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Full of sun - how the warming rays keep you healthy

Are you also going out when the sun shines to enjoy the warm rays? Very good! Because in addition to the warmth, you also fill up on vitamin D3, also called cholecalciferol. The vitamin is formed mainly by sunlight in the skin. But how does it work and what do we need vitamin D3 for anyway?

Prerequisite for the formation of vitamin D3 is cholesterol

Vitamin D3 is a fat-soluble vitamin and is produced in our skin cells from fat cholesterol and the sun's energy-rich UVB rays. You may have come across cholesterol when discussing your blood results. In particular, the HDL and LDL cholesterol values are often mentioned. A little more of the HDL cholesterol usually is a good thing. This is because this cholesterol is packed into smaller packages and can be better transported through the bloodstream. The risk of clogged blood vessels decreases and thus also the risk of heart attack and stroke. A too high LDL cholesterol level above a certain threshold on the other hand increases the risk for stroke and heart attack.

Vitamin D, a real all-rounder

Vitamin D is essential for us and has a hand in almost all systems, because vitamin D receptors are found in almost all cells. However, studies show that the majority of the population has a vitamin D deficiency. The problem is that a deficiency is not noticed right away and happens insidiously. A late consequence of a vitamin D deficiency can, for example, trigger osteoporosis (see blog article: Osteoporosis - Prophylaxis through sport?). This is due to the fact that vitamin D plays an important role in the absorption of calcium and thus bone growth can no longer be properly controlled.

How it works

The sun hits the skin, causing a special cholesterol to be converted into provitamin D in the bloodstream. With the help of vitamin C, the vitamin is now converted in the liver to a hormone precursor, the so-called 25-OH-vitamin D3 calcidiol. Strictly speaking, it can therefore also be called a hormone! However, this hormone precursor does not yet have a great effect on our organism, because in this form it does not trigger a reaction on the vitamin D receptors.

A receptor is a protein structure, which causes a reaction when it comes into contact with a certain substance. You can imagine a receptor like a smoke detector, which is activated by smoke and triggers an alarm. In order to trigger a reaction at the receptor by vitamin D, the calcidiol must now be converted to the fully active vitamin D, the so-called 1,25 vitamin D3 calcitriol. This happens in the kidney with the help of magnesium and vitamin C. Now the vitamin D can dock onto the receptors and trigger an effect, for example in calcium/phosphate homeostasis, in cell proliferation and differentiation or in our immune system.

As you can see, vitamin D production and conversion is a complex process and depends on several systems and resources. Therefore, the whole thing once again briefly summarized: Via the blood, to the liver, to the kidney and with the help of vitamin C and magnesium, vitamin D is activated and made usable. However, there are many other factors that can influence production:

  • The skin type - People with darker skin color need more sun rays to produce vitamin D. The melanin content in the skin provides good sun protection, but also inhibits vitmanin D3 production

  • The sun protection factor - From a sun protection factor of 8 the skin produces less vitamin D3

  • The clothes - the more we are covered, the less sun hits the skin

  • The age - The older a person gets, the less skin-own vitamin D3 can be produced

  • Balanced nutrition - to control calcium absorption and protein production by vitamin D3, an adequate supply of vitamin K is required. Vitamin K is found e.g. in fermented vegetables and sauerkraut

  • Health complaints - diseases such as Crohn's disease mean that vitamin D3 cannot be absorbed properly. However, renal insufficiency or reduced liver function, for example due to fatty liver, can also lead to vitamin D deficiency

  • Obesity - Increased body volume results in a small amount of available 25-hydroxyvitamin D because the volume of distribution is greater

  • Deficiency symptoms - Due to a magnesium or vitamin C deficiency, for example, as the conversion to fully active vitamin D depends on these two vitamins

3 tips to refuel properly

  1. Use the sun to fill the tank! If possible, uncover your arms and head. Just 20 minutes in the sun can be enough to refuel. It is important that you are careful not to overexert your skin and apply sunscreen as needed

  2. Pay attention to a balanced diet. You should prefer unprocessed foods, add vegetables to your diet and eat as varied as possible. Nutrition is very individual! Depending on your current situation, type and needs... an optimal diet for you may differ from others. If you need support here, contact a trainer of your choice

  3. If the sun is not available for a long time or you do not have the opportunity to catch the sun, it makes sense to test the vitamin D level. Before you take a vitamin D supplement, it is advisable to visit your pharmacist, who can give you information and, if necessary, also sell the tests

More facts about vitamin D:

  • Promotes the production of the body's own antibiotics and inhibits inflammation

  • Studies show that vitamin D deficiency has often led to more severe coronary events

  • Vitamin D can mitigate the severity of influenza by reducing the docking sites for viruses

  • Calcium is important for bones, teeth and serves as an acid buffer. For it to enter the bloodstream, it needs vitamin D

  • Analyses show that a deficiency is associated with lower HDL levels and higher cholesterol levels. Too high a cholesterol level increases the risk of cardiovascular disease

Combine sunbathing with fitness? That's possible with our outdoor course in Kaiseraugst, every Monday at 12:15 pm on the basketball court. Participation is free for our members.

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Feel free to contact me with any further questions or chat at:

We wish you a lot of fun in the sun,

Your inicio Team


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