Vitamins are an important part of our diet, but you probably haven’t given a great deal of thought to their chemical structures. This graphic shows chemical structures for all 13 vitamins; though there can be some variability in these structures in sources of the vitamins, these are generally representative. They perform a range of roles in the body; below is a brief discussion, and a look at the evidence for taking vitamin supplements.
First, it’s worth discussing what makes a chemical compound a vitamin. A vitamin is defined as any organic compound that a living organism requires, but which it is not capable of producing itself, or cannot produce in the amounts required by the body. As far as the definition for vitamins goes, this doesn’t include the other essential nutrients that are found in our diet, such as amino acids, fatty acids, carbohydrates and minerals.
Currently, there are 13 recognised vitamins: vitamins A to E, including a range of B vitamins, and vitamin K.
The slightly odd gap in lettering between E and K is a consequence of changes in designations of vitamins; for example, vitamin B7, biotin, was previously referred to as vitamin H.
The compounds originally designated as vitamins F to J were either redesignated, or subsequent research led to them no longer being classified as vitamins.
Generally, we can stick all of the vitamins into two broad categories.
The fat soluble vitamins, vitamins A, D E, and K, can be stored by our bodies in the liver or in fatty tissues. They are stored until they’re required, which consequently means they generally don’t need to be ingested as frequently.
Water soluble vitamins, on the other hand, are not stored in the body. As such, they must be a regular part of the diet in order to avoid deficiency. …