biotin

n.
A colorless crystalline vitamin, C₁₀H₁₆N₂O₃S, of the vitamin B complex, essential for the activity of many enzyme systems and found in large quantities in liver, egg yolk, milk, and yeast.

[Greek biōtos, life; see biotic + -IN.]

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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.

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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.

Description

Biotin is a member of the B complex family, but is not actually a vitamin. It is a coenzyme that works with them. Also known as vitamin H and coenzyme R, it was first isolated and described in 1936. It is water soluble and very unstable; it can be destroyed by heat, cooking, exposure to light, soaking, and prolonged contact with water, baking soda, or any other alkaline element. The body obtains biotin from food and can also synthesize this nutrient from bacteria in the gut.

General Use

Biotin is utilized by every cell in the body and contributes to the health of skin, hair, nerves, bone marrow, sex glands, and sebaceous glands. Apart from being a vital cofactor to several enzymes, biotin is essential in carbohydrate metabolism and the synthesis of fatty acids. It is also involved in the transformation of amino acids into protein. Biotin plays a role in cell growth and division through its role in the manufacture of DNA and RNA, the genetic components of cells.

Adequate biotin is required for healthy nails and hair, and biotin deficiency is known to be a factor in balding and the premature graying of hair. It has been claimed that, as part of an orthomolecular regime, it can reverse the graying of hair. When PABA and biotin are taken together in adequate amounts they can restore hair color. Biotin supplements will also effectively treat weak, splitting nails.

Biotin can be a valuable tool to combat yeast infections, which are notoriously difficult to fight. In their book The Yeast Syndrome, John Parks Trowbridge and Morton Walker describe how adequate levels of biotin can prevent Candida albicans from developing from its yeast-like state into fungal form, in which it sends out mycelium that further invade body organs.

Seborrheic dermatitis, or Leiner's disease, which is a non-itchy, red scaling rash affecting infants during the first three months of life, is also treated with biotin and other B complex vitamins.

Biotin has been used in conjunction with other nutrients as part of weight loss programs, as it aids in the digestion and breakdown of fats.

High doses of biotin are sometimes used by the allopathic medical profession to treat diabetes since it enhances sensitivity to insulin and effectively increases levels of enzymes involved in glucose metabolism. In 2002, one company started clinical trials testing a combination of chromium picolinate and biotin for treatment of type 2 diabetes. Biotin is also used to treat peripheral neuropathy, a complication of diabetes, and patients with Duchenne muscular dystrophy, who suffer from metabolic deficiencies.

Biotin can be found in beans, breads, brewer's yeast, cauliflower, chocolate, egg yolks, fish, kidney, legumes, liver, meat, molasses, dairy products, nuts, oatmeal, oysters, peanut butter, poultry, wheat germ, and whole grains.

Preparations

The recommended daily allowance for adults in the United States is 30 mcg. Daily requirements are estimated at 30 mcg for adults and 35 mcg for women who are nursing. Supplementation ranges from 100–600 mcg per day, and can be obtained in the form of brewer's yeast, which contains biotin as part of the B complex, or as an individual biotin supplement.

Precautions

The body needs biotin on a daily basis since it is not stored to any great extent. Biotin requirements increase during pregnancy and lactation. In 2002, an investigation outlined the need for supplemental biotin during pregnancy. Nearly 50% of pregnant women appear to be deficient in biotin, which could result in birth defects (at least according to animal studies). Researchers suggest that biotin be included in prenatal multivitamin formulas.

Those taking antibiotics should supplement their diets with biotin. Certain individuals are at risk for biotin deficiency, including infants fed biotin-deficient formula or with inherited deficiency disorders, patients who are fed intravenously, and anyone who habitually eats a lot of raw egg whites, because they contain a protein called avidin, which prevents the absorption of biotin.

Mild Deficiency

Because it is synthesized in the gut, deficiency symptoms of biotin are rare. However they may include weakness, lethargy, grayish skin color, eczema (which may include a scaly red rash around the nose, mouth and other orifices), hair loss, cradle cap in infants, muscle aches, impaired ability to digest fats, nausea, depression, loss of appetite, insomnia, high cholesterol levels, eye inflammations, sensitivity to touch, anemia, and tingling in the hands and feet.

Extreme Deficiency

Symptoms of extreme biotin deficiency include elevation of cholesterol levels, heart problems, and paralysis. When extreme deficiency is a problem, the liver may not be able to detoxify the body efficiently, and depression may develop into hallucinations. Infants may exhibit developmental delay and lack of muscle tone.

Biotin deficiency could result in a loss of immune function, since animal experiments have shown that biotin deficiency resulted in a decrease in white blood-cell function. Because biotin is essential to the body's metabolic functions, any deficiency could result in impaired metabolism as well.

Overdose

There have been no reports of effects of overdose of biotin, even at very high doses, primarily because any excess is excreted in the urine.

Side Effects

There are no side effects associated with biotin supplementation.

Interactions

Biotin works in conjunction with all the B vitamins, which are synergistic, meaning they work best when all are available in adequate amounts.

Raw egg white contains the protein avidin, which prevents absorption of biotin.

Sulfa drugs, estrogen, and alcohol all increase the amount of biotin needed in the body. In addition, anticonvulsant drugs may lead to biotin deficiency. Long term use of antibiotics may prevent the synthesis of biotin in the gut by killing off the bacteria which help the body produce biotin. Supplements of lactobacillus may help the body make sufficient amounts of biotin after long term antibiotic use.

Resources

Books

Kenton, Leslie. The Joy of Beauty. Great Britain: Century Publishing Co Ltd., 1983.

Trowbridge, John Parks, and Morton Walker. The Yeast Syndrome. New York: Bantam Books, 1986.

Periodicals

"Biotin Deficiency in Pregnancy. (Nutrition and Pregnancy)." Nutrition Research Newsletter (April 2002): 9–11.

Gaby, Alan R. "Biotin Needed During Pregnancy." Townsend Letter for Doctors and Patients (June 2002): 31.

"Nutrition 21 to Test Chromium/Biotin Combo in Diabetes." Nutraceuticals International (May 2002).

Other

"Vitamins, etc." [cited August 1, 2000] .

[Article by: Patricia Skinner; Teresa G. Odle]

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.

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.

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