Do you really have to lie in the blazing sun to fill your sun vitamin stores? Or is it even possible to fill up on vitamin D through the window? I've done some research for you!
When our bodies lack sunshine, they can't make vitamin D. This is not only noticeable in winter, but also for anyone who has an office job and spends a lot of time indoors instead of outdoors.
Too little of the sun vitamin leads to fatigue, susceptibility to infections and makes and listless.
Instead of lying in the blazing sun on the weekend and risking sunstroke, it should be enough to fill up on vitamin D through the window. Or should it?
That would be a great alternative, especially in the cool winter months.
But is the light that falls through the window panes really enough to form sun vitamins?
I've done some research on this for you. I'll tell you everything you need to know about it and a little bit more.
Table of contents
Can you fill up with vitamin D through the window?
No, it is not possible to make vitamin D through window panes. Almost all windows in homes and windows in cars filter the UVB rays of the sun. But it is precisely these UVB rays that we need in order to be able to fill up on the sun vitamin.
By the way, these are also the rays that make us tan in the summer. Through the brown complexion, our body protects itself from the rays. That means in short: You can neither get a tan behind glass panes (nor get a sunburn) nor form D vitamins.
This was also confirmed by Professor Michael Holick of Boston University School of Medicine at a Interview in the New York Times: "It makes no difference whether and how long you sit behind a window - vitamin D formation is not possible." Even a light-flooded winter garden does not help.
There is an additional problem in winter. In our latitudes, the sun is simply too low - the angle of incidence is not optimal, which is why we cannot form vitamin D even on the sunniest winter day.
Tip: Blood test!
I do a blood test every fall with my primary care physician to know my status. Whoever wants to can a vitamin D test at Cerascreen* can also be carried out at home. You only need to take a few drops of blood from your finger.
Although I am outdoors quite a lot and consciously pay attention to it, my values are usually too low. That's why I start in September at the latest to Vitamin D drops to take. I always buy them online for that because they are twice as expensive in the pharmacy.
If you don't have a favorite yet yourself, I can highly recommend these drops:
Beware of the sun behind glass
Still, sitting in the sun behind a window for hours on end is not a good idea.
While window panes block UVB rays, they allow UVA rays to pass through almost unfiltered. 0.02 % UVB rays and about 80 % UVA rays pass through a classic window.
This type of UV radiation is often overlooked, but it can penetrate deeper layers of the skin and cause damage and accelerated aging. So we get age spots more often and more wrinkles.
But what is the actual situation around Sunburns through the window? I'll tell you in a separate article - but I'll say this much in advance: you'll be surprised!
Fill up on vitamin D: Open the windows!
The good thing about the sunshine vitamin is that our bodies can store it. What this means for you: Starting in March, go outside every day, enjoy at least 15 minutes of sunshine (without sunscreen) and fill your vitamin D stores. By fall at the latest, you need to have built up enough reserves to get you through the winter.
Prolonged sunbathing is not a good idea, as it damages the skin and does not boost vitamin D production in the body.
So when the weather is nice, don't hide behind the window and look outside, go out sometimes - and it's better to do it every day for a short time than once a week for too long.
Alternatively, you can make yourself comfortable on the balcony or fill up on vitamin D through the window if you open it and stand in the light. Only when UVB rays reach our skin unfiltered does the body start producing the vitamin.
Especially from October to March, however, the question still arises: If you can't make vitamin D through the window - how are you supposed to fill your vitamin stores?
Be sure to include foods that contain vitamin D in your diet. Even if you only get a little, it's better than nothing. Fatty fish such as salmon, mackerel and herring are good sources. But there is another whole range sun vitamin foods.
How does the sun participate in vitamin D synthesis?
The human skin consists of several layers, each of which has a specific function. The uppermost layers contain provitamin D3, a precursor of vitamin D. In the skin, provitamin D3 is converted into vitamin D3 by body heat.
Vitamin D3 now has no biological function until it is converted to 25-OH vitamin D in the liver. It enters the bloodstream after absorption and is transported to the liver where it is converted to 25-OH vitamin D (calcifediol).
For vitamin D to act as a hormone in the body, it must first change its chemical form. To do this, the 25-OH vitamin D is transported from the liver via the bloodstream to the kidneys. The kidneys absorb it with the help of megalin, which converts it into physiologically active vitamin D, and finally release it into the blood.
But what does it actually look like in the solarium? We'll tell you here: "Can you make vitamin D in a solarium?"
Our conclusion
Building and refueling vitamin D through the window is not possible. Therefore, you should recharge your batteries from spring to summer to get fit through the winter. Get out in the sun for 10 to 15 minutes every day - that's enough to boost vitamin production.
All the best to you and have fun in the sun!
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