Published on November 9, 2021

New results from the VITAL Trial showed vitamin D and/or omega-3 supplementation reduced autoimmune disease incidence by 25-30% over 5 years

Key Points

  • A new analysis of VITAL Trial data shows a 25-30% decreased incidence of autoimmune disease diagnosis among those taking vitamin D and/or omega-3s vs only placebos, during an average follow-up of 5.3 years
  • There was a 39% decreased incidence of diagnosed autoimmune disease among those taking vitamin D vs placebo, when diagnosis during the first 2 years was excluded (allowing time for vitamin D to take effect)
  • The study only supplemented with 2000 IU vitamin D per day and/or 1000 mg omega-3 fatty acids per day, without adjusting intake to reach target levels – additional benefits may have been achieved if enough supplement was given to reach a target vitamin D level of 40-60 ng/ml (100-150 nmol/L) and/or an Omega-3 Index of at least 8%

A new analysis from data gathered during the VITAL trial, looking at the relationship between supplementation with vitamin D and/or omega-3 fatty acids and the incidence of autoimmune diseases, has now been released. The analysis included data from 25,871 participants (average age 67 years old) who were followed for a median of 5.3 years. The primary outcome studied was the total incidence of all autoimmune diseases, including rheumatoid arthritis, polymyalgia rheumatica, autoimmune thyroid disease, psoriasis, and all others. Probable diagnoses of autoimmune diseases (cases that lacked enough medical record data to confirm existing symptoms and evidence of autoimmune disease) was also tracked and reported on; both are reviewed below.

Supplementation with Vitamin D and/or Omega-3s Reduced Autoimmune Disease Incidence

During the time of the study, there was a

  • 22% decreased incidence of diagnosed autoimmune disease among those taking vitamin D vs placebo (p=0.04)
  • 39% decreased incidence of diagnosed autoimmune disease among those taking vitamin D vs placebo, when diagnosis during the first 2 years was excluded (allowing time for vitamin D to take effect; p=0.005)
  • 15% decreased incidence of diagnosed autoimmune disease among those taking omega-3 fatty acids vs placebo (p=0.20)
  • 25-30% decreased incidence among those taking vitamin D and/or omega-3s vs only placebos

The chart below illustrates the incidence of diagnosed autoimmune diseases among each group during the time of the study.

Click to Enlarge & Print

As you can see, the black line at the top (showing disease incidence among those taking only placebos) is much higher at the end of the 5.3 year follow up than the lines showing results for all other groups (taking either vitamin D, omega-3s, or both). This chart illustrates a 31-32% decreased incidence of any diagnosed autoimmune disease among those taking vitamin D with or without omega-3s versus only placebos.

This second chart shows the incidence of both diagnosed and probable autoimmune disease during the study follow-up time.

Click to Enlarge & Print

Again, the black line is much higher at the end of the study compared to all other groups, with the greatest effect showing a 29% decreased incidence for those taking both vitamin D and omega-3s versus only placebos.

The authors conclude

“Supplementation for 5 years with vitamin D3 and/or n-3 fatty acids reduced incident autoimmune disease by 25-30% in older adults vs. those who received neither supplement. The effect of vitamin D3 appeared stronger after 2 years of supplementation.”

How much vitamin D and omega-3s?

It is important to note that, for the VITAL study, the vitamin D supplementation group was given 2000 IU of vitamin D per day, and this analysis did not compare resulting vitamin D levels to disease incidence, which is essential due to the varying response of individuals to vitamin D supplementation. To get to a vitamin D serum level of 40 ng/ml (100 nmol/L), our scientists’ panel’s minimum recommendation, it would take 5000 IU/day to get approximately 82% of the population to that level – that’s more than twice the amount given during the VITAL trial. Also, studies suggest a level closer to 60 ng/ml may be of greatest benefit to those with or trying to prevent autoimmune disease.

The omega-3 group was supplementing with 1000 mg omega-3 fatty acids per day; similarly, the resulting blood levels of omega-3s, using measurements such as the Omega-3 Index, was not considered in the analysis.

Measure Your Vitamin D and Omega-3 Levels to Make Sure You Are Getting Enough

Having and maintaining healthy vitamin D, omega-3, 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.

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!