The thyroid gland is located in the lower part of the neck near your Adam’s Apple. It secretes two essential thyroid hormones: triiodothyronine (T 3 ) and thyroxine (T 4 ) 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.
The normal thyroid gland secretes all of the circulating T 4 and about 20% of the circulating T 3 . Most of the biological activity of thyroid hormones is due to T 3 . It has a higher affinity for thyroid receptors and is approximately 4 – 10 times more potent than T 4 . Because 80% of serum T 3 is derived from T 4 in tissues such as the liver and kidney, T 4 is considered a prohormone. The ratio of circulating T 4 to T 3 is 4:1. 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.
Hypothyroidism is a condition resulting from insufficient production or diminished action of thyroid hormones. Hypothyroidism is characterized by a generalized reduction in metabolic function that most often manifests itself as slowing of physical and mental activity. The most common signs and symptoms of hypothyroidism 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.
“Wilson’s Syndrome” is a disease state identified by Dr Denis Wilson that exhibits most hypothyroid symptoms although circulating levels of T 3 and T 4 are within normal limits. Conversion of T 4 to T 3 in the liver and cell-membrane receptor sites is impaired resulting with hypothyroid symptoms. Additionally periods of stress or starvation induce the conversion of T 4 into the inactive reverse T 3 . Reverse T 3 is a mirror image of T 3 and fits into the receptor upside down thus preventing the active T 3 binding to the receptor and activating the appropriate response. This condition may be treated with T 3 once adrenal exhaustion, hypoglycemia and/or low sex hormone levels have been ruled out and/or treated and reverse T 3 levels have been shown to outbalance normal T 3 by more than 10:1 (more information available on request).
Thyroid problems may be triggered by any of the following factors:
Genetics
Genetics may be the most common cause of thyroid problems.
Low-Calorie Dieting
Within hours of restricting calories the thyroid will slow down and remain slow until the restriction is lifted. The slow down of calorie burning results in the familiar post-diet rebound weight gain.
Hormonal Events
Hormonal events such as pregnancy and menopause can often trigger thyroid problems. During periods of estrogen dominance the thyroid gland function may be suppressed reducing the secretion of thyroid hormones. Sometimes however menopausal women may appear with hypothyroid symptoms even though their thyroid hormone levels are found to be normal. Dr John Lee has found that in these cases estrogen dominance occurs which he hypothesized blocks the action of thyroid hormones, possibly by competing with thyroid hormone receptors, thus rendering the hormones ineffective.
Adrenal Gland Malfunction
If the adrenals become overactive during periods of chronic stress the thyroid gland tries to compensate by slowing down resulting with a stressed, tired but wired sensation that will not go away (see Adrenal Exhaustion). In addition, an exhausted adrenal gland produces less cortisone, a powerful natural anti-inflammatory that tames the inflammatory and allergic responses of your immune system. This may result with an inflamed thyroid gland thus decreasing thyroid hormone secretion which may eventually further stress the adrenal gland to compensate for low thyroid levels.
Autoimmunity
Hashimoto’s Auto-Immune Thyroiditis is a complex thyroid affliction where the bodies overactive immune system attacks the thyroid gland.
Deficiencies
A lack of Selenium and/or Iodine can adversely affect thyroid hormone production
Aging
Thyroid function may diminish with age.
Physical Injury or Illness
Both reduce thyroid function.
Drug Use
Estrogens, lithium, heavy metals such as mercury, sulfur drugs and anti-diabetic drugs are all well known thyroid inhibitors.
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 as thyroid hormone levels begin to decrease, a compensatory increase in TSH secretion occurs, thus maintaining T 3 and T 4 levels. As thyroid failure progresses the level of thyroid hormones continue to decrease despite further increases in TSH. 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.
Many patients go undiagnosed 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 and anti-microsomal antibodies. T 3 and T 4 levels should be within the normal physiological range while the anti-thyroglobulin and anti-microsomal antibody tests determine if the immune system has waged battle on the thyroid gland causing thyroiditis.
Another simple test can also be performed in order to test thyroid function. By measuring your underarm temperature first thing in the morning before getting out of bed can indicate a sluggish thyroid. If your underarm temperature is consistently subnormal (below 36.5 o C) for 3 days or more your thyroid function is probably low. 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 under active then usually the adrenal glands get overworked and run down while trying to compensate for the low thyroid hormone levels. If you tend to be jittery on thyroid medication or if you are generally overly alert at night, have rapid mood swings, have sugar or salt cravings, feel tired all the time, have dark circles under your eyes and are easily stressed then your adrenal glands may also need help. By having your DHEA and cortisol levels tested an assessment of your adrenal function can also be made. If it too is under active it will also require a little help in the form of supplemented DHEA and possibly pregnenolone/cortisol (see adrenal exhaustion for more details). By addressing all hormones that are out of balance ensures a more complete healing 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.
