Iodine is a trace element and an essential component of thyroid hormones. The body does not make iodine; therefore, it is needed from the diet. In foods, iodine is not abundant. Some processed foods do contain iodine. Being an important mineral, the government has made it mandatory that salt contain iodine. Iodized salt is important to prevent deficiencies and salt is a medium that is commonly used in households for cooking. Since iodine is found in saline water bodies, produce grown in coastal areas contain a higher amount of iodine.

Iodine is needed to produce thyroid hormones thyroxine (T4) and triiodothyronine (T3). These hormones regulate many important biochemical reactions like protein formation, enzymatic activity, temperature regulation and metabolic activity. They also play a role in proper skeletal and central nervous system development in foetuses and infants.

Functions:

During pregnancy, iodine is an important mineral. Thyroid hormones ensure healthy growth and development of the foetus.  This produces healthy birth outcomes and prevents against miscarriages, still births and birth defects. Without sufficient iodine stores, an infant can have low birth weight.

Insufficient iodine during pregnancy can also cause an infant's weight to be abnormally low at birth. Iodine is also important for foetal brain development, myelin which conducts nerve impulses requires iodine. 

Besides regulating thyroid functioning, these hormones are important for the regulation of cellular activity and regulation of body temperature. They also help regulate blood glucose, utilize stored fats and other nutrients when energy is required.

Deficiencies:

A deficiency of iodine can have several negative outcomes, especially during pregnancy. This can result in mental abnormalities and retardation, which is often irreversible. A deficiency of iodine is known as hypothyroidism. This occurs when the gland does not make enough of the thyroid hormone. Since the thyroid controls your metabolism, lack of the hormone causes your metabolism to become sluggish. This affects your body temperature by lowering it (people with this condition tend to feel cold). It also lowers heart beat and your ability to burn calories.

Hypothyroidism is most commonly caused by Hashimoto's thyroiditis, which is an autoimmune disorder. The body produces antibodies that attack and destroy the thyroid gland.

Hypothyroidism causes weight gain due to sluggish metabolism. It can also cause tiredness and lethargy. Body temperature is also affected, those with this condition feel cold.

Sources:

Although sea vegetables boast an impressive amount of iodine, these are not very commonly eaten. Countries like Japan consume sea vegetables and sea weed as part of their diet. Other sources include- iodized salt, dairy foods that have been fortified with iodine (cheese, milk and yogurt), sea fish, shellfish, egg yolks, cranberries, strawberries.

Make sure that you use only iodized salt at home for cooking. Also include dairy products as part of meals. Fish is healthy and can be included in the diet twice a week, provided it is cooked in a healthy way with minimal oil.