Vitamins for pregnant women: iodine for thyroid health

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Vitamins for pregnant women: iodine for thyroid health

I. The importance of iodine during pregnancy

Iodine is an indispensable trace element that is critical for the synthesis of thyroid hormones, thyroxine (T4) and triiodothyronine (T3). These hormones play a key role in regulating metabolism, growth and development of the body, especially the brain and nervous system. During pregnancy, the need for iodine increases significantly, since it is necessary not only to maintain the health of the mother, but also to ensure the normal development of the fetus.

The lack of iodine (iodine deficiency) during pregnancy can lead to serious consequences for both the mother and the child. In the mother, this can provoke hypothyroidism (reduced thyroid function), goiter (increase in thyroid gland), as well as an increased risk of miscarriage, premature birth and postpartum depression. For a child, iodine deficiency is especially dangerous, since it can lead to disorders of the development of the nervous system, delayed mental and physical development, congenital hypothyroidism (cretinism) and increased child mortality.

The need for iodine during pregnancy increases by about 50%, since the fetus is not able to independently produce thyroid hormones in the first trimester and completely depends on maternal iodine. Even a moderate iodine deficiency can negatively affect the cognitive functions of the child, reduce his IQ and academic performance.

II. Recommended daily dose of iodine for pregnant women

According to the recommendations of the World Health Organization (WHO), pregnant and lactating women need to consume at least 250 μg of iodine per day. This significantly exceeds the recommended daily dose for adults who are not in a state of pregnancy (150 μg). In some regions with a pronounced iodine deficiency, as well as in the presence of risk factors, such as a history of thyroid disease, a doctor can recommend a higher dose of iodine.

It is important to note that an excess of iodine can also be harmful, especially in the presence of autoimmune thyroid diseases. Therefore, it is not recommended to exceed the upper permissible level of iodine consumption, which is 500 μg per day. Before you start taking iodine -containing drugs, you need to consult a doctor and undergo a thyroid examination.

To achieve the recommended daily dose of iodine, a balanced diet is necessary, including foods rich in iodine, as well as taking special vitamin complexes for pregnant women containing iodine.

III. Sources of iodine in nutrition

There are several ways to provide the body with a sufficient amount of iodine. The main sources of iodine in the nutrition include:

• Sea fish and seafood: Sea fish, such as cod, sida, pollock, as well as seafood (shrimp, mussels, squid, seaweed) are excellent sources of iodine. The content of iodine in sea fish varies depending on the type of fish and its habitat. Sea cabbage (kelp) is one of the richest sources of iodine.
• Iodized salt: Iodated salt is the most affordable and effective way of preventing iodine deficiency. The addition of potassium or iodide potassium iodide to table salt allows the population to sufficiently iodine. It is important to use iodized salt for cooking and remember that iodine can evaporate with prolonged storage and heat treatment.
• Dairy products: Milk and dairy products, such as yogurt, cottage cheese and cheese, also contain a certain amount of iodine, which depends on the diet of animal nutrition and the use of iodized feed additives.
• Eggs: Eggs are a good source of iodine, especially if chickens receive a sufficient amount of iodine with food.
• Some vegetables and fruits: The iodine content in vegetables and fruits depends on the content of iodine in the soil on which they are grown. In regions with iodine deficiency, iodine content in vegetables and fruits can be low.

When planning a diet during pregnancy, it is important to include products rich in iodine and use iodized salt for cooking. However, only food may not be enough to ensure the recommended daily dose of iodine, especially in regions with iodine deficiency.

IV. Vitamins for pregnant women with iodine

In most cases, pregnant women are recommended to take special vitamin complexes developed taking into account their increased needs for nutrients, including iodine. Vitamins for pregnant women with iodine make it possible to ensure the guaranteed receipt of the required amount of iodine and other important vitamins and minerals, such as folic acid, iron, calcium and vitamin D.

When choosing a vitamin complex for pregnant women, you need to pay attention to the following factors:

• Iodine content: Make sure that the vitamin complex contains at least 150 μg of iodine in one dose. The optimal iodine content in the vitamin complex is 200-250 μg.
• Form of iodine: Iodine can be represented in vitamin complexes in the form of potassium iodide or potassium iodate. Both forms of iodine are well absorbed by the body.
• The composition of vitamins and minerals: The vitamin complex should contain all the necessary vitamins and minerals in optimal dosages that take into account the needs of pregnant women.
• Manufacturer: Choose vitamin complexes from well -known and reliable manufacturers that guarantee the quality and safety of your products.
• Reviews of doctors and consumers: Read the reviews of doctors and other pregnant women about various vitamin complexes to make the right choice.

Before starting taking a vitamin complex for pregnant women, you need to consult a doctor. The doctor will help to choose the optimal vitamin complex, taking into account the individual needs and health status of a woman.

V. Analyzes for iodine level and thyroid function

The following tests can be prescribed to assess the level of iodine in the body and function of the thyroid gland during pregnancy:

• Urine analysis for iodine: This analysis allows you to evaluate the excretion of iodine in urine, which is an indirect indicator of iodine consumption. Urine analysis for iodine is a simple and non -invasive method for evaluating iodine status.
• Blood test for thyroid hormones: This analysis allows you to evaluate the level of thyroidropic hormone (TSH), thyroxine (T4) and triiodotyronin (T3) in the blood. A change in the level of these hormones may indicate a violation of the function of the thyroid gland.
• Blood test for antibodies to the thyroid gland: This analysis allows you to identify the presence of autoimmune antibodies to the thyroid gland, which may indicate autoimmune thyroiditis (Hashimoto disease) or Graves disease.
• Ultrasound of the thyroid gland: Ultrasound of the thyroid gland allows you to evaluate the structure and dimensions of the thyroid gland, as well as identify the presence of nodes or other changes.

The doctor may prescribe one or more of these analyzes depending on the individual risk factors and the clinical picture. Early detection and treatment of disorders of the thyroid function during pregnancy prevents serious complications for the mother and child.

VI. Thyroid diseases and pregnancy

Thyroid diseases, such as hypothyroidism (reduced thyroid function) and hyperthyroidism (increased thyroid function), can negatively affect the course of pregnancy and the health of the child.

• Hypothyroidism during pregnancy: The deficiency of thyroid hormones during pregnancy can lead to miscarriage, premature birth, preeclampsia, gestational diabetes, as well as impaired development of the nervous system and mental retardation in the child. Treatment of hypothyroidism during pregnancy consists in replacement therapy with levotyroxine (synthetic hormone of the thyroid gland). The dose of levotiroxin is selected individually under the control of the TSH level.
• Hyperthyroidism during pregnancy: An excess of thyroid hormones during pregnancy can lead to miscarriage, premature birth, heart failure, thyrotoxic crisis, as well as the development of goiter and hyperthyroidism in a child. Treatment of hyperthyroidism during pregnancy is the use of antitiraoid drugs, such as prophyltioural or metimazole. In some cases, surgical treatment may be required.

It is important to note that many diseases of the thyroid gland are asymptomatic or with non -specific symptoms, so all pregnant women are recommended to screening for impaired thyroid function, especially in the first trimester of pregnancy.

VII. Risk factors for iodine deficiency during pregnancy

Some factors can increase the risk of iodine deficiency during pregnancy:

• Accommodation in the region with iodine deficiency: In regions with a low iodine content in soil and water, the population is at risk of developing iodine deficiency.
• Insufficient consumption of products rich in iodine: The insufficient use of sea fish, seafood, iodized salt and other products rich in iodine can lead to the development of iodine deficiency.
• Vegetarian or vegan diet: Vegetarians and vegans who do not consume sea fish and dairy products are at risk of developing iodine deficiency.
• History of thyroid disease: The presence of a history of thyroid gland, such as autoimmune thyroiditis or goiter, can increase the risk of iodine deficiency during pregnancy.
• Smoking: Smoking can violate iodine assimilation and increase the need for iodine.
• Taking some drugs: Some drugs, such as amiodarone, can disrupt the thyroid gland and increase the risk of iodine deficiency.

If there are risk factors for the development of iodine deficiency, you must consult a doctor for examining and prescribing the appropriate therapy.

VIII. Prevention of iodine deficiency during pregnancy

Prevention of iodine deficiency during pregnancy includes the following measures:

• The use of iodized salt: The use of iodized salt for cooking is the most effective way to prevent iodine deficiency.
• Inclusion in the diet of products rich in iodine: Regular use of sea fish, seafood, dairy products and eggs helps to provide the body with sufficient iodine.
• Reception of vitamins for pregnant women with iodine: Vitamins for pregnant women with iodine make it possible to ensure the guaranteed receipt of the required amount of iodine and other important vitamins and minerals.
• Limiting the use of digital products: Some products, such as cabbage, turnip, rutabaga and soy, contain substances that may prevent iodine absorption. The use of these products in large quantities can increase the risk of iodine deficiency.
• Consultation with a doctor: Regular consultations with a doctor during pregnancy allow you to identify risk factors for the development of iodine deficiency and get recommendations for its prevention.

IX. Iodine and breastfeeding

The need for iodine during breastfeeding also remains high, since iodine is necessary for the production of thyroid hormones in a child. The recommended daily dose of iodine for nursing women is 250 mcg.

Nursing women are recommended to continue to consume foods rich in iodine, and take vitamin complexes for nursing mothers containing iodine. The sufficient intake of iodine with mother’s milk provides the normal development of the thyroid gland and the nervous system of the child.

X. The consequences of an excess of iodine

Although iodine deficiency is a more common problem, an excess of iodine can also be harmful, especially in the presence of autoimmune thyroid diseases. An excess of iodine can lead to the development of iodine-induced hypothyroidism or hyperthyroidism, autoimmune thyroiditis and other thyroid diseases.

Symptoms of an excess of iodine may include:

• Metal taste in the mouth
• Burning in the mouth and throat
• Abdominal pain
• Nausea and vomiting
• Diarrhea
• Fever
• Skin rashes

If the symptoms of an excess of iodine appear, it is necessary to stop taking iodine -containing drugs and consult a doctor.

XI. Alternative sources of iodine (except for additives)

In addition to traditional food sources and vitamin additives, there are alternative ways to increase iodine consumption:

• Seaweed: Various types of algae, such as a combination, vakama and nori, contain a significant amount of iodine. However, the iodine content in algae can vary greatly depending on the type of algae and its growth. It is important to use algae in moderate quantities to avoid an excess of iodine.
• Mineral water with iodine: Some mineral waters contain iodine in small quantities. When choosing mineral water, pay attention to the iodine content indicated on the label.
• Iodized animal feed: Meat and dairy products from animals that received iodized feed may contain more iodine.

XII. Myths about iodine and pregnancy

There are several common myths about iodine and pregnancy:

• Myth 1: Sea air contains enough iodine. Although sea air really contains a certain amount of iodine, the concentration of iodine in the air is usually insufficient to provide the recommended daily dose.
• Myth 2: The use of iodized salt guarantees the lack of iodine deficiency. The use of iodized salt is an important step in the prevention of iodine deficiency, but it is also important to take into account other factors, such as the amount of salt consumed and the content of iodine in other food products.
• Myth 3: iodine intake can cure all diseases of the thyroid gland. Iodine is necessary for the normal function of the thyroid gland, but it is not a panacea from all diseases of the thyroid gland. In some cases, for example, with autoimmune thyroiditis, taking iodine can even worsen the condition.
• Myth 4: Pregnant women do not need to take vitamins with iodine if they eat a lot of sea fish. Even with regular use of sea fish, it can be difficult to provide the recommended daily dose of iodine, so pregnant women are recommended to take vitamins with iodine.

XIII. Individual approach to iodine reception during pregnancy

Despite the general recommendations for taking iodine during pregnancy, it is important to consider the individual characteristics of each woman. Some women may need a higher dose of iodine, while the other intake of iodine can be contraindicated.

Factors that must be taken into account when determining an individual dose of iodine during pregnancy:

• Region of residence: Residents of regions with iodine deficiency need a higher dose of iodine.
• Nutrition diet: Women who do not use foods rich in iodine need an additional technique of iodine.
• The presence of thyroid diseases: Women with thyroid diseases need an individual dose of iodine under the supervision of a doctor.
• Taking drugs: Some drugs can affect iodine assimilation and require dose adjustments.
• The results of the tests for iodine level and the thyroid function: The results of the tests allow you to evaluate the iodine status and function of the thyroid gland and determine the need to take iodine and its dose.

XIV. The role of iodine in the development of the cognitive functions of the child

Iodine plays a critical role in the development of the cognitive functions of the child, starting from the intrauterine period and continuing in early childhood. The thyroid hormones, the synthesis of which depends on iodine, are necessary for the normal formation and functioning of the brain and nervous system.

During pregnancy, iodine deficiency can lead to irreversible disorders of the development of the nervous system of the child, such as:

• Reduced IQ: Iodine deficiency can reduce the IQ of the child by 10-15 points.
• Violation of cognitive functions: Iodine deficiency can lead to impaired memory, attention, thinking and other cognitive functions.
• Relaying speech development: Iodine deficiency can delay the speech development of the child.
• Training problems: Iodine deficiency can make it difficult to teach a child at school.
• Violation of motor coordination: Iodine deficiency can lead to a violation of motor coordination of the child.

Enough iodine consumption during pregnancy and breastfeeding is an important factor that ensures the normal development of the child’s cognitive functions and its success in the future.

XV. Iodine and pregnancy planning

Preparation for pregnancy plays an important role in ensuring the health of the mother and child. Women planning pregnancy are recommended to start taking iodine -containing vitamins a few months before conception.

Reception of iodine before pregnancy allows you to create a stock of iodine in the mother’s body and ensure adequate iodine intake to the fruit in the early stages of pregnancy, when the fetus is especially vulnerable to iodine deficiency.

Before taking iodine, it is recommended to consult a doctor and undergo a thyroid examination.

XVI. The influence of iodine on fertility

Iodine plays an important role not only during pregnancy, but also for fertility. Thyroid hormones, the synthesis of which depends on iodine, are necessary for the normal operation of the reproductive system in both women and men.

Iodine deficiency can negatively affect the fertility:

• In women: Iodine deficiency can lead to violations of the menstrual cycle, anovulation (lack of ovulation) and a decrease in fertility.
• In men: Iodine deficiency can lead to a decrease in testosterone levels, a deterioration in sperm quality and a decrease in fertility.

Sufficient iodine consumption is an important factor that provides normal fertility in both women and men.

XVII. How to choose iodized salt

Iodated salt is an important source of iodine in nutrition, but it is important to choose the right iodized salt so that it retains its beneficial properties.

When choosing iodized salt, attention should be paid to the following factors:

• Date Production: Iodized salt has a limited shelf life, since iodine evaporates over time. Choose salt with the latest production date.
• Package: Iodized salt should be packed in opaque packaging to protect iodine from exposure to light and moisture.
• Iodine content: Pay attention to the content of iodine in salt indicated on the label. Typically, iodine content is 40 ± 15 μg of iodine per 1 gram of salt.
• Storage conditions: Keep iodized salt in a dark, dry and cool place in a tightly closed package.

XVIII. Alternative methods of iodine prevention

In some cases, when the use of iodine -containing drugs or the use of iodized salt is impossible or undesirable, you can use alternative methods of iodine prevention:

• Iodized oil: Iodated oil is vegetable oil enriched with iodine. Iodated oil can be used to refuel salads or added to the finished food.
• Iodized food additives: There are various iodized nutritional supplements, such as iodized starch or iodized sugar.
• Enrichment of food with iodine: In some countries, enrichment of foods with iodine, such as bread or milk, is practiced.

XIX. Modern research on iodine and pregnancy

Numerous modern studies confirm the importance of iodine during pregnancy and its effect on the health of the mother and child.

Studies show that sufficient iodine consumption during pregnancy reduces the risk:

• Miscarriage
• Premature birth
• Precompiles
• Gesture diabetes
• Disorders of the development of the nervous system in a child
• IQ reduction in a child

Studies also show that adequate iodine prevention is an effective and safe way to improve public health.

XX. The role of education and awareness in the prevention of iodine deficiency

The education and awareness of the population play an important role in the prevention of iodine deficiency. It is necessary to increase the awareness of pregnant women, nursing mothers and the population as a whole about the importance of iodine for health and ways to provide sufficient iodine consumption.

Measures to increase the awareness of the population about iodine may include:

• Conducting educational programs and seminars
• Placement of information materials in medical institutions and media
• Support for scientific research on iodine and its impact on health
• Cooperation with healthcare organizations and media to disseminate information about iodine

XXI. The importance of cooperation between a doctor and a pregnant woman

Cooperation between a doctor and a pregnant woman is a key factor in success in ensuring the health of the mother and the child. A pregnant woman should regularly visit a doctor, follow his recommendations and report any changes in her condition.

The doctor, in turn, should inform the pregnant woman about the importance of iodine for health, conduct a thyroid examination, prescribe the necessary tests and give recommendations for taking iodine -containing drugs and nutrition.

XXII. Iodine and multiple pregnancy

With multiple pregnancy, the need for iodine increases even more than with a single pregnancy. Pregnant twins or triplets are recommended to take a higher dose of iodine under the supervision of a doctor.

XXIII. Iodine and autoimmune thyroid diseases

With autoimmune diseases of the thyroid gland, such as autoimmune thyroiditis (Hashimoto disease) or Graves disease, iodine should be strictly controlled. In some cases, iodine intake may be contraindicated.

XXIV. The effect of iodine deficiency on the course of pregnancy in women with diabetes mellitus

Iodine deficiency can aggravate the course of pregnancy in women with diabetes and increase the risk of complications, such as preeclampsia, gestational diabetes and congenital abnormalities in a child.

XXV. Prospects for research in iodine deficiency and pregnancy

Modern research is aimed at studying:

• The influence of various doses of iodine on the health of the mother and child
• The effectiveness of various methods of iodine prevention
• The influence of iodine deficiency on the development of various organs and systems in a child
• The role of genetic factors in the development of iodine deficiency states

The results of these studies will help to develop more effective strategies for the prevention and treatment of iodine deficiency and improve the health of mothers and children.

XXVI. Practical tips to include iodine in the daily diet of a pregnant woman

• Use iodized food for cooking.
• Eat sea fish and seafood 2-3 times a week.
• Include dairy products and eggs in the diet.
• Take vitamins for pregnant women with iodine on the recommendation of a doctor.
• Limit the use of digital products.
• Drink enough water.

XXVII. Legal aspects of iodine prevention

In some countries, there are legislative norms governing iodine prophylaxis, such as compulsory salt iodine or enrichment of food products with iodine.

XXVIII. Economic efficiency of iodine prevention

Iodine prevention is an economically effective event, since the cost of prevention is significantly lower than the cost of treating the consequences of iodine deficiency.

XXIX. International organizations and programs to combat iodine deficiency

There are various international organizations and programs aimed at combating iodine deficiency, such as the World Health Organization (WHO), UNICEF and the International Control Control of IODD -DEFITIONS (ICCIDD).

XXX. Personal experience of women who survived iodine deficiency during pregnancy

Many women who have survived iodine deficiency during pregnancy are divided by their experience and urge other pregnant women to be attentive to their health and provide sufficient iodine consumption.

XXXI. Technology development for iodine status assessment

Currently, new technologies are being developed for assessing iodine status, such as portable iodine analyzers in the urine and methods for assessing the iodine status by hair.

XXXII. The influence of socio-economic factors on the prevalence of iodine deficiency

The prevalence of iodine deficiency is higher in socio-economic dysfunctional regions, where the population has limited access to food, rich iodine, and medical care.

XXXIII. Iodine and vegetarianism/veganism during pregnancy

Pregnant women who adhere to a vegetarian or vegan diet should be especially carefully monitored by iodine and take iodine -containing additives under the supervision of a doctor.

Xxxiv. The role of pharmacists in informing about iodine

Pharmacists play an important role in informing the population about the importance of iodine and the correct use of iodine -containing drugs.

XXXV. Impact of environmental factors on iodine assimilation

Some environmental factors, such as environmental pollution, can affect the assimilation of iodine.

XXXVI. Iodine and genetic mutations

In rare cases, genetic mutations can affect the assimilation and metabolism of iodine.

XXXVII. The consequences of iodine deficiency for subsequent generations

During pregnancy, iodine deficiency can affect the health of not only current, but also subsequent generations.

XXXVIII. New approaches to iodine prevention

New approaches to iodine prophylaxis are developed, such as iodineing of drinking water and the use of iodized fertilizers.

XXXIX. Prospects for personalized iodine prevention

In the future, it is possible to develop personalized iodine prevention, taking into account the individual genetic and metabolic characteristics of each person.

XL. Conclusion on the importance of iodine for the health of the thyroid gland during pregnancy

Iodine is an absolutely necessary element for the normal functioning of the thyroid gland, both for the mother and the unborn child. Its deficit can lead to serious consequences, while adequate consumption provides healthy development and well -being of both. Careful planning and cooperation with a doctor are the key to successful iodine prevention during pregnancy.

XLI. What is iodine and how does it affect the thyroid gland?

Iodine is a chemical element that is a key component of thyroid hormones: thyroxine (T4) and triiodothyronine (T3). The thyroid gland captures iodine from the blood and uses it to synthesize these hormones, which regulate many processes in the body, including metabolism, growth, development of the nervous system and cognitive functions.

Without enough iodine, the thyroid gland cannot produce enough hormones, which leads to hypothyroidism (reduced thyroid function). Hypothyroidism, in turn, can cause various symptoms, including fatigue, weight gain, constipation, dry skin and menstrual disorders.

The effect of iodine on the thyroid gland:

• Hormone synthesis: Iodine is a necessary component of hormones T4 and T3.
• Metabolism regulation: The thyroid hormones regulate the metabolic rate in the body.
• Growth and development: The thyroid hormones are necessary for normal growth and development, especially the nervous system.
• Cognitive functions: The hormones of the thyroid gland affect cognitive functions, such as memory, attention and thinking.

XLII. The effect of iodine on the nervous system of the fetus during pregnancy

Iodine plays a critical role in the development of the nervous system of the fetus during pregnancy. The thyroid hormones, the synthesis of which depends on iodine, are necessary for the normal formation and functioning of the brain and the nervous system of the fetus.

The effect of iodine on the nervous system of the fetus:

• Myelinization of nerve fibers: The thyroid hormones are necessary for the myelinization of the nerve fibers, which ensures the rapid and effective transmission of nerve impulses.
• Neuron development: The thyroid hormones stimulate the development of neurons and synapses (connections between neurons).
• Formation of the structure of the brain: The thyroid hormones affect the formation of the structure of the brain, including the cerebral cortex, hippocampus and cerebellum.
• Migration of neurons: The thyroid hormones are involved in the migration of neurons from the zones of proliferation to the destination in the brain.

During pregnancy, iodine deficiency can lead to irreversible impairments of the development of the nervous system of the fetus, such as a decrease in IQ, impaired cognitive functions, retention of speech development and learning problems.

XLIII. What products are the most iodine?

Some products are especially rich sources of iodine:

• Seaweed (kelp, combi, vakama, nori): Sea algae are one of the richest sources of iodine. The iodine content in algae can vary greatly depending on the type of algae and its growing place.
• Sea fish (cod, sida, pollock, tuna): Sea fish is a good source of iodine. The content of iodine in sea fish varies depending on the type of fish and its habitat.
• Seafood (shrimp, mussels, squid): Seafood also contain iodine, although in smaller quantities than seaweed and fish.
• Iodized salt: Iodated salt is the most affordable and effective way to prevent iodine deficiency.
• Dairy products (milk, yogurt, cheese): Dairy products contain a certain amount of iodine, which depends on the diet of animal nutrition and the use of iodized feed additives.
• Eggs: Eggs are a good source of iodine, especially if chickens receive a sufficient amount of iodine with food.

XLIV. How to store iodized salt correctly to maintain its properties?

Proper storage of iodized salt is important for maintaining its beneficial properties and preventing iodine loss.

Recommendations for storage of iodized salt:

• Keep iodized salt in a dark, dry and cool place. Light, moisture and heat can accelerate the evaporation of iodine from salt.
• Use opaque packaging. Opennect packaging protects iodine from light exposure.
• Store salt in tightly closed packaging. Tightly closed packaging prevents moisture in salt.
• Do not store salt near a slab or other heat sources. Heat can accelerate iodine evaporation.
• Use salt during the expiration date indicated on the packaging. The shelf life of iodized salt is limited, since iodine evaporates over time.

XLV. What factors affect the assimilation of iodine from food?

The absorption of iodine from food can depend on various factors:

• Form of iodine: Iodine in food can be represented in various forms, such as iodide and iodat. Iodide is better absorbed by the body than iodite.
• Availability of enzyme substances: Some products, such as cabbage, turnip, rutabaga and soy, contain zobogenous substances that may prevent the absorption of iodine.
• The condition of the gastrointestinal tract: Digestion and diseases of the gastrointestinal tract can violate iodine absorption.
• Selena deficiency: Selenium is necessary for the transformation of thyroxine (T4) into triiodothyronine (T3), the active form of the thyroid hormone. Selena deficiency can disrupt the thyroid function