Once, a friend told me that he was eating a lot of kelp for iodine these days because he had a thyroid nodule during a physical examination. I was very surprised. He had made a serious mistake that had to be corrected. For a long time, people have been more aware of iodine deficiency caused by endemic goiter (commonly known as “big neck” disease), this is due to the government and related institutions of iodine deficiency disease in-depth, lasting publicity.
However, the situation has changed a lot. With the implementation of iodized salt policy and the popularization of iodized salt, endemic goiter and other iodine deficiency diseases have been basically eliminated in most areas of China. Thus, current thyroid diseases are largely unrelated to iodine deficiency. On the contrary, there is evidence that excessive iodine intake can also cause thyroid problems.
Thyroid nodules, hyperthyroidism (hyperthyroidism), thyroiditis (such as Hashimoto’s thyroiditis), thyroid tumors, thyroid cancers, etc. may be associated with iodine excess. So, with the mandatory iodized salt, are we getting too much iodine? It has become a saliva issue, with some saying too much (which means iodized salt is harmful) and others saying not too much (not reaching the maximum tolerable amount of iodine).
In fact, the Ministry of Health has officially lowered iodized salt standards this year, reducing the iodine intake of Chinese residents. And it is becoming easier to buy non-iodized salt everywhere. Let’s leave aside the question of whether there’s too much iodine.
The next question is, already suffering from thyroid disease, such as thyroid nodule, hyperthyroidism (hyperthyroidism), thyroiditis (such as Hashimoto’s thyroiditis), thyroid tumor, thyroid cancer, whether to eat kelp to fill iodine? Should I continue to eat iodized salt?
The answer is NO!
The thyroid gland is actually made up of 3 million follicles, each 15 to 500 microns in diameter. Follicles are sac-like structures surrounded by a single layer of epithelial cells and are secretory units of the thyroid gland. The follicular epithelial cells take up iodine from the blood and synthesize thyroid hormone, which is then stored in a jelly (thyroglobulin) in the follicular cavity. The ability of follicular epithelial cells to concentrate iodine in hyperthyroidism is known to increase by 100 to 200 times, which means that a hyperthyroidism patient can consume only 1% of the iodine required by a healthy person.
On the other hand, iodine can also stimulate the follicular epithelial cells to become larger and more numerous, which can make the thyroid tissue that already has “hyperplasia” (diffuse enlargement, nodular hyperplasia, tumor) even worse.
Therefore, the above thyroid disease patients should avoid high iodine food (kelp, seaweed, wakame and other seaweed) intake. At the same time, the intake of iodized salt should be reduced, a low-salt diet should be adopted, and all or part of “non-iodized salt” should be selected.