Published on August 13, 2021

Video Friday: This short clip reviews research on vitamin D for immune function, respiratory infections, COVID-19, and the potential for vitamin D toxicity

This short, educational video features Dr. Roger Seheult and Dr. Rhonda Patrick as they discuss how to assess vitamin D requirements for immune function and its toxicity potential.

While the current recommended daily allowance for vitamin D was established based on its role in bone metabolism, there is great reason to question whether these levels are sufficient for optimal immunological functioning. This video clip reviews research to suggest that vitamin D levels below 30 ng/ml (75 nmol/L) are associated with a higher risk of death from all causes, and others that indicate higher vitamin D levels (closer to 50 ng/ml) may benefit the immune response and help protect against SARS-CoV-2.

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After watching the video, be sure to make note of our added details below!

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Vitamin D for Immune Function – How much to take, and what is too much?

Here is a quick summary of what this video discusses, along with additional information and details from GrassrootsHealth:

  • There are several forms of vitamin D. 25-hydroxyvitamin D, or 25(OH)D, is the form that is measured in the blood to determine a person’s vitamin D status. While it is fat soluble, the ratio of vitamin D in the blood vs fat remains constant.
  • Levels below 50 ng/ml (125 nmol/L) have been linked to increase in SARS-CoV2 positivity rate. A meta-analysis on vitamin D and COVID-19 also illustrated the effect of vitamin D on the risk of infection, severity, and death due to COVID-19.
  • Levels associated with improved immune function and decreased risk of infection are much higher than the suggested sufficiency cut-off level of 20 ng/ml (50 nmol/L) set by the IOM (Institute of Medicine, now the National Academy of Medicine) based on bone health
  • In this video, Dr. Keith Baggerly discusses the math and science used to determine the current recommended vitamin D serum levels and supplementation amounts, and where the IOM got it wrong. The mistakes in calculation led to recommendations that are way too low for public health, leading to widespread vitamin D deficiency even among those receiving medical care and attention.
  • A meta-analysis of 32 studies published in 2014 by Garland et al. showed that levels below 30 ng/ml (75 nmol/L) were associated with a higher risk of death from all causes while levels between 40-70 ng/ml (100-175 nmol/L) had the lowest all-cause mortality

And then there’s how to achieve those levels…

The Upper Level Intake was set at 4000 IU per day.
Is that enough? Too much?

  • Vitamin D is most likely the least toxic fat-soluble vitamin. According to a Mayo Clinic publication involving data from over 20,000 people – “There is enough evidence that vitamin D toxicity is one of the rarest medical conditions and is typically due to intentional or inadvertent intake of extremely high doses of vitamin D (usually in the range of >50,000 – 100,000 IU/day for months to years) without monitoring for hypercalcemia.”
  • Another study by McCullough et al. showed no adverse events related to vitamin D supplementation and no cases of vitamin D induced hypercalcemia with doses of up to 50,000 IU per day
  • The vitamin D level responds differently to supplementation with different starting levels, intakes, and other various factors. It is vital to test and re-test to make sure that the daily dose or vitamin D routine is achieving and maintaining the desired target vitamin D level.

Measure Your Level of Vitamin D and Other Nutrients Important for Immune Health

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, selenium 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!