Products
Vitamins are commercially available in the form of pharmaceuticals, dietary supplements, medical devices, cosmetics, and foods, among others. Available dosage forms include, for example, tablets, effervescent tablets, syrups, direct granules and injectables. Vitamins are also combined with other active ingredients and, in particular, with minerals and trace elements in a fixed manner. The name “vitamin” is derived from (life) and amine, the chemical group of substances. However, it should be noted that not all vitamins belong to the amines.
Structure and properties
Vitamins are organic natural substances that are ingested with food and, to a lesser extent, produced by the body itself (vitamin D, nicotinic acid, vitamin K2 by intestinal bacteria). They belong to the group of biomolecules and micronutrients. The provitamin beta-carotene can be metabolized in the body to the active vitamin A. Unlike other biomolecules such as proteins or nucleic acids, vitamins do not have a uniform structure and are structurally very different from each other. They are, for example, steroids, isoprenoids, pyrimidines, pyridines, sugar acids and urea derivatives. Vitamins are divided into fat-soluble and water-soluble representatives. Usually, several related compounds with comparable properties are grouped under a single vitamin, for example, vitamin K1 (phytomenadiones) and vitamin K2 (menaquinones). These are called vitamers. Vitamins, by the way, are not only found in fruits and vegetables, but also in foods of animal origin, for example.
Effects
The 13 vitamins have diverse and vital functions for the growth, development and metabolism of humans. In particular, the vitamins of the B complex are cofactors (coenzymes) with the help of which enzymes catalyze chemical reactions. In addition, the vitamins also have effects that are independent of enzymes. For example, vitamin C and vitamin E have antioxidant effects, and vitamin D has hormonal functions. Unlike other nutrients such as carbohydrates, vitamins do not serve as energy sources. Insufficient intake of a vitamin leads to a deficiency disorder, which is characteristic of almost all vitamins. This is called hypo- or avitaminosis. A vitamin D deficiency, for example, leads to rickets, a vitamin C deficiency to scurvy, and a vitamin B12 deficiency to anemia, a pernicious anemia. In Europe, the supply of vitamins is generally good and deficiency diseases are rare. However, some people have a higher requirement. These include women before and during pregnancy and lactation, alcohol abusers, vegans, smokers, infants and young children. Diseases such as celiac disease, malabsorption and pharmaceuticals can also lead to impaired vitamin status. The fat-soluble vitamins are characterized by the fact that they can be stored in the liver (A, D). This is not true of the water-soluble ones, because they are rapidly eliminated in the urine. This is with the exception of vitamin B12.
Indications for use
All vitamins are used for the prevention and treatment of vitamin deficiency (hypovitaminosis, avitaminosis) and as tonics. Furthermore, additional medical indications exist for all vitamins, typically related to their metabolic functions. For example, vitamin A is administered for skin diseases, vitamin K2 for the prevention of osteoporosis, nicotinic acid for lipid metabolism disorders, pyridoxine for nausea, and riboflavin for the prevention of migraine.
Dosage
Guideline values and information on the maximum daily dose exist for the daily intake of vitamins with food. In many countries, the so-called DACH reference values are used, which are jointly developed by the German (D), Austrian (A), and Swiss (CH) societies for nutrition. The usual daily requirement is in the micro- or milligram range. Doses given therapeutically for deficiencies or diseases are often higher than these reference values. Megadoses should generally be avoided.
Active Ingredients
13 vitamins are known. 4 belong to the fat-soluble vitamins and 9 to the water-soluble vitamins. 1. fat-soluble vitamins (ADEK):
- Vitamin A, e.g. retinol.
- Vitamin D, e.g. cholecalciferol, ergocalciferol, calcitriol
- Vitamin E: tocopherols and tocotrienols
- Vitamin K: vitamin K1, vitamin K2
2. water-soluble vitamins: Vitamin B complex (water soluble):
- Vitamin B1: thiamine
- Vitamin B2: riboflavin
- Vitamin B3: niacin (nicotinamide, nicotinic acid)
- Vitamin B5: pantothenic acid
- Vitamin B6: pyridoxine
- Vitamin B7: Biotin
- Vitamin B9: folic acid, folates
- Vitamin B12: cobalamin
Vitamin C:
- Vitamin C: ascorbic acid
Contraindications
Full details of precautions and interactions can be found in the drug label.
Adverse effects
Vitamins are generally well tolerated at recommended daily doses. Hypersensitivity reactions, digestive disturbances, and skin reactions may occur. Excessive intake, i.e., overdose, can lead to hypervitaminosis and adverse effects. This is especially true of the fat-soluble vitamins such as vitamin A and vitamin D. Taking high doses of beta-carotene can increase the risk of lung cancer and cardiovascular disease in smokers.
