Iodine metabolism on normal diet in relation to prevention of goitre.

Abstract

Since it would require 2,000 years to drink enough Lake Superior water to accumulate 20 mg. of iodine, and since the normal adult thyroid contains about this quantity and at least 50 per cent of persons drinking this or similar water escape goitre, there must be iodine in foods. We found that a man twenty-three years of age, living in a moderately goiterous region (Minneapolis), consumed 0.057 mg. of iodine in three days on a normal diet, and excreted 0.021 mg. of iodine during the same period, having retained 0.036 mg. of iodine in three days. At this rate, it would require about five years to accumulate 20 mg. of iodine.

The question arises why in a goiterous region some persons have goitre and some do not. From the following data it may be seen that persons eating much roughage and drinking much milk of herbivorous animals would be immune to goitre.

The following table shows the cause for immunity in nongoiterous regions (figures denote mg. iodine per ton).