The thyroid is a small butterfly shaped gland that wraps around the trachea and is non-palpable if all is healthy and normal. The thyroid gland has many roles in the body as it plays a key role in metabolism, growth and development.
The thyroid gland works through a negative feedback loop that starts in a region of the brain called the hypothalamus. The hypothalamus secretes thyroid releasing hormone (TRH). TRH causes the pituitary gland to secrete another hormone called thyroid stimulating hormone (TSH). TSH then binds to the thyroid gland tissue and tells the thyroid gland to start making and secreting the two main thyroid hormones, T3 and T4 into circulation.
When levels of T3 and T4 get too high, this sends a signal to the brain and pituitary to decrease production. Similarly, if T3 and T4 levels are low this sends a signal to increase production. In this way the body self regulates the amount of thyroid hormone in circulation.
Symptoms of an under active thyroid
If this feedback loop fails, if there is an autoimmune attack on the thyroid, of if the body does not have all the vitamins and minerals needed to produce thyroid hormones, the thyroid gland is unable to produce enough T3 and T4 hormones. If the thyroid gland is underproducing the T3 and T4 hormones this is called hypothyroidism.
Some of the common symptoms of hypothyroidism include:
When to test your thyroid function
Although a lot of these symptoms are non-specific, if you are experiencing any of the above symptoms persistently it may be time to have your thyroid function assessed. If you are a middle aged woman, it may be even more important to get your thyroid function assessed since hypothyroidism affects women more than men and incidence increases as we age.
Traditionally, the only test run to determine whether the thyroid gland is functioning correctly is ‘Thyroid Stimulating Hormone’ or TSH. Check out my blog on why I always run a full thyroid panel to test thyroid function.