Updated: January 2023
I’ve written a lot of articles about thyroid health. Many of my patients have gut health problems but a significant number of those also have autoimmune thyroiditis such as Hashimoto’s disease or Grave’s disease.
The most common form of hypothyroidism is autoimmune disease in the form Hashimoto’s thyroiditis. Most people with Hashimoto’s are women. Thyroid autoimmune disease is also the most common autoimmune condition in America.
I routinely perform lab testing on my new patients. Something I see over and over again is that even though many patients are hypothyroid and have been diagnosed with hypothyroidism, and are on prescription medications for hypothyroidism, most of them are still hypothyroid.
There is more to the picture when it comes to thyroid health and function than I believe is currently recognized and treated. It’s one thing to have regulated Thyroid Stimulating Hormone (TSH) levels, and another when it comes to thyroid hormone conversion and utilization.
What is TSH?
The pituitary gland makes TSH based off of signaling from the body. It is important to recognize that the thyroid gland doesn’t really make decisions.
The thyroid gland is a responsive organ. If levels of circulating T3 (active thyroid hormone) are normal, then pituitary gland should produce normal amounts of TSH.
When levels of T3 in the blood are low, the pituitary gland will make more TSH. When levels of T3 are high, the pituitary gland will make less TSH.
Really low levels of TSH is a sign of hyperthyroidism like what is seen with Grave’s disease (if thyroid antibodies are present). High TSH is a sign of hypothyroidism such as Hashimoto’s thyroiditis (if thyroid antibodies are present).
Higher levels of TSH will cause a healthy thyroid to produce extra T4. T4 is considered an inactive thyroid hormone. T4 gets converted to T3 in the liver and the peripheral tissues throughout the body.
Since a significant amount of thyroid hormone conversion takes place in the liver, it is important that proper liver health is maintained and supported.
Since T4 is “inactive” thyroid hormone, it doesn’t do much. It is considered a biologically inert hormone. T3 is the real mover and shaker when it comes to thyroid hormones.
What is Proper Conversion of Thyroid Hormones?
Proper conversion of T4 to T3 has to happen in order for someone to have normal thyroid hormone function.
Hypothyroidism is considered to be present when someone doesn’t have enough levels of T3 in the body. Common findings of hypothyroidism on lab testing is a high level of TSH and low levels of T3.
Symptoms of Hypothyroidism
- Chronic Fatigue
- Dry Skin and Poor Complexion
- Coarse or Thinning Hair
- Brittle Nails
- Depression and Anxiety
- Loss of the Outside of the Eyebrows
- Weight Gain or Inability to Lose Weight
How could someone who is taking thyroid medication or natural thyroid supplements still be hypothyroid?
Thyroid conversion is just as important as having good levels of TSH or T4. Often, medications will help regulate TSH levels because many of them are T4 replacements.
In other words, the pituitary gland is looking for good levels of T4 and T3 in the blood and if there is enough T4 and T3, the thyroid gland can help regulate TSH and keep it in normal levels.
Basically, medications for maintaining TSH are T4 replacements. So, by flooding the system with T4, the pituitary gland will see more circulating thyroid hormones and better maintain TSH levels.
The real problem with that is that normal levels of TSH don’t mean normal levels of T3. Enzymes in the body help move chemical reactions along. Enzymes convert one substance to another. When it comes to thyroid hormone conversion, deodinase enzymes convert T4 into T3.
Why is Selenium Important for Thyroid Hormone Conversion?
The deodinase enzymes needed to convert T4 into T3 are selenium dependent. Selenium is a trace mineral that has many functions in the body such as cognitive function and fertility. For our purposes though, low levels of selenium will cause low levels of T3 and lead to hyothyroidism.
It’s sad to say that some of the very substances used to treat thyroid patients will deplete the very mineral that is needed to get proper thyroid hormone conversion. Therefore, someone could have perfectly normal TSH and T4 levels but still be “hypothyroid”.
When I work with hypothyroid patients, my first goal is to identify why they are hypothyroid. What’s going on with the patient? Are they inflamed? Do they have a congested liver? Do they have major life stressors affecting their nervous, endocrine and immune systems?
Are they deficient in lean muscle mass? Do they have blood sugar problems? Are they suffering from a form of malnutrition? Do they have gut health challenges such as leaky gut syndrome? What markers are out of range or functionally high on lab testing?
My second goal with hypothyroid patients is to determine if they have an autoimmune condition that is attacking their thyroid gland.
Do they have food sensitivities that could cause some cross reactivity? Do they have a viral infection that could be doing “molecular mimicry” and driving the autoimmune process?
These are questions that must be answered in order to identify why the house is on fire. The association between the Epstein Barr virus (the virus that causes mononucleosis or “mono”) and Hashimoto’s thyroiditis has been well documented. The body doesn’t just turn on itself for no reason.
Identification of the cause is important and then covering all of the bases such as ensuring that something as simple as a selenium deficiency is not what is contributing to a perpetual hypothyroid state.
Health is Happiness,
Dr. Keith Currie