other critical functions. With the thyroid gland full of a stable iodine source like KI, there’s no room for radioactive iodine to get into the thyroid and cause harm.
What harm am I talking about? When confronted with high levels of radiation, the accompanying radioactive iodine may cause thyroid cancer.
But here’s the rub:
The dose of KI that’s recommended by the WHO and FDA – and broadcast by the media – is 130 milligrams for an adult. This is about 866% percent higher than the Recommended Daily Intake (RDI) of 150 micrograms. (For reference, 1 milligram equals 1000 micrograms.)
This mega-dose of KI carries a significant risk. Just a few days of taking KI at this amount can paradoxically inhibit thyroid gland function – the very organ the person is trying to protect. This inhibition of thyroid function is called hypothyroidism. (There is also a risk of allergic reaction in susceptible individuals.)
The only instance in which the cancer protective benefits of high-dose KI outweigh the hypothyroid risks is when there is high exposure to radioactive iodine 131. Without this high level of exposure, it’s all risk and little benefit.
There’s been a lot of confusion about this point over the last seven days. Credible sources like the New York Times have perpetuated the notion that a high-dose of KI can be taken on an on-going basis. The truth is that a high dose KI protocol is a single-day’s course given during evacuation. In other words, evacuation is the primary “prevention” for high level radiation exposure, during which time KI is given as a secondary measure. It wouldn’t make sense to take high dose KI only to stay put in a radioactive zone.
On March 20, 2011, the Washington State Dept of Health published its airborne radiation data that it collects hourly from four locations in and around Seattle. The conclusion was clear: the readings would have to be hundreds of thousands of times higher than present before high-dose KI is indicated. Here’s the accompanying news release published on March 21, 2011.
While there are many health benefits for smaller, nutritive amounts of KI (around 150-225 micrograms), it’s dangerous to take the “treatment” amount of KI without physician supervision or a directive from the Public Health Officials.
Bottom line: if you feel you must have the high-dose KI supplements, consult your doctor first.
Michael Kaplan, ND is a Washington State board certified naturopathic physician. Dr. Kaplan is Zing Bars’ chief medical advisor and editor-in-chief of the Zing Blog. Dr. Kaplan also serves the community of Redmond, WA as the Lead Practitioner at the renowned Pharmaca Integrative Pharmacy.
 “Guidelines for Iodine Prophylaxis Following Nuclear Accidents.” WHO Update 1999. Published as Iodine_Prophylaxis_Guide.pdf