Aside from resulting in goitre, iodine deficiency can lead to dry skin, hair loss, fatigue, and slowed reflexes. Iodine deficiency is especially serious in the developing fetus and young child. Lack of iodine is a major problem in developing countries and is considered to be the world's number one cause of preventable intellectual disability in children. Another group that may be at risk of iodine deficiency is vegetarians if they do not eat seafood. Instead they can get their iodine from iodised table salt, or seaweed.
Iodised salt is the most common source of iodine in the Western Diet.
An adult only requires approximately one teaspoonful of iodine throughout their life, so eating fish once a week will be enough to fill this requirement. Some vegetables may contain iodine, but only if they are grown in iodine-rich soil. Milk has also been known as a source of iodine due to contamination by cleaning solutions containing iodine that were used in the dairy industry. However changes in processing techniques have now reduced the levels of iodine found in milk. The value of iodine can be reduced by vegetables from the brassica family, which includes cabbage, brussels sprouts, raw turnip, broccoli, and cauliflower.