About 90% of the iodine that a person consumes is absorbed by their body. Iodine is an essential nutrient for a healthy body. Iodine can come from a variety of sources from vegetables to marine animals, kelp, and seaweed. Marine sources have the highest content of iodine. Iodine is used by the thyroid gland for the production of thyroid hormones. Iodine can also be found, in smaller amounts, in other gland throughout the body. The kidney is responsible for excreting iodine. When a person suffers from an iodine deficiency, the brain is the most effected due to the involvement of the thyroid hormones in the central nervous system.