While table salt has iodine, the amount is barely enough to prevent goiters. Moreover, popular non-iodized sea salts and salts in processed foods often lack iodine, limiting its presence in modern diets. Consequences of Iodine Deficiency: ...
Sargassum is edible, it’s harvested to feed livestock too, and you can fry, boil, steam or dry it. It’s played a part in Chinese medicine as far back as the 8th century, treating goiters (high iodine content) — and made into tea to control phlegm. Why so much? No clear answer!