Excerpt from Eva Cwynar, M.D.'s new book, "The Fatigue Solution"
The simplest way to describe your thyroid and its function is to compare it to a furnace that is run by a thermostat (the pituitary gland). Together, they regulate how much energy and stamina you have on a daily basis. The amount of thyroid hormone you have affects how well you have slept, how you feel when you get up in the morning, and how effectively you will make it through your day.
Thyroid function affects every cell in the body. It is the main regulator of basal metabolism, which is the amount of energy needed to maintain essential physiologic functions when you are at complete rest, both physically and mentally. If your thyroid gland is not producing optimally, your cells cannot properly take in the nutrients they need, receive the right amount of oxygen, or get rid of waste materials efficiently. Thyroid hormones also affect your heart, muscles, bones, and cholesterol, to name just several of its jobs.
Introducing the 3s and 4s:
There are two main hormones produced by the thyroid:
- Triiodothyronine, known as T3
- Tetraiodothyronine, known as T4
You many have noticed a portion of the word "iodine" in each of the hormones above. That's because the function of the thyroid gland is to take iodine, found in many foods, and convert it into thyroid hormones. Thyroid cells are the only cells in the body that can absorb iodine.
These cells combine iodine and the amino acid tyrosine to make T3 and T4. The normal thyroid gland manufactures both T3 and T4; it produces about 80 percent T4 and about 20% T3. However, T3 is about four times as potent as T4. T4 is actually a precursor to T3. While traveling through the liver, T4 loses one of its iodine molecules, which converts the T4 to T3.
There is one more factor we have to mention to complete this process, and that is Thyroid Stimulating Hormone (TSH), which is produced by the pituitary gland in the brain and gives that gland its thermostat-like function. So the thyroid is the furnace that provides the "heat" in the form of the T3 and T4 hormones and the pituitary gland is the thermostat that goes on and off according to the amount of heat in the body. TSH tells the thyroid to raise or lower the heat. The process goes like this:
T3 and T4 travel through the bloodstream, producing heat
The pituitary gland senses the heat; the thermostat shuts off; TSH production slows down
The body cools as the level of thyroid hormones decrease
The pituitary senses the decrease in temperature; the thermostat pops on; TSH production increases
The furnace produces more heat.
When your body temperature drops, your metabolic rate drops, too. You produce less energy, and you store more calories as fat - in other words, you gain weight. You also suffer from fatigue, irritability, and the inability to concentrate.
Learn more about this topic below:
Also, to learn more about Dr. Eva Cwynar, visit her website: www.dreva.com