What are the consequences of iodine deficiency?

• A. Iodine is needed for thyroid hormones; deficiency leads to goiter and hypothyroidism and can cause cretinism in severe fetal iodine deficiency.
• B. Iodine is the main energy source for metabolism.
• C. Iodine increases blood calcium.
• D. Iodine is only needed for digestion.

Answer: (A)

Iodine is essential for the production of thyroid hormones, T3 and T4, which regulate metabolism and are crucial for growth and development, especially in the fetus and infancy. When iodine intake is inadequate, the thyroid can’t make enough hormones, leading to hypothyroidism. The pituitary responds by increasing TSH, which stimulates the thyroid and causes it to enlarge, forming a goiter. In severe deficiency during pregnancy, insufficient thyroid hormones impair fetal development, resulting in cretinism, with profound intellectual disability and growth impairment. Iodine is not an energy source, does not directly raise blood calcium, and is not solely involved in digestion.