Vitamins are organic compounds that serve as key nutrients for the human body and are required in moderate doses. The human body needs many different compounds in order to function well. However, vitamins are those that can't be produced internally and must be sourced from the food.
In order to be considered a vitamin, an organic compound has to be vital for a particular species. Vitamin C for example (also known as ascorbic acid) is very important for humans but most animals do not need it. Numerous diseases are caused by a lack of vitamins, which have to be provided from supplements. Many healthy individuals take a surplus of vitamins anyway, even if there is no proof of benefits in this case.
Every vitamin plays one or more roles in the functions of the human body. Some vitamins are powerful antioxidants, for example vitamin E and in some cases vitamin C as well. Others are similar to hormones and regulate the metabolism, one of them is vitamin D. Some types of vitamin A have an influence on the growth and specialization of body tissues.
Most vitamins are classed in the B vitamin complex, these are coenzymes or the building blocks for enzymes. Enzymes are catalysts for a wide range of processes that take place in the metabolism, and coenzymes contribute to their effect. Vitamins that function like this are usually closely grouped with enzymes, like biotin is linked with the enzymes that play a role in the production of essential fatty acids. Some of these vitamins are more closely bound to enzymes than others, their role can be just to ferry single electrons or simple chemical structures from one molecule to another. Folic acid plays such a role and carries a number of compounds like methylene, methyl or formyl inside cells. The ability of vitamins to work with enzymes in such reactions is their best researched role, but they also have other very important functions as well.
Vitamins can be split in two main groups: those that are soluble in fat and those that are soluble in water. The body takes fat-soluble vitamins from the food and deposits them for storage inside the fat reserves, as well as the liver. They are sourced from there, whenever they are needed in the metabolism.
This type of vitamins have the advantage that the body is capable to preserve them for some time. Fat-soluble vitamins can last for as long as 6 months, but some of them can only be stored for just a few days. The vitamins soluble in fat are A, D, E and K. When the body needs them, it uses special transport agents able to fetch them from the reserves and carry the vitamins wherever they are required.
The main difference with the vitamins soluble in water is that we are unable to store them. The body also takes them from the food but they are immediately sent into the blood and travel to the location where they are needed. If they are not used, the vitamins will be eliminated through urine.
Since they can't be stored, the body needs to constantly replenish the supply of water-soluble vitamins. They include the most numerous vitamins, like vitamin C and especially the B group: thiamine (B1), riboflavin (B2), pyridoxine (B6), cobalamine (B12), niacin, biotin, pantothenic acid and folic acid.
Vitamins are very important for the health of the human body and help it function normally. Ideally, a correct and balanced diet will provide all of the required vitamins. However, if a certain vitamin is insufficient, you can get it from supplements. The skin is particularly influenced by a number of vitamins that are required for its health, these include the vitamins A, B, C, E and K. All of them can be sourced from a proper diet but are also found as supplements.
The skin uses vitamin A to repair itself and heal damage. A proper intake of vitamin A can stop the development of acne and keep the skin moisturized, as well as significantly decrease the amount of wrinkles and fine lines on the skin surface. Usually, we can get enough vitamin A from our food and there is no need for supplements. Some of the products rich in vitamin A are milk, eggs, cereals and liver.
Biotin is one of the building blocks of the skin, as well as the structural cells of the hair and nails. It is part of the vitamin B complex and a lack of it will cause itchy skin and eruptions. It is one of the vitamins that can be synthesized inside the body but there are generous amounts in eggs, rice, oatmeal and bananas.
Vitamin C is a powerful antioxidant that can improve the reaction of the immune system. It also plays an important role in the skin, limiting the damage done by sunlight and increasing the healing rate of the tissues. Many fruits and vegetables are great sources of vitamin C but it is also available as a supplement.
Vitamin E also limits the effects of sun damage. It appears to stop lines and wrinkles from developing, while maintaining the smoothness of the skin. The richest natural sources of vitamin E are nuts, but also eggs and some vegetables. Its properties make it a key ingredient in anti-aging cosmetics.
Vitamin K does not have a big impact on the skin when ingested. However, it speeds up the healing of bruises and removes the circles under the eyes when applied externally, so it is included in creams.