Iodine not cause of hypothyroidism
DEAR DOCTOR: I take medication daily for hypothyroidism and borderline high blood pressure. Do I benefit from iodide in table salt, or should I buy plain salt for cooking?
DEAR READER:
Your question highlights how different Western diets are from those in other parts of the world, where iodine deficiency is a significant issue. (For this column, we’ll focus on the element “iodine,” but “iodide” is the safely ingestible form of it.) That deficiency is due to inadequate dietary intake of iodine, which is found in fish, seafood, kelp, vegetables grown in iodine-rich soil, dairy products — and salt.
Although sea salt also contains a small amount of iodine, many table salt brands in the United States contain much more. That’s because both Europe and the U.S. have encouraged the fortification of salt (and some other foods) to maintain adequate iodine intake in the population. Because of those efforts, launched in the U.S. in 1924, we’ve reduced health problems linked to low iodine intake. That’s not to say mild iodine deficiency can’t been found, especially
with more people consuming unfortified salt, just that it’s rare.
In any case, iodine is necessary for the formation of thyroid hormone. With low levels of iodine — a condition known as hypothyroidism — the levels of the thyroid hormones T4 and T3 drop. In trying to produce more thyroid hormone, the thyroid gland enlarges; the externally visible swelling is called a goiter. Low thyroid levels can be risky during pregnancy, especially in the first 12 weeks, when the mother’s thyroid hormone is necessary for the development of the fetal nervous system.
I wouldn’t worry too much about salt’s impact on your thyroid levels. The most likely explanation for your hypothyroidism — autoimmune thyroiditis — is not due to low iodine levels. In this country, hypothyroidism due to low iodine intake is rare.
Because of your high blood pressure, you should still be careful with your salt intake. Instead, increase your intake of fish, seafood and seaweed snacks. You can also get iodine from fortified breads, cereals and waters.