Thyroid 101 – Dr Wendy Davis ND

Thyroid 101


Low thyroid function is probably one of most commonly asked about conditions in my practice.  And with good reason as the rates of hypothyroidism (aka low thyroid) are skyrocketing.

I very occasionally see hyperthyroidism (Grave’s disease) but this is much less common, and so I will focus on the more common hypothyroidism in this blog.


Symptoms of low thyroid function are many and diverse, but some of the most common ones are unrelenting fatigue, weight gain/in ability to lose weight, constipation, dry skin, hair loss especially the lateral ⅓ of the eyebrows, anxiety/depression, high cholesterol and strangely enough, chronic hives.

Even with all of these symptoms it can be a challenge to be properly diagnosed as conventional medicine will typically only test TSH (Thyroid Stimulating Hormone) which has a very outdated reference range leading to excessive underdiagnosis.

The other tests that are often neglected are the actual thyroid hormones (T4, T3 and rT3) as well as thyroid the antibodies TPO and Tg that are associated with Hashimoto’s thyroiditis, an increasingly common auto-immune condition.


If one does get a diagnosis of  hypothyroidism conventional medicine will typically prescribe a synthetic T4 hormone (which is largely inactive and needs to lose an iodine molecule in the peripheral tissues, to become the active T3).

However, if there are issues with one's liver or kidneys, conversion to T3 is reduced, as well as when there are increased levels of stress, a dysregulated gut, estrogen dominance or exposure to excessive hormonal disrupting chemicals and toxicity.  Hashimoto’s thyroiditis also reduces the conversion of T4 to T3.


And so to really get to the root cause of why someone has low thyroid function, extensive blood  testing and additional hormone, nutrient deficiency and toxicity testing can be done.

Once we know the underlying cause of the low thyroid function, it becomes much easier to recommend the proper diet and nutrients to improve thyroid and overall health.


I will typically focus on a gluten-free diet since gluten is one of the most common food sensitivities, and in particular it worsens low thyroid function. Food sensitivity testing can be done to help determine if there are other foods that may be contributing to hypothyroidism.


There are a number of nutrients that can help thyroid function, but I find that they don’t work if the correct root cause of the low thyroid has not been determined. Zinc, selenium, iodine and tyrosine are all useful to support the thyroid gland, but if there are underlying triggers such as auto-immunity or other hormone imbalances, then people don’t tend to see results.


In summary low thyroid function is very common, and it is very treatable too, providing we get to the root cause of the problem.