Why do you need iodine in your food? Which food does contain iodine? What happens if you are iodine deficient? How much do you need?
These are important questions because without sufficient amounts of iodine in the food your thyroid can not function normally and this has consequences.
Both thyroid hormones thyroxin (T4) and triiodothyronin (T3) do contain iodine (iodide) 4 and 3 molecules respectively. Without iodine no thyroid hormone can be synthesised and consequently hypothyroidism and/or goitre may develop. In case of endemic iodine deficiency even cretinism can occur.
The recommended daily intake is 150 µg for an adult and a child aged 13 years or older. During pregnancy and lactation more iodine intake is required: respectively 200-250 µg and 250- 290 µg daily. It is not easy to measure on an individual basis whether a person is taking enough iodine.
Iodine used to be incorpated in table salt, but with decreasing intake of salt other ways have been sought to deliver iodine. In many countries iodine is added to the salt used in the production of bread (in some countries already since many decades). Other high-iodine content foods are: fish/seafood, eggs, milk and other dairy foods. Vegans and others who do not regularly consume dairy foods are at increased risk for iodine deficiency. Not all multivitamins do contain iodine.