Vitamin A is also important for a smooth protein metabolism and the nerve functions. Vitamin A plays a crucial role in the utilization of iron and the formation of red blood cells.
But for the production of white blood cells, which are a mainstay of the immune system, vitamin A is necessary. Vitamin A also strengthens the mucous membranes, which also strengthens the body's resistance to infectious diseases such as colds. The growth of bones and their healing after fractures are largely dependent on vitamin A.
Vitamin A plays a dual role in reproduction: First, vitamin A contributes to the production of sex hormones, and second, the vital substance serves as a regulator in early embryonic development. These functions are complemented by the function of vitamin A as a so-called "radical scavenger". This means that vitamin A converts harmful waste products of the metabolism into harmless substances.
The central functions of metabolism and defenses make vitamin A one of the most important factors for maintaining performance. Among athletes is just the importance of blood formation known. That is why athletic people pay attention to an adequate supply of vitamin A. For optimal oxygen utilization is the basic requirement for a good condition. Those who exercise intensively can support the body's defenses with vitamin A well.
It should be noted, however, that vitamin A is also toxic in overdoses. To circumvent the problem is very simple: The intake of 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 currently required amount of vitamin A is produced from the precursor.
Provitamin A thus protects against both risks: over- and under-dosage (hyper- and hypovitaminosis).
The minimum daily dose of Vitamin A is 1 mg (1 thousandth of a gram). This is about the amount that is contained for example in 50 g of carrots or 300 g of pork. Pregnant women, nursing mothers and adolescents have about a 50% higher demand for vitamin A. It should be noted that the fat-soluble vital substance is optimally absorbed only when it enters the small intestine together with fat.
The effective form of vitamin A is only included in animal foods. In cod liver oil, the salary is highest. In addition, liver from beef or pork is a very good source of vitamin A. Milk and egg yolks are also rich in vital substances. In addition, plenty of vitamin A also contains seafood and freshwater fish. Especially eels are considered excellent suppliers of vitamin A.
Provitamin A uses the body 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. Above all carrots are to be mentioned here.
Typically, the level of vitamin A is highest in red or reddish fruits. Therefore, red peppers or fruits such as mango come as good suppliers of vitamin A in question.