Vitamin D Deficiency and Hashimoto’s

There is scientific support that one of the possible reasons for autoimmune conditions clustering in areas farther from the equator is low Vitamin D status in those living there. This is because the primary way we make Vitamin D is via sunshine on skin that is free of sunscreen.

But even with access to sunshine at the right latitude, there may be other issues in the way of getting enough Vitamin D.

Insufficient sun exposure. Do you spend much time outside all year round? Summertime it is obviously easier to up your sun exposure IF you don’t slather on the sunscreen. But colder months our skin is rarely uncovered and we tend to spend less time outdoors. Studies have shown that absorption could depend on the time of day and the position of the sun when trying to increase your exposure.

Inadequate Vitamin D in diet. Foods highest in Vitamin D include organ meats, fatty fish like salmon, egg yolks and dairy. Many of those foods are rarely eaten in abundance by people, especially vegetarians, and for some people, several of those foods (like dairy and eggs) can trigger immune flares, especially in those with Hashimoto’s.

Chronic gut inflammation and fat malabsorption. Because Vitamin D is fat soluble, you need to be able to digest fat efficiently in order to absorb Vitamin D from food. If there is chronic inflammation in the gut or compromised gallbladder function, it is possible to struggle to get adequate Vitamin D from your diet.

Kidney, Liver, Intestine, Skin diseases. If you have serious disease processes developed in these organ systems, it can have a negative impact on Vitamin D conversion to usable forms for biological functions.

Genetics and absorption issues. Research indicates that ~90% of those with autoimmunity may have genetic issues impacting absorption and using Vitamin D.

Cholesterol levels too low. If your cholesterol levels are low, you can have compromised production of Vitamin D in the skin because cholesterol is the backbone of Vitamin D.

Obesity and old age. Both can create risk for producing and absorbing Vitamin D.

Skin colour. If you have darker skin, that colouration is meant to be protective against sun rays so will reduce your chances of easily producing adequate Vitamin D even with sun exposure in Northern regions.

Certain drug use. Drugs such as phenytoin, phenobarbital, and rifampin are known to cause vitamin D and its metabolites to be degraded at an accelerated rate which could lead to a deficiency if not managed effectively.


It has been estimated that 1 billion people worldwide have low levels of Vitamin D, yet most people don’t realize that they’re deficient. Symptoms are often subtle, so be aware of indications that you may have a Vitamin D deficiency, including:

  • Elevated thyroid antibodies
  • Fatigue and general weakness
  • Muscle, joint and bone pain and weakness
  • Stress fractures (especially in your legs, pelvis, and hips)
  • Depression
  • Impaired wound healing
  • Frequent illness or infections
  • Suppressed immune function
  • Asthma
  • Gum disease
  • Osteoporosis
  • Hair loss


Vitamin D is an essential nutrient and a pro-hormone that plays an essential role in all cells within the body.

Vitamin D has several important functions within the body, including influencing:

  • Bone density
  • Calcium, phosphorus and magnesium regulation
  • Mood regulation (especially over Winter)
  • Brain health
  • Sleep
  • Immune regulation
  • Reducing cancer risk

Of note with autoimmunity, there are vitamin D receptors and activating enzymes on the surfaces of all white blood cells of the immune system! Therefore, immune cells including monocytes, macrophages and various T cells, which are essential to fighting off pathogens like Epstein-Barr virus (known to be tied to many autoimmune conditions), and T-regulatory cells, which are essential for controlling immune responses, all require adequate Vitamin D.

There is a strong correlation between documented Vitamin D deficiency and various thyroid conditions, including Hashimoto’s, Grave’s, thyroid cancer and postpartum thyroiditis. There are studies that have also found Vitamin D reduces thyroid antibodies in those taking the thyroid medication, Levothyroxine, as well as those who have euthyroid Hashimoto’s (normal TSH but elevated thyroid antibodies). It isn’t a great leap to think normalizing Vitamin D levels can slow progression of Hashimoto’s.


Vitamin D levels are determined with blood analysis. In Canada, getting your Vitamin D level tested through subsidized health care is rarely possible. However, independent laboratories do allow for individuals to test their levels as an out-of-pocket expense. At AcuPlus Wellness Clinic, I carry finger puncture test kits from the lab Doctor’s Data, but there are other labs that do similar testing.

Forms of Vitamin D you might like to know more about:

  • Vitamin D2 (ergocalciferol) is the form found in plants, some fortified foods and some supplements.
  • Vitamin D3 (cholecalciferol) is the main form produced in the body, comes from animals and is found in some higher quality supplements.
  • 25-hydroxyvitamin D (25(OH)D) is a measure of Vitamin D2 and D3 and is most commonly measured in blood to monitor Vitamin D status. It is relatively inactive.
  • 1,25-dihydroxyvmtain D is the active, steroid-like form of Vitamin D and is not generally seen as a quality marker of Vitamin D status in a person. It is made in the liver kidneys from the conversion of both Vitamin D2 and D3.

The Doctor’s Data Vitamin D tests I use measures 25-(OH)D levels. The conventional reference range for Vitamin D deficiency is under 30 ng/mL, while a healthier functional range should be between 60 and 80 ng/mL for optimal thyroid and immune system function.

In my experience, Vitamin D and ferritin deficiencies are the most common deficiencies I see in those with Hashimoto’s. I highly recommend evaluating the levels of both, but especially of the fat-soluble Vitamin D because taking excessive amounts can lead to significant health decline.

I recommend at least once book-ending your Vitamin D testing: once in the Fall to see what level you leave Summer with and once in the Spring to see what you leave Winter with. Ideally, however, while supplementing, I recommend testing every 6 months to ensure your levels remain stable; more frequently if taking high doses of Vitamin D3.


  • Sun exposure – at least 15 minutes a day around noon, without sunscreen
  • Take a quality Vitamin D3 supplement or cod liver oil (you may need to take it along with Vitamin K2 in some cases)
  • Take Vitamin D3 with a meal to improve absorption
  • Eat fatty fish like salmon and eggs regularly, if not sensitive
  • Consider safe tanning bed, if appropriate
  • Consider blue light therapy in the mornings

Supplemental dosing of Vitamin D3 should be discussed with your trusted health care provider based on test results and monitored appropriately thereafter. Consequences of overdosing can be significant.

Choosing supplements need not be so complicated though. There are a range of higher quality supplements available now that I would be confident to recommend, including, but not only, Apex Energetics, Pure Encapsulation, Designs for Health and Cyto-Matrix brands.


I regularly test my own Vitamin D levels because I have found they tend to be on the lower side of normal unless I’m vigilant with supplementation. I have a genetic SNP associated with issues regulating Vitamin D, I live in a Northern region (Canada), plus I have food sensitivity issues with dairy and egg so never eat either thus limiting access to some Vitamin D rich food sources.  Supplementing appropriately has been very helpful in my own recovery and in the recovery of many of the ladies I’ve worked with who have Hashimoto’s. Generally, in those individuals with better managed autoimmune conditions, Vitamin D levels tend to be in the functional range compared to those individuals experiencing more complications. In my mind, it is low hanging fruit and therefore a simple, inexpensive and effective way to support immune system dysfunction.


Dr. Krista Coombs

Dr. Krista Coombs

My name is Krista Coombs and I am the owner and practicing Doctor of Traditional Chinese Medicine (DTCM) at AcuPlus Wellness Clinic. I have been treating patients since 2001 using Traditional Chinese medicine (TCM) to help them improve their health. Recently I started pursuing certification in Functional medicine (FM) as well to offer even more health services.

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