Iodine insufficiency is a global problem, and is more complicated than iodine/ iodide intake alone.
Some may have adequate intake but uptake may be inhibited, thyroid function impaired, excretion increased, or digestion reduced by external factors.
The subject of impairment of uptake and function by various inhibiting factors in vegetable foods is discussed earlier in the thread.
Uptake and function inhibition may also be caused indirectly where they are uptaken by animals, and then eaten by humans as in dairy products. The amount of research in this area is limited but historic papers suggest it can in certain circumstances be a real issue.
I raise it here as it is a factor that might have historically contributed to the specific regionality of goiter in Switzerland. Are gotregenic plant present in significant amounts in some Alpine pastures - I have no idea, but it is an interesting question.
THE EPIDEMIOLOOY OF ENDEMIC GOITRE IN THE EASTERN PACIFIC REGION*
http://iris.wpro.who.int/bitstream/h...re_1966_en.pdf
"Practically the whole of Tasmania is goitrous. In 1949 Clements examined 8000 schoolchildren and found visible goitres in approximately 6% of boys and 20%. of girls in the age-group 12-14 years.
Iodine therapy did not control goitres in some areas. Clements and Wishart later suspected a goitrogenic substance in cow's milk which interfered with the synthesis of thyroxine and so the subjects drinking that milk were not amenable to .the standard iodine preventive measures. The goitrogenic substance was consumed by cows feeding on pastures containing a certain variety of Brassica; the children were being given increased quantities of milk under a free milk scheme. later, a goitrogenic iso-thiocyanate was isolated from these plants and the milk of the cows eating them (Bachelard and Triltojus, 1960)."