Iodine is needed because it is a key building block for thyroid hormones, which control metabolism, growth, and brain development from the womb through adulthood.

What is iodine?

Iodine is an essential trace mineral that the body cannot make, so it must come from food or supplements. It is most concentrated in the thyroid gland in your neck, where it is used to produce thyroid hormones.

How iodine works in the body

  • The thyroid uses iodine to make the hormones thyroxine (T4) and triiodothyronine (T3), which regulate how the body turns food into energy (metabolism).
  • These hormones also influence heart rate, body temperature, digestion, muscle control, and skin and bone health.
  • Without enough iodine, thyroid hormone production falls, which can lead to an underactive thyroid (hypothyroidism).

Why we need iodine at different ages

  • During pregnancy and breastfeeding
    • Extra iodine is needed to support the baby’s brain and bone development.
* Too little iodine in pregnancy is a major, preventable cause of intellectual disability worldwide.
  • Babies and children
    • Iodine is crucial for normal growth and for the developing brain and nervous system.
* Deficiency in early life can cause stunted growth and long‑term learning and cognitive problems.
  • Adults
    • Adequate iodine keeps metabolism, energy use, and body weight regulation on track through proper thyroid function.
* Long‑term deficiency can cause an enlarged thyroid (goiter), fatigue, weight gain, and fertility issues.

Health problems if we don’t get enough

  • Goiter (visible swelling in the neck from an enlarged thyroid).
  • Hypothyroidism, with symptoms like tiredness, feeling cold, dry skin, constipation, and weight gain.
  • In pregnancy: increased risk of miscarriage, stillbirth, and impaired brain development in the baby.
  • In children: reduced school performance and lower IQ due to long‑term deficiency.

Where we get iodine from

  • Seafood and seaweed.
  • Dairy products such as milk and yogurt.
  • Iodized table salt, which is regular salt with added iodine to prevent deficiency in the population.
  • In some regions and for people who are pregnant or breastfeeding, health authorities recommend iodine supplements.

Bottom line: we need iodine because, without it, the thyroid cannot make the hormones that power metabolism, growth, and brain development, especially in unborn babies and young children.

Information gathered from public forums or data available on the internet and portrayed here.