by Stephen Smith
Copyright (c) 2009
'Do I have normal thyroid levels?' is a common question that people ask when they are having trouble losing weight. Unfortunately, diagnosing thyroid conditions is often difficult even when a person exhibits low thyroid symptoms.
What Does the Thyroid Do?
The thyroid gland is situated in the lower part of the neck. It secretes two hormones: triiodothyronine (T3) and thyroxine (T4). These hormones are responsible for controlling the metabolism of all body cells and therefore regulate body weight. They also regulate body temperature, heart rate and cholesterol levels.
People who have normal thyroid levels secrete around 90 - 100 mcg of thyroxine (T4) daily. All of this is produced by the thyroid gland. The thyroid gland also produces about 20% of the body's triiodothyronine level (T3), which is about 1/3 the production of T4.
The remainder of circulating T3 comes from the liver and kidneys where it has been converted from T4. These tissues convert T4 into two types of T3 hormones: T3 (active) and reverse T3 (rT3).
T3 is around 4 times more biologically active than T4. Reverse T3, on the other hand, is a T3 antagonist. It binds to T3 receptors, which blocks the action of T3.
It is important that the body maintains the delicate balance between T3 and rT3 conversion from T4. If for some reason the balance between T3 and rT3 becomes uneven and rT3 dominates, then symptoms of low thyroid (hypothyroidism) may result even though levels of circulating T4 and T3 may be considered normal thyroid levels.
These under-active thyroid symptoms result from a malfunction of the conversion of T4 into T3 rather than an insufficient production of thyroid hormones.
The rT3 dominance may result from period of prolonged stress, which causes an increase in the production of the hormone, cortisol. Cortisol blocks the conversion of T4 into active T3, which leads to increased production of rT3. Elevated rT3 levels may also inhibit the conversion of T4 into active T3 thus resulting in even higher rT3 levels.
Diagnosis of Problems with Thyroid
If someone exhibits low thyroid symptoms (under-active thyroid), blood tests for thyroid function are usually conducted. These tests identify levels of Thyroid Stimulating Hormone (TSH), T4 and T3. Rarely do doctors test for rT3.
As a result, many doctors tell their patients that their thyroid is fine, despite the fact that hypothyroid symptoms are present.
Patients usually must request an rT3 test to be done. Then the ratio of T3/rT3 can be found. T3 levels must be slightly higher than rT3 levels. The ideal ratio should be between 1.06 to 1.13. If it is less than 1, then rT3 dominance is present.
If rT3 dominance is present, more tests should be conducted to see if there are problems with adrenal exhaustion, hypoglycaemia, specific nutritional deficiencies and sex hormones levels. They should also begin a supplementation program involving iodine, selenium, zinc, vitamin B6, vitamin B12, vitamin E, tyrosine and iron because these nutrients assist with the production of T4 as well as the conversion of T4 into T3.
In addition to blood tests there are several other ways to assess thyroid problems and therefore provide a more accurate assessment.
Treatment of Thyroid Problems
When it comes to treating any disease in the body, it is essential that the underlying cause is addressed rather than simply masking the symptoms.
If a person is diagnosed with an underactive thyroid, the standard protocol is to simply give them thyroxine (T4) or triiodothyronine (T3) medication. Over time, this approach may result in their body stopping its own production of these hormones completely, which means they will be on the medication for the rest of their life.
Medication is an effective tool in achieving normal thyroid levels but it is not a long-term approach. Many other treatment options are available that may be used individually or in conjunction with medication. Always work with your doctor when considering treating any thyroid problems.
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