Dear Mayo Clinic: I rarely use table salt anymore when cooking. Instead, I like to use sea salt. But I’ve noticed that a lot of sea salts don’t contain iodine. Do I need iodized salt, or are there sources of iodine other than salt that are likely giving me all of the iodine I need?
For most people, iodized salt is probably the easiest way to maintain sufficient iodine intake. Iodine is an important nutrient that your thyroid needs to produce certain hormones. Not getting enough iodine in your diet can lead to problems such as an enlarged thyroid gland (goiter) and an abnormally low level of thyroid hormones (hypothyroidism).
Iodine is a trace element present in the earth. Distributed variably around the world due to the effects of the ice age, iodine has accumulated primarily in coastal areas. The most common dietary sources of iodine are seaweed, fish and dairy products. Inland areas have fewer natural sources of iodine. In the U.S., areas where iodine deficiency was common in the early 1900s — the Great Lakes, Appalachians and Northwest — were known as the “goiter belt.” Researchers from these areas encouraged the U.S. to adopt table salt iodization as an inexpensive, yet universal, way of providing iodine supplementation.
Other sources of dietary iodine include eggs, enriched grain products and plant foods grown in iodine-rich soils. Unfortified sea salt contains only a small amount of iodine.