The term means low thyroid function. Hypothyroidism probably affects hundreds of thousands of people but is often never diagnosed. Clinical signs and symptoms of hypothyroidism include the following (1,2,3):
Low body temperature, dry skin/hair, (red hair is at particular risk for low thyroid), inappropriate weight gain and/or an inability to lose weight, brittle nails, insomnia and/or narcolepsy, poor short-term memory and concentration, fatigue, headaches and migraines, premenstrual syndrome and related problems, menstrual irregularities, depression, hair loss (including outer third of eyebrows), low motivation and ambition, cold hands and feet, fluid retention, dizziness or lightheadedness, irritability, easy bruising, skin problems/infections/acne, infertility, dry eyes/blurred vision, heat and/or cold intolerance, low blood pressure, elevated cholesterol, digestive problems (irritable bowel syndrome, acid indigestion, constipation, etc.), poor coordination, diminished sex drive, reduced or excessive sweating, frequent colds/sore throats, asthma/allergies, slow healing, itchiness, food cravings, recurrent infections, food intolerances, increased susceptibility to substance abuse, anxiety/panic attacks, yellow-orange coloration on skin (particularly palms), yellow bumps on eyelids, slow speech, thickened tongue with scallop-like indentations, fluid in the ears, etc.
Because long-term low thyroid function causes poor circulation and reduces delivery of oxygen to tissue cellular and therefore has an association with heart disease and cancer as well as making you feel miserable, having even a few of these symptoms warrants checking your thyroid function.
THE PROBLEM WITH DIAGNOSING LOW THYROID FUNCTION
With so many different symptoms and so many different organ systems potentially affected by thyroid system dysfunction, one might think that a diagnosis would be easy. However, in spite of the available blood tests for thyroid/pituitary/liver/adrenal function, the diagnosis is often missed.(1,2) One of the most common mis-conceptions regarding thyroid function is the assumption that and reliance on the requirement that the diagnosis of hypothyroidism depends on an elevated TSH level. Normally, the pituitary gland will secrete Thyroid Stimulating Hormone (hence TSH) in response to a low circulating thyroid hormone level. This is thought to reflect the pituitary’s sensing of inadequate thyroid hormone levels in the blood that would be consistent with hypothyroidism. There is no question that an elevated TSH can confirm the diagnosis of hypothyroidism, but it is far too insensitive a measure, in other words the vast majority of patients who have hypothyroidism do not have an elevated TSH level. Some have suggested that perhaps the upper limit of what is considered normal is too high, instead of the normal TSH range being from 1.0-4.5, the range of normal for TSH should be 0.5-1.5. In that way more patients would be considered hypothyroid.
Furthermore, the lab level of TSH tends to vary throughout different times during the day making it less useful to rely on as the average level. MSG (monosodium glutamate) and stress tend to lower the TSH level, for example.
The most commonly used tests of thyroid hormone levels (note that I use the term level rather than function because the two are not always equal) are the T4 (or total T4), T3-uptake, FTI (also called the T7 or Free Thyroxine Index), and total T3 (sometimes called the T3-by-RIA). These tests are also unreliable because they do not reflect the hormone level that is actually available for action. Only the free T4 and free T3 are available to act on the cells. The total T4 and total T3 (as is most commonly measured) is a mixture of protein-bound T4 and T3 (and therefore not available to the cells) and the free T4 and T3. A large percentage of patients have low levels of the free T4 and freeT3 even when all the other more commonly used tests are normal. Complicating the problem is the fact that these symptoms may present themselves while all the usual blood tests (TSH, FI, Total T3, etc) appear to be normal. When patients with Free T4 and Free T3 hormone levels below normal with or without an elevated TSH are given appropriate therapy, many report a tremendous improvement in the symptoms classically associated with hypothyroidism. Even when the labwork does not indicate low thyroid levels, many patients appear to fit the profile for low thyroid action. In fact, many of the best thyroidologists use the response to therapy as the major determinant of whether or not the patient was in fact hypothyroid. The diagnosis was confirmed by the response to the proper therapy. Even many of the most prestigious textbooks validate this approach.
Unfortunately, when the blood work does not reveal obvious low thyroid levels, many doctors are prone to refer these patients to a psychologist because they “cannot find anything wrong” with these suffering patients.(1) Obviously, the hypothyroid patient will not suffer with all of the above symptoms simultaneously. But if you have some of these symptoms, in spite of unrevealing blood tests, perhaps it is time to look further. Due to my biochemical perspective, I see features of potential low thyroid action in non-thyroid blood tests. For example, in one study 12% of women with an elevated cholesterol level were found to be hypothyroid using the TSH level. That implies that high cholesterol could represent low thyroid. A high calcium:phosphorus ratio was shown by Melvin Page, D.D.S. and others to be potentially due to low thyroid action. When the red blood cell size as measured by the MCV (see lab section on blood counts for more information) is elevated, one of the considerations is low thyroid function. Features of what Emanuel Revici, M.D. termed anabolic occur in hypothyroid conditions. He monitored salivary and urinary pH; when there is a consistently low salivary pH and a high urine pH, an anabolic state was likely. The details of this are not warranted for this discussion. The bottom line is that there may be a pattern of low thyroid activity not only in symptoms but also in the biochemical state.
The most common non-laboratory method for monitoring thyroid is basal body temperatures. Low body temperature seems to underlie many of the symptoms. Broda O. Barnes, MD, did the first studies correlating hypothyroidism to low body temperature. He found that having the patient take his/her axillary (in the pit under the arm) temperature for several mornings before getting out of bed could help document the trend correlating with the symptoms(2,3). An axillary temperature of <97.6 degrees F. indicated a hypothyroid state even when the blood tests did not show irregularities(3). Treating the patient with thyroid hormone seemed to relieve him/her of the often debilitating state(2). I would caution you on concluding that a low body temperature is only caused by hypothyroidism. See the Basal Body Temperature webpage for the proper technique and for other causes.
THYROID HORMONE REPLACEMENT THERAPY
After proper identification of hypothyroidism, the next issue is with what substance to treat. The traditional approach is to use levothyroxine (Synthroid®/Levoxyl®/Levothroid®) which is a synthetic preparation of T4. Desiccated pork thyroid (Armour®, Westhroid®, Naturethroid®) is a natural mixture of mono and di-iodothryonine and T3 and T4 that provides the entire range of thyroid hormones. Thyrolar® is mixture of synthetic T4 and synthetic T3. Cytomel® is a synthetic T3 only product that is also available. Choosing between these options is determined by finding the agent that provides the best response. Some clues to choosing the right agent are discussed below.
If the free T3 level is significantly lower than the free T4 level, it is unlikely to use treat with Synthroid/ Levoxyl/Levothroid (T4) only replacements. This is based on the assumption that if the patient could produce enough T3 from their gland or convert enough T3 from T4, then they are unlikely to do so by adding more T4. This is a key issue because T3 is 4-9 times as potent as T4. Most of the T3 found in the blood is made by the conversion of T4 into T3. The thyroid gland only makes about 20% of the T3 that is found tin the blood. Using T4-only preparations assumes that in the body it will convert to T3 in fairly standard amounts and at fairly standard rates. Unfortunately, clinical experience shows this is not true for the majority of patients. Measuring both free-T3 and free-T4 blood levels in hypothyroid patients who are on T4 only therapy proves that this is not a foregone conclusion. While a certain percentage of hypothyroid patients do convert enough T4 to T3 at a sufficient rate for T4 treatment to be adequate as a source of T3; many require both T3 and T4. In fact a recent article in the New England Journal of Medicine showed that no-one who took only T4 did better than those people who took T3 and T4 in terms of psychoemotional function, irritability, fearfulness, tension, anger, tiredness, physical coldness, nausea, etc. Thus there is certainly no advantage in using T4 alone.
You might wonder then why combination T4 and T3 products are not the first choice for all low thyroid patients. For some, pork is not well tolerated. Natural thyroid, despite what the manufacturer claims, is subject to variation between batches – not only in the exact total quantity of thyroid, but in the proportions of T3 and T4. This is rarely a problem. Another consideration is that it is probably best to take preparations that contain T3 twice a day because T3 does not stay in the blood for more than 4-6 hours. Thus, natural thyroid products are not as convenient as the once in the morning T4-only products.
In my practice, my choice is to use a combination of T4 and T3 unless I have a compelling reason not to use it. For the patient who shows no feature of persistent low thyroid function that has been on T4 only, I leave well enough alone.
Cytomel®, a T3-only product, and can be used alone or in combination with a T4-only preparations. Because T3 has a short activity (or “half life”), it needs to be used twice a day. E. Denis Wilson, MD, in his book “Wilson’s Syndrome“, found that many of patients respond best to T3-only (liothryonine). He believes there is a difference between thyroid gland dysfunction and thyroid system dysfunction. Although the TSH and T4 levels may be within the normal range, the important thing is not how much hormone is in the blood, but how effectively the T3 hormone is affecting the cells. At the present time, no tests can test the cellular function.(1) Therefore, he often diagnoses hypothyroidism by observing the patient’s symptoms. Often T3 (liothryonine) therapy will alleviate or eliminate many symptoms even those previously attributed to other causes. Dr. Wilson used T3-only because T3 is 4-9 times as active as T4.
How do I know if I’m on the right dose on thyroid. In addition to relief from many of the obvious symptoms, the basal body temperature can be a guide. As a clinical observation, I have found that when the pulse rate goes up but the temperature does not rise any more, taking more thyroid will not help. You are getting all that you will out of it and side effects or biochemical/hormonal affects from overdosage will become more and more likely.
Over-dosage symptoms, which are frequently only temporary during the adaptation stage. The symptoms may include: palpitations, nervousness, feeling hot and sweaty, rapid weight-loss, fine tremor, and clammy skin. One of the long-term results of excessive thyroid activity is osteoporosis and a tendency to stress the adrenal glands.
NUTRITIONAL AND COMPLEMENTARY THERAPIES
Less severe cases may also respond to nutritional therapy in that the glandular systems can be supported, thereby strengthening the whole body. A thorough understanding of the intricate interrelationships between body systems can provide the foundation for a sound nutritional program. A comprehensive approach will address the entire problem, not just the symptoms. Nutrition for the thyroid should include support for the adrenals, liver, pituitary and spleen. The feedback among these glands determines the levels of circulating hormones in the body(1). Because of the functional interrelationships between these organs, a deficiency in any nutrient can adversely affect thyroid function. The idea should be to promote growth, balance and repair of the thyroid and related organs.
In addition to a well-balanced whole food based multiple vitamin and mineral supplement(s), normalization of the thyroid system often responds beautifully to a multi-glandular approach without the use of thyroid hormones. Because of the body’s hormonal feedback systems, it has been proposed that taking thyroid hormones may actually induce a “welfare state” upon the thyroid gland. This means that supplying the body with its T4 hormone from without will cause the thyroid gland to cease making it on its own. I have not found this to be the case, or at least it is not universally true since many of my patients are able to adjust and in some cases discontinue taking thyroid without their hypothyroid symptoms returning. While many nutritional practitioners use thyroxine-free glandular, most of my patients prefer the more rapid and effective prescription agents.
Ray Peat, Ph.D., has written about the effect of other hormones on the thyroid system. Progesterone and pregnenolone tend to increase thyroid hormone effects because they promote the conversion of T4 to the more active T3. Estrogen has the opposite effect on thyroid hormone conversion(4). This may explain why so many women gain weight when estrogen replacement therapy or birth control pills are prescribed. Therefore, the physician needs to consider the effect of hormone replacement therapy when treating a patient for hypothyroidism.
Supplements that stress the thyroid and adrenals, such as ma huang, ephedra, guarana and excessive caffeine, should be avoided.
Anti-Thyroid effects are seen with alcohol and stress (in part from ACTH). Most pesticides are similar to thyroid hormone (both have 2 benzene rings…) and therefore can block the effect of T3. Excess cadmium or lithium.
The hypothyroid patient also needs to pay particular attention to diet. Molasses, egg yolks, parsley, apricots, dates, prunes, fish, chicken and raw milk and cheeses can supply nutrients necessary for proper thyroid function(3). On the other hand vegetables from the cabbage family should be limited and include broccoli, cauliflower, cabbage, turnips, mustard greens, kale, spinach, Brussels sprouts, kohlrabi, rutabagas, horseradish, radish and white mustard(3,5). These vegetables are often called goitrogens because they have been shown to decrease thyroid hormone production as effectively as prescription anti-thyroid drugs such as thiouracil. (5) Because these foods are antioxidant-rich, supplying other vegetables or even nutritional supplements is advisable.