Iodized Salt
Iodine was first added to table salt in the United States in the early 1920s to help reduce the occurrence of goiters, or swelling of the thyroid gland. Now, both uniodized and iodized salts are sold in the US. Iodized salt contains approximately 71 mcg of iodine in ¼ teaspoon of iodized salt, which is about 47% of the daily recommended intake. Salt also contains high levels of sodium.
Over the past 10 years, the consumption of iodine has reduced in the United States. This is because many health organizations have moved to reduce daily sodium intake to prevent or reduce high blood pressure. Note that salt only increases blood pressure in people that are highly sensitive to salts, which is about 25% of the population.