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This third article discusses additional reasons your thyroid may not be functioning optimally. All these thyroid tests are just as important as the tests I discussed in my first two blogs. Unless you have a physician skilled in Functional Medicine, you will never receive these tests as part of your thyroid evaluation. You may wish to consider them, if you want to uncover every reason why you have a thyroid problem.


A selenium deficiency can increase autoantibody levels in patients with Hashimoto’s Autoimmune Thyroiditis. Supplementation at 200ucg/day for several months reduced antibody levels in all studies. Selenium is needed by two enzyme systems important to thyroid function. One protects the body from oxidative damage. The normal production of thyroid hormone requires hydrogen peroxide. If there is a selenium deficiency, the enzyme, glutathione peroxidase, cannot perform its function, leading to thyroid tissue damage. A second enzyme, 5’-deiodinase, converts inactive T4 into active T3. It requires selenium to function properly.

The best test for determining selenium deficiency at the cellular level is a Trace Mineral Analysis, which uses head hair as the specimen.

Vitamin D

Vitamin D targets over 2000 genes (about 10% of our genes). Current research indicates that vitamin D deficiency is a major factor in at least 17 varieties of cancer as well as heart disease, stroke, hypertension, autoimmune diseases, (including Hashimoto’s Autoimmune Thyroiditis), diabetes, depression, chronic pain, osteoarthritis, osteoporosis, muscle weakness, muscle wasting, birth defects, periodontal disease, and more.

One recent inner-city study showed that 25% of the participants were overtly deficient and that a significant portion had well below optimal blood levels.

Mercury, Lead and Other Toxic Elements

Mercury is a known thyroid toxin. In today’s world avoiding toxic metals is impossible. Exposure comes from thousands of sources. An important fact to understand is that heavy metals have absolutely no function in the body. Their presence, in any quantity interferes with normal function. The only totally safe level is absence. Even low levels have been linked to cancer, heart disease and neurological conditions (including Alzheimer’s, autism and ADD). These toxins are absorbed through the skin, lungs and intestines

There are many ways to test for heavy metals in the body. Probably the best screening method is through head hair.


Female and male sex hormones all interact with thyroid hormone. Increased estrogen levels indirectly cause a corresponding increase in bound thyroid hormones and a decrease in free or active ones. Increased estrogen also increases reverse T3 (rT3) levels, which acts as a metabolic brake, slowing down metabolism, by binding to thyroid receptors on the cell surface and blocking them from binding with FT3. Birth control pills are one cause of increased estrogen levels. Weight gain is often seen in women taking oral contraceptives.


Increased progesterone causes an increase in body temperature by up to a degree by stimulating production of more thyroid hormone. Low levels of progesterone, especially when coupled with elevated estrogen, can cause hypothyroid and menstrual complaints.

Estrogen and progesterone levels are easily accessed through a salivary hormone panel. The advantage of using salivary hormone testing is that it only measures free or active hormones at the tissue level. Blood tests measure total hormone levels (bound + free in the blood, not at the tissue level) and do not distinguish between the two.


Both are highly toxic elements to the thyroid gland widely used in many products, including drugs, pesticides, fire retardants, computers, furniture, automobiles, carpeting, toothpaste, brominated vegetable oil and baked goods. The Iodine Loading Test includes has an option to measure bromide and fluoride.


Entire books have been written on the negative impact gluten has on many people. Anyone with a thyroid condition should be evaluated for gluten sensitivity. It is absolutely mandatory for patients with Hashimoto’s Autoimmune Thyroiditis. Gluten is a major contributing cause for many cases of autoimmunity. Antibodies directed against gluten cross-react with many tissues of the body, including thyroid, pancreas and nerve tissues.

The definitive lab test for gluten sensitivity is through Cyrex Labs. 24 different components of gluten are tested. It is an expensive test. An even better, totally free test is total gluten abstinence from the diet to see how one improves.

C-Reactive Protein (C-RP)

This is a simple, inexpensive blood test that is a measure of inflammation. Elevated levels are an indicator of generalized inflammation that can negatively impact thyroid function.

Glucose, HbA1C and Insulin

A thorough evaluation of glucose metabolism is important for thyroid evaluation. Insulin surges, excess and resistance can inhibit the release of TSH, decreasing thyroid hormone release.


About the Author: Dr. Douglas L. Weed

Dr. Weed practices Functional Nutrition, Chiropractic care, and offers weight loss solutions in Napa, CA at Heun Chiropractic, Inc. He has a doctorate in Chiropractic care and he has received certifications in physical rehabilitation and as a Qualified Medical Examiner. With a post-graduate certification in Functional Medicine, focusing on functional endocrinology, digestive disorders and Peripheral Neuropathy, he is committed to lifelong education and helping patience transform their health.