TABLE OF CONTENTS Like minerals, vitamins are required in small amounts. They were originally perceived as minor constituents or activities which could be derived from food and which were essential in small amounts for maintenance of health. There are about 12 major vitamins which the body requires in order to maintain a healthy metabolism. Deficiency in one or more of these vitamins can lead to serious illnesses. Different foods can be good sources of one or more vitamins, but it is important to take into account the fact that some vitamins (especially the B group vitamins and vitamin C) are not completely stable to processing and cooking. Having said this, the widespread occurrence and levels of most vitamins in foods means that deficiency diseases in the Western world are uncommon, despite bioavailability issues and processing and cooking losses.
Vitamin C and the B-group vitamins are water-soluble, whereas vitamins A, D, E and K are fat-soluble.
The concept of vitamins as individual chemicals is actually misleading. The terms were originally developed to describe a biological activity, without knowing what entity was causing it. Thus, while vitamins A and C can be related to retinol and ascorbic acid respectively, vitamin D and E activities are actually the result of more than one chemical. Furthermore, the elucidation of the vitamin B complex of activities resulted in a very mixed situation, with some B vitamins not having a number at all, and some compounds being given different designations as different groups of researchers independently described...
