Manganese

I've seen a few folk blaming Iodine for one problem or another, but blaming an essential mineral like iodine, is equivalent to blaming calcium or any other mineral. I would wager it is almost always the case in the instances of "problems" with iodine, that the causative issue is not the iodine, but elsewhere. Think of what this passage means:

"Most of the vitamins of the B group are helpful. But B1 should be used with caution especially in cases with a history of thyrotoxicosis and in the early stages of the disease. For unless it is balanced with the manganese intake, it may seriously aggravate the effects of the manganese deficiency." E.M. Josephson, MD pp.97 of "The Thymus, Myasthenia Gravi, Manganese" Chedney Press 1961

Or

"Deysach and Ray (352) and Baumann and Metzger (353) reported that Mn salts injected in rats and guinea pics accumulate selectively, for a time, in the thyroid. The latter suggested that Mn may temporarily displace Iodine in the thyroid, and that this might lead to an upset of thyroid function and block the normal assimilation of Iodine by the gland." ibid, pp 85 Tweet