The thyroid is a butterfly-shaped gland that sits in the front of the neck. It’s commonly called the master gland or energy gland. This is because the thyroid’s job is to regulate and control the energy processes that occur in the entire body. The thyroid produces hormones that regulate our temperature, our metabolism, our hormones, our mood and many other processes, including how efficiently we burn calories and how easily we lose weight. When you stop and think about that you can imagine how an under-functioning (hypothyroidism) or over-functioning (hyperthyroidism) thyroid will affect multiple system in the body.
The thyroid gland has cavities that are filled with thyroglobulin, which is produced by cells called thyrocytes. Thyroglobulin (Tg) contains tyrosine, an amino acid. This is the starting material used for thyroid hormone synthesis. Thyroglobulin is also used for the storage of iodine. Iodide, from food, circulates in the blood and is taken up by the thyroid gland. This form of iodide is converted into the usable form, iodine, by the enzyme thyroid peroxidase (TPO). The reactive iodine is now able to bind to tyrosine. The molecules bond to form either triiodothyronine (T3), three iodine molecules, or thyroxine (T4) which has four iodine molecules. T3 is 300 times more biologically active than T4. 80% of the active T3 hormone is produced by the conversion from T4 to T3. Zinc is required for this process to occur.
Low levels of T4 and T3 signals the release of TSH, thyroid stimulating hormone, and, high levels of T4 and T3 stop the release of this hormone. This feedback loop should keep the thyroid functional at optimal performance.
Hypothyroidism and Hyperthyroidism
Thyroid hormone imbalances are usually classified as inadequate thyroid hormone production (hypothyroidism), or an overabundance of thyroid hormone production (hyperthyroidism). For this article, I will focus on the condition in which the thyroid hormone is inadequate. This is hypothyroidism.
There are two kinds of hypothyroidism. The first is primary hypothyroidism. When there is a deficiency in the nutrients needed for the production and conversion for thyroid hormone, then the body is not able to produce enough thyroid hormone. These nutrients are iodine, selenium, zinc and tyrosine. Primary hypothyroidism is the leading cause of thyroid disorders in under-developed countries where diets are very deficient in nutrients like iodine and selenium.
In North America and Europe, Hashimoto’s Thyroiditis, or auto-immune hypothyroidism, is the leading cause of thyroid disorders.
This is an autoimmune condition where the immune system is attacking the thyroid gland causing lowered function and its eventual destruction. In the beginning stages of Hashimoto’s, the body compensates by producing more thyroid hormone, so the initial lab tests may show and elevated TSH while T4 and T3 appear in the normal ranges. This person will often be experiencing symptoms of hypothyroidism by this time.
As more of the gland is being destroyed, the thyroid loses its ability to compensate, and the T4 and T3 levels drop as well. Eventually the gland can lose all ability to produce thyroid hormones. In Hashimoto’s, two types of reactive antibodies can be observed through a blood test. These are, thyroid peroxidase antibodies and Thyroglobulin antibodies.
Both symptoms of hyperthyroidism and hypothyroidism can be experienced in this scenario because as the thyroid is being destroyed, stored hormones flood the circulation and cause hyperthyroid symptoms.
Symptoms of Thyroid Imbalance
Some of the symptoms of hyperthyroidism are weight loss, anxiety, palpitations, tremors, irritability, menstrual disturbances, fatigue, heat intolerance and increased appetite.
Some of the symptoms of hypothyroidism are fatigue, poor sleep quality, constipation, leaky gut and acid reflux. There can be sudden weight gain with no apparent change in diet or exercise. This weight can be significant and is difficult to lose. The cardiovascular system is often affected with high cholesterol. Carpal tunnel, plantar fasciitis, joint, tendon and muscle pain and weakness are very common as well. Anxiety and depression are associated with an under functioning thyroid. The thyroid regulates hormones, so fertility problems, irregular periods/cycles, miscarriage, difficulty producing breast milk and postpartum depression can occur. Inversely, Hashimoto’s disease can happen soon after puberty, postpartum, peri-menopause and menopause.
Hashimotos thyroiditis is also associated with other autoimmune diseases such as Type 1 diabetes, lupus, rheumatoid arthritis, MS, celiac disease, Addisons disease, pernicious anemia and hypoparathyroidism.
Conventionally, the test used to monitor thyroid levels is thyroid stimulating hormone (TSH). But, TSH does not always reflect thyroid abnormalities. TSH fluctuates throughout the day and does not become permanently elevated until the Hashimotos is advanced. Because of that, people will suffer hypothyroidism for years with fatigue, weight gain and other symptoms before TSH levels become abnormal.
The better test for Hashimoto’s thyroiditis is a blood test that tests both T3 and T4, TSH and one or two types of antibodies.
Most doctors believe the progression from healthy thyroid hormone levels to hypothyroidism is irreversible and leads to complete thyroid destruction. It has been reported, however that thyroid function spontaneously returned to normal in twenty percent of patients. Studies also show that the thyroid can regenerate itself under the right conditions and support. Lifestyle factors can restore, regenerate or slow down the process of Hashimoto’s thyroiditis.