They acknowledge that most of the world is deficient in iodine, unfortunately their recommendation is to up the content of Iodine in iodized salt, and they claim that there are problems with Iodine over 2 mg! I scanned the full PDF,
here's the relevant excerpt:
"an excess of iodides impairs the Iodide pump (and NIS) and the cellular trophism of I-concentrating tissues, resulting
in functional damage, including the well-known Wolff-Chaikoff effect, which occurs in the thyroid even with a
dosage just in excess of 2 mg, as well as degenerative and necrotic lesions in some other I-concentrating tissues
(salivary gland and gastric mucosa). Joanta et al. (2006) reported that I-excess exerts oxidative stress in some
target tissues, in fact I-excess has pro-oxidant effects, leading to an increased lipid-peroxides level and catalase activity
in target tissues and in blood. Inorganic iodine regulates the production of epidermal growth factor (EGF) in isolated
thyroid cells, and controls DNA synthesis and cell proliferation (Tramontano et al., 1989); this action probably occurs
in salivary glands and in gastric mucosa too. "
Maybe the Wolff-Chaikoff effect has been discussed here before. I looked it up
"The Wolff–Chaikoff effect, discovered by Drs. Jan Wolff and Israel Lyon Chaikoff at the University of California in 1948, is a reduction in thyroid hormone levels caused by ingestion of a large amount of iodine."
I'm still pretty new to all this and would welcome input...