What is Hypothyroidism?
Hypothyroidism is a condition resulting from insufficient production or diminished action of either triiodothyronine (T3) and/or thyroxine (T4) thyroid hormones. Hypothyroidism is characterized by a generalized reduction in metabolic function that most often manifests itself as slowing of physical and mental activity.
Symptoms of Hypothyroidism
The most common hypothyroidism symptoms are: weight gain, fatigue, lethargy, sleepiness, cold hands and/or feet, low body temperature, depression/anxiety, constipation, headache, menstrual problems, reduced sex drive, hair loss, swollen eye lids and general fluid retention, poor memory and concentration and dry skin, hair and/or nails.
Thyroid Hormone Production and Regulation
The thyroid gland is located in the lower part of the neck near your Adam’s Apple. It secretes two essential thyroid hormones: T3 and T4 which are responsible for regulating cell metabolism in every cell in your body. They promote optimal growth, development, function and maintenance of all body tissues. They are also critical for nervous, skeletal and reproductive tissue as well as regulating body temperature, heart rate, body weight and cholesterol.
In a healthy patient a normal thyroid gland secretes all of the circulating T4 (about 80 to 90mcg daily) and about 20% of the total circulating T3 (about 8mg out of the total 32mcg daily). The T4 made by the thyroid gland circulates throughout the body and is converted into roughly equal amounts of T3 and reverse T3. All of the biological activity of thyroid hormones is due to T3. Because 80% of serum T3 is derived from T4 in tissues such as the liver and kidney, T4 is considered a pro-hormone. No receptors have ever been identified for T4. Normal physiological production ratio of T4 to T3 is 3.3:1. Reverse T3 is virtually inactive having only 1% the activity of T3 and being a T3 antagonist binds to T3 receptors blocking the action of T3. Normal metabolism of T4 requires the production of the appropriate ratio, or balance, of T3 to rT3. If the proportion of rT3 dominates then it will antagonize T3 thus producing hypothyroid symptoms despite sufficient circulating levels of T4 and T3.
The synthesis and secretion of the two thyroid hormones is influenced by a hormone released by the pituitary gland called thyroid-stimulating hormone (TSH). The synthesis and release of TSH from the pituitary gland is influenced by thyroid hormone levels as well as a hormone released from the hypothalamus called thyrotropin-releasing hormone (TRH). The activity of the thyroid gland is regulated by a negative feedback loop, in which thyroid hormones interact with receptors in the pituitary gland to inhibit TSH and at the hypothalamus to inhibit TRH secretion.
Causes of Hypothyroidism
Hypothyroidism can be the result of adrenal fatigue and its associated over stimulated nervous system (high cortisol levels depresses TSH and inhibits conversion of T4 into T3), insufficient substrates for thyroid production (low tyrosine, iodine, Vitamin D, etc), estrogen dominance, autoimmune reactions, genetic defects, oxidative damage and toxicities (fluoride poisoning). As with other hormones thyroid production also declines with age.
Reverse T3 Dominance
Reverse T3 dominance, also known as Wilson’s Syndrome is a condition that exhibits most hypothyroid symptoms although circulating levels of T3 and T4 are within normal test limits. This is a condition when T4 metabolism produces an excess of reverse T3 in relation to T3, thus being a problem with T4 metabolism rather than a lack of thyroid production. Periods of prolonged stress may cause an increase in cortisol levels as the adrenal glands respond to the stress. The high cortisol levels inhibits the conversion of T4 into T3 thus reducing active T3 levels. The conversion of T4 is then shunted towards the production of the inactive reverse T3. This reverse T3 dominance may persist even after the stress passes and cortisol levels have returned to normal as the reverse T3 itself may also inhibit the conversion of T4 to T3. Reverse T3 has the same molecular structure as T3 however its three dimensional arrangement of atoms is a mirror image of T3 and thus fits into the receptor upside down thus preventing or antagonising the active T3 from binding to the receptor and activating the appropriate response.
Unfortunately standard blood tests such as TSH, T4 and T3 will NOT be able to diagnose this condition. To overcome this diagnostic problem there is a special test that specifically measures reverse T3 alone and should be requested to rule out reverse T3 dominance. Both T3 and reverse T3 need to be ordered and their values compared as the ratio is of most importance and not their respective numbers. For more information on reverse T3 dominance click here.
Causes of Reverse T3 Dominance
Factors that adversely affect conversion of T4 into T3 include: high cortisol levels, nutritional deficiencies such as selenium, zinc, iodine, Vitamin B6, B12 and E, antibody reactions, insulin resistance, toxicities such as heavy metals and environmental toxins.
Functional Hypometabolism
Functional Hypometabolism or thyroid resistance occurs in some patients where they still suffer from hypothyroid symptoms despite the fact that thyroid hormone levels are optimal and normal hormone protein binding and metabolism occurs. Causes may include suboptimal levels of Vitamin D which is required for receptor response, suboptimal Iron (measured by Ferritin levels) which is required for thyroid peroxidase activity and thyroid transport, low cortisol levels which causes lower thyroid receptor density and response, genetic defect with receptors, receptor dysfunction associated with toxicities (fluoride poisoning).
Unfortunately there are many patients with thyroid resistance that are not properly diagnosed and subsequently their dose of T4 gradually escalates over time with little benefit which can actually aggravate this condition even further as it only increases binding and thus reducing the free and active form.
High thyroid binding globulin (TBG) can also be a problem as it binds to T3 and T4 reducing the level of free and active form of these hormones. High TBG can be the result of high estrogens and liver problems where it is metabolized.
Testing for Hypothyroidism
The TSH Debate
Physicians routinely require blood analysis when diagnosing hypothyroidism. The most common test is the TSH test. Hypothyroid state may first manifest itself with elevated TSH levels. This is because “theoretically” as thyroid hormone levels begin to decrease, the brain registers this decrease and tries to compensate by increasing TSH secretion in order to stimulate the thyroid gland to produce more thyroid hormones. In practice the TSH test is not the most accurate indicator of thyroid problems and is considered by several experts as a scientifically outdated method of diagnosis. It may be inaccurate if there is inflammation, infection, stress, dieting, or the patient is older. TSH is only validated as a screening test and it is not supported anywhere in the literature to be used to diagnose or adjust dosage, although this is the common practice.
TSH is a test that can at best only give a vague indication of thyroid function and not considered accurate enough in my opinion. It often does patients more harm than good as we routinely encounter blood test results where the TSH is within the normal range, indicating a normal functioning thyroid gland, however when T3,T4and reverse T3 levels are checked they are often low or unbalanced with the patient presenting with many signs and symptoms of hypothyroid. Therefore if we relied totally on the presence of elevated TSH results an incorrect diagnosis would have occurred. It has also been shown that pituitary TSH production is inhibited by cortisol therefore many hypothyroid patients whom also suffer from stage 1 adrenal exhaustion (high cortisol levels) may be suppressing the much needed TSH production required for hypothyroid states and thus falsely reducing TSH test results. In addition there is a lot of debate as to the validity of the so called “normal range” and how it should be applied to specific individual cases. Most laboratories in Australia indicate the “normal range” of TSH is from 0.3 to 5mIU/L however investigations have shown that levels greater than 2 may actually indicate adverse health risks. On November 2002, the American Association of Clinical Endocrinologists changed the normal TSH values. Previous normal bounds were 0.5 to 5.0, and these were changed to 0.3 to 3.04. The US National Academy of Clinical Biochemistry, wants to change them again and says “In the future, the upper limit of the serum TSH reference range will be reduced to 2.5 mIU/L. A serum TSH result between 0.5 and 2.0 mIU/L is generally considered the therapeutic target for a standard L-T4 (thyroid hormone) replacement dose for primary hypothyroidism. For more detailed information refer to the work of thyroid specialist Dr Lowe.
Many patients therefore are incorrectly diagnosed as their TSH levels are in the “normal range” failing to reflect the true state of thyroid affairs.
For a more accurate method of diagnosis you should ask your doctor to order the following blood tests as a more accurate assessment of thyroid function can be made: TSH, T4, T3, reverse T3, anti-thyroglobulin, anti-microsomal antibodies, 24hr iodine urine excretion test and Vit D.
The correct interpretation of your results is essential for appropriate treatment. Click here for details. T3 and T4 levels should as a generalization ideally be within the upper one third of the “normal” physiological range with a 1:3.3 ratio while reverse T3 and T3 should be appropriately balanced.
Anti-thyroglobulin and anti-microsomal antibody tests will determine if the immune system has waged battle on the thyroid gland causing thyroiditis, Graves disease or Hashimoto’s while low iodine levels may be responsible for low thyroid hormone production.
To complicate things further there appears to be a subgroup of patients whom exhibit many signs and symptoms of hypothyroidism yet their T3/T4/rT3 test results indicate that their current levels are within the “normal range”. Many of these patients respond well to thyroid supplementation. This is due to the fact that blood tests only measure the levels of thyroid hormones in the blood stream and not in tissue where they actually have their effect, thus not giving a true measure of thyroid function. In this case there would appear to be a thyroid receptor problem. Deficiencies in Vit D and iron can cause receptor uptake problems and should be treated if found to be low. Therefore the limitations of blood tests should be well understood by the physician and not relied upon 100% to determine their coarse of action. Signs and symptoms of the patient in addition to body temperature (discussed below) and blood tests should all be used together in order to gain a bigger picture and thus determine the appropriate therapy.
As mentioned above thyroid function can also be estimated by measuring your underarm body temperature. If your underarm temperature is consistently subnormal (below 36.5 C) for 3 days or more your thyroid function may be low. But do not forget that adrenal function also influences your metabolic rate and therefore body temperature. So adrenal function must also be considered if you have low body temperature. This fact is often ignored by many.
An integrated approach should be taken when diagnosing hypothyroidism making use of all the diagnostic tools as well as using signs and symptoms of low thyroid function. If doctors rely totally on the TSH test without considering signs and symptoms, which has become common practice, then many patients with a sluggish thyroid go undetected and are therefore not treated appropriately.
If the thyroid is found to be under active then it is very common for adrenal fatigue issues to also be present which can amplify some of the symptoms. Adrenal function should also be tested for by measuring DHEA and Cortisol levels. If it too is under active it will also require treatment in order to treat the complete picture and not just a part of it. By addressing all hormones that are out of balance ensures a more complete treatment instead of addressing only one or two of them. Remember all of our endocrine glands are intimately connected and if one hormone is out of balance a cascade effect can occur which will throw them all out if left untreated.
Treatment for Hypothyroidism
(1) In mild to moderate cases certain nutrient combinations may be potentially useful to support thyroid function which include nutrients such as iodine, tyrosine, selenium, zinc and Vitamin .
Alternatively if reverse T3 is elevated you may require the nutrients required by the 5-deiodinase enzyme to function more efficiently and convert T4 into T3 and not rT3.
NOTE: Thyroid blood test results would determine which of these would be more suitable.
(2) Moderate to severe cases may require stronger treatments which may include thyroid supplementation which should ideally be tailor made to the specific needs of each individual.
We also strongly recommend adrenal support, only if tests indicate the need, as adrenal and thyroid function are closely related. Many thyroid patients we see also have adrenal problems and both need to be addressed for a full recovery.
Finally thyroid problems energetically are the result of a stagnation of energy in the throat area as a result of not expressing yourself, holding back or not saying what you really think and/or feel. Therefore in order to energetically heal your thyroid problem you need to start speaking your truth and not hold back out of what ever fear you may have of expressing yourself.
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