The body is unable to generate iodine on its own, making it a trace mineral. Thyroid hormones T3 and T4 are produced using it. The thyroid gland, a key metabolic regulator, depends on these hormones to function properly. Iodine is essential for the development of the neurological system, energy production, and body temperature regulation.

Natural foods contain trace levels of iodine. The richest sources include:

• Sea fish (cod, mackerel, tuna), shellfish
• Seaweeds (nori, kombu, wakame)
• Milk, yogurt, cheese
• Eggs
• Iodized table salt
• Plants not grown in lead-contaminated soil (e.g., processed grains)

Iodine is not found in natural salts; "iodized salt," which is used at the table, is a unique product that has been enhanced with iodine. Make sure the salt is iodized if you wish to obtain iodine from it.

One of the best sources of bioavailable iodine is seafood. The iodine need can be considerably met by eating even tiny servings two to three times each week. 

Cod fish, seaweed, iodized salt, dairy products, and eggs contain the most iodine. 

In inland and mountainous areas, a lack of iodine in the soil can result in low levels of iodine in grains and vegetables. These goods could be a factor in iodine deficiency. 

The following groups could think about taking iodine supplements, even if a balanced diet is usually adequate:

• Pregnant and breastfeeding women (WHO recommends 250 µg/day)
• Individuals on a vegan diet
• People with gastrointestinal diseases that affect iodine absorption
• Those who consume foods low in iodine

However, as too much iodine can also be detrimental, a person's condition should always be evaluated before beginning supplements.

The thyroid gland cannot create T3 and T4 hormones without iodine. Hypothyroidism and metabolic problems can result from a decrease in hormone production caused by inadequate iodine intake. Goiter may be the outcome of a chronic deficit. On the other hand, too much iodine might raise the risk of autoimmune thyroid diseases and cause hyperthyroidism.

Excessive iodine intake (over 1100 µg/day) can overstimulate the thyroid, leading to hyperthyroidism or inflammation. Diagnosis may involve:

• Urinary Iodine Concentration (UIC)
• TSH, T3, T4 hormone tests
• Evaluation of thyroid autoantibodies

Most common symptoms include:

• Fatigue and weakness
• Weight gain, cold sensitivity
• Hair loss, dry skin
• Mental slowness, forgetfulness
• Goiter

If identified early, these symptoms can be corrected with simple solutions.

• Delayed thyroid hormone production → hypothyroidism
• Lower IQ and mental retardation in children
• Growth retardation
• Miscarriage, preterm birth, congenital disorders in pregnancy
• Complex thyroid issues and goiter

For the development of the brain, enough iodine intake during pregnancy and childhood is essential. Iodine shortage may cause an IQ drop of 10–15 points, according to studies. Iodine supplementation has been shown to boost neurodevelopment in children.

Inadequate iodine during pregnancy may cause:

• Miscarriage, stillbirth
• Permanent damage to intelligence and motor development
• Serious neurological disorders such as cretinism
• Impaired maternal thyroid function during and after birth

The introduction of iodized salt, which started in the 1920s, was a significant advancement in public health. Iodine deficiency worries have been resurrected, nevertheless, by contemporary trends including a return to "natural" salts, dietary changes, and changes in the food business. Thus, the most effective way to safeguard the health of mothers and children is still to use iodized salt on a daily basis.

• All salt contains iodine → False. Only salt labeled as "iodized" contains iodine.
• Natural salts contain iodine → False. Natural salts are often poor in minerals.
• More iodine is always better → False. Excessive intake can cause thyroid problems.

Even in trace concentrations, the element iodine has a profound effect. We can protect thyroid health, cognitive development, and metabolic balance by using iodized salt, eating a balanced diet, and keeping an eye on those in risk categories. Children and pregnant women should get extra care.