In this post I cover off the various ways that are used to identify Underactive Thyroid Symptoms and uncover the possible underlying causes.
1. Functional Testing
To properly assess thyroid function you need to get the whole picture. This means ensuring that ALL of the following tests are performed:
TSH- Thyroid Stimulating Hormone. This hormone is released by the pituitary gland and is the most common measure of thyroid function. It essentially tells your body how much of the thyroid hormones (below) to produce. Elevated levels indicate an underactive thyroid, while low levels indicate an overactive thyroid.
Free T4- In its simplest description this hormone is the inactive form of thyroid hormone.
Free T3- In its simplest description this hormone is the active form of thyroid hormone.
Reverse T3- This hormone binds T4 irreversibly and is not an active form of thyroid hormone.
Thyroid Antibodies- This marker indicates whether your body’s immune system is attacking itself, in particular the thyroid gland.
Thyroid binding globulin- This is a marker of the protein that carries thyroid hormone around your body before it is released into cells and allowed to act.
NOTE: I strongly advise working with a health care practitoner who practises functional medicine or has a holistic approach to health and interpreting lab results. Always ask your GP for a copy of your results. Remember that results coming back “normal” doesn’t always mean “optimal”. The reference ranges developed for standard lab tests are based on a largely sick population and don’t always take into account the levels that may be optimal for you. Nor does it account for the balance or relationship between these figures.
2. Body Temperature Tracking
Do some of your own health detective work with body temperature tracking. This means tracking your basal body temperature at the same time each morning. It is an easy, non-invasive and inexpensive way to detect if you have some issues going on with your thyroid. Please see this post for details on how to track your temperature and what it means.
3. Assess Nutrient Levels
If the above 2 areas come back suboptimal, then consider assessing the levels of the following nutrients. These are important co-factors for adequate thyroid production:
Iodine- via a urinary spot iodine test. Note that this test is just a snapshot in time but I still find it to be a part of the story. No test is perfect but can be a helpful tool nonetheless. To eliminate measurement error I would advise that you avoid any supplements or food containing iodine 24 hours before the test, and do the test fasting first thing in the morning.
Selenium- via blood or urinary spot test.
Tyrosine- via urinary spot test. I don’t ALWAYS find this 100% necessary but if you want to be thorough then by all means!
Carbohydrate intake- This one you can assess yourself. Keep a food diary for a few days and see what your average carbohydrate intake is like. You can do this by entering it into a food/nutrition calculator online such as MyFitnessPal (you don’t need to do this everyday, it’s merely to get an average of what you’re consuming). I usually like to see females up around the 100-150g mark. However, there are exceptions to this rule i.e. there will be some of you who do better on a little less and some of you who will be better on much much more- listen more to carbohydrate intake here.
4. Underactive Thyroid Symptoms
- Hair loss
- Feeling or looking “puffy” or “inflamed”
- Dry skin
- Carpal Tunnel Syndrome
- Tingling hands and/or feet
- Brain Fog
- Thinning of the outer third of your eyebrows (this usually only happens in more extreme cases)
- Weight loss resistance
- Weight gain
- Depression or anxiety
- Cold hands and feet
- Cracked heels
NOTE: The above Underactive Thyroid Symptoms are primarily symptoms of LOW thyroid, not high.
5. Family History Of Autoimmune Conditions
This is often an overlooked area for investigation, but ask around in your family circles to see if they’re receiving treatment for autoimmune conditions, especially Hashimoto’s Thyroiditis or Grave’s Disease. Sometimes they may not even know themselves, so be mindful of the list of Underactive Thyroid Symptoms above when discussing this topic.
6. Other Possible Causes Of Low Thyroid Function
The following conditions can all impact on your Thyroid Function:
– Poor liver detoxification
– Dysregulated cortisol (both high and low)
– HPA axis dysregulation (“adrenal fatigue”)
– Poor sleep quality/quantity
– Inadequate food intake and/or chronic dieting
– Excess estrogen
NOTE: This list isn’t exhaustive but are some of the more common things I see in clinical practice. Most of these will need to be assessed through a practitioner using both clinical symptoms, medical history and functional testing.