Kelp is one of the best sources of iodine, a mineral necessary for thyroid health. It is a good source of other minerals as well, including potassium, magnesium, calcium and iron. Food Sources: Iodized table salt, seafood, bread, dairy products, seaweed. Causes of Defi ciency: A diet low in iodine-rich foods. Symptoms of Defi ciency: Obesity, sluggishness and hypothyroidism. Complementary Nutrients: Chromium. HOW IT WORKS: The body uses the trace mineral iodine to make the thyroid hormones that regulate growth, development, reproduction, body temperature and metabolism. Rich in iodine, kelp can be beneficial in cases of obesity caused by iodine deficiency and hypothyroidism. Iodine may also help treat cyclic breast pain.