Thyroid Thursday Episode 38: Is Hypothyroidism Caused By Adrenal Problems?
I recently had a patient asked me if her hypothyroidism was caused by an adrenal problem. The simple answer for her question was yes. It’s was a great question and I thought it would be one I would cover on today’s Thyroid Thursday video.
Both thyroid and adrenal physiology are impacted by stress. I’m going to explain how stress impacts both thyroid physiology and adrenal physiology and how these two systems are interwoven together.
Under stress, there is decreased peripheral cellular transport of thyroid hormone. That means there is decreased transport of T4 and T3 hormone from the bloodstream into the peripheral tissues. Along with decreased cellular transport, there’s also decreased conversion of T4 to T3. With the less T4 being converted T3, there is less active T3 to stimulate metabolism. While there is decreased conversion of T4 to T3, there is increase conversion of T4 to reverse T3 and increased T3 conversion to T2. Both reverse T3 and T2 are inactive forms of thyroid hormone.
Under stress conditions, the pituitary gland acts a bit differently. There is increased transport of T4 into the pituitary gland and there is increased T4 to T3 conversion within the pituitary gland. This results in a saturation of the pituitary gland T3 receptors.
What we see under high stress or chronic stress is an increase of T4 to T3 conversion and a saturation of the pituitary gland resulting in a lower level of TSH. At the same time, there are lower levels of active T3 in the peripheral cells. The pituitary gland saturation and lower TSH can make thyroid physiology appear healthy or normal and yet the person will experience hypothyroid symptoms.
What’s important is that thyroid hormone is critical for cortisol metabolism. Without sufficient levels of active thyroid hormone, cortisol cannot be metabolized resulting in increased levels of circulating cortisol. Elevated levels of circulating cortisol can create several problems including elevated blood sugar, increased insulin resistance, increased belly fat, as well as a significant impact on thyroid physiology.
Under stress situations, the adrenals increase cortisol, norepinephrine, and epinephrine production. As cortisol levels increase, we see an increase in D2 and D3 activity and a decrease in D1 activity. This results in the increase of T4 to T3 conversion in the pituitary gland and increased levels of reverse T3 in relationship to T3 levels in the peripheral cells resulting in cellular hypothyroidism.
As cortisol levels increase, there is a decrease in estrogen clearance leading to an elevation of circulating estrogen also known as estrogen dominance. The elevated levels of estrogen cause an increase in thyroid binding globulin (TBG). TBG is the protein that carries thyroid hormones around the body. When thyroid binding globulins are high, there’s a tendency to have more thyroid hormone bound to the thyroid binding globulin leaving less “free” thyroid hormone available to be transported into the cells. This results in normal blood levels but cellular hypothyroidism.
Elevated cortisol will also slow the activity of COMT enzyme resulting in increased anxiousness and further increasing the stress response. Elevated cortisol will cause suppression of the anterior pituitary which will result in decreased TSH production. Reduced TSH over time will result in lower levels of blood T4 and T3 eventually contributing to the lower cellular levels of T4 and T3. Elevated cortisol will block thyroid hormone receptors, preventing thyroid hormone from binding to its receptor sites again inhibiting thyroid physiology.
What you can see is that these two systems are intimately related with each other especially under stress conditions. If you look at the symptoms of high cortisol and hypothyroidism the symptoms are nearly identical.
If you have an adrenal problem, do you likely have a thyroid problem? The answer is yes. If you have a hypothyroid problem, do you likely have an adrenal issue? The answer is yes.
How do you go about addressing this problem?
The number one thing to address is not necessary to impact the thyroid hormones or cortisol levels directly. The best thing you can do is to try to reduce your stress load. Evaluate yourself. Do you have physical stressors that are causing problems with both thyroid and adrenal physiology? Have you had a recent trauma or injury? Are you over training? Chronic stress is a big problem for endurance athletes.
Do you have chemical stress or emotional stress that are creating challenges with thyroid and adrenal physiology? If you do, you must address them. Lastly, work with a functional medicine practitioner to find out if it’s a microbial stress. You may have bacterial, yeast, parasitic or viral infections overloading the system which is potentially driving a chronic stress response.
If you are looking to have your adrenal hormones tested, the best test in my opinion is the DUTCH test. It’s a dried urine test that’s available at www.precisionanalytics.com. You can work with a functional medicine practitioner to get this test performed.