The sunshine vitamin
Vitamin D ensures that our calcium and phosphate metabolism works well. In doing so, it promotes the absorption of calcium from the gastrointestinal tract and thus supports the hardening of bones. In addition, vitamin D also boosts muscle strength and promotes a strong immune system. (If you’re interested, you can read more about the immune system here.) As the term ‘sunshine vitamin’ suggests, our body’s vitamin D levels depend, among other things, on the sunlight absorbed by our skin. But how does that work during autumn and winter? The fact is that in most regions of Europe, our skin receives too little sunlight during these seasons. Instead, we can meet our vitamin D requirements through our diet and with the help of vitamin D supplements. But what is vitamin D, exactly?
Strictly speaking, vitamin D isn’t a vitamin at all. After all, a vitamin is an organic compound that must be taken regularly with food, as the body cannot produce sufficient quantities of it on its own. Yet the human body can produce vitamin D itself, provided that the skin is exposed to enough sunlight. By getting enough sunshine on our skin, we can produce up to 90% of our vitamin D requirement. Nevertheless, we can’t get any more than 20% of our required amount of vitamin D from food. That makes it all the more important to ensure that we make up this 20% of our vitamin D by eating the right food during the months when there’s much less sunshine. The more sunlight the skin is exposed to in spring and summer, the better we fare during the gloomier seasons. This is because the human body can store vitamin D in its fatty tissue and muscles, and access these reserves if necessary. You don’t need to put in hours of sunbathing, however – how much time you can spend out in the sun will depend on your skin type. It goes without saying that you should never run the risk of getting sunburned.
How much vitamin D do people need?
Every human body is unique, and age, skin type, any previous illnesses and the intensity of the sunshine where you live will all have a bearing on your vitamin D requirement. The German Society of Nutrition estimates the daily vitamin D requirement to be 20 micrograms per day. Infants aged up to 1 require about half this amount. It is impossible to overdose on vitamin D through your food intake or exposure to the sun; this can only occur if you take excess vitamin D supplements. Essentially, if you want to get ready for winter and are thinking of buying some vitamin D supplements from a pharmacy, be sure to consult with your doctor first. Both overdose and lack of vitamin D can have serious consequences for your health, with hair loss, muscle weakness, muscle aches, bone pain and misshapen bones just some of the potential symptoms.
Which foods contain vitamin D, and how much?
Vitamin D in micrograms (mcg) per 100 g of food
Cow’s milk (3.5% fat)
Fish & seafood:
Chicken’s egg yolk