The case for iodized salt

Imagine how just over 100 years ago, nearly one-third of people in the upper Great Lakes and upper Midwest regions walked around with a goiter on their neck. A goiter is a lump on the throat, which could be as big as an orange, a grapefruit or larger. Actually an enlargement of the thyroid gland, a goiter can come from an overactive thyroid gland, an under-active thyroid gland or an autoimmune condition, but in the United States before the 1920s, the reason was almost always deficiency of iodine.

Iodine is required for making thyroid hormones. In addition to having a goiter, those with iodine...