J Clin Endocrinol Metab. 1994 Feb;78(2):393-7.
Association between dietary iodine intake and prevalence of subclinical hypothyroidism in the coastal regions of Japan.
Konno N, Makita H, Yuri K, Iizuka N, Kawasaki K.
Source
Department of Internal Medicine, Hokkaido Central Hospital for Social Health Insurance, Sapporo, Japan.

"These results indicate that 1) the prevalence of hypothyroidism in iodine sufficient areas may be associated with the amount of iodine ingested; 2) hypothyroidism is more prevalent and marked in subjects consuming further excessive amounts of iodine; and 3) excessive intake of iodine should be considered an etiology of hypothyroidism in addition to chronic thyroiditis in these areas."
 
These coastal Japanese eat a lot of sea weed!
Just a caution....
 
Ray Audette
NeanderThin