KEYWORDS: Vitamisn, avitaminosis, hypovitaminosis.

Amongst all the essential nutrients, vitamins are particularly important from a nutritional point of view. By its very definition, a "vitamin" is in fact an element that the body is unable to synthesise in sufficient quantities, hence we must take them through the food we eat. Another feature of vitamins that the very name implies is the small quantity required by the body. From a metabolic point of view, vitamins work as coenzymes or precursors of coenzymes, thus they have a catalytic function or help to regulate certain biological processes. The lack of a vitamin in the body may lead to developing a specific disease.

A GEOGRAPHICAL AND SOCIAL PROBLEM
Currently, there are 13 vitamins that have been identified. Actually, their classification is based more on their function, not on their chemical structure. In fact, when we speak of “vitamin A”, we actually refer to a series of chemical substances - named vitamers - capable of performing the activities associated to this ...