Iodine | What we need to know

Iodine is an essential trace element that cannot be produced in the body, so it must be obtained from food or supplements. It is a chemical element that exists in the form of salts and compounds practically everywhere, including in the air. Its main source in nature is sea water. Iodine also occurs naturally in some foods, supplements, and salty seasonings. It is necessary for the production of thyroid hormones thyroxine and triiodothyronine, which promote protein formation and enzyme activity, as well as regulate normal metabolism.

Without enough iodine, these thyroid hormones cannot function properly and can lead to an underactive or overactive thyroid, causing hypothyroidism and hyperthyroidism in the body. Iodine deficiency during pregnancy increases the risk of miscarriage and premature birth. Fetal growth retardation or brain abnormalities may be detected. If a child born with iodine deficiency is not treated in time, mental retardation and cretinism develop. The newborn may have congenital hypothyroidism or some kind of defect.

Iodine and health

in pregnant women and children

During pregnancy, the production of thyroid hormones increases, which also requires an increase in iodine. Both the fetus and the newborn need sufficient iodine for normal physical growth and brain development. Breast milk contains iodine, although its amount is individual and depends on the body. High doses of iodine intake in women are not always recommended, as it can lead to thyroid diseases.

In children, moderate to severe iodine deficiency can lead to low IQ and stunted growth. Accordingly, in such children, iodine supplementation improves both physical and mental development.

Hypothyroidism and hyperthyroidism

Hyperthyroidism is a pathologically increased activity of the thyroid gland. This means that the gland produces far more hormones than necessary: ​​thyroxine and triiodothyronine, which causes a set of symptoms known as thyrotoxicosis. The signs of hyperthyroidism are non-specific and often coincide with the symptoms of various diseases, which complicates the diagnostics process in some cases. One of the causes of hyperthyroidism is an excess amount of iodine in the body.

Hypothyroidism is an underactive thyroid gland (when it doesn't produce enough hormones). Hypothyroidism is more common than hyperthyroidism. Hypothyroidism is often caused by iodine deficiency, a disease in which the thyroid gland produces fewer hormones than it needs.

Food sources

Iodine is found in varying amounts in the soil and ocean. In food products, it is mainly found in animal protein foods and sea vegetables. Smaller amounts in bread, cereals and milk.

Products rich in iodine are:

• seaweed (nori, kelp, kombu, wakame);
• fish, shellfish (cod, canned tuna, oysters, shrimp);
• table salt labeled "iodized";
• dairy products (milk, cheese, yogurt);
• egg
• beef liver;
• Chicken.

Signs of deficiency and toxicity

Iodine deficiency

Iodine regulates metabolism, the conversion of food into energy in the body, which helps cells function and grow. Thus, iodine deficiency can interfere with normal growth and development, and is especially dangerous for pregnant women and infants, because iodine deficiency can lead to miscarriages, stillbirths, growth retardation, and decreased cognitive processes (difficulty in reading, writing, speaking, problem solving, and social skills).

In adults, an iodine deficiency of less than 10-20 micrograms per day can lead to underproduction of thyroid hormones, a condition known as hypothyroidism, which interferes with normal metabolic functions such as regulation of heart rate, body temperature, and body weight. The development of hypothyroidism is often accompanied by neck swelling (goiter). Other symptoms of hypothyroidism include:

• Fatigue;
• Weakness;
• sensitivity to cold;
• Constipation;
• dry skin and hair;
• weight gain

Iodine excess

Excessive consumption of iodine is quite rare. Iodine excess occurs more often as a result of excessive dosage of pharmacotherapy prescribed for iodine deficiency. Sometimes, people who live near the sea get excess iodine by eating seafood and algae, drinking water containing iodine, for example, this happens in northern Japan.

Taking too much iodine does not usually have a negative effect on thyroid function, although there are some exceptions. Iodine can cause the thyroid gland to become overactive and produce too much thyroid hormone (hyperthyroidism). As a result, the thyroid gland grows and forms the so-called gout. When you consume too much iodine, you may develop an iodine taste in your mouth and begin to salivate excessively. Irritation of the digestive system and rashes on the body.

Taking too much iodine can lead to hypothyroidism, especially if the thyroid gland was already underactive.

Treatment

If the doctor suspects the presence of hyperthyroidism or hypothyroidism based on symptoms, patients who take iodine-containing drugs or live in an area with a high risk of thyroid diseases should be careful. E.g.: near the sea, where seafood and seaweed are abundantly used as food. In the high-risk population, thyroid hormones and thyroid-stimulating hormone are determined, as well as radiological studies (ultrasound examination).

In regions containing excess iodine, it is recommended to use salt that does not contain iodine, and the consumption of iodine-containing products should be limited. Iodine restriction alone is often sufficient to treat hypothyroidism caused by excessive iodine intake, although there are cases in which the patient may require lifelong thyroid hormone supplementation.

source

• https://www.hsph.harvard.edu/nutritionsource/iodine/
• https://ods.od.nih.gov/factsheets/Iodine-HealthProfessional/

Alexander Tsintsabadze