Thyroid hormone controls your energy, growth and metabolism. If you are low on thyroid you might notice fatigue, sluggishness, intolerance of cold or cold body temperature, brittle thinning hair, or dry skin. You might have uncontrollable weight gain, trouble losing weight, constipation or indigestion. You might even be depressed, apathetic, have "brain fog" or low sex drive. Abnormal menstrual cycles or trouble getting pregnant can be due to low thyroid.
The thyroid gland sits in the front part of the neck and makes thyroid hormone from iodine and an amino-acid called tyrosine. Eighty percent of thyroid output is tyrosine with four iodine molecules attached, called T4, but this is not the active thyroid hormone.Out in the body, in the muscle, liver, kidney and brain, T4 must have one of its iodine molecules removed to form the active thyroid hormone, called T3, which is the form that gets into the cells to do its work. Thyroid binds to nuclear receptors and commands a whole array of energetic and building processes, from growth, to metabolism, to energy production and detoxification.Control of thyroid production is overseen by the pituitary gland, a small pea-sized gland that resides in the lower central portion of the brain. The nearby brain area called the hypothalamus determines if there is enough thyroid hormone in the body, and if not, sends a signal to the pituitary to increase thyroid production. The pituitary then releases thyroid stimulating hormone (TSH) which urges the thyroid to ramp up production of thyroid hormones.Low thyroid is called hypothyroidism and "primary" hypothyroidism is when the thyroid gland is impaired and quits making thyroid hormone. "Secondary" hypothyroidism is when the thyroid gland is fine but the pituitary is damaged and does not send the proper TSH signal, or the thyroid gland does not get the signal.The most common textbook form of primary hypothyroidism is called Hashimoto's, in which the body makes antibodies that attack the thyroid and turn off thyroid production. We find this most commonly in women, age 30-50, often after pregnancies or around menopause. In recent years we have learned that this condition, like other autoimmune diseases, can be cured if we can find and remove the "trigger" that upset the immune system's regulating cells. Some people have low thyroid due to iodine deficiency. There is debate as to whether the iodine in our table salt supply is really enough for optimal health. We recommend testing for iodine levels and supplementing only if indicated.Secondary hypothyroidism can be due to anything that damages the pituitary or interferes with the ability of TSH to work properly. Inflammation and the stress hormone cortisol both interfere with pituitary output, causing a low grade impairment of TSH production from the pituitary. Head injuries are a common cause of subtle pituitary damage.I have hundreds of patients with low thyroid that are "under-converters." For various reasons some people do not convert their T4 to T3, and as a result are low on thyroid. The lack of conversion can be due to aging, stress, prolonged illness, toxic metal or chemical exposures, other hormone imbalances, nutrient deficiencies and medications, amongst others.
The standard blood test for diagnosing and monitoring thyroid conditions is thyroid stimulating hormone (TSH) from the pituitary gland. TSH goes up to promote thyroid production, so if TSH is high, it suggests low thyroid, and visa versa.There is conflicting opinion about how well this test can be trusted and in my opinion it is not at all sufficient to monitor thyroid status. I recommend patients also get a free T4 and free T3 blood test, as well as two tests for antibodies to the thyroid, TPO and thyroglobulin antibody.Sometimes even the better blood tests are not accurate in determining thyroid status. The blood level of thyroid hormone may not reflect the level that actually gets into the cells or the cells may be resistant to thyroid hormone. There are numerous reasons that TSH may not accurately reflect thyroid status. In practice there is much controversy over this concept, yet there are dozens of studies from the endocrinology research that confirm these phenomena.Not every low thyroid condition requires thyroid hormone. We strive to correct other imbalances that have led to low thyroid production or resistance to thyroid hormone action. Often Hashimoto's is curable. Controlling high stress and cortisol can improve thyroid function. Eliminating sugar and high glycemic foods from the diet will improve all hormone functions. Supplying nutrients for thyroid production, eliminating exposures to thyroid-toxic chemicals or chelating heavy metals out of the system can help improve thyroid function.Most physicians use T4-only thyroid hormone for replacement, such as Levothyroid or brand name Synthroid. This is just fine as long as people convert the T4 to the active T3. Some patients do markedly better on forms of thyroid hormone that contain both T4 and T3, such as brand name Armour thyroid. And still other patients will only feel normal by taking a T3-only type of thyroid replacement.
Aside from feeling poorly, low thyroid will increase the risk of diseases such as obesity, diabetes or heart disease. Low thyroid also causes problems with the function of other hormones causing them to work poorly. For example, women need thyroid hormone to ovulate and make enough progesterone which is required for a normal menstrual cycle or pregnancy. Men and women need enough thyroid hormone to allow the sex hormones to promote a healthy sex drive. As you can see, thyroid is a critical player in the symphony of hormones.If you have symptoms of low thyroid and they don't seem to relate to anything else, then you are very likely low on thyroid hormone. The routine blood tests might be "normal" even if your thyroid function is NOT!So, know the symptoms of low thyroid. If you are suspicious that you have a problem, ask your physician to check the blood tests suggested above. This will give you a starting point for treatment. If the blood levels are within the normal range, but you still have symptoms of low thyroid, you may need to consider some of the conditions mentioned above in order to have your thyroid "normal" for you.At last count I have 12 paperbacks and two textbooks on my shelf specific to the thyroid. I recommend several as resources, including "Stop the Thyroid Madness" by Janie Bowthorpe, and "Why Do I Still Have Thyroid Symptoms? When My Lab Tests are Normal" by Datis Kharrazian.Scott Rollins, M.D., is board certified with the American Board of Family Practice and the American Board of Anti-Aging and Regenerative Medicine. He specializes in bioidentical hormone replacement, thyroid and adrenal disorders, fibromyalgia and other complex medical conditions. He is founder and medical director of the Integrative Medicine Center of Western Colorado (www.imcwc.com) and Bellezza Laser Aesthetics (www.bellezzalaser.com). Call 970-245-6911 for appointments or more information.