Hypothyroidism (underactive thyroid) is caused by a lack of the thyroid hormones T3 and T4. In areas where iodine is abundant, Hashimoto's disease (autoimmune thyroiditis) is the leading cause of hypothyroidism. In the following article, we offer you all the test-relevant facts about hypothyroidism such as symptoms, diagnostics, therapy and much more. You are optimally prepared for exams and hammer exams!
People with an underactive thyroid (hypothyroidism) usually have to take hormone tablets for life to replace the missing thyroid hormones. However, it must not be taken together with calcium-rich drinks or food such as milk, dairy products and fruit juices, because calcium blocks the absorption of the drug. Here you can read everything you need to know about diet for hypothyroidism!
What Thyroid Hormones Are There?
The production of thyroid hormones is controlled by different centers in the brain. Part of the brain (the hypothalamus) releases the hormone TRH. TRH signals another part of the brain (the pituitary gland) to release the hormone TSH. TSH ultimately stimulates the production of the thyroid hormones triiodothyronine (T3), thyroxine (T4) and calcitonin. If we have sufficient thyroid hormones, production is inhibited. An underactive thyroid can result from disorders on all three levels.
The Thyroid Hormones T3 And T4
In addition to iodine, the body needs protein to produce the two thyroid hormones triiodothyronine (T3) and thyroxine (T4). Thyroxine is the precursor to triiodothyronine. T4 is mainly used to transport iodine and its effects almost exclusively after it has been converted into T3. For this reason, T3 also reacts two to four times more effectively and faster than T4.
Both hormones stimulate protein metabolism and thereby contribute to the growth and maturation of the brain and bones, among other things. In addition, the increased protein synthesis increases the basal metabolic rate. So we burn more energy without increasing our physical activity. In addition, the thyroid hormones influence the effect of other hormones and thus also stimulate the carbohydrate metabolism and support the fat metabolism.
The Thyroid Hormone Calcitonin
Calcitonin is mainly produced in the thyroid gland. As the name suggests, the hormone has something to do with calcium, more precisely it regulates the calcium and phosphate balance in the body. As a result, it plays an important role in bone metabolism. Calcitonin reduces the calcium level in the blood, which means that less calcium is released from the bones. In summary, one can say: the thyroid hormone protects our bones from the development of osteoporosis.
How Does An Underactive Thyroid Develop?
An underactive thyroid can result from disturbances in hormone production on all three levels (hypothalamus, pituitary gland and thyroid gland). The disease can be congenital or develop in the course of life. In most cases, however, an underactive thyroid is caused by chronic inflammation of the thyroid gland (Hashimoto's thyroiditis).
With Hashimoto's thyroiditis, healthy thyroid tissue is broken down, which means that fewer cells are available for hormone production. Initially, the need for hormones is compensated by the remaining cells. However, if too much tissue is damaged, the healthy cells can no longer produce enough hormones, which leads to a deficiency of hormones. For this reason, an underactive thyroid usually goes unnoticed at first and develops slowly.
The reduced hormone concentration in the blood can also lead to an increased release of TRH. In this case the thyroid tries to cope with hormone production by increasing in volume. This leads to an enlargement of the thyroid, which is also known as goiter or goiter formation.
What Happens When The Thyroid Is Underactive?
With an underactive thyroid, the thyroid produces fewer hormones than we need. Since the thyroid hormones influence almost all metabolic processes, an underactive thyroid also has an effect on weight: in most cases, weight gain results.
The following processes are to blame for the increased weight in the case of an underactive thyroid: The lack of the thyroid hormones T3 and T4 reduces protein synthesis. In addition, the carbohydrate metabolism is not sufficiently stimulated and lipolysis is no longer supported. In addition, the body temperature also drops and the effect of other hormones is negatively influenced. All of this has the consequence that the basal metabolic rate also decreases. The entire metabolism is shut down and the body burns fewer calories.
In most cases, it takes a while for an underactive thyroid to be detected. The process is gradual and the symptoms are often misinterpreted. Since the thyroid hormones affect the entire organism, the symptoms can also appear all over the body:
- Poor performance and poor concentration
- Memory problems
- Increased sensitivity to cold
- Weight gain
Hypothyroidism: How Eating Right Can Help
In the case of an underactive thyroid (hypothyroidism), diet plays a major role. Read here which foods have a positive effect on the thyroid and which vitamins and trace elements play a special role.
Diet Is Especially Important
Diet plays a particularly important role in patients with hypothyroidism. Among other things, it is important that patients are adequately supplied with iodine. The trace element iodine is a kind of “fuel” for the thyroid gland in order to produce the vital hormones triiodothyronine (T3) and thyroxine (T4) in combination with protein. Both play a key role in ensuring that our body functions properly: The thyroid hormones regulate the sugar, fat and connective tissue metabolism. They also control our cardiovascular system, affect digestion - and even our mood. Patients with hypothyroidism should ensure adequate iodine intake by consuming food. Sometimes the attending physician also advises using dietary supplements. If the thyroid gland is only slightly underactive, it is usually treated first with an iodide preparation.
Important Sources Of Iodine
The recommendations for adequate iodine intake are age-dependent and increase from 40 to 80 µg / day in infants to 200 µg / day in adolescents and adults. Often iodine is found in the salt used in cooking. Top suppliers are sea fish, e.g. saithe (around 170 μg iodine per 100 g fish) and plaice, but also haddock, cod and seafood. Grains such as rye and dairy products (50 μg to 0.3 l milk) are also ideal sources of food iodine. Good sources are a serving of lamb's lettuce (62 μg), carrots (23 μg) or broccoli (22 μg).
Vitamins, Zinc And Selenium Are Important For An Underactive Thyroid Diet
Almost as important for the functioning of the thyroid gland as iodine is the intake of zinc and selenium. If there is a deficiency, the organ cannot produce enough hormones. Selenium is mainly found in sesame, barley, sunflower seeds, meat and fish. The DGE recommends a daily intake of 60-70 µg. Supplementary preparations cover the daily requirement of 30 to 70 µg. Pulses, dairy and whole grain products, on the other hand, are considered zinc-containing foods.
Vitamins B12, A, E and D in particular can have a positive effect on the symptoms of an underactive thyroid, such as sensitivity to light and tiredness. Meat, poultry, eggs and fish provide a lot of vitamin B12. This also applies to milk and dairy products. There is a particularly high amount of vitamin A in carrots and green vegetables. Avocados, black currants and peppers are valuable sources of vitamin E. Vitamin D, on the other hand, is contained in foods such as eggs, herring, avocados and beef liver.
Be careful with soy products: Excessive consumption can further limit the activity of thyroid hormones.