The thyroid gland secretes two hormones called triiodothyronine (T3) and thyroxine (T4), which regulate many functions and metabolism in our body. Hypothyroidism is a common disease in the society, especially in women, which is often caused by insufficient production of these hormones, and rarely by their ineffectiveness in the tissues. The most common cause is Hashimoto’s disease, which is caused by our immune system’s perception of the thyroid gland as foreign and producing antibodies that block its functioning. Genetic factors are largely responsible for the occurrence of the disease, so it is not a preventable disease. However, after its emergence, it is possible to slow down its course and to stay away from the negative effects of hypothyroidism by regulating the deficient hormone levels. Iodine deficiency is also among the causes of hypothyroidism. In addition, exposure to excessive iodine in people with a predisposition may cause a decrease in hormone production and release into the blood, and temporary hypothyroidism by blocking organification, which is one of the steps in thyroid hormone production (Wolff-Chaikoff effect). Transient hypothyroidism can be seen in some stages of a disease called subacute thyroiditis. In addition to these, thyroidectomy, various drugs, radiotherapy to the neck region, radioactive iodine treatment, pituitary tumors are among the causes of hypothyroidism.
The most common findings of hypothyroidism are; weakness, chills, fatigue, increased need for sleep, constipation, dry skin, hair loss, deepening of the voice, muscle pain, edema around the eyes and hands and feet, weight gain, changes in blood pressure and pulse, changes in blood lipid profile. After the cause of the disease is determined, all findings can be regressed with appropriate treatment. Due to the metabolic effects of hypothyroidism, nutrition is gaining importance in addition to treatment with thyroid hormone drugs.
IODINE It is the most important nutrient for normal thyroid function. Its deficiency and excess both cause adverse effects in terms of hypothyroidism. In our country, in 1994, 50-70 mg/kg potassium iodide or 25-40 mg/kg potassium iodate was added to table salt according to the “Turkish Food Codex Table and Food Industry Salt Communiqué” within the scope of the “Iodine Deficiency Diseases and Salt Iodization Program”. The World Health Organization (WHO) recommends that the amount of iodine in the diet is 90 µg/day for 0-5 years old, 120 µg/day for 6-12 years old, 150 µg/day for adults over 12 years old, 250 µg/day for pregnant and lactating women. recommends. For individuals who have a natural and balanced diet and do not use excessive salt, daily food and regular use of iodized table salt is sufficient for hypothyroidism. Iodine intake should not be too little or too much. To determine iodine intake, the cause of hypothyroidism should be determined. If the cause is iodine deficiency, iodine intake should be increased, and if Hashimoto’s disease is limited, it should be.
IRON Deficiency of thyroid hormone may also decrease thyroid hormone synthesis (TPO) by reducing some enzyme activities in thyroid cells. In people with hypothyroidism, blood iron levels should be controlled and treated if it is deficient, and iron intake with diet should be at a sufficient level.
SELENIUM It is an essential element for the body. In addition to antioxidant, anti-inflammatory effects, it participates in the structure of some proteins that play a role in thyroid hormone synthesis. There are publications reporting a relationship between selenium deficiency and hypothyroidism and autoimmune thyroiditis (Hashimato hst. etc.). In a study conducted in individuals with Hashimoto’s disease, it was shown that selenium supplementation can lower antibody levels. High intake of selenium is toxic. For this reason, it is recommended to add selenium-rich foods to the diet, and if this is not possible, 50-100 µg/day selenium supplementation is recommended. After 2-3 months of use of drugs containing this supplemental mineral, a 1-month break is required to prevent accumulation and toxicity. Foods rich in selenium; seafood, red and white meat, whole grains and some oil seeds. Due to the high iodine content of seafood, care should be taken not to consume it excessively (1-2 days a week). Sardines, turkey, chicken, sunflower seeds, dried beans, lentils, cashews, mushrooms, spinach, walnuts, lamb livers and eggs are foods rich in selenium.
GLUTEN: There is an intolerance to gluten in celiac disease, and it is reported to be frequently associated with other autoimmune diseases such as Hashimoto’s disease. In addition, in individuals with hypothyroidism, an improvement in thyroid functions and a decrease in antibody levels are observed with a strictly applied gluten-free diet. It is known that gluten-free diet prevents the development of other autoimmune diseases, especially in those with celiac disease.
WEIGHT GAIN: Due to the decreased thyroid hormone level, the metabolic rate and the energy expenditure level of the body decrease, and weight gain or obesity may occur despite careful attention to nutrition. Weight loss has a positive effect on thyroid functions. Studies have reported that thyroid function can improve up to normal limits in hypothyroid patients with weight control. Regular exercise provides great benefits in this regard. Exercise and a balanced diet are also very important in regulating insulin resistance, metabolic syndrome and negative changes in lipid profile, which are frequently encountered in hypothyroidism.
BLOOD PRESSURE AND HYPERLIPIDEMIA: Increased blood cholesterol and triglyceride levels are frequently found in individuals with hypothyroidism. In conditions where thyroid hormone levels reach normal limits with treatment, the lipid profile usually normalizes. However, it is very important to support it with a diet and exercise that is low in animal fats. It should be noted that the intake of saturated fat should be less than 10% of the energy, the carbohydrate ratio in the diet should be in the range of 45-55%, the intake of simple sugar should be less than 10% of the total energy intake, and the dietary fiber intake should be increased. Contrary to what is expected in hypothyroidism, an increase in blood pressure is still a common condition. When combined with hyperlipidemia and metabolic syndrome, this situation, which poses a risk for cardiovascular diseases, can be improved with thyroid hormone replacement. Rich in vegetables and fruits, protein, fiber, magnesium, calcium and potassium; A diet low in sodium, fat and cholesterol is effective in regulating blood pressure. During this period, serum electrolyte levels should also be monitored regularly.
INSULIN RESISTANCE: It is the body’s biological unresponsiveness to insulin. Low thyroid hormone levels and insulin resistance are parameters that increase and trigger the effects of each other, since both conditions are associated with weight gain. In addition, increased blood glucose levels or insulin resistance can be seen in hypothyroidism due to the effects of thyroid hormones on glucose use and insulin sensitivity. During the treatment process, it is recommended to maintain an appropriate body weight, limit saturated fats and carbohydrates in the diet, and create a diet rich in vegetables, fruits and whole grain products.
OMEGA 3: Omega-3 fatty acids have functions such as reducing inflammation in thyroiditis, supporting thyroid hormone production and protecting the thyroid gland against tissue damage. It also has a protective effect against cardiovascular diseases, which is one of the increased risk factors in individuals with hypothyroidism. A deficiency in omega-3 intake reduces thyroid hormone secretions and impairs normal brain functions such as memory and cognitive thinking. Seafood is an important food source containing balanced amounts of iodine, selenium and omega 3. However, care should be taken not to overdo it. Apart from seafood, flaxseed and walnuts are also important sources of omega 3.
VITAMIN D: Low vitamin D levels are associated with an increased risk of hyperthyroidism and bone density loss. Vitamin D is most absorbed from sources such as salmon, sardines, egg yolks, milk and mushrooms.
ZINC: Zinc is also a trace mineral required for thyroid hormone synthesis. Zinc deficiency contributes to the symptoms such as dry skin, hair loss, depression, numbness and cramps, which are often seen in hypothyroidism. Organic eggs, seafood, especially salmon, pumpkin and chia seeds, as well as spinach and almonds are important sources of zinc.
VITAMIN A: It plays a role in the production and secretion of thyroid hormones. It helps in converting T4 to T3, normalizes TSH (thyroid stimulating hormone) and aids iodine uptake by the thyroid. The richest sources of vitamin A are carrots, sweet potatoes, zucchini, spinach and dark green leafy vegetables.
VITAMIN E: It contributes to normalize the immune response in autoimmune thyroiditis by reducing oxidative stress. Raw almonds, chard, spinach, avocados, olives and green leafy vegetables are rich in vitamin E.
VITAMINS B : It can directly affect thyroid functions. Vitamin B6 has functions such as reducing symptoms of hypothyroidism and supporting thyroid hormone production. It is also effective in regulating the immune response in autoimmune thyroid diseases. Consuming foods rich in B-complex vitamins can help reduce symptoms of hypothyroidism. Vitamin B12 may also be beneficial in terms of gastrointestinal complaints of hypothyroidism and findings such as forgetfulness and numbness. Bell peppers, spinach, red meat, pistachios, eggs, salmon and tuna are foods rich in B-complex vitamins.
TYROSIN: An amino acid, tyrosine, along with iodine, is a building block for thyroid hormone production. It also plays an important role in the function of the brain and immune system. In studies conducted in hypothyroid patients with symptoms of depression, fatigue, and decreased immunity, tyrosine supplementation was effective in raising thyroid hormone levels and regulating neurological functions. Beans, turkey meat, oats, chicken, eggs and cheese are high in tyrosine.
C VITAMIN: The antioxidant effect of vitamin C in individuals with thyroid disease has effects such as reducing tissue damage and slowing the course of the disease. Thus, it is beneficial in preventing the decrease of thyroid hormone levels. Vitamin C also increases the absorption of thyroid hormone drugs by creating an acidic environment in the stomach. The best sources of vitamin C; bell pepper, strawberry, lemon, broccoli, grapefruit, orange and kiwi. It is also beneficial to take vitamin C supplements.
CONCLUSION AND RECOMMENDATIONS
v Pay attention to the consumption of fruits and vegetables, but avoid excessive consumption of vegetables such as cabbage, broccoli, turnip, cauliflower, soybean and radish, which are considered goitrogens.
v Try to consume it 1-2 times a week, as seafood is an important source of iodine, omega 3 and selenium, which are important for thyroid function. Since excessive iodine intake is inconvenient in hypothyroid patients, pay attention to its amount and frequency.
v Choose whole grain products with high fiber content and consume legumes 1-2 times a week.
v Take care to include foods such as flaxseed, raw almonds and walnuts, which are high in vitamin E, selenium and zinc, in your diet.
v Reduce salt intake to avoid excessive iodine intake. Salt will also affect the increase in edema that will occur in hypothyroidism. In addition to reducing salt consumption, try to drink 2-2.5 liters of water a day.
v Adequate and high-quality protein intake provides a source for essential vitamins, minerals and amino acids for thyroid gland function.
v Regular exercise will make your metabolism work faster, and it will be of great benefit in terms of weight control as well as insulin resistance and protection from cardiovascular diseases.