What foods contain iodine?

Lack of iodine can cause a malfunction in the body’s metabolic processes, emotional lability and even a decrease in mental abilities. But an excess of the substance is fraught with unpleasant consequences, including tachycardia, sweating and fatigue. This is why the balance of microelements in the body is so important.

What role does iodine play in the human body?

Iodine (lat. Iodum) is  a trace element that is primarily necessary for the production of thyroid hormones: thyroxine and triiodothyronine. They participate in the formation of the skeleton, soft tissues, organs, regulate metabolic processes, protein synthesis, the functioning of the cardiovascular and nervous systems, and the liver.

In addition, iodine acts as an antioxidant – it prevents the destructive effects of free radicals. The microelement slows down the aging process of the body, prevents the development of oncology, pathologies of the heart and blood vessels, and has an anti-inflammatory effect.

The substance also affects  cognitive functions : memory, speech, concentration, intelligence and thinking.

Foods with the highest iodine content

The microelement is not produced by the human body, but comes from outside: with food, complexes with vitamins and minerals. Foods rich in iodine include  fish and other marine life,  meat (in particular pork and beef), and cereals – buckwheat, oatmeal, millet. There are also many trace elements in  dairy products : a glass of milk contains from 56 to 88 mcg. The element’s concentration is also high in dry milk formulas – up to 55 mcg. There is a substance in  poultry – chicken, turkey.

We have summarized the iodine content in various products in a table:

Iodine is also found in foods of plant origin, primarily in berries,  fruits and vegetables :

For example:

To prevent deficiency of the substance, doctors recommend consuming iodized salt. One gram of it contains 40 mcg of microelement. 

Daily norm

The dosage of the substance recommended by doctors depends on the age and health status of the person.

Daily iodine intake, mcg:

The two main categories of such goitrogens are cruciferous vegetables and soy-based foods. The list of goitrogenic foods includes:

• white cabbage, Brussels sprouts, cauliflower;
• broccoli;
• sweet potato;
• turnip;
• corn;
• watercress;
• horseradish;
• cassava;
• turnip;
• soy;
• tofu;
• peanut;
• pearl millet;
• horseradish;
• cashews;
• flax-seed;
• Rapeseed;
• lima beans.

Due to a lack of clinical trials, scientists are unable to determine the exact list of goitrogenic foods that cause thyroid dysfunction. But it is known that when eating raw cabbage for more than 7 days in a dosage of 1–1.5 kg, myxedema may develop as a result of a deficiency of thyroid hormones.

Excess and deficiency of iodine: symptoms and consequences

Excess of the substance in the human body is rare, especially in Russia, which is characterized by widespread iodine deficiency. But an excess is often observed in Japan and Korea, where the population has the most seaweed in their diet. 

But even if there is a slight excess of iodine, healthy people tolerate it well without any negative consequences. But in patients with autoimmune diseases of the thyroid gland and chronic iodine deficiency, goiter and hyperthyroidism may develop from this. 

Signs of severe overdose:

• accelerated metabolism with weight loss;
• heart rhythm disturbance – increase in its frequency;
• sweating;
• irritability;
• hand trembling;
• fatigue.

In addition, due to long-term excess of the substance, the risk of developing thyroid cancer increases. And severe poisoning with a trace element as a result of taking large doses can be accompanied by vomiting, fever, abdominal pain, burning in the mouth and even coma.

But much more often people suffer from iodine deficiency. This is due to dietary habits, insufficient substance content in water and soil due to sparse vegetation – due to excessive grazing, intensive deforestation, and the use of certain types of fertilizers. 

About 2 billion people on the planet experience a deficiency of the element. The list of countries with moderate deficiency of the substance in the diet of the population includes Russia, Italy, Finland, Haiti, Israel, Ukraine, Lebanon, Mali, Madagascar, Vietnam, Burkina Faso, Sudan, Burundi, Angola, Mozambique, Vanuatu, Liechtenstein, Samoa.

More than 70% of the territory of the Russian Federation is located in iodine-deficient areas. Compatriots consume three times less of the substance than recommended by doctors – up to 50-80 mcg per day. 

At the same time, disproportions are observed between individual regions of the country. A moderate shortage of the element is noted in the Far East, North, and Siberia. And pockets of high iodine deficiency were found in Khakassia, Tyva, Yakutia, and the Arkhangelsk region.

Signs of substance deficiency:

• dry hair, skin;
• weight gain;
• constipation;
• weakness;
• severe sensitivity to cold;
• fatigue.

The most dangerous thing is a lack of iodine for the fetus during intrauterine formation and infants. Deficiency during the period of intensive development of the child leads to irreversible impairment of physical and mental health, growth retardation, and mental disorders. 

Pregnant women who consume little of the element experience increased miscarriage. Because of the possible consequences, it is important to monitor and treat even mild iodine deficiency in the expectant mother. Iodine deficiency increases the risk of infant mortality, premature birth, anemia, cretinism and hypothyroidism in the offspring. At an older age, the deficiency can cause difficulties with reading, writing, and speech for the child, delayed puberty, and problems with social skills.

So, what causes a deficiency of a substance in the human body:

• goiter;
• congenital anomalies;
• mental retardation;
• deafness;
• dwarfism;
• hypothyroidism;
• cognitive impairment;
• decreased labor productivity;
• increased absorption of radioactive elements from the environment.

Important and interesting facts about iodine

• As we said earlier, due to natural conditions and dietary characteristics, the majority of the Russian population is iodine deficient. But there are also exceptions. Excessive iodine consumption was recorded among residents of the city of Turinsk, which is located in the Sverdlovsk region. Scientists have found out why this happens: because of a hot mineral spring flowing into the Tura River. The water in it is saturated with iodine and enters the central communications. As a result, the concentration of the substance in tap water is four to five times higher.
• The risk group for element deficiency includes not only the population of regions with a lack of iodine in soil and water, but also those who do not consume iodized salt. And also vegans and people who drink little milk and do not have enough fish, seafood and eggs in their diet.
• According to  research by Chinese scientists, children living in regions with iodine deficiency and who do not additionally receive it in vitamin and mineral supplements have an average IQ of 12.45 points lower than their peers who do not lack the element in their diet.

This is confirmed by  Olga Dukhareva , chief physician of the Moscow Endocrinological Dispensary:

“Severe iodine deficiency in the fetus leads to cretinism, and mild deficiency leads to a decrease in the child’s intelligence by 10–15 levels. Do you think this is not enough? For comparison, the average IQ for people is 90–100. If children have a score below 70, they cannot study in a regular school.

At the same time, it is impossible to restore mental abilities by replenishing the level of iodine in the body later. For the normal development of a child, it is necessary to maintain the required dosage of substance consumption during its development.

This is why women are prescribed iodine-containing medications during pregnancy and breastfeeding. And in general, prevention of element deficiency is needed at all critical moments of a person’s life.”

• The opinion that the iodine network helps to compensate for the deficiency of the substance is a myth.

Yulia Kakhturia , endocrinologist at the European Medical Center (EMC): 

“Of course, a certain amount of microelement is absorbed into the body through the skin. But it is impossible to determine the dosage in this case. The form of the drug matters – ointment or alcohol solution, skin characteristics, coverage area, air temperature. All this can affect the result. Instead of drawing a grid, I suggest using iodized salt. This is a simpler and more effective way to fill the gap.”

Conclusion

Adults should consume at least 150 mcg of iodine daily. Pregnant and lactating women have even more – 220–290 mcg. If a microelement is not enough in a child’s diet, physical, mental and mental development disorders occur. And in an adult, goiter, fatigue, and hypothyroidism develop. To prevent this from happening, be sure to include seafood, milk, eggs and iodized salt in your diet.