Worldwide, iodine deficiency is common. When a pregnant woman is iodine deficient, it can significantly and negatively impact the baby’s brain development or even kill the baby.
Iodized salt has long been the answer to this deficiency but with many people avoiding or at least decreasing their salt intake, iodine deficiency is becoming more common in developed countries. The best way to assess for an iodine deficiency is with a urine level of this element. A deficiency will be apparent on the results of this test long before the individual develops a goiter and has decreased thyroid hormone production.
Most iodine in the environment is in the form of iodide, and the majority of it is in seawater. Ground water and soil near the sea has the highest amount of iodide. Seafood is a major source of this precious chemical. Although seafood is often a good source of iodine, eggs and cheese also contain it. Drinking water is another source, but, of course, the content varies.
Most absorbed iodide is taken up by thyroid gland. It is incorporated into the thyroid hormones. When there is insufficiency iodine, the thyroid gland enlarges, producing the goiter many know is the hallmark of an iodine deficiency. An uncorrected iodine deficiency can lead to hypothyroidism. Thyroid hormone stimulates glucose to be metabolized for energy rather than stored as fat, thus weight gain and fatigue are common with hypothyroidism. Because thyroid hormone is needed by almost all tissues, there are many other signs and symptoms of hypothyroidism.
Iodine is needed for other body functions as well, so iodine deficiency extends beyond hypothyroidism. Not all those functions are clearly understood. Research conducted in Japan suggests an iodine deficiency may contribute to breast cancer development.