Unlike all other vitamins, vitamin D can be produced by our bodies. When exposed to ultraviolet light, which is a component of sunlight, the skin makes this substance from certain precursors. But be careful! Moderation is necessary, since one must protect himself from ultraviolet rays.
In the intestine vitamin D enhances the intake of phosphorous and calcium from food and it is responsible for the incorporation of those elements into the bones. A person who is rarely out in the sun and ingests little vitamin D with his food can easily get an insufficient amount of this substance. Even babies, who for good reason are not exposed to sunlight, readily develop vitamin D deficiencies. This can lead to rickets, which is a bone-formation disturbance, in childhood. Rickets is, however, rare nowadays, since a prophylaxis with vitamin D is usually recommended and also adhered to.
The elderly often receive too little, however, since they tend to be inactive, sick or weak. Vitamin D deficiency leads to bone destruction, as a result of which the bones become fragile. This kind of demineralization of the bones, designated as “osteoporosis”, is much more common in women than in men. During menopause the female body produces smaller quantities of the sexual hormones which previously protected them from bone deterioration.
With the help of this sun vitamin we can keep our bones and teeth firm and healthy. Vitamin D is only found in foods from animal sources, such as fish (herring, eels, salmon...), as well as in eggs, butter and milk.
Source: Dr. Volker Schmiedel, “Fit und gesund mit Vitalstoffen“ (Fit and Healthy with Essential Nutritional Substances), by Gräfe und Unzer, Munich