Hypothyroidism is a disease that is characterized by a deficiency or abnormal action of thyroid hormones and affects about 1-6% of the population, being 4- 5 times more common in women than in men. It can be primary, secondary, innate or acquired. The primary hypofunction is the result of damage to the thyroid gland. The cause of this damage may be thyroid surgery (strumectomy) or its inflammation (Hashimoto).
Secondary hypothyroidism is caused by a deficiency of the thyroid-stimulating hormone (TSH). This type of hypothyroidism results from damage to the pituitary gland or the abnormal functioning of the hypothalamus. Congenital hypothyroidism is usually also primary. It is caused by inhibition or thyroid dysfunction, but it can also occur due to inherited disability by enzymatic defects of enzymes involved in the synthesis of hormones. Another cause of hypothyroidism may be iodine deficiency during pregnancy. Acquired hypothyroidism affects primarily women aged 30 – 60 years. Among the primary, acquired hypothyroidism, the most common cause is chronic autoimmune thyroiditis, or Hashimoto’s disease.
What is the role of the thyroid in our body?
The main task of the thyroid is the production and secretion of triiodotrinin hormones – T3, thyroxine – T4 with the effect of increasing the metabolism of the body and calcitonin – a polypeptide hormone, reducing the level of calcium in the blood and increasing its deposition in the bones. Thyroid gland hormones also affect the metabolism of proteins, carbohydrates, fat and cholesterol. In addition, they play an important role in the stimulation of the myocardium and the work of the nervous system of the brain. They also affect the functioning of most body tissues and are characterized by the widest spectrum of activity among the known hormones. Thyroid gland is responsible for about 30% of the resting metabolism, that is why when the thyroid hormone deficiency is delivered with food, energy is stored in the form of adipose tissue,which can lead to overweight and obesity. Problems with maintaining a healthy body mass, in turn, affect the normalization of the hormonal balance.
The most common cause of acquired hypothyroidism is chronic autoimmune thyroiditis, or Hashimoto’s disease. It is a disease in which the immune system produces antibodies against thyroid peroxidase (anti-TPO) and against thyroglobulin (anti-TG), which is the excessive production of antibodies against thyroid antigens. This leads to the formation of lymphocytic infiltrates on the thyroid gland and the disappearance of the follicular cells of the gland. Hashimoto’s disease is diagnosed more often, even 10-20 times, in women, and the risk of getting sick increases with age. Treatment primarily involves the administration of L-thyroxine. It is believed that the development of Hashimoto’s disease is influenced by genetic and environmental factors to which we can include smoking, stress or viral or bacterial infections, external irradiation,treatment with radioactive iodine, nutritional (selenium deficiency, excess iodine) as well as other autoimmune diseases that may co-exist with Hashimoto’s disease, among which we can mention, among others, Type I diabetes, pernicious anemia, celiac disease, vitiligo, psoriasis, systemic lupus erythematosus and others.
General symptoms of hypothyroidism are very diverse and depend on the cause of the disease, duration, dynamics of development and severity of hormone secretion disorders . In the advanced stage of the disease, the main symptoms of Hashimoto’s disease and hypothyroidism include hair loss, decreased life-time drive, hearing impairment, depression, anxiety, decreased concentration, deterioration of intellectual performance, drowsiness and fatigue, thyroid gland, difficulty in losing weight, feeling cold and swelling of the hands and eyelids.
Diagnosis of thyroid diseases
In the diagnosis of hypothyroidism, the basis for hormonal tests as well as imaging diagnostics provides the main basis for the diagnosis of hypothyroidism.
The most commonly used test evaluating hormonal thyroid function is the determination of TSH concentration. It is assumed that normal serum thyrotropin concentration ranges from 0.2 to 4.5. A result within this range confirms the normal function of the thyroid gland. Elevated levels of TSH may be the cause of primary hypothyroidism, acquired or congenital, pituitary adenoma secreting TSH. In turn, a reduced level of TSH may indicate primary hyperactivity, secondary hypofunction, hypothalamic hypothyreosis or the effect of some drugs, such as, for example, glucocorticosteroids or severe systemic diseases. Conversely, FT3 and FT4 concentrations are measured when the TSH concentration exceeds the reference range to identify the type of hormonal dysfunction (hyperactivity,hypothyroidism). The reference range is for FT3 – 1.5-4.0 ng / l, for FT4 – 0.89-1.7 ng / l. A significant role in laboratory diagnostics is also played by the determination of antithyroid antibodies such as Anti-TPO and anti-TG. They allow to diagnose thyroid autoimmune diseases and its inflammation.
Principles of nutrition in hypothyroidism
According to the principles of rational nutrition, the diet of people with hypothyroidism should contain 4-5 meals, consumed at regular intervals. The last meal should be eaten 3-4 hours before bedtime. Such a distribution within days will not reduce the metabolic rate. The supply of calories for each person should be adjusted individually taking into account gender, age, lifestyle, physical activity, physiological condition and co-existing disorders or diseases such as diabetes, hypertension, inflammation or abnormal lipidogram.
It is the thyroid that accounts for about 30% of the resting metabolism, so the reduced metabolism of the body and the resulting problems with maintaining due weight are very common among people with this disease entity. Weight loss is important for normalizing hormone levels in the blood, but drastic lowering of energy should be avoided because it can increase TSH concentration and reduce the rate of metabolism, which is why it is so important that the calorie diet is appropriately selected. Due to the immunological background of Hashimoto’s disease and inflammation in the body, the diet used should be anti-inflammatory.
Protein supply in people suffering from hypothyroidism and Hashimoto disease should be greater than in healthy people, which is necessary to increase metabolism and which is a beneficial effect in the case of reduced metabolism in these people. In addition, it was noted that the correct supply of protein inhibits hair loss, which is one of the main symptoms of the disease. It is recommended that wholesome protein of animal origin – which is also a source of vitamin B, as well as iron, sea fish – containing iodine, n-3 fatty acids (anti-inflammatory), eggs and pulses, which like meat abound with vitamins from B group and iron, moreover they contain complex carbohydrates.
Due to the disturbed carbohydrate metabolism in hypothyroidism, it is recommended to choose carbohydrates with a low glycemic index. They should be provided in the form of cereal products made from wholly grist (groats, pasta, bread), providing more minerals, vitamins and fiber. The appropriate amount of fiber in the diet, ie AI> 25g / day, can prevent constipation, which is the result of slow bowel motility in people with hypothyroidism, besides, it binds toxins in the intestines, prevents their absorption, shortens the time of fecal mass passage, prevents constipation and thus hemorrhoids, stimulates intestinal blood supply, reduces serum glucose and cholesterol, reduces postprandial glucose and lowers insulin levels.A good source of dietary fiber are also vegetables and fruits, which additionally provide minerals, vitamins and antioxidants. The diet should eliminate all highly processed products being a source of simple sugars such as sweets, cakes, cakes, biscuit, chocolate, chips, sticks, crackers, sausages, fast food, high-sugar jams, Chinese soups, canned food, carbonated drinks and orangeade.
Persons suffering from hypothyroidism and autoimmune thyroiditis should pay attention not only to the quantity, but also to the quality of food intake fat. It is not advisable to use low-fat diets that may cause disorders in the immune system and lead to a deficiency of fat-soluble vitamins. Energy derived from fat should not exceed 30% of the daily requirement, however, it is recommended to limit animal fats that are rich in saturated fatty acids, and to increase the consumption of fats containing unsaturated fatty acids found in vegetable oils (rapeseed, linseed, sunflower, soy oil, olive oil), nuts, avocados, seeds and fish once. Very important are polyunsaturated fatty acids from the omega-3 family, which stimulate the transformation of T4 into T3 in the liver, and also improve the sensitivity of tissues to thyroid hormones. They also affect the reduction of inflammatory processes,which is particularly important in the prevention and treatment of hypothyroidism caused by Hashimoto’s disease. In addition, they contribute to the reduction of serum triglycerides, as well as antithrombotic and antiatherogenic effects. The main sources of omega-3 fatty acids in the diet are sea fish, linseed oil, rapeseed oil, avocado and walnuts.
Minerals necessary for proper thyroid activity
One of them is iodine, which is a part of thyroid hormones and plays a key role in its proper functioning. Both iodine deficiency and its excess may be the cause of thyroid dysfunction, insufficient amount may cause thyroid gland, and excess iodine in people with Hashimoto’s disease may increase the inflammatory response of the immune system. The main source of iodine in food is seafood, and fish (mainly cod and halibut).
Thyroid is an organ whose tissues are characterized by a relatively high concentration of selenium. This element is a component of enzymes associated with the thyroid hormone management. The proper functioning of selenium occurs, however, when adequate supply of iodine is ensured because these two elements mutually modify their activity and have an effect on thyroid function. This element affects the inflammation – it does not cause its complete extinction, but may reduce the inflammatory activity. Selenium improves the functioning of the immune system and reduces inflammatory activity, but does not cause the disease to subside. The most abundant sources of selenium in food include fish (especially cod and halibut) and crustaceans, eggs, shrimps, sardines, garlic, mushrooms, milk and its products depending on its content in animal feed.
Very important in the etiopathogenesis of thyroid diseases is also vitamin D. A deficiency of this vitamin was observed in almost 80% of people with Hashimoto’s disease. The importance of this vitamin to the proper functioning of the thyroid gland, in the tissues of which its receptors have been found, is increasingly underlined. It was also noticed that the thyroid stimulating hormone (TSH) had the higher value, the greater the deficit of this vitamin. In addition, vitamin D deficiency in people with Hashimoto’s disease may cause disturbed intestinal calcium absorption. Vitamin D sources include fish and oils, and smaller amounts are found in dairy products (butter) and meat.
The diet should pay attention to Zinc, which participates in the proper functioning of the immune system. It has anti-inflammatory and antioxidant properties. With the decrease in the concentration of zinc in the blood serum, the titer of antithyroid antibodies increases, which may confirm the role of zinc in the functioning of the body’s immune defenses. In addition, insufficient amount of zinc in the body reduces the rate of hormone metabolism. The richest sources of food are eggs, buckwheat, rennet cheese, pumpkin seeds as well as whole-wheat bread and meat.
Another very important and essential element in the diet of people with hypothyroidism is iron. Iron deficiency causes reduced synthesis of thyroid hormones through reduced synthesis of T4 hormones to T3 and contributes to increased secretion of TSH. Anemia very often (because up to 60% of people with hypothyroidism) is diagnosed, therefore it is recommended to pay special attention to enriching the diet with this element. A good source of iron in the diet is red meat (beef, lean pork), egg yolk, chicken liver or veal liver, whole-grain cereals and parsley.
It should be known that the diet of people with Hashimoto’s disease should cover the need for antioxidant vitamins (A, C, E) that counteract free radicals and alleviate oxidative stress, a factor that destroys thyroid tissue cells. Vitamin E in the diet can be found in vegetable oils (rapeseed oil, linseed oil, sunflower oil, almonds, hazelnuts, pumpkin and sunflower seeds.The most vitamin C can be found in the fruits of wild rose, black currants, strawberries, parsley, citrus fruits and cruciferous vegetables. A good source of vitamin A is butter, eggs, milk, fatty fish, carrots, tomatoes, red peppers, apricots.
Pharmacotherapy in hypothyroidism is the most important element of treatment, but a properly balanced diet, provides essential nutrients used for the synthesis of thyroid hormones, as well as avoiding products that can disrupt this process is important as an adjunctive treatment.