Immunologic Effects of Vitamin D on Human Health and Disease – Nutrients 2020, 12(7), 2097

Vitamin D is responsible for regulation of calcium and phosphate metabolism and maintaining a healthy mineralized skeleton. It is also known as an immunomodulatory hormone. Experimental studies have shown that 1,25-dihydroxyvitamin D, the active form of vitamin D, exerts immunologic activities on multiple components of the innate and adaptive immune system as well as endothelial membrane stability. Association between low levels of serum 25-hydroxyvitamin D and increased risk of developing several immune-related diseases and disorders, including psoriasis, type 1 diabetes, multiple sclerosis, rheumatoid arthritis, tuberculosis, sepsis, respiratory infection, and COVID-19, has been observed. Accordingly, a number of clinical trials aiming to determine the efficacy of administration of vitamin D and its metabolites for treatment of these diseases have been conducted with variable outcomes. Interestingly, recent evidence suggests that some individuals might benefit from vitamin D more or less than others as high inter-individual difference in broad gene expression in human peripheral blood mononuclear cells in response to vitamin D supplementation has been observed. Although it is still debatable what level of serum 25-hydroxyvitamin D is optimal, it is advisable to increase vitamin D intake and have sensible sunlight exposure to maintain serum 25-hydroxyvitamin D at least 30 ng/mL (75 nmol/L), and preferably at 40–60 ng/mL (100–150 nmol/L) to achieve the optimal overall health benefits of vitamin D.

Units used to measure Vitamin D

For some reason two different units are used in parallel to describe 25(OH)-Vitamin-D blood concentration, namely Nanogramm per Milliliter [ng/ml] and Nanomol per Liter [nMol/l]. As a result there is some likelyhood of confusion when comparing  different diagnostic test results or reading scientific literature. Allways check the units, when comparing  lab results or Vitamin D related lectures, publications, guidelines or recommendations.

However, the  two units Nanogramm per Milliliter [ng/ml] and Nanomol per Liter [nMol/l] can be easily converted by either multiplying or dividing with the factor 2.5 (1 ng/ml = 2.5 nMol/l).


How fast does my Vitamin-D level drop, without sufficient sunexposure or supplementation?

Half-time of Vitamin D metabolites

Under good conditions our body produces some 10.000 international units Vitamin D from sun exposure within just a few minutes day by day. This seems quite a huge amount, but in fact our body consumes most of this Vitamin D within the next 24 hours. Many experts state that we have a minimum daily consumption of 6.000 i.u. Vitamin D to keep all Vitamin D dependant regulatory systems on a good level.

As a consequence the blood-concentration of 25-OH-Vitamin-D may drop quite fast if the self-production goes down (e.g. in winter) and is not refilled by supplementation. Another factor, that contributes to the significant drops in blood Vitamin-D levels non-adequate supplemented people is the quite limited half-time of the Vitamin-D main metabolites. For best consultation, regarding indiviudual Vitamin D supplementation and monitoring it is thus important to minimize the time to result of a Vitamin D test.

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What can I do for my best Vitamin D status?

1. Vitamin D comes from sun exposure, not your diet.

When you expose your skin to the sun, your body makes vitamin D, lots of it. On the other hand, there isn’t much vitamin D found in foods. This means that getting enough vitamin D depends on getting frequent and moderate sun exposure, not eating a balanced diet.

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2. Scientists and doctors agree that at least a third of the world is deficient in vitamin D.

Some scientists think even a greater percentage are deficient. This is because we live in an indoor society, more so now than ever before in human history.

3. If you don’t get frequent moderate sun exposure or take a vitamin D supplement, you’re likely deficient in vitamin D.

Some people get tested for vitamin D by their doctors and are shocked to find out they’re deficient. But unless you get frequent moderate sun exposure or take a supplement, it shouldn’t come as a surprise at all. These are the only reliable ways to get the vitamin D your body needs. While there is a little bit of vitamin D in fish and fortified milk, there isn’t enough to make sure you’re sufficient in vitamin D.

4. Moderate midday sun exposure is the best for making vitamin D.

In order to make vitamin D, the sun needs to be high up in the sky, high enough so that your shadow is shorter than you. If your shadow is longer than you, the sun isn’t intense enough to help your body make vitamin D. Midday sun exposure is best; this is when the sun is high and your shadow is shorter than you are.

5. You don’t need to burn to make vitamin D.

To make good amounts of vitamin D, you should spend half the time out in the sun that it would take for your skin to turn pink.

6. Vitamin D supplements are a good option in the wintertime to get the vitamin D you need.

In the northern hemisphere, the sun starts focusing more on the southern hemisphere. The sun’s rays strike the northern hemisphere at a different angle, an angle that isn’t quite as intense as during the summer. In consequence, your body has a harder time making vitamin D in the winter compared to the summer. The further north you live, the more difficult it is to make vitamin D in the winter.

Remember you can always check to see if you’re making vitamin D by looking at your shadow. If it’s longer than you, you aren’t making much vitamin D. And in the winter, your shadow is often longer than you.

Have no fear that you can’t make vitamin D! Vitamin D supplements are a good option in the wintertime. Low-pressure sunbeds and UV light units are also options to help you make vitamin D during the winter.

7. Vitamin D is important for many things, including your bones, heart, respiratory system, brain, and likely cancer prevention.

Scientists are still discovering the effects of vitamin D on disease prevention, but researchers believe it may play a central role in preventing autoimmune diseases like multiple sclerosis and type I diabetes, preventing cancers like breast and colon, and keeping the heart healthy, by influencing muscle function and hormones involved in heart health.

8. Consider getting tested for vitamin D, to see if you’re getting enough.

Vitamin D tests are pretty easy. You can ask your doctor to add it to your next routine blood panel.

While not all doctors agree how much vitamin D you need, a group of 42 of the world’s top vitamin D researchers think the optimal vitamin D level is between 40-60 ng/ml [100-150 nmol/l] or, a level the majority of northern populations fall well below.

[SOURCE: Vitamin-D Council,]

VHC Vitamin-D quantitative Vitamin D testing at any Point of Care

VHC Vitamin-D quantitative Vitamin D testing at any Point of Care

By end of June 2017 the VHC Vitamin-D quantitative Vitamin-D test has been CE marked and we produced the first batch in order to serve our early bird customers. The success of the VHC Vitamin-D was bejond our initial expectations so far. We have been sold our several times and are producing the fourth bath right now.

In parallel to scaling up the production of the VHC Vitamin-D from batch to batch, we work closely together with our partners and customers to offer them optimal training and support.

For more information about the VHC Vitamin-D test and its handling, please follow this link.