The thyroid is the key driver of our metabolism. Some of the functions of the thyroid hormone include temperature regulation, metabolism, cerebral function, and maintaining and producing energy. In other words, thyroid determines how we produce energy, how we think, and how we process food and the calories that we eat. Pretty good for a gland that weighs less than one ounce.
If someone’s thyroid function is impaired, all these processes will be affected. The resulting symptoms include fatigue, memory loss, coldness, low energy, thinning hair, dry skin, constipation and weight gain. The abnormal metabolism leads to high cholesterol (several decades ago, before cholesterol was known as a marker of heart health, it was considered a marker of thyroid health). Bodily functions are impaired so there may be symptoms of irritable bowel and irritable bladder. In other words, those with thyroid problems feel lousy.
The pituitary gland in the brain sends a chemical called thyroid- stimulating hormone (TSH) that tells the thyroid to make more hormone. The thyroid produces predominantly two types of thyroid hormones: triiodothyronine (T3) and thyroxine (T4), with the number based on the number of iodine molecules attached to the hormone. The thyroid makes 80 percent T4 and 20 percent T3. An important point is that T3 is the active form of thyroid so T4 needs to be converted to T3 for optimal thyroid function.
Thyroid status is primarily measured by lab tests. When thyroid function is impaired, this is called hypothyroidism or Latin for low thyroid. There are different types of hypothyroidism. Subclinical hypothyroidism occurs when the TSH is elevated while the thyroid hormone levels T3 and T4 are normal. The normal thyroid levels suggest there is no problem but the elevated TSH suggests that the brain seems to think it needs to work harder to stimulate the thyroid. One study showed an increased relative risk of heart disease of 2.2 with subclinical hypothyroidism, or more than double the risk.
Primary hypothyroidism manifests by elevated TSH while thyroid hormone levels are decreased. There is near unanimous agreement that this condition should be treated with thyroid hormone replacement. The question then becomes what type of thyroid hormone will be used. The most common thyroid used is levothyroxine (Synthroid), which is T4. The problem is that there are patients that do not feel any better when taking only T4. Another option is to take a thyroid preparation, which has a combination of T3 and T4. The most common of these is desiccated thyroid, which is porcine derived, though a compounded combination of synthetic T3 and T4 is available. I have seen many patients not feeling well when taking T4 who feel much better when taking a combination of T3 and T4.
Secondary hypothyroidism occurs when there is poor conversion of T4 to T3. Some of the factors that predispose to this are stress, fasting, illness or old age. TSH and T4 are normal but the T3 is decreased so it is necessary to check this. The reason that some patients feel lousy when taking T4 is that they are not able to convert T4 to T3, which as noted is the active thyroid hormone essential for metabolism. For this condition, treating with a combination of T4 and T3 is essential.
Tertiary hypothyroidism occurs when the receptors for thyroid function are insensitive to thyroid hormone. The hormone is present but is unable to effect action at the cellular level. Therefore, one will have symptoms of low thyroid while their thyroid lab studies are normal. Because of the normal lab values, this is very difficult to diagnose. Due to the thyroid resistance, a higher dose of thyroid hormone may be required to achieve therapeutic benefit.
However, thyroid replacement is controversial because of the potential problems that may result. One potential problem is cardiac arrhythmia. This results from thyroid’s stimulant effects on cardiac tissue. If the dose is adjusted slowly with symptoms and response monitored, palpitations can be minimized and avoided. A common misconception is that thyroid replacement leads to osteoporosis. Hyperthyroidism or excess thyroid may predispose one to osteoporosis. However, multiple studies have shown that thyroid replacement does not cause osteoporosis. It should also be noted that low T3 is associated with vertebral fractures related to osteoporosis so thyroid replacement can actually prevent these fractures.
It is important to understand the health risks associated with untreated hypothyroidism. Low thyroid levels are associated with increasing disability, decline of global function and increased mortality. The increased risk of heart disease with hypothyroidism is similar to smoking and high cholesterol. Those with hypothyroidism have increased risk of cognitive deficits. I have seen patients with cognitive deficits improve with optimized thyroid.
For those with thyroid dysfunction, thyroid replacement to an optimal level can dramatically improve quality of life as the symptoms resulting from the dysfunction improve. I have seen many new patients where those on thyroid replacement still felt lousy with tiredness. When I work with them to optimize their thyroid, improvement is often dramatic. This is achieved by using thyroid formulations that combine T3 and T4 and adjusting the dose to minimize symptoms.
The psychiatry literature is replete with studies that show that thyroid replacement is effective for the treatment of depression. Considering all the other benefits of optimizing thyroid, this is a great option for treating depression, especially when compared with the commonly prescribed selective serotonergic reuptake inhibitors which have so many side effects and don’t work for everybody. My expertise with thyroid developed with optimizing thyroid to improve fibromyalgia, especially when associated with chronic fatigue and depression.
For those with hypothyroidism, optimizing thyroid function can have valuable effects of improving metabolism and reducing visceral fat. It is very common for someone with hypothyroidism to tell me that despite eating well and eating less, they can’t lose weight. Optimizing thyroid may be the catalyst to losing weight and giving you the energy to make the lifestyle changes to improve your health.
In summary, thyroid hormone is essential for metabolism, brain function and general well being. While the thyroid is generally assessed by looking at lab values, there are certain conditions that cause misleading labs. The key to successful treatment with the best outcomes for one with thyroid dysfunction is to treat not just the labs but to treat the patient and the symptoms. This is rewarding for myself and the patient as we work together to see dramatic improvement.
By Warren Slaten, M.D.
Dr. Slaten is a wellness physician specializing in regenerative pain treatments and lifestyle counseling. He is certified in advanced bioidentical hormone replacement. For more info, check out his website, njhormones.com, or his weekly radio show Sundays at 9PM on 77WABC.