Trace Minerals: Iodine

Posted on by Paula Gallagher

yogurtIodine is next in our series, A to Zinc. Iodine is found in nature bound to other minerals in a “salt” formation. It appears naturally in soil as a trace element. Unfortunately, in many parts of the world, soil contains insufficient quantities of iodine and so it is added to salt to prevent iodine deficiency. Our bodies use iodine in the production of thyroxin, an important hormone that increases metabolic rate and regulates growth. Taken into the body as a water-soluble mineral in food, it is stored in the thyroid gland, where it is bound into active thyroid hormones: T-2, T-3 and T-4. Iodine also seems to be active in regulating estrogens. The recommended daily allowance for iodine is quite low: 150 mcg per day for adults, 220 mcg per day in pregnancy, and 290 mcg per day during lactation. Most healthy adults consume their daily requirement from food or iodized salt. More iodine may be needed if your diet includes high amounts of food containing “goiterogens,” naturally occurring substances that block absorption of iodine. Goiterogenic foods include cabbage, turnips, rapeseed (canola), peanuts, cassava and soybeans. Cooking deactivates goitrogens. Extreme iodine deficiency is rare in North America. Symptoms of deficiency include swollen thyroid gland, goiter and low metabolism. Supplementing with iodine should be done under the care of a health practitioner. Good sources of iodine are nuts and seeds, raisins, green leafy vegetables, turnips, bananas, watermelon, yogurt, shellfish, seaweeds, sea salt, fish, whole cereals and grains. Photo from here, with thanks.