Vitamin B7 (also known as biotin or vitamin H) is a water soluble vitamin and part of the B complex group (eight vitamins that were initially thought to be the singular vitamin B). The discovery of vitamin B7 dates back to the 1927 when M.A. Boas realised that feeding rats raw eggs for several weeks would lead to a condition called ‘egg white injury’ (where they would develop a skin condition similar to eczema, lose all their hair, become paralysed and bleed under their skin). Soon after this Boas discovered that a substance in liver which he named ‘protective factor x’ could treat ‘egg white injury’. In 1940 a biochemist called Vincent Du Vigneaud finally made the breakthrough and discovered that this ‘protective factor x’ was actually a vitamin which became labeled vitamin B7.
The main function of vitamin B7 is to help the body’s cells breakdown fats and carbohydrates and use them for energy. It is therefore essential for growth. However, it has a number of other benefits which include:
– Helping the body’s cells convert amino acids into blood sugar.
– Helping the body’s cells breakdown protein into urea.
– Possible protection against diabetes (according to How Stuff Works).
– Strengthening the fingernails.
The recommended daily allowance (RDA) for vitamin B7 is 0.03mg in men and 0.01mg in women. Like many of the other B complex vitamins, it is present in almost every food but certain foods are particularly rich in it. Liver, milk and egg yolks are all good animal sources whilst nuts and mushrooms are good vegetable sources. On top of this the body can also produce small amounts of vitamin B7 via bacteria in the intestine.
Vitamin B7 deficiencies are rare. When they do occur they are mainly caused by alcoholism, genetic disorders, extended use of antibiotics and consuming large amounts of raw egg whites. Alcoholism can lead to a deficiency because alcohol interferes with the absorption of vitamins. Certain genetic disorders can also increase a person’s vitamin B7 requirements leading to a deficiency. Prolonged use of certain antibiotics can destroy the intestinal bacteria which produces vitamin B7 and therefore contribute to a deficiency. Excessive consumption of raw egg whites can lead to a deficiency because they contain a substance called avidin (which is deactivated when the eggs are cooked) that inhibits the absorption of vitamin B7.
If a deficiency does occur it can lead to rashes, fungal infections, dry skin and hair loss. An extended deficiency can cause depression and pains in the muscles. Overdosing on vitamin B7 does not have any known side effects at the time of writing. However, it is still advisable to stick to the RDAs.
Like the other B complex vitamins, B7 is required for normal growth and your daily requirements of this vitamin should not be overlooked. As I have already discussed a deficiency is unlikely but it is still possible. Therefore, I advise you to review your diet and make sure that you are consuming enough of this vital vitamin.