The failures of containment in Japanese nuclear reactors following the recent earthquake and subsequent tsunamis have generated fresh concern about radioactive-exposure risks.
This issue was raised at the recent Smart Life Forum during the Forum portion of the program (see www.smartlifeforum.org for possible streaming video of that event).
Let me start by stating that there are two, distinct issues of very divergent risk. First, there is the radiation. This is actually a minor risk. Radiation is endemic in the environment. It comes from the earth, air, water, sun and space. Our natural adaptive mechanisms are quite effective at adjusting to long-term changes in “background” radiation levels. For example, people living in Denver are exposed to roughly double the radiation that those living in San Francisco are exposed to (the atmospheric shielding is less due to the higher altitude of Denver compared to sea level). Our bodies actively adjust to this background radiation by increasing production glutathione peroxidase, catalase and superoxide dismutase. This “endogenous” antioxidant defense system is singularly competent for dealing with gradually changing radiation levels.
This does not happen with intermittent radiation exposure, like you would get from medical x-rays, pet scans or security scans at the airport.
Second, there are radioactive elements. This is actually the important risk to consider. Radiation hitting you from the outside is not as dangerous as radiation that is generated deep within your body. This is especially true of alpha-emitters (like plutonium), which release radiation in the form of high-mass alpha particles (a two-neutron-plus-two-proton particle). This radiation is very damaging at close range and very non-damaging at longer distances. The dead skin on the outside of your body is enough to stop almost all alpha radiation, but if you breath alpha-emitters into your lungs, you get lung damage from alpha-particle radiation. So you can get lung cancer. There is no dead-skin layer in your lungs.
Another risk of this second type are elements that are used by your body naturally. For example, iodine is needed by the thyroid gland to make thyroid hormone. The risk comes from radioactive iodine, which your body cannot distinguish from non-radioactive iodine. When your body absorbs iodine, both the radioactive and non-radioactive iodine are concentrated by the thyroid gland. Radioactive iodine is a cause of thyroid cancer.
The body can absorb radioactive potassium, radioactive cesium, and other radioactive versions (isotopes) of naturally occurring “nutritional” minerals that may be carried on the wind, deposited in soils and incorporated into foods. Volcanic ash is the largest natural exposure that people are subjected to. The ash from Mount St. Helens was more radioactive than mine tailings from uranium mines, and that ash covered major portions of three states. So this natural exposure to radionuclides (radioactive isotopes) is far from trivial. The question I would ask is: is the exposure from these reactor accidents greater than volcanic ash? And which elements are greater?
This nuclide risk can be mitigated by taking non-radioactive versions of the radioactive elements. Taking non-radioactive iodine, for example, “washes out” the radioactive iodine. It is a dilution effect. If you take 10 times more of something than you need, 90% gets dumped. If you take 100 times more than you need, 99% gets dumped. This is why iodine doses 1000 times higher than nutritional requirements are routinely recommended during radioactive iodine exposures.
Since I know a lot about iodine, let me fill in some practical issues regarding prophylactic iodine use.
Some people are sensitive or allergic to iodine.
People with goiters (an adaptation to long-term inadequate iodine nutriture) can develop acute hyperthyroid symptoms (rapid pulse, agitation, anxiety, sleeplessness, mania, obsessive ideation, compulsive behaviors, bulging eyes, elevated body temperature, elevated metabolic rate, etc.) in response to iodine supplementation.
Iodine (the element) comes in two forms. Iodide (I-) is the salt form of iodine, usually found as potassium iodide, which you might find in “iodized” table salt. This is the usual form of iodine recommended as a dietary supplement or radiation mitigation treatment. Iodine (I2) is the elemental form of iodine, which you might find in tincture of iodine in your drug store or the old-fashioned “bluing” used in laundry as a kind of bleach. Both iodine and iodide are nutritionally bioavailable and compete with radioactive iodine. Tincture of iodine can be applied to your skin (see allergy warning above) for absorption, or breathed in through the lungs as iodine vapor from tincture of iodine applied to a piece of paper or cloth placed on your night table next to your bed while you sleep.
Recently, drug stores have introduced “decolorized” tincture of iodine. This is straight potassium iodide, instead of the traditional tincture which is a roughly equal mixture of iodide and iodine. I prefer the iodine-iodide mixture over the iodide-only tincture. I apply roughly ten swaths per week. For peak protection, I apply ten swaths per day.
Some sites ascribe goiter and hypothyroidism to high iodine dosage. I think somebody screwed up their information. Goiters are an adaptation to inadequate iodine nutriture, not excessive intake. And hyperthyroidism is the near-universal result of taking high-dose iodine with a goiter. I have never seen or heard of anybody getting a hyperthyroid reaction from taking iodine in excessive dose (12-50 mg daily for months) who does not have a goiter.
Using iodine as a radio-protectant usually involves iodine doses that are at least 100 times nutritional requirements and may be 1000 times higher.
For additional signs of dangerous reactions to potassium iodide, see Robert Gilbert blog at
That’s all for now. —Steve