When Cortisol can be a possible cause of Thyroid Diseases
Adrenal glands are tiny glands situated on top of your kidneys. Among other functions they are in charge of producing Cortisol.
Cortisol, also known as "the stress hormone", is in charge of controlling metabolic and hormonal functions. Moreover, it modulates inflammation depending whether it is released chronically or only in acute phase.
Anther important function of cortisol is to control immune system. When cortisol is high it down regulates immune system(1). But the problem again, does not stand in the acute phase but rather in chronic high release of cortisol. When chronically released, cortisol will act as an enemy. In so far, it increases pro inflammatory molecules as well as increasing chance of developing autoimmune conditions.
Why is it important for your thyroid?
Cortisol can reduce the amount of thyroid hormones (T4 and T3) in the circulation. It reduces the conversion of T4 into T3, as well as increasing the production of reverse T3.
Cortisol makes your pituitary gland release less TSH. This to slow down your thyroid activity.
But why?
Being known as stress hormones implies that cortisol is released when you are dealing with a stressful situation. In this scenario, you need to have more glucose available (down regulation of insulin production), your heart has to pump faster, your digestive and genitourinary systems are decreased, your immune system is decreased, your thyroid activity is slowed down. Your body needs to concentrate all your energy fuels on brain and muscles. You need to react quick, the rest is irrelevant.
Thus, depending on how much cortisol we produce, we will experience different symptoms.
It is also important to assess for how long we release cortisol. Physiologically we produce the max amount of cortisol in the morning (peak at 8am), then declines during the day.
Chronic diseases, chronic inflammation, stress and increase estrogens cause an increase in cortisol levels.
Can you have constant high release of cortisol forever?
Of course NO. Eventually, your adrenal glands will be first fatigued* and then you develop what's known as adrenal insufficiency. (2)
*few words on adrenal fatigue: Unfortunately, it is not recognised yet by the medical community because there are no tests that prove it. Thus, doctors will not diagnose it.
Overall we can say there are two stages:
1. overproduction of cortisol
2. decrease production of cortisol due to adrenal fatigue or adrenal insufficiency.
Does Thyroid have a role in controlling Cortisol?
Yes. There are researches that shows how thyroid activity influences the metabolism (execration) of Cortisol.
What does it mean for your thyroid?
Hypothyroidism can be caused by an increase in circulating cortisol. Moreover, Hypothyroidism has shown to decrease the metabolism of Cortisol which can cause Hypercortisolemia. (3)
As we said, too much cortisol decreases thyroid hormones and increase reverse T3. However, over time adrenal glands can become fatigued and decrease cortisol production, causing adrenal fatigue or adrenal insufficiency.
If you develop either fatigue or insufficiency, then it can become a bit harder to distinguish between hypothyroidism or adrenal related problem. This is because they both share the same symptoms.
Moreover according to an article (4), Subclinical Hypothyroidism, defined as increased TSH with normal T4 and T3, is associated with increase in cortisol.
Hyperthyroidism instead has a particular relationship with adrenal glands. There are studies that connect Thyrotoxicosis (7) with adrenal insufficiency (low cortisol levels). Moreover, another study connects Graves’ Disease with adrenal insufficiency(5,6). When cortisol is reduced we have more thyroid hormones circulating.
Hyperthyroidism can accelerate metabolism and cause adrenal insufficiency.
Both conditions eventually lead to Adrenal fatigue or insufficiency.
Is this important?
Yes!!! Cortisol is needed for survival. If we do not have cortisol we can develop what are known as Addison's crisis, that can be life-threatening.
Why is this important to you?
If you develop a thyroid related problem you MUST assess your adrenal glands functions.
What to do?
Change your life style
Assess any chronic disease that is causing increase in cortisol
Recall any trauma with your physician. It can be the cause of your adrenal problems
Change your diet. Refined sugars and carbohydrates can impair your adrenal glands
Perform a 24h urine test to check the level of cortisol
Let us know about you:
Have you been diagnosed with adrenal problems?
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4866171/