21st Century Thyroid Testing

by Dr. Joseph Debé

You’ve been to the doctor with complaints of weight gain, fatigue, cold hands and feet, and "brain fog". The doctor examines you and performs some blood tests, including thyroid tests. The doctor can find nothing wrong with you. All the tests come back normal. But you were sure you must have an underactive thyroid. You have all the symptoms. You go home without any treatment, sentenced to a life of unwellness. This scenario is played out again and again because the thyroid blood tests simply are not sensitive enough to pick up many cases of hypothyroidism.

Salivary thyroid testing to the rescue! That’s right. Your saliva holds the key to identifying the presence of an underactive thyroid. This brand new technology promises to change the lives of the millions of individuals suffering with an undiagnosed underactive thyroid.

Anne is among the first people to be helped by this new test. She came to me for treatment of chronic fatigue, difficulty losing weight, dry skin, hair loss, and lack of sex drive. These are all possible symptoms of an underactive thyroid. [Other common symptoms of hypothyroidism include depression, constipation, low body temperature, cold intolerance, hoarseness, muscle weakness, joint pain and stiffness, muscle pains, morning headaches, carpal tunnel and similar syndromes, goiter, hypertension, impaired kidney function, slow heart rate, yellow skin, thin brittle nails, shortness of breath, water retention, impairment of concentration and memory, learning disabilities, altered immunity, coarse dry brittle hair, elevated blood cholesterol and triglycerides, menstrual irregularities, miscarriage, premature deliveries, still births and infertility.] Other clues to Anne’s condition were the prescription medicines she was taking. Anne’s medical doctor had her on cholesterol-lowering medication and an antidepressant drug. Over the eight years that Anne had been feeling poorly, she was tested about a dozen times for thyroid function. The blood tests were always normal. The doctors she consulted could find nothing wrong with her. Frustrated with her condition, Anne began researching her symptoms. She felt that her symptoms, in combination with her low body temperature, were proof enough that her thyroid was low and, for whatever reason, the blood tests were just not picking it up. She asked her doctor to give her thyroid hormone medication but her doctor refused because the blood tests were normal. I agree with her doctor’s decision because an underactive thyroid is only one possible explanation for low body temperature and the symptoms Anne was experiencing. Another very common cause of these problems is elevation of the stress hormone, cortisol. Treating for an underactive thyroid based on low body temperature is a mistake many holistic practitioners make. This approach (when the thyroid is not the problem) can lead to further elevation of cortisol and suppression of thyroid hormone levels.

I had Anne take this brand new test for assessment of thyroid function. The test showed that Anne was indeed hypothyroid! What is this new test and why did it find an underactive thyroid when all the other tests did not? This new test is not a blood test. It is a test performed on a saliva sample. It uses chemiluminescence technology, which allows for more discrimination of low-end values. The sensitivity it provides can be compared to the difference between using a ruler to measure inches versus millimeters. Another important reason for the difference in results stems from the measurement of what are referred to as free versus total hormone levels. Total hormone consists of both protein-bound and non protein-bound hormone. Free is another term for unbound hormone. In the case of the thyroid hormones, T4 and T3, more than 99% is normally protein-bound in the blood. Less than 1% is free. Only the free hormone exerts biologic activity. The protein-bound hormone is inactive. The saliva test is a more accurate and sensitive way to assess thyroid function because new technology allows for direct measurement of the free thyroid hormones. Blood testing of free thyroid hormones is done by an indirect method, which is prone to error. This new saliva test therefore, gives a truer picture of the amount of thyroid hormones available for the regulation of metabolic rate in every cell in the body.

The thyroid salivary test measures the two main thyroid hormones, T4 and the more powerful T3. The thyroid gland manufactures both of these hormones but most T3 is produced in other tissues, primarily the liver, by structural modification of T4. The salivary test also measures free TSH. TSH, secreted by the pituitary gland at the base of the brain, stimulates the thyroid gland to produce and release its hormones. TSH levels increase in an effort to get an underactive thyroid to produce more hormone. Therefore, elevated TSH levels are often seen in hypothyroidism. On the other hand, some cases of hypothyroidism are secondary to inadequate pituitary stimulation of the thyroid. This is signified by subnormal levels of TSH. The salivary thyroid test also measures antibodies against thyroperoxidase, an important enzyme in production of thyroid hormone. Positive antibodies are sign of an autoimmune process-the immune system attacking the body’s own thyroid tissue. A fifth compound, free r (reverse) T3 will soon be measured as part of the thyroid panel, as well. Reverse T3 is slightly different in structure from T3 and does not appropriately bind to receptor sites, as does T3. Its action is like putting a left-handed glove on your right hand. The rT3 blocks T3 from binding to receptor sites and exerting biologic activity, and fails to exert thyroid action of its own. The result is a slowing of metabolism. All this information on thyroid hormones leads to specific treatments.

One treatment option for hypothyroidism is to use thyroid hormone replacement therapy. In my opinion, a better approach is to investigate and correct the underlying causes of the hypothyroidism. A multitude of factors can alter thyroid function at different points of metabolism: accumulation of iodine within the thyroid gland (T4 and T3 are composed of iodine and tyrosine), production of thyroid hormone, release of thyroid hormone from the thyroid gland into the blood, transport of thyroid hormone within the bloodstream, conversion of T4 to the more active T3, binding of thyroid hormone to cell receptors, transport of thyroid hormone into the cells (where it produces its activity), and elimination of thyroid hormone from the body. The modifiable causes of low thyroid function include a variety of dietary factors, fasting, anorexia nervosa, nutrient insufficiencies, stress, inflammation, various disease states, exposure to environmental pollutants and other toxins, radiation exposure, dysbiosis (imbalanced intestinal flora), smoking, imbalance of other hormones, inactivity and even certain medications.

So what did we find in Anne’s case and what are we doing about it? Anne was found to have low levels of free T3 and elevated levels of free TSH. So what we need to do is raise her free T3 levels. This can be done with hormone replacement. Anne however, has opted to take a holistic approach because she understands that whatever factors have reduced her thyroid function will not be addressed by simply taking hormone replacement. Initial investigation in Anne’s case has revealed several contributing factors. Anne had been eating a low carbohydrate diet in an unsuccessful attempt to lose weight. Low carbohydrate diets have been found to inhibit conversion of T4 to T3. We therefore increased Anne’s intake of unrefined nutrient-rich plant foods to provide a more balanced carbohydrate to protein ratio. We also found that Anne is lacking in the mineral selenium, which is necessary for the function of the enzyme that converts T4 to T3. Anne has therefore begun taking a selenium supplement. Testing also revealed mercury toxicity. We are instituting a mercury detoxification protocol to remove this thyroid-suppressing heavy metal from her body. It is too early to tell how well Anne’s thyroid function will recover but she is feeling better already and has begun to lose weight. Additional therapies (holistic or conventional) may or may not be necessary.

The new salivary thyroid test has the potential to change the lives of millions of Americans who are suffering the ill effects of having an undiagnosed underactive thyroid. In addition to the symptoms mentioned above, hypothyroidism may cause greater risk to diabetes and cardiovascular disease. Importantly, the salivary thyroid panel is also more accurate than the blood tests in identifying an overactive thyroid. Hyperthyroidism is associated with a different set of symptoms and increases risk to osteoporosis. Saliva is becoming the specimen of choice for investigating hormones because of the ability to measure the free fraction as well as the other advantages associated with the ease of obtaining multiple samples. Other hormones that can be measured from saliva include estrogen, progesterone, testosterone, androstenedione, cortisol, DHEA, and melatonin. Evaluating these hormones gives a wealth of information, leading to treatments to improve a wide range of conditions and Anti-Aging.

Also be sure to read Reviving Your Thyroid