Saturday, March 26, 2011

Why Take Potassiuim Iodide in a Nuclear Crisis?

This post will address I-131, Potassium Iodide and the pros and cons of its use during the current Japanese nuclear crisis.

To understand this question, you first must understand the basics of thyroid function. 

The thyroid is a gland that secretes hormones responsible for the metabolism of every cell in your body.  This gland utilizes Iodine to make these hormones.  The two main thyroid hormones are called T4 and T3.  The numbers 3 and 4 indicate how many molecules of iodine the thyroid has attached to create the hormone.  T4 is storage hormone - the body can't use it with 4 molecules of iodine attached, it must convert it to T3 when needed before the body can use the hormone.

If your thyroid is an engine, Iodine is the fuel.

Potassium Iodide is a form of iodine that the thyroid uses for fuel to make T4 and T3.

The body needs a precise amount of iodine at any given time.  Excess iodine is flushed out of the body when the thyroid and the body are working properly.  Sometimes the thyroid doesn't work properly.  If a person is only taking in an appropriate amount of iodine in each day, they may not realize they have a thyroid problem.

The thyroid has an 'emergency overload system' that tries to prevent an accidental overdose of T4 and T3 because you might have eaten too much iodine.  If you consume lots of iodine, the thyroid senses this and shuts down.  It stops using iodine and stops producing thyroid hormones.  This process is not immediate - it takes some time for the thyroid to sense the extreme overload and shut itself down.

About Radiation risk:

The nuclear radiation in Japan that everyone is talking about right now is in the form of I-131.  In this case, the I stands for Iodine.  We are talking about radioactive iodine - the same substance used in thyroid cancer patients and Graves' Disease patients to destroy (ablate) their thyroid tissue and tumors.  

Radioactive substances are measured in part by their "half-life".  Their half life is the time of period it takes for half of the radiation to dissipate.  The half life for I-131 is about 8 days.  This means if you are exposed to 30 millirems of I-131, in about 8 days your radiation levels will be about 15.  8 days later it will be about 7.5.  8 days later it will be about 3.75 and so on....  Millirems is an older term that is being replaced in many countries by the term Millisieverts.  10 Millirems = .1 Millisieverts.

To give you an idea of how many MIllisieverts might be dangerous, let me give you some examples:

A chest X-Ray exposes you to about .1 Millisieverts
A CT of the abdomen is about 10 MIllisieverts
The average exposure of evacuees of the Chernobyl disaster was about 31 Millisieverts
The spike noted in Japan was about 400 Millisieverts
Radiation sickness begins at about 1 Sievert (1000 Millisieverts)

This said, there is much evidence that there is increased danger of cancer to those who undergo x-ray imaging and CT scans.  Chernobyl victims have an increased history of cancer too.

Taking too much potassium iodide with a normal acting thyroid can cause a condition called Thyrotoxicosis.  This means the thyroid pumps out too much thyroid hormone creating an acute hypERthyroid state that can be dangerous, or even fatal.  In those with thyroid disease - either diagnosed or undiagnosed - the chances of thyroid storm or thyroid toxicosis is greatly increased.  For some diseases such as Graves' Disease or for those with "hot" thyroid nodules it is a virtual surety.

Why do we take potassium iodide in a nuclear crisis?

Our thyroids are built to absorb iodine and use it to produce T4 and T3.  Those with poor diets are often slightly deficient in iodine.  This makes our thyroids slightly "hungry" for iodine.  When iodine is absorbed in any form ( the body doesn't care what form you take it) the thyroid acts like a sponge and tries to absorb it all.  When that happens, it turns it into T4 and T3 and those hormones end up in the bloodstream.

I-131 damages thyroid tissues.  Unfortunately it also damages other tissues in the body as well, but it is especially good at killing the thyroid.  This is why it is used in Graves' and cancer patients.

Potassium Iodide (and any other halide) can block I-131 from attaching itself to your thyroid.  It helps to prevent thyroid damage from the radioactive iodine because the I-131 will then be excreted out of the body.  It is vitally important that potassium iodide (KI) is taken only immediately before exposure to I-131.  KI will stay in your system about 24 - 72 hrs after swallowing it.   KI may help to protect your thyroid from the damage of I-131, but it does nothing to protect the rest of your body from I-131 damage or damage by other types of radioactive isotopes.

Here are some of the possible implications of KI use:

++ becoming hypERthyroid
++ unmasking a dangerous thyroid condition you didn't know you had
++ hypOthyroidism caused when the thyroid shuts itself off

Both hypERthyroidism and hypOthyroidism left untreated can be fatal, so this is quite serious. 

There is much controversy about the stockpiling many people are doing with potassium iodide.  Right now experts tell us this is really unnecessary in the United States, but probably very useful in Japan where the risk from radioactive I-131 is measurable.  Those living within a certain range of nuclear plants in the United States are already provided with a supply of potassium iodide for their protection should a nuclear incident occur.  These folks should keep this on hand, but it is otherwise probably unnecessary for others to do so.

It should be noted that the iodine in table salt is also protective for your thyroid, but it is unlikely you will be able to consume the amount of iodine through that route without doing other damage to your system by way of the salt the iodine is attached to.  Consuming too much salt is dangerous and should be avoided.

If you are deficient in iodine, making sure your body is tested and being fed the appropriate amount of this trace mineral is helpful for your health overall, taking into consideration of course that you have been cleared from autoimmune and other thyroid problems that could potentially lead to hyperthyroid toxicosis or storm which is very damaging and could even be fatal.

There is a much greater damage in the United States from bromide and fluoride (both halides and from the same family as iodine) blocking the body's use of iodine than a risk of radioactive I-131 hitting our shores from Japan.  If you are concerned about your thyroid and your health from a very realistic standpoint, testing for fluoride and bromide levels should be a part of the testing you do to find your iodine and thyroid status before considering the supplementation of potassium iodide or other form of iodine for any reason.

I have written frequently about autoimmune thyroid disease here at WEGO Health and a quick search through the archives will reveal many other articles as well.  Autoimmunity of the thyroid is highly under-diagnosed as is iodine deficiency, so finding a doctor who specializes in thyroid care is tantamount to receiving not only a proper diagnosis but also appropriate treatment for this important condition.

 JordanB on March 28, 2011 at 2:41pm
While I agree that this is a real issue in the areas directly affected by the recent (and ongoing) nuclear disaster, in the US it is just the latest irrational scare fad. In the last few weeks I've seen a number of stories on the AP wire and in other news outlets on iodine pills and on how at risk people are in the US. Nuclear power is still the sector of the energy industry with by far the fewest deaths associated (you run an exponentially greater risk of dying from being struck by lightning). It's just fascinating to see the hype-machine behind this as the dozens of articles dissecting risk of exposure to the US all invariably seem to wind their conclusion to a fairly unqualified "no".

Still, thank you Ellen, it's good to read an article which goes some towards quelling the cycle of irrational public response and action. I won't go running out for the iodine pills any time sooner than I'll start practicing "ducking and covering" under my desk.
Comment by Ellen S on March 28, 2011 at 4:05pm
Jordan, I'm glad you see the direction I was subtly heading with this.  It is not a bad idea to have potassium iodide tablets on hand if you live near a nuclear facility, but as I stated in the article, those at risk are provided those when the plant goes live.  They know who they are.  As far as stockpiling them, I do believe in preparation, but it's unfortunate that most people have gone from wanting to be properly prepared for a disaster to obsessed with being over-prepared for everything under the sun.   Potassium iodide can be dangerous - very dangerous - if not used appropriately.  If folks are going to keep it on hand for whatever reason they choose, they need to be educated about it...
Comment by Joan Penfold on March 30, 2011 at 10:49am
I live within 30 miles from a Nuclear Power Plant and it's alarming system is going off as it is detecting the radiation from Japan.  I actually find it comforting that it can pick up such a small amount of radiation so if it ever has a problem we will know early enough!
I try to speak with my son regarding the amounts being found in the US as he is a Nuke in the navy and I get complete silence and he either can't or wont answer me.  That does bother me a little but I think if it was a real issue he would somehow let me know.
Comment by Ellen S on March 31, 2011 at 10:43am
Joan, AppRoximately where in the US are you currently living?
Comment by Joan Penfold on March 31, 2011 at 10:58am
I am in Florida near the Crystal River Nuclear Power Plant.
Comment by Ellen S on March 31, 2011 at 11:10am
Joan, I've been there! Beautiful spot to call home. I didn't know that anybody in the US was detecting anything (nuclear plant wise anyway). I'm on the west coast right now hoping all will remain okay here as the Japanese struggle so in their country. As an RAI patient, I don't think any I-131 is good and sure wish it wasn't a worry for anyone. With the high dose I got as treatment before, I'm sure not excited about being exposed to more... For any reason or in any amount.
Comment by Joan Penfold on March 31, 2011 at 11:19am
The leaks over there are alot worse as there are more meltdowns Ellen in more reactors and yes it has been detected over there before here!  Hawaii really has high numbers but they are so close. I know that about 3 plants with newer monitoring devices like here have been alarming.  Where are you on the west coast?  I don't like this whole thing at it is the object of many nightmares throughout my life and one of my biggest fears, and yet I moved near a plant, go figure!
Japan has 17 plants, with a majority on the water. They are frantically trying to update now before they have another Tsunami.  They continue to have quakes, this week another at 6.5 and it is all unstable over there.  My son does have some friends that were sent there and I pray he stays where he is at, Charleston SC, teaching at Navy Nuke school!
Sigh, it is a worry but life must go on, but have had to increase my Xanax here and there!
Comment by Joan Penfold on March 31, 2011 at 5:59pm
Comment by Ellen S on April 1, 2011 at 10:11am
Joan, I saw a story on this tonight. Most are downplaying it, which I have mixed feelings about. You see they discuss I-131 and compare it to the radiation from the sun. Yes the body gets radiation from the sun, but that is body-wide. I-131 concentrates eventually in the thyroid which is a very tiny gland that is easily damaged. I haven't had a chance yet to look up the numbers, but if you consider the fact that damaged thyroids and those that are malfunctioning are already terribly prevalent, one must wonder what this additional damage, no matter how small, might eventually result in. How long will milk be tainted? Days? Years? If it is in milk, it will also be in meat and plantstuffs. Thyroid patients already have difficulty getting a diagnosis from doctors who are lacking in up to date rudimentary knowledge in how to diagnose and treat these patients. I suppose the good news might be that if more cases of thyroid disease or cancer become a problem that these doctors may be forced to become better educated and the result may be better treatment for all. As for me, I will not downplay even a little radiation because ft increases the load and burden of the radiation we already are exposed to. For those like me who have already had a large load due to medical treatment or diagnosis, every little bit counts... especially if we hope to live many years into the future... especially when we really are not sure what that future may bring. A reason to panic? Probably not, but certainly at least a reason for caution and to educate ourselves and our communities. I wish I could give a snapshot to what thyroid communities - especially Graves' communities are discussing from day to day re: this type of radiation...
Comment by Joan Penfold on April 1, 2011 at 11:12am
I  know they are down playing all of this.  Many years ago I was diagnosed with Hoshimotos but now test negative for any Thyroid issues.  Thank GOD as I have enough to deal with!
I have probably had 6 Cat Scans in the last year and cant tell you how many in the last 5 years and that is more radiation than I want to be exposed to and now this? I think it will be getting a lot worse as the reactors meltdown more as they do not have control of it at all.  We should all walk around with dosimeters on! I think we would me amazed.
I think back to my grandmother years ago when there was not iodized salt and she passed with a huge goiter finally choking her to death.  Makes me wonder, with genetics, how I will be affected. I am told several of my diseases are hereditary but we can't seem to trace back.
I think if I try to discuss this with my Drs I would be thought of as paranoid! I already drill them but I am going to drill them again and they will have to deal with it as the radiation levels are only going to increase.  FYI the beef in Japan is already affected, the nearby sea water is radiated so it is affecting fish, will that travel to our sea water? There is so much uncertainty.
I am wondering what happened with all the radiation from chernobyl as I do not remember the hype, but then again I was much longer and thought I was invincible!
I can ramble on but will save for further discussion.

Comment by Joan Penfold on April 1, 2011 at 11:13am
Darn I cant go back and edit. My eyes are barely open this morning as I had a bad night. Hope you can read between the mistakes!
Comment by Ellen S on April 1, 2011 at 6:59pm
Joan, the good news is that I-131 has a short half life.  This means that it doesn't remain super active for a long period of time.  In the case of I-131 the half life is about 8 days.  This means in reality the greater danger to the food supply for right now is the effects of exposure to I-131 which is either prolonged or too high.  I-131 does cause cancer and it does cause thyroid damage and can trigger autoimmune disease in some people.  Additionally, those with Graves' Disease may suffer terribly with too much iodine of any kind including I-131 as this can cause a disease flare that can be very serious.  For anything or anyone exposed to high levels of I-131, they will remain carriers of this radiation for longer periods of time, potentially exposing others to the radioactivity which can damage them as well.  To be honest with you, there is probably much greater danger form those who have undergone I-131 medical treatments and are out wandering around the public - sitting in airplane seats next to our children or pregnant moms, standing next to us in the grocery store or even contaminating bed linens at hotels.  We don't know when we come into contact with these folks and are exposed.  Animals are kept in strict quarantine for a minimum of a month when they undergo the same treatment.  People are not.

No comments: