The multiple important roles that vitamin D plays in immune function have been a major focus over the past year, especially in relation to COVID-19. As part of our What is Vitamin D Good For? series, this post will attempt to summarize those roles to clearly show how the immune system relies on vitamin D to function properly. Because vitamin D acts as a protector and regulator of all cell types, tissues, and organs, it is required for the proper functioning of each system of the body to help keep us healthy. This is especially true for our immune system, since vitamin D has specific regulatory effects on immune cells and inflammation. 

So far, we have covered how vitamin D contributes to the health of the musculoskeletal system, dermatological system, reproductive system, respiratory system, cardiovascular system, digestive system, and to cancer prevention and cognitive and mental-emotional wellness. A deficit in vitamin D can lead to impairment or disease in each of these systems – from brittle bones to heart disease, cancer and dementia. With this in mind, why take a chance at being deficient in vitamin D?

Vitamin D insufficiency has been associated with increased susceptibility to all types of infections. Vitamin D intake and blood levels have potential effects on disease risk, severity, and mortality. Infections that have been associated with low vitamin D levels include: 

Being exposed to viruses, bacteria, and toxins is a part of a normal day. They are in the air we breathe, the food we eat, in the water we drink and on surfaces we touch. Your immune system has been training since you were born to protect you from the “pathogens” that cause infection or disease. But sometimes, infection takes hold and your immune system has to fight off those pathogens. What you may not realize is that the nutrients in your diet directly influence the ability of your immune system to function. 

There are two main immune reactions. The innate immune system works to stop the initial invasion of pathogens. It is the body’s first line of defense, and includes barriers such as our skin, mucous membranes, stomach acid, and microbiota, as well as the generalized inflammatory response. It is a quicker response that does not differentiate between pathogens – it just identifies that there is a problem, and works to eliminate it.

The adaptive immune reaction involves a more complicated, strategized set of actions to identify which pathogen has invaded and then create immune cells specifically designed to destroy that pathogen; a process that can take days to weeks – as is often the case with viral infections. The adaptive immune response can also use antigens to “remember” that specific pathogen which makes future responses more efficient.

Vitamin D plays a crucial role in regulating immune system activity – both innate and adaptive responses. The innate immune system is responsible for the initial defensive front with a central role played by phagocytes. Vitamin D stimulates expansion of these phagocytes (monocytes and macrophages), increasing their ability to fight off the virus by increasing their numbers, as well as increasing their killing capacity through stimulating the production of the anti-viral and anti-microbial protein cathelicidin. Vitamin D also acts to regulate the maturation of dendritic cells which are important for activating CD4+ T cells and in turn the rest of the immune response (see more below).

Vitamin D is a potent regulator of both cell-mediated (T cell) and humoral (B cell) immunity. This is a vital part of the body’s defense against pathogenic invader, allowing white blood cells to recognize, bind to, and destroy pathogens – a process that relies on vitamin D to function properly.

The diagram below outlines many specific ways vitamin D affects different immune cells of both the innate and adaptive immune response.

Charoenngam et al., Endocrine Practice, 2021.

Vitamin D is especially critical to the activation and modulation of T cells, which help identify and destroy pathogens. In this step, vitamin D becomes an essential component to how well the immune system responds to infection. T cells are able to directly and indirectly kill infected cells, depending on which type of T cell it is. There are several types of T cells that are important to a viral immune response, including helper T Cells (CD4+ T Cells) that help identify and direct the immune response, cytotoxic T cells (CD8 T Cells) that bind to and kill infected cells, and memory T cells that remember the pathogen and how to defeat it. Important to their function are the T cell receptors, which must be activated in order for the T cells to bind to the infected cells. Helper T cells also release specific proteins called cytokines (such as interleukin) in order to orchestrate the binding and activation of the T cells, ultimately causing the destruction of the infected cells.

Vitamin D acts to regulate T cell response through initiating dendritic cell tolerance. These dendritic cells in turn stimulate the increased production of T regulatory (Treg) cells and their production of anti-inflammatory interleukin (IL)-10, switching the response from being Th1-driven and pro-inflammatory to a Th2-driven anti-inflammatory response.

Vitamin D acts to suppress the production of inflammatory cytokines (such as IL-1, IL-6 and IFN which are predominant in the cytokine storm characteristic of severe COVID-19). Vitamin D also has an effect on the actions of B-cells and inhibits the production of antibodies. Overall, the immunomodulatory actions of vitamin D play a very important role in preventing the activation of an inappropriate hyper-inflammatory immune response, therefore preventing the now infamous cytokine storm.

Nutrients work synergistically to help immune cells carry out specific actions during an immune response. Without these necessary nutrients, immune function may still be hindered, even with enough vitamin D. To summarize, some of the other nutrients that support immune health include:

By joining the GrassrootsHealth projects, you are not only contributing valuable information to our study, but 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. Do you know what your status of vitamin D, omega-3s, and other essential nutrients is? Could your levels be improved? Test now to find out!

We now have a NEW GIFTING SERVICE that allows you to quickly send ‘Gift Cards’ to friends, family and coworkers who you consider might need immediate access to testing, and to Claim the Joy of Your Health TODAY. Give the gift today!

It's TIME to start saving lives! If you can help PREVENT the majority of the death, it's time! What's it costing you/us not to take action NOW?

There is much published research that supports a clear link between vitamin D and COVID-19 showing that higher vitamin D levels are related to:

Everyone needs vitamin D! Here’s how to tell how much you might need, and who may need more – people who are overweight or who have darker skin are among those at increased risk of deficiency.

Be sure to educate yourself on the benefits and importance of vitamin D for immune health, and take steps to ensure you and your loved ones are getting enough.

You can review all of the COVID-19 and immune health information we have shared on this page.

Correcting a vitamin D deficiency at any age and any time of life decrease potential disease severity and improve outcomes! Test your vitamin D level today, learn what steps to take to improve your level, and take action to achieve and maintain a vitamin D level of 40-60 ng/ml (100-150 nmol/L).

Using the GrassrootsHealth Custom Kit Builder, you can create a test kit that measures your status of vitamin D and other important nutrients (such as omega-3s, zinc and magnesium), as well as your CRP level to measure inflammation. Click here to build and order your test kit today – measure your status and take the steps necessary to improve them if needed; make an impact on your health today and for your future! When you know what your levels are, you can determine next steps to take and how much supplementation may be needed if you are not at your target levels.

Enroll now with the Full Immune Boost Panel (which includes tests for vitamin D, Omega-3 Index, magnesium, zinc, selenium, copper, and hsCRP), and get 10% off when you use coupon code BoostTen at checkout.

NEWS ALERT: States, Governments Acknowledge the Need for Vitamin D to Build the Immune System;

Vitamin D*action has achieved a major milestone of ‘Moving Research into PRACTICE’!

EVERYONE needs to know about the benefits of vitamin D... We need your help to do this. Donating $25.00 today will positively affect millions of lives!

We will take this opportunity to use our extensive network to get pertinent information on vitamin D to the new US COVID Panel as well as local and state government representatives around the world.

Donate $25 today (or more) to help support this outreach effort (and, let us know if your employer could match the donations made by individuals from now until January 1, 2021!). You can also "text-to-give" by simply texting Daction to 44321.

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…

Have a beautiful and HEALTHY day.

Onwards,