Vitamin D: it is one of the most supplemented vitamins. A great deal has already been written and researched about the effect of different dosages and the importance of the different forms of vitamin D. Many research areas are still open-ended, resulting in new knowledge and applications.

All things vitamin D

Vitamin D is commonly associated only with vitamin D3, but it comes in different forms (vitamins). D3 is the main shape and is produced by the body. Do you know the other shapes?

They are:

  • Vitamin D1: arises from the 1:1 combination of ergocalciferol (vitamin D2) and lumisterol
  • Vitamin D2: ergocalciferol. This vitamin is only formed in fungi or yeasts; in some countries it is added to margarine and breakfast cereals.
  • Vitamin D3: cholecalciferol, produced by UV-B light on bare skin and plays a role in bone formation and maintenance and calcium absorption.
  • Vitamin D4: 22-dihydroergocalciferol. This vitamin can only be found naturally in mushrooms.
  • Vitamin D5: sitocalciferol. This synthetically created vitamin is also used in treatments of prostate cancer because, unlike D3 in higher doses, it does not cause hypercalcemia.

With all the information out there about vitamin D3, it is inevitable that noise develops—and it has. For example, D3 is often referred to as the 'sun vitamin', while this is not entirely correct. This is because the vitamin D3 that our skin produces under the influence of sunlight is not the same form as the one you find in dietary supplements, and therefore does not have the same properties. For more about this and other interesting information about supplemental vitamin D3 see here.

What you didn't know about vitamin D3

As mentioned, the information from recent scientific research on vitamin D3 keeps coming, sometimes refuting old beliefs, at other times announcing new discoveries about the absorption of vitamin D3 and about which nutrients and behaviors accelerate or counteract this. The influence of human behavior on the absorption of nutrients should not be underestimated and it plays an indispensable role in how much of the vitamin D3 consumed can be effectively used by your body. For example, were you aware of the following facts about vitamin D3 absorption?

  • Excessive alcohol consumption inhibits vitamin D3 absorption in the small intestine as well as processing in the liver. Long-term alcohol consumption has a corrosive effect on the delicate intestinal wall in the small intestine, making it stiffer and allowing fewer nutrients to pass through. After absorption vitamin D3 is metabolized to bioavailable components in the liver. With excessive alcohol consumption, the liver, which also breaks down alcohol, is considerably overloaded, in fact irreparably damaged in the long term, making the liver less able to do its many jobs.
  • Determining whether you have sufficient vitamin D3 in your blood is difficult to determine without a blood test. A method by which you can estimate this yourself is the compression test: here you exert light pressure with your thumb on the center of your sternum or shins. Does that hurt? Then you may have a vitamin D3 deficiency. Find more about the compression test here.
  • If your vitamin D 3 status turns out to be low after taking a blood test, you can see this as a measure of your need for essential sunlight - do you get enough sun exposure without sun protection? What is special is that vitamin D3 that you absorb via sunlight cannot cause an overdose! Unprotected tanning seems controversial with the current consensus, but sunlight on bare skin has a multitude of indispensable properties. For details see an earlier blog on the pros and cons of sunlight.
  • Not just people: edible mushrooms, too, synthesize vitamin D under the influence of UV light. But where D3 is generated in humans, mushrooms mainly synthesize D2 and to a lesser extent D3 and D4. By eating fresh mushrooms, you can get your daily vitamin D requirement in a natural, vegetable way. This vitamin is otherwise only found in animal sources.
  • Caffeine can prevent optimal calcium metabolism, a possibility that has also been identified in the metabolism of vitamin D3. Under the influence of a daily caffeine intake of 300 mg or more (the effect proved more pronounced as the dose of caffeine was increased) during a scientific study, the D3 receptors in osteoblasts (cells responsible for the mineralization and construction of bones) bound to less vitamin D3 and consequently less D3 was metabolized. The continued drinking of lots caffeine drinks thus, in the long run, may have a negative affect bone density.
  • According to the first results of recent research, resveratrol (available as a dietary supplement, but also found in red wine) appears to be able to improve the absorption of vitamin D3, because it can potentially activate and stimulate D3 receptors in the body to binding with vitamin D3. Drinking red wine is healthy, in moderation!

Vitamin D and the immune system

The involvement of vitamin D in a well-functioning immune system is a well-known fact: scientific research has repeatedly demonstrated this property. At the same time, in a large part of the population the need for vitamin D is higher than obtainable with food. This is especially the case in the dark months of the year when less D3 can be absorbed from sunlight, and with people spending less time outside or would benefit from a healthier diet. It is not without reason that vitamin D has recently started to be mentioned again across various media now that the days are getting shorter and staying indoors is a bigger share of our day.

The UK Prime Minister even decided to respond in a revolutionary way. In Scotland, the NHS (the UK National Health Service) have already decided on a 4-month vitamin D supplement stock intended for all among the population of Scotland from whom vitamin D intake is a concern. This is now also being considered in England.

What do you think: should all governments provide free vitamin D supplements to their population for an annual resilience boost? Or is better education about responsible tanning and nutrition the better way?

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