Where does 'excessive' levels get defined??

[Guest guest]

Hi everyone,

I've been reading about iodine for a while now, and I have not seen any

reference to where anyone has come up with 'excessive' or 'toxic' levels

of iodine. Yet, I came across it once again. I was apprehensive about

supplementing at first because I found information about it being toxic

starting at 1100 mcg per day. That was last year and couldn't say

exactly where I read that.

A new book at the library caught my eye this week and I checked out " 100

Questions and Answers about Thyroid Disorders " by Warner M. Burch MD.

He repeats the 150 RDA and states the 'excess' level to be 1,000

ug/day. The 'u' is a special symbol I don't know how to access with my

keyboard, and if my understanding is correct, a ug is the same as a

microgram.

To briefly quote the answer to question 24 about what causes

hypothyroidism, he says:

" Iodine deficiency is by far the most common cause of hypothyroidism

worldwide. Some 29% of the world's population live in regions of iodine

deficiency (see question 8). Less known is the fact that, in some

individuals, iodine excess (greater than 1,000 ug/day) causes

hypothyroidism by blocking thyroid hormone synthesis. Normally, the

thyroid protects itself by escaping from the effect of too much iodine.

However, patients with unidentified thyroid disease are particularly

susceptible and do not overcome the blockade of excessive iodine,

leading to hypothyroidism. This is not a problem for hypothyroid

patients already taking levothyroxine. In these treated individuals who

have no thyroid, iodine has no effect. "

No citations are listed. In fact, the entire book has no bibliography

at all. He has a question about natural thyroid also to which he

concludes:

" ...to determine whether you are taking natural thyroid is open the pill

bottle and sniff. If it stinks, you have 'natural' thyroid. When

referring to use of desiccated thyroid for thyroid hormone replacement,

it is often said that 'natural thyroid is natural only to pigs and not

to humans.' "

The author is professor of medicine at Duke University with 32 years of

experience and examinations of 20,000 individuals. No mention of ties

to pharmacuetical companies are mentioned, but I have to wonder how

would one find out what his ties might be. The only snide remarks he

had about levothyroxine was in regard to the generics and how it would

probably be better to take the name brand. Seems to me there's

something besides desiccated a thyroid pill that stinks here. I'm sure

there will be several group members with opinions! Sorry this got so long.

Jana