Most people with overt hypothyroid conditions have high TSH levels, and low or depressed thyroid hormone levels. Then there are people with subclinical hypothyroidism, characterized by an elevated TSH and normal thyroid hormone levels. Many people with Hashimoto’s Thyroiditis are considered to have subclinical hypothyroidism, as while the damage the immune system is causing to the thyroid gland usually results in high TSH levels, it usually takes many years before the thyroid hormone levels become depressed. However, a small percentage of people have the condition known as thyroid resistance.
Thyroid hormone resistance is characterized by elevated thyroid hormone levels (free T3 and/or free T4), and normal or elevated levels of TSH (1) [1]. It’s not uncommon for people with this condition to have a goiter, but the hypothyroid symptoms usually are very mild, and sometimes the person doesn’t experience any hypothyroid symptoms at all. In the past I’ve spoken numerous times about insulin resistance, where the cells don’t respond to the actions of this hormone. In other words, the body produces normal amounts of insulin, but the body becomes resistant to the effects of this hormone and is unable to utilize it efficiently. It’s a similar situation with thyroid resistance, as there might be sufficient levels of free T3 and free T4, but the cells don’t respond to the actions of thyroid hormone.
What Causes Thyroid Resistance?
Although genetics can play a role in insulin resistance, this condition is commonly caused by lifestyle factors, such as eating too many refined foods and sugars. With thyroid hormone resistance, there can be numerous causes. Some of the potential causes include genetic mutations, drugs, chemicals, metabolites, and autoimmune antibodies that may impair thyroid hormone action in the cell (2) [2]. In addition, certain conditions such as chronic fatigue syndrome and chronic renal failure can be accompanied by acquired thyroid hormone resistance caused by inhibition of thyroid hormone metabolism, cell uptake, and thyroid hormone receptor binding and transcription (2) [2]. As I’ll discuss later in this post, certain nutrient deficiencies can also play a role in thyroid hormone resistance.
Sometimes it can be challenging enough to find out if someone has thyroid hormone resistance, but even if this has been determined, how can one find out the cause of this condition? This also can be a challenge, as I’m not aware of any specific testing which is available to patients or healthcare professionals which will determine if someone has a genetic mutation which is causing this. Certain environmental toxins such as PCBs and dioxins might cause thyroid resistance, although such chemicals might play a greater role in congenital hypothyroidism (3) [3]. Other toxins might also inhibit the binding of thyroid hormone to the receptor (4) [4]. While it is possible to test for some of these environmental toxins, doing so can be quite expensive, and so it’s probably more cost effective to just do things to detoxify your body. Other substances that might affect the thyroid receptors including iodocontrast agents (5) [5], amiarodone (6) [6], and phloretin (7) [7]. A few different drugs can also bind to specific thyroid receptors (8) [8], and so if someone started taking a certain medication and soon thereafter developed a thyroid condition, one has to consider the possibility that taking this drug was responsible for this.
Can Natural Treatment Methods Help With Thyroid Resistance?
If someone has a genetic polymorphism which is causing thyroid hormone resistance then there isn’t a way to reverse this problem. However, this is rare, and many cases of thyroid resistance can be helped through natural methods. As I mentioned earlier, certain environmental chemicals can bind to the thyroid receptors and cause thyroid resistance, and so doing things to detoxify your body would be a good place for many people to start. I discussed this in a blog post I previously wrote entitled “3 Ways People with Thyroid and Autoimmune Thyroid Conditions Can Detoxify Their Body [9]“. Detoxification can also help someone who developed thyroid resistance due to a certain medication they’re taking, although if someone suspects that a prescription drug is responsible for their thyroid condition then it would be a good idea to run this by their medical doctor so they can take the person off of the drug, or perhaps switch them to a different drug which hopefully won’t have the same side effect.
Certain nutrients can affect the thyroid receptors and can alter the effect of T3 at the gene transcription level (9) [10]. Since the binding of T3 to the receptor is retinoic acid-dependent (10) [11], taking vitamin A might benefit people with thyroid hormone resistance. Of course you want to be careful about taking high doses of vitamin A, as this can be toxic. The T3 receptor is thought to require zinc to adopt its biologically active conformation (11) [12], and so a zinc deficiency can play a role in thyroid resistance. There is also evidence that taking fish oils can support the thyroid receptors as well (12) [13].
This isn’t to suggest that everyone with thyroid hormone resistance should “load up” on vitamin A, zinc, and fish oils. The first thing one should do is make sure they’re eating a diet consisting of whole foods, while minimizing the refined foods and sugars. If someone is deficient in these and other nutrients it’s usually due to a poor diet, although it can also be due to absorption problems. If this is the case then the absorption issue needs to be addressed in order to obtain maximum benefits from the food you eat, and any supplements you might take.
In summary, thyroid resistance is a condition characterized by elevated thyroid hormone levels, and normal or elevated TSH levels. Numerous factors can cause thyroid resistance, such as mutations, drugs, environmental toxins, and nutrient deficiencies. Many cases of thyroid resistance can be helped naturally. Since toxins are a common cause of this condition, doing things to detoxify your body and increase glutathione levels would be a good idea for most people. If a medication is responsible for this condition then of course this needs to be addressed. Certain nutrients affect the thyroid receptors, such as vitamin A, zinc, and fatty acids, and so making sure you’re getting these nutrients in your diet is also very important.