What is iodine deficiency?

In adults, an iodine deficiency can lead to inadequate thyroid hormone production, called hypothyroidism. This disrupts normal metabolic functions like regulating heart rate, body temperature, and body weight.

In pregnant women, severe iodine deficiency can permanently harm the fetus by causing stunted growth, intellectual disability, and delayed sexual development. Less severe iodine deficiency can cause lower-than-average IQ in infants and children and decrease adults’ ability to work and think clearly. A lump or swelling in the neck, called goiter, often accompanies hypothyroidism. Goiter, an enlarged thyroid gland, is often the first visible sign of iodine deficiency.

Common iodine deficiency symptoms:

  • Neck lump
  • Goiter
  • Fatigue
  • Weakness
  • Sensitivity to cold
  • Constipation
  • Dry skin
  • Weight gain

What causes an iodine deficiency?

  • Diet lacking in iodized salt
  • Pregnancy 
  • Following a vegan or vegetarian diet
  • Living in regions where soils have low iodine levels

Further reading: Harvard School of Public Health, National Institutes of Health