Iodine, selenium, zinc and iron in hypothyroidism
Hypothyroidism is a disease that we have heard about more and more in recent years. Untreated, it may contribute to dyslipidemia, hypertension, cognitive impairment, infertility, and neuromuscular dysfunction. The incidence increases with age and is greater in women than in men. Hypothyroidism can occur as a result of a thyroid malfunction or insufficient stimulation of the gland by the hypothalamus or pituitary gland.
In hypothyroidism, it is extremely important to have a healthy, balanced diet, and above all an adequate amount of iodine, selenium, zinc and iron. They are essential for the thyroid gland to function properly.
Iodine
There is about 15 – 20 g of iodine in our body, of which 70 – 80 percent. in the thyroid gland. Thyroid hormones contain iodine, so it is obvious that the right amount of it is crucial in maintaining all functions of this organ. If there is not enough iodine in the body, the concentration rises to start with the hormone TSH, and then the levels of thyroxine and triiodothyronine decrease. Cohort studies have also shown that even a slight iodine deficiency is present causes enlargement of the thyroid gland and the formation of a goiter.
According to the World Health Organization (WHO), the daily recommended amount of iodine should be 150 μg for adolescents and adults, and 175 – 200 μg for pregnant and lactating women. Similar values are provided by the Food and Nutrition Institute. The best sources of iodine are fish and marine crustaceans, especially mackerel, clams, cod and oysters. In addition, it has been shown that people who drink small amounts of milk are at a higher risk of developing thyroid disease. The amount of iodine in milk, however, depends on the abundance of this element in the soil on which the plants eaten by the animals grew.
In Poland, there is obligatory salt iodization, which has brought the intended effects.
Iron
One of the key enzymes for the thyroid gland, namely iodine peroxidase, contains iron in its molecule, therefore the amount of this mineral affects the functioning of the thyroid gland. Iron deficiency reduces the synthesis of thyroid hormones in the plasma, increases the secretion of TSH, leads to an increase in the thyroid gland and the development of hypothyroidism. Moreover, people with anemia caused by iron deficiency respond less well to supplementing possible iodine deficiency. According to the nutritional standards recommended by the Food and Nutrition Institute, the daily diet of men and postmenopausal women should provide 10 mg of iron, and in women up to the menopausal period – 18 mg. The main source of this mineral in Poland is meat and its products and cereal products.
Selenium
Selenium is part of the enzyme (deiodinase), which participates in the transformation of thyroxine into triiodothyronine. If selenium is not enough in the diet, the production of triiodothyronine in the tissues and its concentration in the plasma decrease. At the same time, the activity of the thyroid gland is lowered. Its long-term deficiency may be the cause of poor absorption of iodine.
It has been proven that selenium supplementation does not change the concentration of thyroid hormones.
The recommended average selenium intake was determined at the level of 45 μg. Good sources of selenium are fish, shellfish, Brazil nuts and dairy products (if the animal’s food was rich in this element). Out of vegetables and fruits, greater amounts of selenium can be found in legumes and mushrooms.
Zinc
Zinc is necessary for the proper synthesis of thyroxine and is part of the triiodothyronine receptor proteins. The recommended intake of this element has been set at 11 mg / d for men and 8 mg / d for women. They contain the most zinc wheat germ, flax seeds, pumpkin seeds and cereal products (whole grain bread, buckwheat and millet).
In addition to the above-mentioned four minerals, an important role in hypothyroidism is also played by: vitamin A, vitamin D, B vitamins. Often, the diet requires individual exclusions, such as the elimination of gluten or lactose from the diet of a person suffering from intolerance.