Dear Patients and Friends:
One of the common concerns I deal with in my medical practice are patients who feel they have thyroid problems. Measuring a person’s TSH (thyroid stimulating hormone) is the generally accepted method of diagnosing thyroid status. A high TSH is thought to always indicate a hypothyroid (low thyroid) state and a low TSH is thought to indicate a hyperthyroid (too much thyroid) state from either an overactive thyroid gland or too much replacement thyroid hormone. A reference range TSH is thought to reflect “normal” thyroid function. But are there limitations in using the TSH level to determine thyroid function? The TSH reference range varies from lab to lab, but in general is around 0.26 at the low end of the range, and as high as 4.5 to 5.0 at the high end of the range. So if a person has a TSH of 5.2 they might be told their thyroid is “sluggish” and they might benefit from thyroid medication therapy. If that same person has a TSH of 4.8, he or she might be told their thyroid is ‘normal’ and that they do not need thyroid replacement. Some endocrinologists and physicians believe the TSH level of normal function should be 3.0 or less.
What if a person has symptoms of fatigue, weight gain, cold intolerance, low libido, low body temperature and/or hair loss and the TSH test is within the reference range? My experience has been these patients have been told their thyroids are “normal” and that their symptoms are not related to thyroid disease. Some of these patients may even be taking Synthroid or a similar product for hypothyroidism and still have symptoms of low thyroid function. In the following article I will discuss some of the limitations in using the TSH and/or routine thyroid tests. The concept of “non-thyroidal hypothyroidism” is not generally accepted by traditional medicine, but is widely accepted by integrative medicine.
What is the Thyroid Gland?
The thyroid gland is located in the lower part of the neck, below the Adam’s apple, wrapped around the trachea (windpipe). It has the shape of a butterfly with two wings (lobes) attached to one another by a middle part called the isthmus. It makes and stores hormones that help regulate the heart rate, blood pressure, body temperature, and the rate at which food is converted into energy and the rate of chemical reactions in the body (metabolism).The thyroid also helps children grow and develop. The function of every cell in the body depends on the presence of an adequate amount of thyroid hormones. The thyroid combines iodine, a mineral found in some foods and in iodized salt, with the amino acid tyrosine, to make its hormones. The two most important thyroid hormones are thyroxine (T4) and triiodothyronine (T3). Thyroid stimulating hormone (TSH), which is produced by the pituitary gland, acts to stimulate hormone production by the thyroid gland. The thyroid gland also makes the hormone calcitonin, which is involved in calcium metabolism and stimulating bone cells to add calcium to bone.
Thyroid Hormones and Symptoms of Hypothyroidism
So what happens when a person’s thyroid is not working as well as it should? When your thyroid gland makes thyroxine (T4), it stores about 90% of it in the gland itself. Thyroxine is converted into triiodothyronine (T3). T3 is three to four times more active than T4, and T3 is critical for the cells of the body to produce energy. If your muscles don’t have enough thyroid hormone, they might feel weak and tired or they might hurt as in fibromyalgia. If your brain is deficient in thyroid hormones, it will be hard to think or you could experience “brain fog.” Your joints might swell and hurt if thyroid hormones are not getting into the cells where they can do their work. Your intestines might not have enough energy to function and you could experience constipation, or paradoxically, you could have diarrhea. Low thyroid affects sex hormones and can be associated with PMS, inability to get pregnant and low libido. Other symptoms can include cold extremities, chronic fatigue syndrome, weight gain, depression, diabetes and high levels of cholesterol. Children who are born with low thyroid function can have cretinism where their physical and mental development is severely stunted.
My Lab Tests are Fine, But I’m Not
A standard thyroid panel consists of a TSH and a reflex T4 — and these two tests don’t tell the whole picture of how a person’s thyroid system is functioning. As previously stated, the ranges for TSH and T4 vary from lab to lab and are based on a bell curve of people who come to the lab for testing. The ranges are not based on research that tells us what a “healthy range” is. If a lab bases its “normal” range on test results from sick people (the one’s primarily getting lab work), does that tell us anything about what a “healthy” range should be? It is important to know that about 90% of T4 and T3 are bound to protein (thyroid binding globulin), and while bound to protein, these hormones are unavailable for use. At the Center, we have your lab measure not just TSH, but free T4 and free T3, which are the non-protein bound thyroid hormones available to the cells in your body.
Thyroid physiology is complex and the production, conversion and uptake of thyroid hormone in the human body involves a number of steps. A problem in any of these steps can result in hypothyroid symptoms, but may not show up on standard lab tests.
Some of the Causes of Hypothyroid Symptoms
One cause of hypothyroid symptoms is pituitary dysfunction. The pituitary is a tiny gland in the brain that signals the thyroid gland to produce T4, but if the pituitary isn’t sending the right messages you can still have a TSH level within the lower lab reference range with the gland producing a suboptimal amount of T4. Some of the causes of this can be related to pregnancy or a previous pregnancy (Sheehan’s syndrome), active infection, glucose metabolism problems, or chronic stress.
Another cause of hypothyroid symptoms is under-conversion of T4 → T3. T4 is a pre-hormone and T3 is the active form of thyroid hormone. This conversion occurs in cell membranes. Inflammatory cytokines can damage cell membranes and impair the conversion of T4 into T3. (Inflammatory cytokines are small proteins that bind and activate their respective receptors to promote inflammatory responses.) High cortisol, a stress hormone, also suppresses this conversion.
Reverse T3 Acts Like a Brake
T4 can also be converted into reverse T3 (RT3) instead of T3. It has been hypothesized that RT3 acts like a “brake” and blocks the effects of T3, slowing a person’s metabolism down in times of stress. So a person’s lab results may show reference range levels of free T3, but at the same time that person may have high amounts of reverse T3 blocking the action of T3 at a cellular level. Labs do not measure “free reverse T3” but we know a physiologically normal production should be about one tenth that of the total T3. At the Center we may have the lab run a RT3 level and total T3 level to calculate the total T3/RT3 ratio. If this ratio is too low, a person may benefit from the addition of a T3 supplement or medication such as Cytomel, or a product such as Armour thyroid or Nature Thyroid, which contain both T4 and T3.
We can also see persons with reference range thyroid hormones and TSH that present with hypothyroid symptoms due to thyroid resistance. Thyroid resistance can be caused by chronic stress and resultant elevated high cortisol levels. It can also be caused by genetic factors or other factors such as an increased retention by the body of toxic metals, especially mercury. Chronic illness and certain drugs such as steroids and beta blockers, to name a few, may also lower T3 levels in the blood and tissue.
Hormonal Imbalance and Effects on Thyroid Function
Other causes of “non-thyroidal” hypothyroidism include either a too high or a too low thyroid binding globulin (TBG). When levels of TBG are high, levels of free T4 and free T3 will be low, leading to hypothyroid symptoms. The most common cause of high TBG levels is high estrogen, which can be due to estrogen dominance, birth control pills, or estrogen replacement therapy. When the levels of TBG are low, the levels of T4 will be normal, but the levels of free T3 will be high. Even though there is more than enough T3 hormone, the cells in the body develop a resistance to it, and hypothyroid symptoms can be present.
Thermography, also known as digital infrared thermal imaging, is a test of physiological function and may be a useful tool in evaluating both estrogen dominance and thyroid system dysfunction. With thermography, a very sensitive digital thermal imaging camera records temperature patterns of the skin that correspond to specific dermatomes that reflect reactions within the sympathetic nervous system. Imaging the thyroid thermal patterns can indicate, in many cases, whether there is thyroid dysfunction or even nodules. It does not differentiate between low and high thyroid function, as this would be a lab analysis. If a women is suspected to have estrogen dominance, thermography is often useful in demonstrating whether high estrogen (or low progesterone) levels are having an effect on the thermal patterns and temperature differentials of the breasts. This is not the same thing a mammogram, which is an x-ray. Unlike mammography, breast thermography, has no radiation or compression of the breasts. Breast thermography is not a replacement for mammography, but it can demonstrate a pattern of estrogen dominance which is a risk factor for an increased risk of developing breast, uterine and ovarian cancers. The thyroid gland thermal patterns are also seen at the same time as a woman’s breasts with breast thermography.
We offer thermography services on Fridays. Please call Gainesville Thermography at (352) 332-7212 for information or an appointment.
Patient Success Stories – Patient Taking Medication for Hypothyroidism But Still Having Symptoms
Mrs. C is a patient who recently consulted me for her thyroid problems. This patient has been hypothyroid since 1970. She initially was taking Armour thyroid and when this was unavailable, switched to Synthroid by her primary care physician. Mrs. C had symptoms of hypothyroidism in spite of taking Synthroid: weight gain of 6-8 pounds in the past year, dry skin, “fatigue all the time,” hair loss and cold intolerance with her feet being especially cold. Mrs. C requested a T4 and T3 level be run from her physician, but was refused because her TSH level was “normal.” She was told her symptoms were not due to low thyroid function. I ordered a full thyroid panel and Mrs. C was found to have both a low total T3 and a high reverse T3 level. Cytomel (T3) was prescribed in progressively increasing doses and within two months this patient’s fatigue and cold intolerance had improved considerably. Her total T3 and reverse T3 labs were repeated and had returned to normal.
Ms. N is a registered nurse who has been in our practice for many years. She has hypothyroidism as a result of Hashimoto’s thyroiditis. This is a condition where the body produces antibodies that attack the thyroid gland and can also attack hormones and their receptors, altering their function. She was taking Armour thyroid for years with good results but later came under a great deal of stress from caring for her mother with cancer. She also had a very stressful nursing job working with critically ill patients. She began feeling more and more fatigued and also started having increased muscle and joint pains from flare ups of her fibromyalgia that had previously been under control. Ms. N was also taking bio-identical hormones, having undergone a surgical menopause from a previous hysterectomy and she wondered if her hormone levels were off. It was felt there were multiple causal factors contributing to her symptoms of thyroid dysfunction. Lab results confirmed a high reverse T3 level. Ms. N was started on Cytomel, which can reduce reverse T3 levels. She was also started on natural adrenal support therapy and was advised to take a break from her stressful job for a few weeks.
Mrs. C is a 65 year old respiratory therapist who initially saw me for hypothyroidism, obesity and hypertension. She was taking Levothyroxin 100mcg to 112mcg daily for years. Concerned about her weight being in the 215 pound range, she consulted us about placing her on a diet program. The Releana diet program was originally developed by Dr. Simeons, a British physician. He hypothesized that the “abnormal fat” around a person’s waist and thighs was difficult to lose due to a hormonal imbalance in the hypothalamus. He developed a program using a 500 calorie restriction, low carbohydrate diet plus HCG injections. Dr. Simeons was treating patients in an Italian hospital and his patients would average a 1 pound weight loss a day. At the Center, we do not give HCG injections, but use a prescription/pharmaceutic grade sublingual HCG from Releana. This program must be physician supervised. Mrs. C lost 60 pounds on the Releana diet and noted her hair, which was thinning, started growing back and she no longer required hypertensive medications. She was very pleased with the outcome.
However, within a year of completing the program her weight started creeping up. She admitted she was under a lot of stress from caring for her elderly, virtually blind mother at home. Mrs. C had started eating more carbohydrates and foods not on the maintenance plan. Her temperatures were in the 97.5 F range. She had good energy and her basic thyroid labs showed reference range TSH, free T4 and a free T3 at the lower end of the reference range. She was placed on selenium, which is a necessary mineral in the conversion of T4 → T3. She keep a temperature record for a 2 month period of time. Her temperatures ranged from a normal of 98.6 F down to 97.1 F. She found she was sleeping better after using the selenium and her constipation symptoms decreased. Cytomel was added in divided doses due to the borderline low free T3 and she felt much better with the addition of this medication. She continues under stress from her job and caring for an elderly mother, but feels she is able to handle this stress better, and is now working on limiting her carbohydrate intake to bring her weight down once more.