By Dr. Shawna Darou, ND
Your thyroid gland is central to your metabolism, and it impacts almost every system in the body. It can cause menstrual cycle changes and infertility, it can increase cardiovascular risk factors, cause depression and cognitive issues, impact gut motility, and lead to swelling in the body.
Thyroid issues are extremely common, impacting so many women. In this article I will be explaining the mechanisms that cause thyroid dysfunction, and steps you can take to rebalance your thyroid now. Once you understand how the thyroid functions, you’ll understand that there’s a lot more to correcting thyroid imbalance than medication alone.
Thyroid Symptom Checklist
Here are the most common signs of thyroid dysfunction:
- Weight gain, or inability to lose weight that doesn’t make sense with current nutrition and exercise.
- Cold intolerance with cold hands and feet.
- Feeling tired and fatigued.
- Slow pulse and/or low blood pressure.
- Diffuse hair thinning, and more dry or brittle hair.
- Dry, scaly, itchy skin.
- Low mood or depression.
- Difficulty with concentration.
- Swelling around the eyes, face, hands, feet or legs.
- Menstrual cycle changes – usually heavier and coming a little farther apart.
- Difficulty getting pregnant or miscarriage.
- Muscle aches and joint pains.
If you have several of these symptoms, you may have a thyroid disorder. The next step is a thorough test of your thyroid function with a full blood panel.
Complete Thyroid Testing
It is extremely important to test thyroid function thoroughly, especially if you are experiencing several of the symptoms above. A simple TSH may miss issues with T4 to T3 conversion, or the start of autoimmunity. Below is a thorough thyroid panel. Optimal range is where you ideally want your levels to be. Reference range is the standard range provided on a lab test.
- TSH: 0.5-2.5 mIU/L (optimal range); 0.32-4.0 mIU/L (reference range)
- Free T4: 14-19 pmol/L (optimal range); 9-19 pmol/L (reference range)
- Free T3: 4-5.8 pmol/L (optimal range); 2.6-5.8 pmol/L (reference range)
- Reverse T3: 8-18 ng/dL (optimal range); 8-25 ng/dL (reference range)
- Thyroglobulin Antibody: < 40 kIU/L
- Thyroperoxidase Antibody: < 35 kIU/L
TIP: If you are currently on thyroid medication but still have thyroid symptoms, it is important to thoroughly test thyroid function. You may still have low free T3 levels or high reverse T3.
Nutrients required for thyroid function
An important place to start is to ensure that you have all of the nutrients required for thyroid function. The list is much more comprehensive than just iodine, and many of them work synergistically.
- Zinc: zinc deficiency can impact the production of both free T4 and free T3. This is a very common nutrient deficiency, and it can also be impacted by copper exposure.
- Selenium: selenium plays an important role in conversion of T4 to T3, and deficiency of selenium is also correlated with thyroid antibodies.
- Iron: iron-deficiency impairs thyroid hormone formation overall, and optimizing iron levels will significantly raise T4 and T3 production. TIP: Another factor to look into if you’re on thyroid medication and not feeling better is your iron stores. In women with persistent hypothyroid symptoms on medication, restoring ferritin levels to above 100 ug/L improves symptoms.
- Iodine: iodine is perhaps the most complicated nutrient because both low and high iodine is associated with hypothyroidism. It also works synergistically with iron and selenium.
- Vitamin D: low level of vitamin D is associated with autoimmune thyroid disorder, and may be a causal factor.
- Vitamin A: vitamin A improves the cellular sensitivity to thyroid hormones, and deficiency of vitamin A reduces conversion of T4 to T3.
Conversion of T4 to T3 – activating your thyroid hormones
If your TSH and free T4 are both in an optimal range, it is important to also test for free T3 levels to ensure that your body is utilizing and converting the hormone optimally. T3 or triiodothyronine, is the activated form of thyroid hormone. It is not present in levothyroxine medications so your body needs to do this conversion. If your free T3 level is low, you will have many of the hypothyroid symptoms listed above.
Conversion to T3 is not really a thyroid issue as it happens outside of the thyroid gland.
Here are some of the top contributors to low T3 levels:
- Prolonged high stress
- Trauma (physical or emotional)
- Low-calorie diet
- Toxins (pesticides, mercury, cadmium, lead)
- Infections (ex. low T3 is common after the flu or any major illness)
- Liver or kidney dysfunction
- Certain medications (ex. Beta blockers)
The way to think of this is that your body is deliberately slowing down your metabolism for some reason. Usually for rest / repair / recovery. It is therefore important to get to the root of it to restore optimal free T3 levels and metabolism.
Autoimmunity and Thyroid Function
The most common form of hypothyroidism is “Hashimoto’s thyroitis” which is an autoimmune condition. You can learn more about Hashimoto’s in this article: https://drshawnadarou.com/2019/04/23/healing-hashimotos/
Thyroid autoimmunity is extremely common, and again we need to look for underlying causes of immune system dysregulation. The thyroid is extremely sensitive to environmental influences, gut imbalances and overall inflammation.
Here is a list of factors that can contribute to thyroid autoimmunity:
- Toxins: pesticides, mercury, cadmium, lead
- Celiac disease
- Deficiencies in selenium and vitamin D
- Excess or deficiency of iodine
- Infections: ex. Epstein Barr virus, Yersinia enterocolitica
- Gut dysbiosis and intestinal permeability
If caught early, thyroid autoimmunity can be reversed before there is significant thyroid damage. This is again why it is important to thoroughly test the thyroid when there are symptoms pointing to hypothyroidism.
Summary: Influencers of Thyroid Function
Treating with medication
In some cases even after addressing all of the factors above, we still may need to consider thyroid medication. This depends on how far out of balance the levels are (ex. TSH > 10, the length of time of the imbalance, how long thyroid antibodies have been high causing thyroid damage, and how much stress the body is under which can prevent repair.
Standard treatment for hypothyroidism involves the daily use of synthetic thyroid hormone called levothyroxin. This hormone provides only T4, and compensates for under-production of thyroid hormones. When using levothyroxine, it is still important to address possible autoimmunity, and especially support T4 to T3 conversion in order to fully resolve thyroid symptoms.
An alternate treatment which naturopathic doctors can prescribe is desiccated thyroid. Desiccated thyroid is animal derived (porcine), and contained all 4 natural thyroid hormones: T4, T3, T2 and T1. This can be an effective treatment especially if we cannot fully resolve T4 to T3 conversion issues, as desiccated thyroid provides a substantial amount of T3.
Special note about fertility and pregnancy. At this point, the most studied and safest medication for pregnancy is levothyroxine, not desiccated thyroid.
If you would like to look at your thyroid function in depth, addressing nutrients, autoimmunity, nutrition, and thorough thyroid testing using a naturopathic and functional medicine approach, we can certainly dig deeper. Whether your numbers are in the subclinical / borderline range, or you are already on thyroid medication but still do not feel great, there is so much we can do to optimize your hormone balance and wellness.
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