I wasn’t really sure if and how I should write this article. Since for the last few years, there is somehow a real hype about vitamin D and it is discussed quite controversial. So today I’ll try to explain (with a neutral position) what vitamin D is, how it is formed and how we can supply it. Whether you join in on the hype is then entirely up to you, I am also not quite sure how to decide yet :-) General facts first:
- Vitamin D is a fat soluble vitamin that can be produced by the body itself (through liver and kidney), so actually it is a hormone.
- It controls the entire calcium balance and ensures that the calcium is absorbed from food in the body and spread or stored to the organs and in the bones.
- It also controls the mineral deposition in the teeth and supports our body’s defense system by activating white blood cells.
The precursors of vitamin D can be obtained from food and then converted to active vitamin D under the influence of UV light. But through diet we can contribute only up to 20% to cover our needs (or would you like to take in tons of cod liver oil?) Most of the vitamin D requirement covers the body itself. For example, through cholesterol, which is transported (by the liver) to our skin, where, under the action of sunlight, Vitamin D is produced and then is subsequently stored in adipose tissue.
So, we need sunlight for vitamin D supply. You probably already knew that.
But here in Germany we don’t have sunshine in a constant intensity throughout the year. It is said, therefore, that only from April to September between 11-15 o’clock (or if your shadow is smaller than you are) we can „fill up our Vitamin D stores through sunlight“. It is recommended to expose 1/4 of our skin for at least 10-15 minutes to the sun (so free your face and arms in your lunch break! At best without sun cream if your skin allows). From October to March then unfortunately, the power of the sun is not strong enough for vitamin D synthesis. But don’t be sad, our bodies are not stupid! We can store Vitamin D (as it is a fat-soluble vitamin) and live the rest of the year from these reservoirs. In addition, we may, as already said, cover 20% of our needs through diet (fatty fish, eggs, milk, mushrooms and whole grains).
Now comes the part that is controversial and triggers the hype for many people:
According to statistics, more than half of the people in Germany suffer from vitamin D deficiency, elderly even 3/4 (as they leave the house less and vitamin synthesis through the skin no longer works so well). There are people who say that the reservoirs are not big enough to supply us through the winter and due to vitamin D deficiency we are often sick in winter. Therefore we should take vitamin D supplements and check our vitamin D levels in the blood. IThey also say that many other diseases are caused by vitamin D deficiency or can be favored (e.g. irritability, depression, obesity, chronic inflammation, even diabetes, autoimmune diseases, cardiovascular diseases or cancer). At this point I am out! I have no idea if this is true and there are of course also other smart scientists who think this is nonsense. Both have their arguments and statistics. You can find and read tons of it in the internet.
My solution is thus as follows:
I’m trying to soak up lots of sunshine all year round and eat a healthy diet. If it works, I love to take some days off in winter and travel south (below the 42nd parallel, since there is lots of vitamin D for us ;-)). And if I really feel very tired and sick in winter and I have no other explanation, I might think about checking my blood. All in all, I think, that the human body and nature work quite well together and I trust that if I don’t stay inside all day and eat burgers, it will hopefully work out without supplements (like the last 32 years) .
So enjoying the last days of summer and refuel properly!