Published on August 9, 2021

Study shows supplementing to achieve a vitamin D level of at least 40 ng/ml (100 nmol/L) significantly decreased auto-immune thyroid disease

Autoimmune disease happens when our own immune system begins attacking our own cells. Examples of autoimmune diseases include multiple sclerosis (affecting the myelin, a substance that protects nerve cells), type 1 diabetes (which affects cells of the pancreas), celiac disease (affecting the small intestine), and auto-immune thyroid diseases, such as Hashimoto’s thyroiditis and Grave’s disease. Vitamin D deficiency is a risk factor for many auto-immune diseases, and correcting vitamin D deficiency or overcoming vitamin D resistance can be key in addressing autoimmune disorders.

What are Auto-Immune Thyroid Diseases?

Auto-immune thyroid diseases are the most prevalent organ-specific auto-immune diseases, with Hashimoto’s thyroiditis being the major cause of hypothyroidism and Grave’s disease being the major cause of hyperthyroidism. Vitamin D status may affect the presence of both of these diseases, with an increased risk of measures indicative of thyroid autoimmunity, including increased thyroid autoantibody levels, increased anti-thyroid peroxidase (anti-TPO), and increased anti-thyroglobulin (anti-TG) antibodies, associated with vitamin D deficiency (levels below 20 ng/ml or 50 nmol/L).

Vitamin D Levels Above 50 ng/ml Decreased Auto-Immune Thyroid Disease Activity

A study by Mirhosseini et al. reviewed the effects of vitamin D on multiple aspects of thyroid function. The study provided vitamin D supplementation (average dose 6000 IU/day) with the intention of achieving a vitamin D level of at least 40 ng/ml (100 nmol/L). Vitamin D and thyroid measures (including TSH, FT4, FT3, and thyroid antibodies) were taken at baseline and at follow-up, about one year later. The study found a 30% reduced risk of hypothyroid at the end of the supplementation program (findings covered in detail in a previous post here) and a 32% reduced risk of elevated anti-thyroid antibodies among participants whose vitamin D level was 50 ng/ml (125 nmol/L) or higher.

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Average anti-thyroid antibody levels among the participants were elevated at the beginning of the study, but significantly decreased after participating in the vitamin D supplementation program. Among those whose anti-thyroid antibody levels were elevated at the start, anti-TG levels normalized among 77.5% by follow up (with a 78% decreased risk of elevated anti-TG for those achieving 50 ng/ml vitamin D or higher, p<0.001), and anti-TPO levels normalized among 42.2% by follow up (with an 86% decreased risk of elevated anti-TPO for those achieving 50 ng/ml vitamin D or higher, p<0.001).

By the end of the vitamin D supplementation program, only:

  • 20% had at risk anti-TPO levels, compared to 32% at baseline
  • 21% had at risk anti-TG levels, compared to 93% at baseline
  • 9% had both at risk levels of anti-TPO and anti-TG, compared to 29% at baseline

Overall, for those at-risk for autoimmune thyroid disease at the beginning of the study, more than 60% were no longer considered at-risk at follow-up.

Make Sure You Are Getting Enough Vitamin D and Other Important Nutrients – Measure Your TSH as Well!

Having and maintaining healthy vitamin D levels and other nutrient levels can help improve your health now and for your future. Choose which to measure, such as your vitamin D, omega-3s, and essential minerals including magnesium and zinc, by creating your custom home test kit today. Take steps to improve the status of each of these measurements to benefit your overall health. You can also track your own intakes, symptoms and results to see what works best for YOU.

Enroll and test your levels today, learn what steps to take to improve your status of vitamin D (see below) and other nutrients and blood markers, and take action! By enrolling in the GrassrootsHealth projects, you are not only contributing valuable information to everyone, you are also gaining knowledge about how you could improve your own health through measuring and tracking your nutrient status, and educating yourself on how to improve it.

Help everyone Move Research into Practice with vitamin D and other nutrients! As a special birthday gift to everyone, in honor of the science, we have created a special scholarship fund for anyone to donate to that will go towards helping others participate. Your donation will allow anyone to get help with funding their participation when they need it.

Text-to-give: Text Daction to 44321 to add to our Scholarship Fund.

What Does it Take YOU to Get Your D to 40 ng/ml (100 nmol/L)?

Did you know your health could be greatly affected by making sure you have a vitamin D level of at least 40 ng/ml (100 nmol/L)? Help us help you.

STEP 1 - Do you know what your vitamin D level is? If not, be sure to test today to find out.

STEP 2 – Determine your target level. Are you at your target level? Experts recommend a level of at least 40-60 ng/ml (100-150 nmol/L).

STEP 3 – Need to boost your level? Use the D*calculator to see how much vitamin D it may take to reach your target. Opt for the Loading Dose for a quicker boost.

STEP 4 – Optimize how your body absorbs and utilizes vitamin D with co-nutrients and these simple steps.

STEP 5 – Re-Test! This is an important step to make sure you have reached your target level, and to ensure you are not taking too much! Re-testing after 3-4 months is recommended.

STEP 6 – Adjust, Repeat…

Give your immune system the nutrients it needs to support a healthy you and protect yourself from unnecessary diseases, especially COVID-19.


The first Randomized Controlled Trial on vitamin D and COVID-19 has shown a 96% lower risk of ICU admission for those receiving vitamin D (as 25(OH)D to quickly boost vitamin D blood levels) along with the standard treatment, compared to those receiving standard treatment alone.

These results support many previous observational studies showing a relationship between vitamin D levels and intake and COVID-19 severity.

Review the Latest Nutrient Research for COVID-19

GrassrootsHealth Nutrient Research Institute has launched the new Immune Boost project with the use of our myData-myAnswers nutrient health system that nearly 15,000 people are already using for their health. Specific markers that influence immune health are suggested for testing as part of this project including:

  • Vitamin D
  • Omega-3 Index
  • Essential elements magnesium, selenium, and zinc
  • hsCRP

Our goal is to demonstrate how one can use the Nutrient Research Model established by Dr. Robert Heaney to show the effect of vitamin D serum levels of at least 40 ng/ml (100 nmol/L) on risk reduction for all ethnicities in the population. Status and intake of other nutrients will also be analyzed for any type of relationship to immune status and symptom severity. Join the project today!

Please let us know if you're interested in helping sponsor this project.

CLICK HERE for updates and new information about the project.

Through GrassrootsHealth Nutrient Research Institute, you can also test your essential elements magnesium, copper, zinc and selenium, toxins such as lead, mercury and cadmium, as well as your omega-3 levels, inflammation levels and thyroid stimulating hormone (TSH) level. Find out your levels today! Log on to the test selection page (click the link below) to get your tests and see for yourself if your levels can be improved.

Make sure you track your results before and after, about every 6 months!

Click Here to Access the Test Page

How can I track my nutrient intake and levels over time?

To help you track your supplement use and nutrient levels, GrassrootsHealth has created the Personal Health Nutrient Decision System called

For each specific supplement, you can track what days you take it, how much, and many other details.  This will help you know your true supplemental intake and what patterns of use work for you to reach and maintain optimum nutrient levels. Check it out today!