The German Nutrition Society (DGE) lists in a table how high the recommended daily dose of vitamin D should be depending on age. While infants without endogenous synthesis through exposure to sunlight need 10 µg (ie 10 micrograms, which correspond to 0.01 milligrams) of vitamin D3 per day, people of both sexes from the age of 1 should have 20 µg of vitamin D3 daily. Pregnant and breastfeeding women do not have an increased need for the vitamin.

While a severe vitamin D3 deficiency is rare in Germany, mild deficiency symptoms are much more common. According to the Federal Office of Consumer Protection and Food Safety (BVL), almost 60 percent of the German population is inadequately supplied with vitamin D3 according to international criteria. Risk groups include people who rarely spend time outdoors, especially those with chronic illnesses and those in need of care. Dark-skinned people also often have a vitamin D3 deficiency, as the high melamine content of the skin shields them more effectively from UVB radiation. Older people are particularly at risk, as the skin's ability to produce vitamin D3 decreases with age.

If you have an increased need for vitamin D3 and cannot or do not want to cover this need through sufficient sunlight on bare skin and the consumption of certain foods due to your eating habits or illnesses, we recommend taking vitamin D3 as a dietary supplement.

Vitamin D belongs to the group of fat-soluble vitamins. It functions as a prohormone in the body and must first be converted into its active form, vitamin D3 (cholecalciferol), in the liver and especially in the kidneys in order to be able to act as a hormone. Vitamin D is absorbed through food on the one hand. On the other hand, it can also be produced in the body with the help of ultraviolet radiation from the short-wave portion of solar radiation. This process is known as endogenous synthesis.

As one of the most important vitamins for calcium metabolism, the "sunshine vitamin" plays a crucial role in bone structure and tooth development. Vitamin D3 improves the absorption of calcium and phosphate from the intestines. Vitamin D3 also increases bone mineralization and increases the reabsorption of calcium in the kidneys.

In addition, vitamin D3 is of great importance for the stability of our immune system. A sufficiently high vitamin D3 level is, among other things, a prerequisite for an appropriate cellular immune response in the event of an infection with viruses, fungi or bacteria and for the body to be able to mobilize defense cells against invading pathogens.

Especially during the cold season, the "sun hormone" is one of the essential vitamins for our health. During the cold season, the body often does not have the ability to synthesize sufficient amounts of vitamin D3 from solar radiation. Even when the sun shines, it is too low in the winter to provide the skin with sufficient ultraviolet radiation. Although a healthy person can survive for a while on vitamin D reserves in their fatty tissue, deficiency symptoms often occur, particularly at the end of the dark season. Therefore, taking vitamin D3 as a dietary supplement can be useful during this period.

Vitamin D3 is essential for our immune system, which is why it is one of the indispensable vitamins for our health, especially during the cold season.

Good to know: According to the National Consumption Study II 2008 (NVS II), the average intake of vitamin D3 is significantly below the reference values. 94% of older men and 97% of older women do not reach the recommended vitamin D3 intake. Adolescents and young adults aged 14 to 24 also fall below the recommended daily intake. 86% of men and more than 96% of women lack vitamin D3. The clear risk groups include adolescents, young adults and senior citizens.