How important is vitamin D?

What does it protect us from?

The German Zukunftsinstitut (Future Institute) has identified a new luxury trend: good health and quality of life. And when Germans are asked what they understand by luxury, it’s not just good health that occurs to them. The term increasingly encompasses healthy eating. 

And healthy eating includes vitamins

Everyone knows that vitamins are indispensable. Vitamin deficiencies can have serious consequences for our health. Without vitamins, the human body cannot function properly. Vitamins perform a range of vital tasks in our body. Our eyes, bones, skin, blood, nerves and organs all need vitamins to function properly and keep us healthy. 

Vitamins are involved in the extraction of energy from carbohydrates, fats and protein and also in the formation of hormones, enzymes and blood cells. In addition to vitamins, we also need minerals such as potassium, calcium, magnesium, sodium, chloride, phosphate and sulphate. Our body also needs trace elements such as iron, iodine, fluoride, zinc, selenium and even copper. An adult’s daily nutritional requirement consists of 55-60% carbohydrates, 10-15% protein and 30% fat.

Why do we need vitamins?

Let’s take a look at the most important tasks performed by vitamins. Vitamin C strengthens our immune system, helps build tooth enamel, strengthens connective tissue and influences our mood. We need vitamin A with its precursor beta-carotene for our eyes and skin and to grow properly. Vitamin E aids cell renewal and promotes blood circulation.

The body needs vitamin K for blood clotting and wound healing. It is also involved in bone formation, as is vitamin D. Vitamin D also regulates our calcium and phosphate metabolism and has a positive effect on our teeth and the immune system.

Vitamins B1 and B2 are important for the metabolism of energy. We also need vitamin B1 for our muscles. Vitamin B3, also known as niacin, helps the body convert food into glucose for energy.We need vitamin B12 for our nervous system and the formation of red blood cells. Vitamin B6 is important for nerve function, among other things.

Vitamin B5, also known as pantothenic acid, is important for the metabolism of energy and the synthesis of neurotransmitters. It reduces fatigue and promotes mental performance. Vitamin B7 ensures healthy skin, shiny hair and strong nails. Vitamins B8 (folic acid) and B9 (biotin) are involved in numerous metabolic reactions in the body. They promote hair growth and are good for our skin.

Vitamin B9 is also indispensable for cell division and the formation of new cells, as well as playing a role in the metabolism of iron and vitamin B12B9 is an essential vitamin. The body cannot produce vitamin B9 itself, so it has to be absorbed through what we eat. It is important for the production of DNA and the formation of red and white blood cells.

To stay healthy, we need to make a conscious effort to eat foods rich in vitamins. But the 13 essential vitamins are not all contained in the same foods. This is why we need to eat a diverse range of foods.

The most important essential vitamins and the foods which contain them

Below is an overview of the essential vitamins and the foods that contain them:

Vitamin A: spinach, egg yolk, whole milk, red peppers and liver

Vitamin B1: peas, pork and wholegrain products

Vitamin B2: meat, fish, broccoli and fish

Vitamin B3 (niacin): leafy greens, meat, liver and eggs

Vitamin B5 (pantothenic acid): mushrooms, sunflower seeds and liver

Vitamin B6: avocado, bananas, milk, meat, potatoes and walnuts

Vitamin B7 (biotin): egg yolk, lentils, yeast and liver

Vitamin B9 (folate): cabbage, leafy greens, spinach, oranges, Swiss chard, lamb’s lettuce, endive and wholegrain products

Vitamin B12: dairy products, eggs, meat, fish and liver

Vitamin C (ascorbic acid): sea buckthorn, blackcurrants, kale, peppers, broccoli, Brussels sprouts, cauliflower, kohlrabi and citrus fruit

Vitamin D: certain types of fish such as salmon, eel, cod, tuna, mackerel, oysters, but also in butter, milk, eggs, dandelion sprouts, porcini mushrooms, shiitake mushrooms, oatmeal, sweet potatoes, chanterelles, mushrooms, beef liver. The body can also produce vitamin D using UV radiation.

Vitamin E: vegetable oils, nuts, butter and eggs

Vitamin K: green salads, cabbage, spinach and watercress

We have to get vitamins from what we eat because our body cannot produce them itself, with the exception of vitamin D and, in small quantities, also vitamin B3. Of course, if you want your food to be rich in vitamins, you have to make sure to buy it fresh

Now we come to vitamin D

We have already mentioned the foods in which vitamin D occurs. But why is it so important for our health? Vitamin D is involved in numerous processes in the body. It plays a vital role in building strong bones and teeth. In addition, the sun vitamin is of great importance for our immune system, and plays numerous roles in our metabolism.For this reason, it is extremely important that we receive a good supply of vitamin D from childhood onwards. For example, babies under the age of one year receive a prophylactic dose of vitamin D to prevent the bone disease rickets.

Not only does vitamin D play a role in the mineralisation of bones and teeth, it also ensures that calcium and phosphate are absorbed from the small intestine and stored as calcium phosphate in bones and teeth. This is what makes our bones able to harden. Furthermore, vitamin D ensures normal muscle function, as it regulates the formation of muscle cells and cell metabolism.

Vitamin D also regulates the immune system and counteracts inflammatory processes in the body. And above all, vitamin D prevents osteoporosis. In combination with calcium, vitamin D is part of the basic treatment for osteoporosis and is used to prevent bone lossOsteoporosis is the most common bone disease in old age, especially in women.

More women are affected by osteoporosis and broken bones than by breast cancer, strokes and heart attacks combined. But it also affects men. An estimated 30-40 percent of all women (over 60) and 20-30 percent of all men develop osteoporosis in their lifetime.

To sum up: Vitamin D is active in almost all cells in the body. It supports calcium absorption, regulates the parathyroid hormone level, supports the remodelling of the bones (renewal and mineralisation), has a stimulating effect on the muscles, improves physical function and increases bone mineral density.

The sun vitamin, our natural source of health

The most important source of vitamin D is sunlight: if our skin is exposed to sufficient sunlight, it synthesises large quantities of vitamin D. We can get up to eighty percent of our vitamin D requirement from sunlight. However, as people are spending less and less time outdoors, they are increasingly suffering from vitamin D deficiencies. If we expose ourselves to the sun in a healthy manner, we can counteract this deficiency.

We cannot counteract a vitamin D deficiency through what we eat. As an example: we would have to eat one portion (approx. 400 g) of fatty fish a day to absorb the recommended dose of vitamin D. Alternatively, we would have eat several kilogrammes of pork, 16 to 20 eggs, or drink 20 litres of whole milk.

Diabetes, cardiovascular diseases, obesity and high blood pressure all have one thing in common: if you have any of these underlying conditions and you get COVID-19, you are more likely to suffer severe symptoms. And these conditions have another thing in common: they are often associated with low levels of vitamin D.

This is especially true of the elderly, who often suffer from vitamin D deficiencies and who are among the COVID-19 high-risk groups. Prof. Dr. Hans-Konrad Biesalski from the University of Hohenheim in Stuttgart points out this connection (see NFS – Nutrition and Food Science Journal 2020, Volume 20, pp. 10-21).  Many people around the world suffer from a vitamin D deficiency, emphasises Prof. Dr. Biesalski.


University of Hohenheim

Osteoporose Selbsthilfegruppen Dachverband e.V. (OSD, osteoporosis self-help group umbrella organisation)

Recommended reading: “Superhormon Vitamin D” (Vitamin D, the Superhormone”) by Prof. Dr. Jörg Spitz

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Nachhaltiger Neujahrsvorsatz 2023