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[at-l] iodine for a thru-hike

Hello all --

Charlie and I have been discussing long-term iodine water treatment (i.e.
thru-hike) over the past couple of weeks, and I thought I'd post to the list
what I have found out, together with Charlie's input, about the subject.
DISCLAIMER: "I am a pharmacist, not your doctor.  While I have searched
various references and talked to other pharmacists and doctors about long
term iodine treatment and I am providing the best info that I can, remember
that the suggestions given below can in no way apply to _everybody_ on this
list. If you already have tyhroid problems or family history of such, check
with your doctor before using iodine to treat your water.  Stop iodine
treatment if you experience any of the side effects listed below."  Sorry,
but had to say all that to cover my butt. 
Also, if any are interested, I can put together a "hiker's guide to common
drugs" over the next few weeks.  Any suggestions as to what to include?

Anyway, here it is.  I tend to be a little wordy, so bear with me....

Got the treatment guidelines from the CDC home page  
        http://www.cdc.gov/travel/yellowbk/page182c.htm


Treatment of Water with Tincture of Iodine (2% solution of iodine, 20mg/ml)
Drops to be added per quart or liter
    Clear water - 5 drops (equals 5mg)
    Cold or cloudy water - 10 drops                
    1 drop = 0.05ml
                  

A Potable Aqua tablet contains about 8mg iodine per tablet.  My guess is
that most iodine water treatment solutions or tablets deliver 5-10mg iodine
per liter of water in order to comply with the CDC.  If you figure that a
hiker will consume 8 liters a day, thats a total of 40-80mg iodine a day, or
more if the water is really dirty/cloudy. Here is where it gets a little
weird.  The US RDA of iodine for a normal adult male is 150 MICROgrams (0.15
milligrams).  (For children up to 10 years old, its about 100micrograms)
So, according to the above calculations, a thru-hiker treating his water
with iodine could receive up to 500 times the RDA of iodine.  Wow!  Remember
also that normal table salt is "spiked" with iodine at a concentration of
about 100micrograms per gram of salt.  That's why there are barely any
reports of iodine-deficiency induced hypothyroidism in the US.  There is
hardly anyone in the US that eats only a gram of salt a day, so most of us
already exceed the USRDA anyway (but not by 500 times!!).

The following is a quote from a very well-respected pharmacology text,
Goodman and Gilman's (my comments are in brackets[]):  "In euthyroid
[normal] individuals, the administration of iodide from 1.5 to 150mg daily
results in small decreases in plasma [blood] thyroxine and triiodothyronine
[thytroid hormones] and small compensatory increases in serum [blood] TSH
[hormone that stimulates the thyroid gland] values, with all values
remaining in the normal range."

This means mega doses of iodine will very slightly decrease the activity of
the thyroid gland causing a small decrease in thyroid hormone.  But the
values still stay in the normal range, so all is OK.  Note that this is for
the NORMAL individual with no history of thyroid problems.

More quote: The most commonly prescribed iodine-containing drugs are certain
expectorants, topical anitseptics, and radiology contrast agents.  
  
I know of a heart medication that contains 75mg of iodine per tablet
(Amiodarone),  and many people on are on this medicine for years.  But the
important thing to remember is that these patients have normal thyroid gland
function to start with, and their thyroid hormones are monitored twice a
year to make sure the drug is not screwing things up.

Strangely, iodine is used to treat hypothyroidism (under producing thyroid)
in patients with iodine deficiency (ever see a goiter?) but more commonly it
is used to treat hyperthyroidism (over producing).  Its use in
hyperthyroidism is not very well understood, but for some reason it works.  

To make a long story short, it APPEARS to be OK to treat water for a long
period of time with iodine and not have any effects __as long as you don't
have thyroid problems to start with__.  The body can pee out what it doesn't
need to some extent.

Possible side effects of high iodine levels (iodism):
umpleasant brassy taste and buring in the throat, as well as soreness of
teeth and gums; increased salivation; sneezing and itching of the eyes with
swelling of the eyelids; "head-cold" like symptoms; severe headaches that
originate from the frontal sinuses; irritation of mucous glands in the upper
respiratory tract causing a productive cough (expectorant action); swollen
salivary glands, resembling mumps; skin lesions, some being very nasty;
diarrhea, which may be bloody; fever; anorexia; depression.  

Sounds like the description of your average thru-hiker, huh? <VBG>

All of these side effects of iodism disappear spontaneously within a few
days of discontinuing administration of iodine.  I would definitely stop
iodine treatment immediately and switch to filters if any of these symptoms
appeared.  The hard part will be figuring out if you just have a "head-cold"
due to a virus or if its due to the iodine.  I don't know how to get around
that one. 

Maybe it wouldn't be a bad idea to get a complete physical, including a
thyroid work-up, before going on a thru-hike, especially if you are going to
use iodine tablets to treat all of your water.

It does not appear that iodine can affect the absorption or metabolism of
energy sources, except maybe as a consequence of some of the side effects
noted above.

Are there any thru/long distance hikers out there that used iodine for
extended periods of time?  Have any side effects or problems? Would like to
hear from you.

Happy thyroids,

Bruce





  
Bruce A. Waldrop, RPh
College of Pharmacy
Division of Pharmacology and 	
   Experimental Therpeutics
University of Kentucky
Rose Street
Lexington, KY  40536-0082
Lab: (606) 257-2556
Fax: (606) 257-1460
e-mail: bawald0@pop.uky.edu

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