Biotin
Biotin
Definition
Biotin, also known as vitamin H or vitamin B7, 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.
Purpose
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.
Description
Biotin is one of the less familiar B vitamins. It was discovered in the 1930s by researchers experimenting with different diets for chickens and rats, and later it was discovered to be essential to human health. Bacteria, yeasts, mold, algae, and some plants make biotin. The human large intestine (colon) contains some bacteria that synthesize biotin. Researchers believe that a portion of this biotin is absorbed into the bloodstream, but they are uncertain how much or how available it is to the body.
Biotin is essential to life because it combines with four different enzymes that control different metabolic reactions related to energy production and building new molecules from simple nutrients. These are:
- Forming glucose from fats and amino acids (but not from carbohydrates)
- Building fatty acids
- Synthesizing leucine, an amino acid necessary for health
- Metabolizing amino acids, cholesterol, and some fatty acids
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 |
(Illustration by GGS Information Services/Thomson Gale.)
Some researchers have found that biotin binds to proteins called histones that open up chromosomes so that their DNA becomes accessible and can be copied. If this is true, then biotin could play a role in gene expression.
Dietary supplement makers promote biotin to treat brittle fingernails, dry skin, and to prevent hair loss. It is sold as a dietary supplement in capsules or tablets, either alone, in a multivitamin, or combined with brewer’s yeast. Biotin is also added to cosmetics and skin creams. In animal studies, biotin improves the condition of horse hooves, but no controlled studies have shown the same effect on human fingernails. Biotin deficiency does cause hair loss, but there is no proof that supplemental biotin prevents hair loss.
Normal biotin requirements
The United States Institute of Medicine (IOM) of the National Academy of Sciences has developed values called Dietary Reference Intakes (DRIs) for vitamins and minerals The DRIs consist of three sets of numbers. The Recommended Dietary Allowance (RDA) defines the average daily amount of the nutrient needed to meet the health needs of 97–98% of the population. The Adequate Intake (AI) is an estimate set when there is not enough information to determine anRDA. The Tolerable Upper Intake Level (UL) is the average maximum amount that can be .
KEY TERMS
B-complex vitamins —A group of water-soluble vitamins that often work together in the body. These include thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7 or vitamin H), folate/folic acid (B9), and coba-lamin (B12)
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.
taken daily without risking negative side effects. The DRIs are calculated for children, adult men, adult women, pregnant women, and breastfeeding women.
The IOM has not set RDA values for biotin because of incomplete scientific information. Instead, it has set AI levels for all age groups. AI levels for biotin are measured by weight (micrograms or mcg). No UL levels have been set for biotin because large doses of biotin do not appear to cause any side effects.
The following are the AIs for biotin for healthy individuals:
- Children birth-6 months: 5 mcg
- Children 7-12 months: 6 mcg
- Children 1-3 years: 8 mcg
- Children 4-8 years: 12 mcg
- Children 9-13 years: 20 mcg
- Children 14-18 years: 25 mcg
- Adults age 19 and older: 30 mcg
- Pregnant women: 30 mcg
- Breastfeeding women: 35 mcg
Sources of biotin
Biotin is found in small quantities in many foods. Bacteria in the large intestine also make biotin. Unlike some vitamins, biotin is recycled and reused by the body. Daily intake does not need to be high because only small amounts are lost in urine. Biotin is stable and little is lost when foods are exposed to heat, light, or air.
The approximate biotin content in common foods is:
- Bread, whole wheat, 1 slice: 6 mcg
- Egg, 1 cooked: 25 mcg
- Liver, cooked, 3 ounces: 27 mcg
- Chicken, cooked, 3 ounces: 3 mcg
- Pork, cooked, 3 ounces: 2 mcg
- Salmon, cooked, 3 ounces: 4 mcg
- Swiss chard, cooked, 1/2 cup: 5.2 mcg
- Cauliflower, raw, 1/2 cup: 2 mcg
Biotin deficiency
Biotin deficiency is very rare worldwide. Only a few conditions are known to cause biotin deficiency. Two rare inherited genetic disorders cause the body to need excessive amounts of biotin. These disorders are treated with high-dose biotin supplements. Prolonged (months or years) consumption of raw egg whitescan also cause a deficiency. A protein in raw egg whites binds biotin and makes it unavailable to the body. Cooking the egg releases the biotin. Receiving all nutrition through intravenous feeding (total parenteral nutrition or TPN) for an extended period may also lead to a shortage of biotin in the body.
Symptoms of biotin deficiency include skin and hair problems, such as a red scaly rash on the face, increased susceptibility to fungal infections, brittle hair, and hair loss. Individuals may also develop seizures, problems with coordination, and muscle cramps. Biotin deficiency has not been known to cause death. These symptoms have many other causes that should be considered first because biotin deficiency is so rare.
Precautions
In many species, pregnant animals who are biotin deficient give birth to offspring with birth defects at a higher rate than animals who have adequate levels of biotin. The same effect has not been seen in humans. However, blood levels of biotin tend to drop in pregnant women, causing concern among researchers that pregnant women may develop marginal biotin deficiency with no visible symptoms. Dietary supplements of biotin are not routinely recommended for women who are pregnant, but these women should make a special effort to get an adequate intake of 30 mcg biotin daily through diet. Pregnant and breastfeeding women should not take a biotin dietary supplement unless directed by their healthcare provider.
Interactions
Biotin is known to interact with a few drugs and dietary supplements
- Antibiotics taken over a long period may reduce the amount of bacteria in the large intestine that synthesize biotin.
- Long-term use of drugs used to prevent seizures such as phenytoin (Dilantin), primidone (Mysoline), car-bamazepine (Tegretol), phenobarbitol (Solfoton) and possibly valproic acid cause a reduction in the blood level of biotin.
- High doses of pantothenic acid may decrease the amount of biotin absorbed from the large intestine.
Complications
No complications are expected from biotin. Even when large doses are taken for long periods, there are no reported side effects.
Parental concerns
Biotin deficiency is rare and biotin excess is so benign that parents should have almost no concern about their children’s biotin needs being met by diet.
Resources
BOOKS
Berkson, Burt, and Arthur J. Berkson. Basic Health Publications User’s Guide to the B-complex VitaminsLaguna Beach, CA: Basic Health Publications, 2006.
Gaby, Alan R., ed. A-Z Guide to Drug-Herb-Vitamin Interactions Revised and Expanded 2nd Edition: Improve Your Health and Avoid Side Effects When Using Common Medications and Natural Supplements TogetherNew York: Three Rivers Press, 2006.
Lieberman, Shari, and Nancy Bruning. The Real Vitamin and Mineral Book: The Definitive Guide to Designing Your Personal Supplement Program4th ed. New York: Avery, 2007.
Pressman, Alan H., and Sheila Buff. The Complete Idiot’s Guide to Vitamins and Minerals, 3rd edIndianapolis, IN: Alpha Books, 2007
Rucker, Robert B., ed. Handbook of Vitamins. Boca Raton, FL: Taylor & Francis, 2007.
ORGANIZATIONS
Linus Pauling Institute. Oregon State University, 571.
Weniger Hall, Corvallis, OR 97331-6512. Telephone: (541) 717-5075. Fax: (541) 737-5077. Website: <http://lpi.oregonstate.edu>.
OTHER
Higdon, Jane. “Biotin.’ Linus Pauling Institute-Oregon State University. June 1, 2004. [cited April 28, 2007] <http://lpi.oregonstate.edu/infocenter/vitamins/biotin>.
Scheinfeld, Noah S. and Stephanie B. Frelich. “Biotin.
Deficiency.” emedicine.com, June 22, 2006. [cited April 28, 2007]. <http://www.emedicine.com/ped/topic238>.
Tish Davidson, A.M.
Biotin
Biotin
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] <http://www.bookman.com.au/vitamins/biotin.html>.
Patricia Skinner
Teresa G. Odle
Biotin
Biotin
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 digestive tract.
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 eradicate. 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. Biotin is also used to treat peripheral neuropathy, a complication of diabetes, and those 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, and should be supplemented in anyone who is taking antibiotics. 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 digestive system, 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 digestive tract 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.
KEY TERMS
Coenzyme— A non-protein organic compound that plays an essential role in the action of particular enzymes.
Lactobacillus— A bacteria present in the digestive tract of healthy people.
Mycelium— Fine thread-like tendrils sent out by a fungus to seek nutrition, capable of invading body organs.
Peripheral neuropathy— Weakness and numbness of the nerves in the fingers and toes, which may progress up the limb—often a complication of diabetes.
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.
OTHER
"Vitamins, etc." 〈http://www.bookman.com.au/vitamins/biotin.html〉 (August 1, 2005).
Biotin
Biotin
Biotin is a member of the vitamin B family. It is water soluble (dissolvable) and an important coenzyme. Biotin is involved in the metabolism (the process in living organisms and cells that breaks down food into nutrients and waste matter) of carbohydrates and in the synthesis (formation) of fatty acids. Like many vitamins, biotin was "discovered" several times by different people and was given a new name by each of its discoverers.
In the 1920s different researchers isolated a growth factor for yeast that some named "bios," and others called "vitamin H". In 1927, biochemist M.A. Boas was the first scientist to demonstrate a requirement for this compound in animals. Boas found that rats who were fed a diet high in raw egg whites soon developed severe skin rashes, lost their fur, and became paralyzed. This syndrome is known as "egg-white injury." Boas also found a substance in liver that could cure this injury. He called the substance "protective factor x." We now know that egg whites contain the protein and avidin, that—unless destroyed by heat—keeps biotin from being absorbed by the body.
Finally, in 1940, Vincent Du Vigneaud, an American biochemist working for a leading pharmaceutical company, realized that biotin was identical both to vitamin H and to "protective factor x." Intrigued by this discovery, Du Vigneaud went on to work out the coenzyme's complicated two-ring structure. Once the structure was known, it became possible for biotin to be synthesized.
Biotin is now known to be present in virtually every food. Moreover, the body can synthesize it from intestinal bacteria. A biotin deficiency, therefore, is extremely rare. It is usually seen in infants born with a genetic disorder and in people who eat large quantities of raw eggs.
[See also Vitamin ]
biotin
biotin
biotin
bi·o·tin / ˈbīətin/ • n. Biochem. a vitamin of the B complex, found in egg yolk, liver, and yeast. It is involved in the synthesis of fatty acids and glucose. Also called vitamin H.