As soon as the sun shines in spring, many people head outside. But how strong is the sun in March – and does the body already produce enough vitamin D? This rule applies.
The gloomy, dark winter has a negative impact on many people’s moods. This is hardly surprising, because according to the German Nutrition Society, between 40 and 60 percent of people in this country suffer from a vitamin D deficiency in the dark months.
That’s how important vitamin D is
Vitamin D is a hormone of which 80 to 90 percent is produced by the body through the skin and only 10 to 20 percent is absorbed through food.
In order for the body to produce vitamin D, a certain dose of UVB rays, i.e. sunlight, is necessary. These rays penetrate the upper layers of the skin before they initiate the production of vitamin D3 via various intermediate steps.
If the body gets little to no sunlight, it cannot produce vitamin D. This is also the case in winter or in the months from October to March.
Spring: When does the body produce a lot of vitamin D?
When the sun shines really nicely again for the first time in spring, people understandably want to go outside.
Many people hold their faces in the sun in the hope that the body will immediately start producing vitamin D. But are the weak rays in the first few months of the year actually enough to stimulate production?
Unfortunately no. Because the human body can only produce vitamin D at a certain point. It doesn’t matter how warm the gentle spring sun may seem.
In spring the sun is too low, even at midday
Although the sun is undoubtedly good for you and can make you happy even in the spring months, in Germany it is not enough to stimulate the body’s significant production of vitamin D.
We are simply at the wrong latitude for this. From mid-October to the end of March, the angle of incidence of the sun’s rays is simply too shallow – even at midday.
The reason for this is simple: the flatter the angle at which the sun’s rays hit the earth, the longer their path through the ozone layer. However, this means that some of the UV radiation is lost and the rays are no longer sufficient for vitamin D production. In April this angle begins to become steeper.
This vitamin D rule of thumb applies
As a rule of thumb, you can remember: If your shadow is longer than your height, unfortunately there is no significant vitamin D production.
In order for your body to produce vitamin D through the skin, the angle of the sun above the horizon must be at least 42 degrees.
Skin type influences vitamin D production
But skin type also plays a decisive role in the production of vitamin D.
The more sensitive your skin is to sunlight, the faster it produces vitamin D. People with dark, less sensitive skin type therefore need more sunlight, while light-skinned people need less.
So if you have a dark complexion, your body will only start producing vitamin D when exposed to even more intense radiation.
Display the height of the sun in spring
The further north you are, the shorter the intervals in which the sun’s angle of incidence is sufficient. Then, even in the summer months, the sun may not be high enough in the morning and evening hours.
If you want to fill your vitamin D stores at the beginning of spring or late summer, you can use a calculator to determine the height of the sun.
All you have to do is specify your location and choose what time you want to sunbathe. The calculator then shows the angle and you can see whether vitamin D production is even possible.
Avoid midday sun in summer
In the summer months between the astronomical start of spring and autumn, the sun is best between 11 a.m. and 3 p.m. so that the body can produce vitamin D.
Theoretically, the best time would be around 1 p.m. However, for the sake of skin health, you should avoid strong radiation around midday.
Depending on your skin type, just 15 to 30 minutes of daylight in summer is enough for the body to produce enough vitamin D3. Even with light cloud cover, the body can convert the rays well. So don’t underestimate the sun and always apply good cream.