What Are Vitamins?

In a number of my previous articles I have mentioned vitamins in passing.  However, I have never really expanded on this topic further and discussed exactly what vitamins are.  So today I thought I would write about this exact topic and answer the question ‘What are Vitamins?’

Vitamins are essential nutrients that your body needs to help the cells function properly.  They contain no calories and do not provide the body with energy but they are required for a number of important functions.  Vitamins are distinguished from minerals because they are organic compounds (they come from plants and animals) whereas minerals are inorganic (they come from the soil and water).

The value of vitamins was noted long before vitamins themselves were actually discovered.  For example, the ancient Egyptians used liver to cure night blindness (which we now know is the result of a vitamin A deficiency) and in the eighteenth century it was discovered that citrus fruits could be used to prevent scurvy.  The discovery of vitamins stems from work by Dr William Fletcher in 1905 in which he discovered that if special factors (which would later be identified as vitamins) were removed from food, diseases would develop.  Between 1906 and 1907 Sir Frederick Gowland Hopkins performed a number of experiments which suggested mice could not survive on basic foodstuffs alone.  In 1912, based on these experiments, Sir Frederick Gowland Hopkins announced that there was an unknown part of our diet which was not a carbohydrate, fat, protein or salt.  This unknown part of our diet became known as a vitamin, a term first used by Polish chemist Chashmir Funk in 1911.

There are thirteen vitamins in total and these can be broken down into two groups; fat soluble (vitamins A, D, E and K) and water soluble (vitamins B and C).  Your body cannot produce vitamins (with the exception of vitamin D) so they need to be obtained from other sources.  Food is the primary source of vitamins, although vitamin D can also be produced by the skin when exposed to sunlight and Vitamin K can also be produced by bacteria in the intestines.  Vitamins are also available in supplement form with vitamin supplementation becoming increasingly popular in recent years.

1) FAT SOLUBLE VITAMINS:- As I mentioned above vitamins A, D, E and K are all fat soluble vitamins.  Fat soluble vitamins are given this name because they dissolve within the body’s fat cells.  They are largely found in fats and fatty foods such as animal fat, dairy products and vegetable oils.  Fat soluble vitamins are preserved in foods even when they have been cooked.  If they are not needed immediately they can be stored in your liver and fatty tissues for later use.  Therefore, you do not need to consume fat soluble vitamins every day because your body can get what it needs from these stores.  Letting these stores build up too much has been linked with a number of health problems and because of this excessive consumption of fat soluble vitamins is believed to be dangerous.

2) WATER SOLUBLE VITAMINS:- Vitamins B and C fall under the term water soluble vitamins and are given this name because they need to be taken with water to dissolve.  They are largely found in fruits, vegetables and grain.  Water soluble vitamins are not preserved as easily as fat soluble vitamins and can be lost during cooking and preparation.  Exposure to air and heat can destroy them whilst exposure to water can cause them to be washed out of the food.  Another difference with water soluble vitamins is that they cannot be stored by the body with any excess vitamins being excreted in your urine.  Therefore, it has been suggested that excessive consumption of water soluble vitamins is not harmful.  However, new evidence suggests that excessive consumption of certain water soluble vitamins may also be dangerous meaning that overdosing on any type of vitamin could potentially put your health at risk.

So how much of each vitamin do we need?  The table below lists the recommended daily allowances (RDA) for each of the thirteen types of vitamin:

Sources: http://www.brianmac.co.uk/vitamins.htm

I hope the above article has given you a better understanding of the different types of vitamins.  In my next few articles I will be discussing in more detail exactly what the different types of vitamins do, where they can be sourced and the drawbacks of overdosing.

Until then I would like to hear your opinions.  Are you currently getting enough vitamins?  Do you get the majority of your vitamins from your diet or from vitamin supplements?

Sources:
Diet Recommendations (NHS)
Fat Soluble Vitamins Information (Colorado State University Extension)
The History of Vitamins (The Vitamins & Nutrition Center)
Vitamins Information (Brian Mac)
Vitamins Information (How Stuff Works)
Vitamins Information (Life Clinic)
Vitamins and Minerals Information (Food Standards Agency)
Water Soluble Vitamins Information (Colorado State University Extension)