Women’s Health – Thyroid Balancing
In 1995, researchers studied 25,862 participants at the Colorado statewide health fair. They discovered that among patients not taking thyroid medication, 8.9 percent were hypothyroid (under-active thyroid) and 1.1 percent were hyperthyroid (over-active thyroid). This indicates 9.9 percent of the population had a thyroid problem that had most likely gone unrecognized. These figures suggest that nationally, there may be as many as 13 million Americans with an undiagnosed thyroid problem.
Thyroid Hormones and Iodine
Thyroid cells are the only cells in the body which can absorb iodine. These cells combine iodine and the amino acid tyrosine to make T3, or triiodothyronine, and T4, or thyroxine. T3 and T4 are simply iodinated amino acids. A normal thyroid gland produces about 80 percent T4 and about 20 percent T3. The remainder of T3 is produced in peripheral tissues by the deiodination of T4. T3 possesses about four times the hormone “strength” as T4 and is really the physiologically active hormone. T3 controls metabolism (conversion of oxygen and calories to energy). Every cell in the body depends upon thyroid hormones for regulation of their metabolism.
Thyroid hormones (T3 and T4) are relatively insoluble; therefore, they are transported in the plasma bound to carrier proteins. Approximately 99.9% of T3 and T4 are protein bound. Only a small amount of unbound hormones are free to enter into peripheral cells. It is important to know that tissues respond to the concentration of free hormones, not the concentration of bound hormones.
Control of the thyroid gland is regulated by thyroid releasing hormone, or TRH, occurring in the hypothalamus deep within the brain. TRH triggers the pituitary gland to release thyroid stimulating hormone, or TSH, or thyrotropin, which in turn causes the thyroid gland to produce its hormones.
Thyroid function can easily be tested by evaluating hormone levels, though results can be confusing unless the practitioner has a complete understanding of each hormone, including its origin and function. There are three thyroid hormones that are commonly tested, either alone or as part of a panel: T4, T3, and TSH. You will see choices of testing total or free T3 and T4. It is important to test free T3 and T4 (fT3 and fT4) levels in order to establish an accurate picture of thyroid function. TSH is often used as an initial screening test for thyroid function or as a tool to monitor thyroid replacement therapy. A high TSH level is indicative of thyroid gland failure, while a low level reflects an overactive thyroid. However, TSH is not a sensitive test and may not accurately reflect thyroid status and therefore, should always be ordered in combination with fT3 and fT4. Sometimes hyper/hypothyroidism is caused by autoimmune destruction of the thyroid gland. Autoimmune thyroiditis can be evaluated by measuring the antibody thyroid peroxidase (TPO) in serum.
Another important aspect of thyroid function is iodine. Without it the thyroid gland simply cannot produce adequate quantities of hormones. The names of the hormones reflect their iodine components: T3 has three iodine molecules, T4 has four. It is easy to see then, how a deficiency in iodine can result in hypothyroidism. Iodine levels can easily be tested in the urine. It has been proven that iodine replacement greatly improves, if not eliminates, symptoms of a poorly functioning thyroid gland.¹
Together with our salivary hormone testing menu, Center for Wellness and Healing offers urine iodine testing along with blood tests that include TSH, fT3, fT4 and TPO. These may be ordered individually or as a panel. Give us a call for more information.
Books to Read:
- Hypothyroidism: The Unsuspected Illness ~ by Broda Barnes
- David Brownstein, MD. “Iodine Why You Need It Why You Can’t Live Without It” 2nd edition