It is well-known that potassium iodide works to protect against damage from radioactive iodine by saturating our body (the thyroid gland, specifically) with harmless iodine, so that our bodies are unable to absorb radioactive iodine from nuclear accidents.
For example, the World Health Organization notes:
The thyroid gland is at particular risk from irradiation from radioactive iodine because the thyroid uses iodine to produce hormones that regulate the body’s metabolism. The thyroid gland does not differentiate between non-radioactive and radioactive iodine.
When taken at the appropriate dosage and within the correct time interval around exposure to radioactive iodine, KI [i.e. potassium iodide] saturates the thyroid gland with stable (non-radioactive) iodine. As a result, radioactive iodine will not be taken up and stored by the thyroid gland.
However, KI only protects against one particular radioactive element, radioactive iodine, which has a half life of only 8.02 days.* That means that the iodine loses half of its radioactivity within 8 days. For example, after the initial Fukushima melt-down, radioactive iodine was found in California kelp.
But the longer-term threat lies elsewhere. As the New York Times noted – in addition to iodine-131 – the big danger is cesium:
Over the long term, the big threat to human health is cesium-137, which has a half-life of 30 years.
At that rate of disintegration, John Emsley wrote in “Nature’s Building Blocks” (Oxford, 2001), “it takes over 200 years to reduce it to 1 percent of its former level.”
It is cesium-137 that still contaminates much of the land in Ukraine around the Chernobyl reactor.
Cesium-137 mixes easily with water and is chemically similar to potassium. It thus mimics how potassium gets metabolized in the body and can enter through many foods, including milk.
The Environmental Protection Agency says that … once dispersed in the environment … cesium-137 “is impossible to avoid.”
Fortunately – while little-known in the medical community – other harmless minerals can help “saturate” our bodies so as to minimize the uptake of other harmful types of radiation.
The U.S. Department of Defense’s Army Medical Department Center and School explained in its book Medical Consequences of Radiological and Nuclear Weapons (Chapter 4):
One of the keys to a successful treatment outcome is to reduce or eliminate the uptake of internalized radionuclides before they can reach the critical organ.
The terms “blocking” or “diluting” agent can, in most cases, be used interchangeably. These compounds reduce the uptake of a radionuclide by saturating binding sites with a stable, nonradioactive element, thereby diluting the deleterious effect of the radioisotope. For example, potassium iodide is the FDA-recommended treatment to prevent radioactive iodine from being sequestered in the thyroid…. Nonradioactive strontium compounds may also be used to block the uptake of radioactive strontium. In addition, elements with chemical properties similar to the internalized radio-nuclide are often used as blocking agents. For example, calcium, and to a lesser extent phosphorus, can be used to block uptake of radioactive strontium.
After the U.S. military conducted above-ground nuclear tests on Bikini Island, scientists found that adding potassium to the soil reduced the uptake of radioactive cesium by the plants:
The first of a series of long-term field experiments was established on Bikini Island during the late 1980s to evaluate potential remediation techniques to reduce the uptake of cesium-137 into plants (Robison and Stone, 1998). Based on these experiments, the most effective and practical method for reducing the uptake of cesium-137 into food crop products was to treat agricultural areas with potassium fertilizer (KCl).
John Harte – Professor at the University of California at Berkeley in Energy and Resources and Ecosystem Sciences, a PhD physicist who previously taught physics at Yale, a recipient of the Pew Scholars Prize, Guggenheim Fellowship, the Leo Szilard prize from the American Physical Society, and who has served on six National Academy of Sciences Committees and has authored over 170 scientific publications, including six books - notes:
Marine fish are usually about 100 times lower in cesium-137 than are freshwater fish because potassium, which is more abundant in seawater, blocks uptake of cesium by marine organisms.
The same is true in mammals. The U.S. Department of Health and Human Services’ Agency for Toxic Substances and Disease Registry notes:
Cesium is a close chemical analogue of potassium. Cesium has been shown to compete with potassium for transport through potassium channels and can also substitute for potassium in activation of the sodium pump and subsequent transport into the cell.
Elimination rates of cesium may be altered by potassium intake. Following the intraperitoneal injection of 137 Cs in rats, a basal diet supplemented with 8–11% potassium resulted in cesium clearance of 60 days compared to about 120 days for rats receiving the unsupplemented basal diet that contained 1% potassium
(Richmond and Furchner 1961). After 20 days on the diets, rats receiving supplemental potassium had body burdens of 137 Cs that were one-half those of the rats not receiving supplemental potassium. This finding shows that supplemental potassium reduces the uptake and increases the elimination of ingested 137 Cs.
Dr. Ingrid Kohlstadt – a medical doctor with a master’s of public health, on the Faculty at the Johns Hopkins Bloomberg School of Public Health, editor of the best-seller Food and Nutrients in Disease Management – says that the same is true for humans:
Plutonium is treated like iron by our bodies. So getting enough iron will help reduce absorption of plutonium. And see this. (Plutonium is a very heavy element, and so normally cannot travel too far. Therefore, adequate iron intake is primarily important for those living in Japan.)
Here are the recommended daily allowances (RDA) for various minerals (data from the U.S. Department of Agriculture):
In addition to these minerals, getting enough of certain vitamins is helpful.
Numerous studies show that Vitamin C helps to protect the body against radiation.
Radiological health expert Daniel Hayes, Ph.D., of the New York City Department of Health and Mental Hygiene suggests that a form of vitamin D could be one of our body’s main protections against damage from low levels of radiation. Writing in the International Journal of Low Radiation, Hayes explains that calcitriol, the active form of vitamin D, may protect us from background radiation and could be used as a safe protective agent before or after a low-level nuclear incident.
“Vitamin D by its preventive/ameliorating actions should be given serious consideration as a protective agent against sublethal radiation injury, and in particular that induced by low-level radiation,” concludes Hayes.
It takes a couple of weeks or months to build up our body’s levels of Vitamin D. You cannot just pop a bunch of pills and raise your Vitamin D level. You should never take more than the recommended dose, and – even if you did – it wouldn’t raise your vitamin D level all at once. As such, we should start now …
Here are the RDAs for vitamins (data from the U.S. Department of Agriculture):
Antioxidant-rich foods also help protect you against low-level radiation. See this for the science behind antioxidant protection from radiation, tips on inexpensive, anti-oxidant rich foods ... and other valuable tips on how to protect yourself from radiation.
The bottom line: starting to saturate your body now with the right types of healthy vitamins, minerals and antioxidants can help protect you against radiation if it hits in the future.
Postscript: We only advocate taking the RDA for various nutrients, which is healthy for you anyway. We are not talking about mega-doses.
We have spent hours looking through medical journal articles for other foods which help protect against radiation. Here are the results.
For a more complete discussion of commonly-accepted scientific consensus on different prevention and treatment options, please review the Army’s Medical Consequences of Radiological and Nuclear Weapons and the The American Association of Physicists In Medicine’s Medical Management of Radionuclide Internal Contamination.
* You should not take potassium iodide supplements unless you are exposed to high doses of radioactive iodine, because it can damage some people's health. These supplements are only for short-term, high-dose ratiation protection, not for years-long low-dose exposure. For long-term exposures, a daily, baseline level of iodine is healthier.
Potassium iodide is found in most common table salt. However, if exposed to air, the iodine content can largely evaporate within a month or so. So store your salt in as air-tight a condition as possible. Also, it is important not to ingest too much potassium iodide, and most of us already get a lot of salt in our diets from processed foods. (The RDA for “sodium” – i.e. salt – is listed in the table above on the RDAs for various minerals)
Here is RDA for iodine:
And here are some iodine-rich foods.
Click here for a discussion by two medical doctors about preventative iodine doses.
Disclaimer: We are not doctors or health professionals, and this should not be taken as medical advice. Nothing contained herein is intended to diagnose or treat any condition.