In the expressed form of avitaminosis, we are now observed less and less. Nevertheless, the problem of vitamin deficiencies remains relevant for the practitioner. As the physiological role of vitamins and their importance in pathology becomes more and more clear, the presence of light, "erased" forms, which are more correctly called hypovitaminosis, becomes more and more obvious. Experience shows that the generally accepted ideas about the conditions for the occurrence of avitaminosis should be revised. Not only in the absence or in the absence of one or another vitamin in food, vitamin deficiency can develop. More and more observations are accumulating showing that a weak or even strongly pronounced vitamin deficiency can appear in a person who receives a completely complete diet. This phenomenon, paradoxical at first glance, can take place under the following circumstances: with digestive disorders associated with impaired absorption; with liver diseases (the latter is especially important for vitamin A deficiency, since the conversion of carotene into vitamin A suffers); when the need for vitamins is increased against the norm, for example, in rapidly growing children or in lactating women who excrete significant amounts of vitamin C with milk; with increased destruction of vitamin stores in the body, which is observed with all kinds of infections and other febrile and debilitating diseases. To what has been said, it must also be added that very often our food turns out to be poor in vitamins, due to irrational preparation, improper storage of food, peculiar deviations of appetite, etc. In the earliest stages, when even mild clinical symptoms do not yet exist, modern methods of studying vitamins can the presence of latent hypovitaminosis. This is especially evident in the example of the scourge.
CMO1 Deficiency Abolishes Vitamin A Production from β-Carotene and Alters Lipid Metabolism in Mice