Vitamin A, together with vitamin D, E and K, is one of the fat-soluble vitamins in the body and occurs in three different configurations: Retinol, retinal and retinoic acid. These three substances are usually also referred to as “retinoids”, even though strictly speaking they act in different places in the body. What they have in common is the precursor beta-carotene, from which they can all be made.
Beta-carotene is found mainly in carrots, but also in other yellow vegetables. Due to its fat solubility, the vitamin is difficult to excrete and can therefore accumulate in the body. Caution is therefore required when taking appropriate vitamin preparations.
Symptoms of vitamin A deficiency
The symptoms of a vitamin A deficiency result from the areas of action of the various forms of vitamin A: Retinal plays a major role in the visual process. This is because it is a basic building block for the production of molecules (so-called rhodopsin) that indicate the incidence or absence of light rays in the visual cells of the retina. Visual disturbances, especially in the dark, are therefore the most common symptom of vitamin A deficiency.
The other forms of vitamin A, retinol and retinoic acid, play an important role in the regulation of genes and the maintenance of tissues, such as mucous membranes, nerve cells, bones or connective tissue. Accordingly, a vitamin A deficiency can also become noticeable through defects in these tissues. Children in particular need vitamin A for their bone development.
Vitamin A also plays an important role in embryonic development, where it ensures that the nervous system is properly set up. As retinol and retinoic acid, vitamin A ensures the maintenance of almost all tissues. A deficiency can therefore also be detected in the skin and mucous membranes: Dry, cracked or inflamed skin can be an indication of a chronic vitamin A deficiency.
Typical examples are torn corners of the mouth (rhagades) or acne (acne vulgaris). Rosacea (copper lichen) can also be a consequence of a vitamin A deficiency. However, all these symptoms are extremely unspecific and can have many other causes.
Should these problems occur, they should therefore always be considered in the larger context. For this purpose, it must be clarified whether other symptoms of a vitamin A deficiency can be recognized and whether a cause for a deficiency could be present. Vitamin A also ensures healthy skin by maintaining the body tissues, and thus also the so-called skin appendages.
These include hair and nails, for example. A lack of Vitamin A can thus also show up here: If the nails are thin and fragile, this can indicate a lack just like intensified loss of hair or thin and fragile hair. Vitamin deficiency syndromes are rare, especially in First World countries, because there is always a sufficient food supply.
In addition, the liver always has a certain amount of vitamins in store. A vitamin deficiency therefore develops very slowly and only in the case of chronic undersupply. Symptoms of hair, nails and skin should therefore be observed over a longer period of time and only develop over a longer period of vitamin deficiency.
Vitamin A and especially the retinal configuration is fundamentally involved in the visual process, since the so-called rhodopsin is produced from it. A typical early symptom of vitamin A deficiency is impaired vision and night blindness. On the retina there are the photoreceptors, in which a chain reaction is triggered by light incidence.
This chain reaction contains several molecules that take on a different configuration during this process – for example, like when the first stone of a domino row is knocked over: one after the other, the stones take on the configuration “knocked over”. In the case of vitamin A deficiency, some cells now lack one stone in the row, namely rhodopsin. Accordingly, the transmission of the light stimulus in these cells is impeded. This does not lead directly to blindness, but in chronic deficiency more and more cells are missing the necessary rhodopsin. Vision disorders initially manifest themselves as night blindness, later blurred or blurred vision and light sensitivity are also possible.