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Potassium Iodide and Prussian Blue

March 18, 2011 Written by JP    [Font too small?]

No matter where in the world you’re reading this, you’re almost certainly aware of the crisis that’s unfolding in Japan. Among other things, the tragic events of this past week have drawn much attention to two otherwise obscure substances that are used to protect against radioactive fall out. Potassium iodide is the better known of the two. Prussian blue isn’t making much news yet, but that may change as the level of concern about radiation exposure continues to spread.

The most important details to note about potassium iodide and Prussian blue is what they can and can’t do. An awareness about the potential side effects also needs to be factored in before using either as a preventive measure without good cause. Here is some data I’ve collected for both radioprotective substances from the most reliable sources I know:

Potassium iodide (KI) is a stable form of non-radioactive iodine that protects the thyroid from radioactive iodine exposure. It does so by saturating the thyroid gland and essentially blocking entry of the radioactive form of this essential mineral.

According to Dr. Irwin Redlener, of Columbia University, potassium iodide is “not a radiation antidote in general”. In fact, KI is primarily beneficial for children and pregnant women whose thyroids are active and growing and more likely to absorb radioactive iodine. Dr. John Boice of Vanderbilt University goes on to say that in general, “it’s not recommended that adults over the age of 40 take potassium iodide. The benefit is miniscule because our thyroid glands are not that sensitive”.

Timing is vitally important when using KI. Taking it a few hours or so prior to radiative contact is best. However, it still may afford some degree of protection if administered up to three to four hours post exposure. (1,2)

While iodine is contained in some foods (select seaweeds in particular) and in iodized salt, the quantities present aren’t high enough or reliable enough to be used as an alternative to standardized KI pills. As such, dulse and kelp supplements that are commonly available in health food stores should be avoided for this purpose.

Finally, although iodine is an essential nutrient and generally considered safe, very high dosages can cause allergic reactions, “intestinal upset, nausea and rashes”, and “abnormalities of thyroid function”. This is why some leading natural health experts such as Dr. Alan Gaby have publicly stated that he “would not take a large dose of iodine without any clear evidence of radiation exposure”. (3,4)

Note: Appropriate potassium iodide dosages can be found on the Food and Drug Association’s Bioterrorism and Drug Preparedness page (link).

Thyroid Cancer Mostly Affects Younger Populations Exposed to Radiation

Source: HORMONES 2009, 8(3):185-191 (a)

Prussian blue is a vibrant blue dye that is capable of binding with radioactive cesium in the intestines, thereby preventing the radioactive material from being re-absorbed by the body. Once cesium is bound to the dye, it can be passed out of the body through normal elimination. Modern research indicates that the administration of Prussian blue shortens the retention or biological half-life of radioactive cesium from roughly 110 days to about 30 days. (5)

Prussian blue is only available by prescription. It’s typically given in a capsule dosage of 500 mg, 3 times/day for 30 days. Exact dosages vary based on age, body weight and degree of exposure. As is the case with potassium iodide, Prussian blue also carries the risk of certain adverse effects including: allergic reactions, constipation and intestinal upset. Experts advise that patients inform treating physicians about pregnancy, the use of other drugs and/or any stomach problems prior to beginning a course of Prussian blue.

No one knows for sure what the coming days will bring for the people living in the areas surrounding Japan’s Fukushima Daiichi nuclear power plant. Another unknown is how real the threat of radiation spread will be for regions far beyond Japanese borders. The only thing we do know for certain is that this yet another reminder that we all need to be prepared as best as possible in the event of any major emergency. The Centers for Disease Control and Prevention have a specific site that provides practical advice about how to prepare for and deal with a radiation emergency. Keeping a supply of potassium iodide and Prussian blue on hand appears to be a reasonable step to take as part of a larger preparedness effort. However, it’s important that we all understand that neither are radioactive panaceas and both should only be used as intended. (6)

Be well!


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Posted in Alternative Therapies, Detoxification, General Health

9 Comments & Updates to “Potassium Iodide and Prussian Blue”

  1. WP @ The Conscious Life Says:

    Thanks for the useful info, JP! I haven’t heard about prussian blue previously, so I’ve learned something new today! Thanks for pointing out that potassium iodide is not a cure-all for damages caused by radiation. It only protects the thyroid, and radioactive iodine is definitely not the only radioactive particle released in a nuclear fallout. There are also others like radioactive potassium, uranium and cesium as you’ve mentioned. Cheers.

  2. JP Says:

    Thank you, WP. 🙂

    Be well!


  3. Pat Veretto Says:

    I want to thank you, too. We’ve heard so much about iodine lately, that it’s good to have the facts!

  4. Orna Izakson, ND, RH (AHG) Says:

    Hi JP —

    I’ve been following this, too, as you can imagine. And while I see that the CDC site says the half-life of Cesium 137 is 110 days, everywhere else I look says it’s 30 years. For instance, this EPA site: http://www.epa.gov/rpdweb00/radionuclides/cesium.html. Or this one, from the US Department of Commerce: http://www.nist.gov/pml/data/halflife-html.cfm.

    The way I’m reading things, one of the main issues with Cesium 137 is not just initial inhalation, but rather soil deposition and resultant bioaccumulation up the food chain. I haven’t done a pubmed search to confirm, but this article says amending soils with potassium can help keep cesium out of crops: http://www.theregister.co.uk/2010/02/12/bikini_atoll_radiologically_safer_than_home/.

    The bottom line seems to be that radioactive compounds mimic certain needed vitamins and minerals. Radioactive cesium will fill empty spots where the body wants potassium, radioactive strontium looks for calcium deficiency, radioactive iodine, zinc and sulfur look for their nonradioactive analogues. What this tells me — dealing with people on the West Coast freaking out about potential radioactive plumes blowing east from Japan — is that general supplementation and repletion in cases of known depletion is the way to go here.

    So KI and Prussian blue is appropriate for people in and arguably around Fukushima Daiichi. But stateside, until we have a clearer idea of what’s actually heading our way, I believe seaweed and multivitamins are a great start.

  5. JP Says:

    Thanks, Pat!

    Be well!


  6. JP Says:

    What an excellent post, Orna! Thank you for sharing your insightful thoughts with us. Truly appreciated!

    Be well!


  7. Liverock Says:

    One good unintended consequence of the rush to start taking iodine, which people will do whether anybody advises them to or not, is the possible detoxing of heavy metals and fluoride.

  8. JP Says:


    My hope is that the (very high) potassium iodide dosage used to protect against radioactive iodine won’t be used without good cause. – especially over the long-term.

    There are certainly many upsides to getting enough/optimal iodine. But, as you know, more is not always better. I’m concerned that such a scenario could develop in instances like this.

    Be well!


  9. Jenna Says:

    I’m trying to heal my thyroid after a radioactive iodine ablation that happened when I was 15 and diagnosed with Grave’s disease/hyperthyroidism. Does anyone know how potassium iodide prussian blue might affect the damage that has been done to my thyroid already?

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