biotin

View more Science videos

For more information on biotin, visit Britannica.com.

A vitamin, widespread in nature. It is only sparingly soluble in water; it is stable in boiling water solutions, but can be destroyed by oxidizing agents, acids, and alkalies. Under some conditions, it can be destroyed by oxidation in the presence of rancid fats. Biotin's occurrence in nature is so widespread that it is difficult to prepare a natural deficient diet. Biotin deficiency in animals is associated with dermatitis, loss of hair, muscle incoordination and paralysis, and reproductive disturbances. Biotin deficiency produced in humans by feeding large amounts of egg white resulted in dermatitis, nausea, depression, muscle pains, anemia, and a large increase in serum cholesterol. See also Coenzyme.

---

A vitamin, sometimes known as vitamin H, required for the synthesis of fatty acids and glucose, among other reactions, and in the control of gene expression and cell division. Biotin is widely distributed in foods such as liver, kidney, egg yolk, yeast, vegetables, grains, and nuts; dietary deficiency is unknown. There is no evidence on which to base reference intakes other than to state that current average intakes (between 15-70 μg/day) are obviously more than adequate to prevent deficiency; the US/Canadian adequate intake is 30 μg. See also avidin.

A vitamin of the B complex, also known as vitamin H. Biotin is found in small amounts in body tissues, combined with protein. It plays an important role in many reactions, including the release of energy from carbohydrates, fats, and proteins. Biotin also helps to maintain normal blood glucose concentrations from protein when carbohydrate sources have been exhausted. There is some evidence that biotin is needed for normal vitamin B₁₂ activity. Deficiency results in a scaly skin, muscular pain, pallor, loss of appetite, nausea, fatigue and elevated cholesterol levels. Deficiency is extremely rare in adults but it can be induced by consuming too much raw egg white. The egg white contains avidin, a chemical which binds to biotin, preventing it from being absorbed. Avidin is destroyed by heat. Some biotin is synthesized in the gut by bacteria. Dietary sources include yeast extracts, liver, egg yolk, and legumes. Although there are no official recommended dietary intakes, it has been calculated that 10-200 micrograms is a safe and adequate range of intake.

vitamin H

A member of the vitamin B complex. Biotin acts as a coenzyme involved in the metabolism of fatty acids and the movement of pyruvic acid into the Krebs cycle. Deficiency causes mental and muscle dysfunction, fatigue and nausea. Food sources include liver, eggs, and yeast. Some biotin is synthesized by intestinal bacteria There is insufficient information to set recommended levels.

KEY TERMS B-complex vitamins—A group of water-soluble vitamins that often work together in the body. These include thiamine (B), riboflavin (B), niacin (B), pantothenic acid (B), pyridoxine (B), biotin (B or vitamin H), folate/folic acid (B), and coba-lamin (B) Coenzyme—Also called a cofactor; a small non-protein molecule that binds to an enzyme and catalyzes (stimulates) enzyme-mediated reactions Dietary supplement—A product, such as avitamin, mineral, herb, amino acid, or enzyme, intended to be consumed in addition to an individual’s diet with the expectation that it will improve health Enzyme—A protein that changes the rate of a chemical reaction within the body without themselves being used up in the reaction. Fatty acids—Complex molecules found in fats and oils. Essential fatty acids are fatty acids the body needs but cannot synthesize. They are made by plants and must be present in the diet to maintain health Glucose—A simple sugar resulting from the breakdown of carbohydrates. Glucose circulates in the blood and is the main source of energy for the body Vitamin—A nutrient the body needs in small amounts to remain healthy but that the body cannot manufacture for itself and must acquire through diet Water-soluble vitamin—A vitamin that dissolves in water and can be removed from the body in urine.

    Description
    Precautions
    Interactions
    Complications
    Parental concerns
    Resources

What is Biotin?

Biotin, also known as vitamin H or vitamin B, belongs to the group of B-complex water-soluble vitamins. Humans make only a small amount of biotin, so most biotin must come from the foods they eat. Biotin is involved in conversion of carbohydrates, fats, and protein into usable energy in the body.

What is the Purpose of Biotin?

Biotin joins with enzymes that regulate the breakdown of foods and their use in the body. Some researchers believe that biotin also plays a role in the duplication and “reading” (replication and transcription) of deoxyribonucleic acid (DNA—genetic material). Biotin is often promoted as a dietary supplement to help improve the strength of fingernails and prevent hair loss. These claims are unproven.

Biotin

Age	Recommended dietary allowance (mcg/day)
Children 0–6 mos	5
Children 7–12 mos	6
Children 1–3 yrs	8
Children 4–8 yrs	12
Children 9–13 yrs	20
Children 14–-18 yrs	25
Adults 19> yrs	30
Pregnant women	30
Breastfeeding women	35
Food	Biotin (mcg)
Liver, cooked, 3 oz	27
Egg, 1 cooked	25
Bread, whole wheat, 1 slice	6
Swiss chard, cooked, ½ cup	5.2
Salmon, cooked, 3 oz	4
Chicken, cooked, 3 oz	3
Cauliflower, raw, ½ cup	2
Pork, cooked, 3 oz	2
mcg =microgram

cis-tetrahydro-2-oxothieno[3,4-d]imidazoline-4-valeric acid; hexahydro-2-oxo-1H-thieno[3,4-d]imidazole-4-pentanoic acid; vitamin H; formerly known as bios IIB and coenzyme RCO₂. A substance whose (+) enantiomer is very widely distributed in cells and serves as a carrier in a number of enzymic β-carboxylation reactions. In biotin-containing enzymes it is covalently bound at the active site to the ɛ-amino group of a lysine residue. It is a growth factor for yeasts. Compare biocytin. See also streptavidin.

Previous:	biotechnology, biosynthetic pathway, biosynthetic
Next:	biotin carboxylase, biotinidase, biotinyl

A member of the vitamin B complex, required by or occurring in all forms of life tested; prosthetic group of carboxylase enzymes. Called also vitamin H, coenzyme R.

• b. nutritional deficiency — natural animal diets are unlikely to be deficient in biotin. Experimental deficiency causes paralysis in calves. In pigs the syndrome includes alopecia, dermatitis and cracking of the hooves. The vitamin may be an important factor in the maintenance of pig hoof health. See also porcine footrot. Deficiency in dogs and cats is associated with dry scurfy skin, alopecia, especially around the eyes, and a papulocrustaceous dermatitis. It can be caused by a diet with very high levels of uncooked egg whites. See also avidin.

See words rhyming with "biotin."