The Japan Nuclear Nightmare: should you pop iodine pills?

The recent massive earthquake in Japan has resulted in a significant amount of damage to several nuclear reactors, setting off fears that a possible meltdown can occur, as happened in Chernobyl in 1986. While the Japanese government has issued statements saying that there is no immediate danger from any reactor meltdowns, conflicting reports about just how serious the extent of the damage is has led many people to become proactive. “Proactive” in this sense means rushing out to purchase potassium iodide tablets. This is based on the fact that nuclear reactor meltdowns produce a variety of radioactive substances, many of which are absorbed by breathing and in food. Two such radioactive products are iodine 129 and 131.Both of these are rapidly taken up by the thyroid gland, which could lead to thyroid cancer. The idea of taking potassium iodide tablets is that the tablets, which contain massive amounts of iodine, will saturate the thyroid gland, thereby preventing the uptake of radioactive iodine. To work effectively,however, the potassium iodide tablets need to be taken prior to exposure to radioactive iodine. This explains the current run on potassium iodide tablets.
Taking the tablets after exposure will not only not help, but may lock the radioactive iodine (assuming you were exposed) into the thyroid gland, making matters worse.In addition, the tablets will only protect the thyroid gland from radioactive iodine exposure; it will not protect against any other radioactive material, nor will it protect other parts of the body besides the thyroid gland. Other parts of the body are capable of concentrating iodine intake, including the salivary glands and the gastrointestinal tract. These are the areas of the body most likely to show side effects if you go overboard taking potassium iodide tablets. You can also experience severe allergic reactions, including a sudden drop in blood pressure.
The major function of iodine is for use in synthesizing the two major thyroid hormones, T3 and T4. Once in the thyroid gland, iodine is oxidized by hydrogen peroxide, a free radical reaction. Keep this in mind next time you read how bad free radicals are. There are some useful purposes for them, and thyroid hormone synthesis is one of them. After being reacted with hydrogen peroxide, the iodine combines with residues of the amino acid, L-tyrosine to form the thyroid hormones. The suggested daily adult requirement for iodine is 150 micrograms. You need only 70 micrograms to synthesize thyroid hormones. The upper safe limit of iodine is about 1,000 micrograms. The amount of iodine in a potassium iodide pill is 130 milligrams. One thousand micrograms equals one milligram. Do the math, and you’ll realize just how potent potassium iodide pills are. They should not be ingested more than once every 24 hours, and should not be used once the threat of any nuclear radiation passes. Within hours after the Chernobyl incident 25 years ago, the Polish government handed out potassium iodide pills to parents of children in exposed areas. As a result, the children did not experience any increase in pediatric thyroid cancer. In contrast, in other fallout areas such as the Ukraine, Belarus, and Russia, pills were not handed out as generously. Those areas showed significant increases in thyroid cancer. The pills contain 77% iodine.
When I competed in bodybuilding contests in the 70s, a popular supplement often suggested for fat burning was kelp tablets. Kelp, or seaweed, concentrates iodine. The idea was that taking kelp tablets would speed up your thyroid gland, and thus help you burn fat more efficiently. While a couple of kelp tablets didn’t cause any harm (although they were also high in sodium), what wasn’t known then was that iodine has a J-shaped curve in relation to thyroid function. Simply put, ingesting too much iodine provides the paradoxical effect of slowing down thyroid output. As such, many competitors who were ingesting as many as 100 kelp tablets daily were hampering their precontest dieting efforts without being aware of it. Even 100 kelp tablets,however, don’t contain as much iodine as a single potassium iodide tablet. This stuff is potent, so keep that in mind, and don’t consider taking it for days on end as a preventive against radiation exposure.