The thyroid gland is a butterfly shaped gland situated at the base of the neck. It is a part of a large network of glands comprising the endocrine system. The thyroid gland produces hormones that regulate metabolism, growth and development. Thyroid diseases occur when the gland produces either too little hormone (hypothyroidism) or too much hormone (hyperthyroidism).
The most common thyroid diseases are:
- Hashimoto’s Thyroiditis
- Grave’s Disease
- Thyroid Nodules
Hashimoto’s Thyroiditis (HT) and Graves’ Disease (GD) are Autoimmune Thyroid Disorders (AITD). Autoimmune conditions develop when your own immune system considers your own tissue as harmful foreign invaders that need to be destroyed.
This is also known as chronic lymphatic thyroiditis and is the commonest cause of hypothyroidism worldwide. Some of you may have it but not know it because, you have not been tested for Thyroid Antibodies. A regular thyroid test done by most practitioners does not include an Anti TPO or Antithyroglobulin Antibody (Anti TG) test. The main reason being that in conventional medicine there is nothing much that can be done to reduce the antibodies apart from prescribing Levothyroxine (Synthroid/Eltroxin/Thyronorm). However, this is where the Functional and Metabolic Medicine approach differs. We know that when we address gut health, nutrient depletions, your HPA Axis dysfunction (Dysregulated Stress response), reduce toxic exposure, maintain adequate Vitamin D3 and help you make lifestyle changes, antibodies to many autoimmune conditions either reduce or disappear. Am I suggesting that you should stop your thyroid medications? Definitely not! However, the amount of medication that you need may be less. Some of you will still need lifelong thyroid medication if your immune system has destroyed most of your normal tissue or you have been diagnosed late.
Symptoms of hypothyroidism:
- Weight gain
- Cold feet & palms
- High cholesterol
- Lack of motivation
- Slow movements
- Hoarse voice
- Loss of libido
- Ringing of the ears
- Hair loss
- Intolerance to heat or cold
- Carpal Tunnel syndrome
- Loss of outer third of eyebrow
- Memory loss
- Poor concentration
- Loss of drive
- Mood swings
- Irregular menstruation
- Goiter (enlarged thyroid)
THYROID HORMONE SYNTHESIS
The two most important hormones produced by the thyroid gland are tetraiodothyronine (thyroxine or T4) and triiodothyronine (T3).
HYPOTHALAMIC-PITUITARY-THYROID (HPT) AXIS
As shown in the picture, the thyroid gland is influenced by two other hormones.
- Thyroid Releasing Hormone (TRH) from the hypothalamus in the brain and
- Thyroid Stimulating Hormone (TSH) from the pituitary gland, located at the base of the brain.
The hypothalamus, pituitary and thyroid glands along with the hormones they produce are together called the Hypothalamic-Pituitary-Thyroid (HPT) Axis. The thyroid gland produces T4 and some T3. The more active form of the hormone is T3. The conversion of T4 to T3 happens mostly in liver, kidneys and brain. Most of the thyroid hormones are bound to thyroid binding globulin (TBG). It is the unbound form of the hormones, the Free T3 and Free T4 that are important for thyroid hormone actions. This is why measuring only TSH, Total T3 & Total T4 do not provide an accurate picture of thyroid function.
If thyroid hormone levels are low in the blood, the hypothalamus and pituitary detect this.TRH released from the hypothalamus stimulates the pituitary to produce TSH, which in turn acts on the thyroid gland to produce thyroid hormones.TSH levels can go up if adequate thyroid hormones are not produced as a result of autoimmune destruction of thyroid tissue or because of nutritional deficiencies, like iodine deficiency.
There are few enzymes called deiodinases which are important for activation and inactivation of T4. One of them called the DIO2 (Type2 Deiodinase), which is present in the brain, is very important for thyroid hormone actions. This is relevant in thyroid hormone replacement (Ref Chapter 7).
FUNCTIONS OF THYROID HORMONES:
It is likely that every cell in the body is a target for thyroid hormones. The most important functions are:
Lipid Metabolism: Thyroid hormones are important for lipid metabolism. This is the reason for raised cholesterol and triglyceride levels when your thyroid function is deficient. Thyroid hormones are also important for carbohydrate metabolism.
Brain Development in the fetus is dependent on the mother’s thyroid function. This is the reason for checking thyroid function before contemplating a pregnancy. Normal thyroid hormone levels are also important for normal development of children.
Reproduction: Thyroid dysfunction can lead to infertility in some people.
Cardiovascular System: Thyroid hormones increase heart rate, contractility and cardiac output.
Central Nervous System: Thyroid hormones are intimately associated with mental state. In fact, about 20 % of people with depression may have undiagnosed hypothyroidism.
FACTORS AFFECTING THYROID FUNCTION
- Selenium Vitamins A, B complex, C, D& E
- Drugs like lithium, amiodarone.
- Heavy metal toxicities
- Exposure to Endocrine Disruptors like Bisphenol-A
THYROID FUNCTION TESTS:
Below is a list of thyroid function tests. All the tests may not be necessary for all of you. However, this is a decision to be made by you in consultation with a knowledgeable doctor.
- Free & Total T3
- Free & Total T4
- Anti TPO & Anti Thyroglobulin Antibody (For Hashimoto’s Thyroiditis)
- Anti-TSH receptor Antibody (For Graves’ Disease)
- Thyroid Binding Globulin
- Tests for nutrient depletions like Iron,vitamin D3, Selenium,Zinc, Iodine etc.
- Tests for heavy metal toxicities
TRH is usually not tested for because the TSH test is sufficiently sensitive.
TREATMENT : Please check my previous post:http://www.betterforlife.in/blog/2016/05/thyroid-hormone-replacement-only-t4-or-a-combination-of-t3-and-t4/
- Get the right tests done. If you have not been tested for thyroid antibodies, you DO NOT KNOW whether you have Hashimoto’s Thyroiditis (Autoimmune Thyroid Disease)
- Do not stop or reduce your thyroid medications without discussion with a knowledgeable doctor.
- Maintain adequate Vitamin D3 levels
- Check for nutrient depletion.
- Maintain good gut health.
- Look for anemia.
- Reduce your toxic burden
- Address your dysregulated stress response.