- Dr. Trish Pearce
9. The Adrenal-Thyroid Connection
Is the health of your thyroid affected by adrenal dysfunction? Of course! The thyroid is one organ of many that is negatively impacted under conditions of chronic stress and sustained cortisol production. When you have adrenal maladaptation, your body believes that it is in a state of duress, forcing other important physiological actions like digestion, immune function, and thyroid hormone production to slow in favor of dealing with the stressor. In other words, “running from the bear,” is prioritized over digesting your meal or growing hair and nails.
Adrenal dysfunction has many negative effects on thyroid health:
1. Decreased communication of the brain-endocrine axis: Remember the HPA axis? A similar version of this axis exists for all endocrine (hormone-producing) organs. The hypothalamic-pituitary-thyroid, or HPT, axis is affected by high cortisol levels due to the negative feedback system telling the hypothalamus to slow down hormone production. Not only does the hypothalamus attempt to slow down production of cortisol, but will slow thyroid hormone production as well. 2. Increased thyroid-binding proteins: High cortisol is associated with high estrogen levels, and high estrogen has been shown to increase “thyroid binding globulins,” the tiny taxi cabs that thyroid hormones use to travel around our body. These globulins attract free thyroid hormone, binding it up so it has a hard time being used by our cells. 3. Decreased conversion: The conversion of the inactive T4 hormone to the active T3 form is essential for proper thyroid activity. However, cortisol will slow this process by affecting the way the enzyme that converts T4 to T3 does its job. 4. Suppressed immune system: Cortisol is a powerful immune suppressant. This can lead to increased infections as well as imbalances in the immune system that can exacerbate autoimmune forms of thyroiditis. 5. Decreased cell sensitivity: The cells of the body are made less sensitive to thyroid hormone during the stress response. 6. Decreased function of detoxification pathways: Hormones that are no longer active or needed by the body are eliminated through the liver. Since the stress response can dampen liver function, unused hormones are left to continue to circulate in the body, making cells more “resistant,” or less sensitive, to thyroid hormone.
While adrenal dysfunction has a direct effect on thyroid health, it is also important to consider that poor thyroid and adrenal function often share a root cause. As discussed in previous articles, common causes of adrenal dysfunction are poorly regulated blood sugar, states of high inflammation, chronic infections, co-existing autoimmune conditions, and environmental toxins.
The bottom line: Reducing stress and correcting adrenal dysfunction will absolutely improve thyroid health, and help you feel better!