Iodine deficiency in US, Canada rare
Dear Dr. Roach: Everyone has been told to reduce their sodium intake for many years. My mother was told this in the 1970s. Because of high blood pressure, she didn’t add salt to anything she cooked, and I mostly continued that practice when I got married. Many people no longer add iodized table salt to food. Over the past 15 years, my husband, adult daughter and I all have been diagnosed with hypothyroidism. Several members of my husband’s immediate family also have thyroid issues. Our adult son does not, so far.
Several years ago, I called a well-known soup company and asked if the salt in their foods contained iodine. I was told it didn’t.
I don’t know if that is accurate or whether most processed foods don’t use iodized salt. We know a lot of people with thyroid issues, and I wonder if lack of iodine could be the problem. Even though we are getting lots of salt/sodium in our diets, maybe we aren’t getting enough iodine?
J.C. Answer: Iodine deficiency in the United States and Canada is rare, with almost no severe deficiency, and moderate deficiency found in 1% of all people in the U.S. and about 6% of Canadians. In both countries, iodine deficiency is more likely in young adults than in children or older adults. Also, in both countries, iodine intake has reduced over the past decades, probably because of food companies (such as the soup company you called) using non-iodized salt and because of lower salt intake overall.
Dairy producers and commercial bakers also use less iodine than they used to. Still, there are many sources of iodine in the North American diet.
Severely low iodine intake is indeed a rare cause for low thyroid levels, although it is more likely to cause an enlargement of the thyroid (called a goiter). In areas of the world where there is adequate iodine, such as all North America, the most common cause of low thyroid levels is the autoimmune disease Hashimoto’s thyroiditis. This may run in families.
You should ask your doctor the cause for your family’s low thyroid level. It’s unlikely to be low iodine.