Re: Lugol's, while we're on subject
You're right to be concerned, absolutely.
Iodine is one of the trickier minerals to get right dosage wise. It feeds the thyroid and it's definitely one of those things where too much is toxic. Too much of a good thing is the same as taking a bad thing! argh! and
Iodine has a small threshold for error.
The problem is it is so insidious. A deficiency does terrible things throughout the entire body, including infertility. An overdose tends to just have one noticeable affect: an acne-like rash on the face/jaw. Lots of teensy tiny bumps as if the pores are goose-bumpy. When you see that, you know you've eaten too much seaweed. ;) If you don't see it, you could end up damaging your thyroid temporarily.
When people talk about using
Iodine to take out Giardia, they're usually talking about adding Iodine to water in order to purify it. to have that same principle work in the body is a huge longshot. The only time I ever used Iodine to take out the baddies is when backpacking, drinking from a stream, and even then we looked for something better, less toxic over time.