Thyroid Dysfunction

The thyroid gland is an endocrine gland located at the front of the neck below the thyroid cartilage. It's crucial for human life quality because it produces key hormones:

1. Triiodothyronine – contains 3 iodine atoms, referred to as T3.

2. Thyroxine - contains 4 iodine atoms, referred to as T4.
These two hormone substances significantly influence growth and development. Since they affect the metabolism of carbohydrates, proteins, and fats, the amount they produce also regulates the quality of metabolic processes.

3. Calcitonin - affects calcium metabolism, thus influencing, for example, bone density.

If there is a deviation from the balanced function of this organ, it affects the entire organism on both a psychological and physical level.

The most common thyroid dysfunctions are:

Hypothyroidism.
It is caused by a lack of hormones, in other words, decreased thyroid function. It is most commonly caused by an autoimmune inflammation but can be congenital in children. Typical symptoms include reduced vitality, fatigue, cold intolerance, weight gain, slowed intestinal peristalsis leading to constipation.

Hyperthyroidism (thyrotoxicosis).
It is caused by an excessive production of hormones, thus increased thyroid activity. The most common cause is an autoimmune response of the body. Typical manifestations include high blood pressure, heart palpitations, nervousness, insomnia, hair loss, significant weight loss. The metabolism of affected individuals accelerates, which also affects their relationship with food (they digest faster and become hungry sooner). Increased occurrence of osteoporosis is also common.

Both disorders may involve enlargement of the thyroid gland - known as goiter. Global statistics indicate that thyroid dysfunctions are much more common in women.
Thyroid dysfunctions are treated with substitution therapy. In the case of hypofunction, this involves administering drugs containing specific hormones, and in the case of hyperfunction, antithyroid drugs with possible surgical intervention or radioiodine treatment.

Influence of Diet on Thyroid Function

Aside from the fact that the thyroid gland influences nutrient utilization in the body through hormone production, it is also true that diet quality affects the functioning of this organ to a certain extent. The following factors have the greatest influence:

Iodine intake.
Iodine is part of the structure of thyroxine and triiodothyronine, so its sufficient presence in the diet greatly influences the functioning of the entire organ. It is reported that approximately ¼ of the world population suffers from iodine deficiency, thus it's necessary to adjust dietary planning to ensure adequate iodine supply. The recommended daily intake for adults is 150 micrograms, with rich sources being marine products (fish, shellfish, seaweed, salt) or black chokeberry.

Amount of selenium.
Selenium is a component of the enzyme responsible for converting thyroxine to triiodothyronine. Therefore, the amount of selenium in the diet affects thyroid function and thus the entire metabolism. The selenium content in foods depends on its amount in the soil, which is a highly variable factor. Ensuring sufficient selenium in a regular diet is problematic in some parts of the world, particularly in Europe where the population suffers from deficiency. Unlike iodine, where the thyroid gland can tolerate higher doses well, selenium can easily lead to overdosing. It is therefore advisable to maintain intake levels at or somewhat below the recommended daily dose (55 micrograms).

Amount of antioxidants.
Antioxidant intake has an indirect impact on thyroid function. Their main role is to mitigate oxidative stress, which affects acid-base balance and stress hormone production when in excess. Such a situation triggers inflammatory reactions in the body, also affecting hormonal regulation of the thyroid gland.

Amount and quality of proteins.
The content of proteins, including their quality, influences the entire metabolism's functioning in terms of the balance between catabolic and anabolic processes. It also applies to the thyroid gland, so it's essential to ensure a protein intake in the daily diet that meets each individual's needs.

Proportions of macronutrients.
The ratio of the main energy sources for cells, namely carbohydrates and fats in the diet, determines how quickly energy will be produced. This affects the rate of metabolic processes. A higher proportion of fats generally slows down energy processes, while a high proportion of carbohydrates (their glycemic value plays a role as well) speeds up the metabolism. By altering the proportions of macronutrients in the diet, it's possible to indirectly affect the thyroid gland's functioning quality.

Content of antinutritional substances.
Certain antinutritional substances (specifically a group called goitrogens) have the ability to disrupt thyroid function and promote its enlargement (the term "goitrogenic" is derived from the term "goiter"). This occurs through blocking iodine intake into cells, reducing TSH (thyrotropic hormone) production, or disrupting enzyme function binding iodine into hormones produced by the thyroid gland.

Most goitrogens are found in cruciferous vegetables (broccoli, cabbage, Brussels sprouts, cauliflower, spinach, turnip...), some grains (corn, buckwheat), seeds (flaxseeds, pine nuts), legumes (beans, soybean products - milk, tempeh, tofu), and fruits (strawberries, pears, peaches). The content of goitrogenic substances in these foods can be somewhat reduced by certain cooking methods.

The consumption of these foods should be limited mostly by individuals with thyroid dysfunction, as there is no increased risk of undesirable thyroid function impact among healthy individuals.