Vitamin B8, also known as biotin, is a B-complex compound that is available in many foods, such as dairy products, oatmeal, and peanut butter, and is produced in the human body via bacteria in the intestines. Technically, it is not a true vitamin — it is a coenzyme that acts in conjunction with B vitamins to facilitate a number of bodily functions, such as metabolism of nutrients. Like vitamins B and C, vitamin B8 is water-soluble, meaning that it cannot be stored in the body and the excess is eliminated through the urinary system. It is widely used in beauty products, as it is known to strengthen hair, skin, and nails. One of its major benefits is helping to maintain the immune and nervous systems, as well.
As a process, vitamin B8 is involved in the metabolism of all three of the macronutrients obtained from food: carbohydrates, fats, and protein. It helps break down carbohydrates into simple sugars and may aid in stabilizing blood sugar. Similarly, it breaks down fats into chains of fatty acids; as such, it has been reported to have weight-loss benefits. It also plays a role in metabolizing amino acids, such as leucine, into usable proteins.
Another notable function of biotin is that it is essential to nail and hair health. Not only does it aid in nail and hair growth, but it prevents premature graying as well as prevents hair loss. In fact, vitamin B8 supplements are recommended for the treatment of both graying hair and splitting nails.
Vitamin B8 is also linked to the maintenance of a healthy immune system and nervous system. Though biotin deficiency is rare, those who present with this condition demonstrate impaired immune function, such as increased vulnerability to bacterial infections, as well as neurological symptoms, such as depression, hallucinations, and tingling in the hands and feet. These and other symptoms of deficiency, such as hair loss and metabolic problems, can often be treated with biotin supplementation.
The Recommended Dietary Allowance (RDA) for vitamin B8 is 30 micrograms (mcg) for an adult and is 35 mcg for women who are pregnant or nursing. Available in supplement form, it can also be taken in the form of brewer’s yeast, which supplies the entire B-vitamin complex. Foods rich in vitamin B8 include dairy products, liver, rice, wheat germ, bran, oatmeal, peanut butter, and egg yolks. It should be noted, however, that a diet rich in raw egg whites — namely consumption of 20 or more a day — can cause vitamin B8 deficiency, as the protein avidin in egg whites binds to it and renders it inactive.