Iodine is a micronutrient used by the thyroid to support the creation of thyroid hormones. It does this by adding iodine to the amino acid tyrosine. Its only function in the body is for thyroid hormone synthesis. Thyroid hormones are required to keep our bodies functioning and help us with a variety of processes, such as how to utilize energy properly. The thyroid gland supports the function of the brain, heart, muscles and other organs.
The trick here is balance. Either too much or too little iodine could be an issue. An iodine deficiency may lead to hypothyroidism (low iodine is not the only cause of this, though) or eventually an enlarged thyroid gland, commonly referred to as a goiter. If someone consumes too much iodine, it may inhibit thyroid gland synthesis. The Recommended Daily Allowance (RDA) is 150 micrograms with a maximum level of 1,000 micrograms.
Iodine is most often found in iodized table salt, seafood (including shellfish, fish and seaweed), whole grains, vegetables and dairy. Generally speaking, iodine deficiency has been rare in the U.S. due to the addition of iodine to table salt. However, the increased use of non-iodized salt, such as Himalayan pink salt, kosher salt, sea salt, etc., may affect those individuals who do not use iodized salt and are not regularly eating enough iodine-containing foods .
If someone follows a vegan diet and does not use iodized salt, they may still be reaching their daily needs with a diet rich in vegetables, seaweed, and whole grains. There is one point to mention, though, regarding goitrogens. Goitrogens are foods that release goitrin when broken down, which may interfere with iodine metabolism and thyroid function. Overconsumption of cruciferous vegetables (brussels sprouts, broccoli, cabbage, etc), soy products and millet may be an issue. However, I would like to note that only people low in iodine seem to have an issue with goitrogens.
If you follow a vegan diet and eat many cruciferous vegetables, then using an iodized salt or a possible iodine supplement may be a good addition to your routine.
Chef Abbie Gellman, MS RD CDN is a spokesperson, recipe and product developer, educator and nationally recognized culinary nutrition expert. She creates, produces and hosts cooking and nutrition videos and works with a wide variety of food companies/brands, commodity boards, foodservice operators, health professionals and private clients. She appears in local and regional broadcast media and contributes to many publications as both an expert and an author; her first cookbook, The Mediterranean DASH Diet, was published in November 2019, and her second cookbook, Mediterranean Pressure Cooking, was published in December 2020.