What Is the Thyroid?
The thyroid is a small, butterfly-shaped gland located at the front of your neck, just above your collarbone. It’s a crucial part of your endocrine system, which is the collection of glands that secrete hormones into your bloodstream to regulate various bodily functions.
Your thyroid produces hormones that regulate growth, maturation, and metabolism. These hormones, T3 and T4, are created through a hormonal chain reaction. While the thyroid produces these hormones, it is controlled by the pituitary gland, which in turn is regulated by the hypothalamus.
What Do Thyroid Hormones Regulate?
When thyroid hormone levels are low, the hypothalamus produces a hormone called thyrotropin-releasing hormone (TRH). This stimulates the pituitary gland to produce thyroid-stimulating hormone (TSH). TSH then stimulates the thyroid to produce T4, some of which is converted to T3 in the thyroid, liver, and pituitary gland.
T4 and T3 are primarily composed of converted iodine. T4 is more common throughout the body, making up about 80 percent of thyroid hormone production, but T3 is far more potent. Both T4 and T3 act as chemical messengers and affect the metabolism of every cell in the body.
Growth & Development
From the womb and throughout life, thyroid hormones are essential for growth and development. For example, tadpoles deprived of thyroid hormones fail to develop properly into frogs, and the effects on humans are similar. In fetuses, infants, and children, a lack of T4 and T3 stunts physical growth and impairs brain development. Therefore, pregnant women should monitor their thyroid health to ensure their baby receives complete nutrition.
Metabolism & Body Temperature
Thyroid hormones also regulate metabolism. T4 and T3 increase oxygen consumption in all tissues, governing the rate at which your body burns fat and processes carbs. As a side effect of their role in metabolism, T4 and T3 also affect body temperature. If you find yourself always feeling colder or warmer than others, imbalanced thyroid hormone levels might be the cause.
Calcitonin Production
A third hormone, calcitonin, is also produced in the thyroid. Although its biological role is not as well understood as T3 or T4, calcitonin is produced in special thyroid cells called C-cells. It seems to lower calcium and phosphate concentration in the blood, and some theorize it plays a role in the distribution of calcium and phosphate in bones, though this hypothesis is not conclusively proven.
Doctors can run a hormone panel to check the levels of these hormones in your blood, including TSH, T3, and T4, along with other hormones such as estrogen, progesterone, and testosterone, to rule out other causes.
Role of Essential Minerals for the Thyroid
For the thyroid to create vital hormones, it requires raw materials. Just as you can’t build a house without wood, stone, and metal, the thyroid can’t synthesize T3 and T4 without iodine, selenium, iron, and zinc.
Iodine is an essential mineral, possibly the single most important for maintaining thyroid health. It’s a core component of your thyroid hormones. Within the thyroid, specialized cells convert iodine and the amino acid tyrosine into T3 and T4. Without enough iodine, your thyroid cannot produce these hormones.
Lack of iodine can cause several disorders, including:
- Goiter: a severely enlarged thyroid gland that appears as a large mass on the neck
- Stillbirth and infant death
- Permanent cognitive impairment
- Stunted growth
- Deaf-mutism
- Cerebral palsy
Iodine deficiency is a significant concern and is one of the leading causes of cognitive impairment in children worldwide. The effects of iodine deficiency are completely preventable. Many countries add iodine to table salt to ensure everyone gets this essential nutrient. Despite these efforts, iodine deficiency still affects around 2 billion people globally.
How Iodine Affects Your Thyroid
Ensuring you have enough iodine in your diet is crucial for thyroid health. Without it, your thyroid cannot produce the hormones necessary for regulating growth, development, and metabolism.