Vitamin A (retinoic acid, retinal, retinol) is a fat-soluble vital substance that occurs in some variations. The photosensitive substance is used in the retina of the eye to perceive light.
Mode of action of vitamin A
Typically, the content of vitamin A is highest in red or reddish fruits. Therefore, red peppers or fruits such as mango are also good sources of vitamin A.
Vitamin A is also important for smooth protein metabolism and nerve function. Vitamin A plays a decisive role in iron utilization and the formation of red blood cells.
But vitamin A is also necessary for the production of white blood cells, which are a mainstay of the immune system. Vitamin A also strengthens the mucous membranes, which also strengthens the body’s defenses against infectious diseases such as colds. The growth of bones and their healing after fractures are significantly dependent on vitamin A.
The importance of vitamin A in reproduction is twofold: firstly, vitamin A participates in the production of sex hormones, and secondly, the vital substance serves as a regulator in early embryonic development.
In addition to these special tasks, vitamin A functions as a so-called “radical scavenger”: this means that vitamin A converts harmful waste products of metabolism into harmless substances.
Importance
The central functions of metabolism and defense make vitamin A one of the most important factors in maintaining performance. Among athletes, especially the importance for blood formation is well known. That is why people who are active in sports make sure they have a sufficient supply of vitamin A. Because an optimal oxygen utilization is the basic condition for a good condition. Those who do intensive sports can support their immune system with vitamin A.
However, it must be taken into account that vitamin A also has a toxic effect in the case of overdoses. This problem can be avoided very easily: taking provitamin A is completely harmless. Provitamin A is a precursor of the effective vitamin. The body converts provitamin A into the actual vitamin A. This process is controlled by the body so that only the amount of vitamin A currently needed is produced from the precursor.
Provitamin A therefore protects against both risks: The overdose and the underdose (hyper- and hypovitaminosis).
The minimum daily dose of vitamin A is 1 mg (1 thousandth of a gram). This is about the amount contained, for example, in 50 g of carrots or 300 g of pork. Pregnant women, nursing mothers and adolescents have an increased need for vitamin A by about 50%. It should be noted that the fat-soluble vital substance is optimally absorbed only when it enters the small intestine together with fat.
Occurrence in food
The effective form of vitamin A is found only in animal foods. In cod liver oil, the content is the highest. In addition, liver from beef or pork is a very good supplier of vitamin A. Milk and egg yolks are also rich in the vital substance, and seafood and freshwater fish also contain a lot of vitamin A. Eel in particular is an excellent source. Especially eel is an excellent supplier of vitamin A.
The body utilizes provitamin A according to the biologically effective vitamin A. These precursors of vitamin A are also called “carotenoids” and are present in sufficient quantities in many vegetables. First and foremost among these are carrots.
Typically, the content of vitamin A is highest in red or reddish fruits. Therefore, red peppers or fruits such as mango are also good sources of vitamin A.
