For hair thinning, lowers blood sugar,90 tablets.
We at Nutriscreen Inc. have had good results with our patients using this product and have decided to keep it in stock.
- Serving size: 2 tablets
- Amount per serving: Biotin 20 mg
Biotin is a water-soluble vitamin that is generally classified as a B-complex vitamin. After the initial discovery of biotin, nearly 40 years of research were required to establish it as a vitamin (1). Biotin is required by all organisms but can be synthesized only by bacteria, yeasts, molds, algae, and some plant species (2).
Biotin is attached at the active site of five mammalian enzymes known as carboxylases (3). The attachment of biotin to another molecule, such as aprotein, is known as "biotinylation." Holocarboxylase synthetase (HCS)catalyzes the biotinylation of apocarboxylases (i.e., the catalytically inactive form of the enzyme) and of histones (See below). Biotinidase catalyzes the release of biotin from histones and from the peptide products of carboxylase breakdown.
Each carboxylase catalyzes an essential metabolic reaction:
- Acetyl-CoA carboxylase I and II catalyze the binding of bicarbonate to acetyl-CoA to form malonyl-CoA. Malonyl-CoA is required for the synthesis of fatty acids. The former is crucial in cytosolic fatty acidsynthesis, and the latter functions in regulating mitochondrial fatty acid oxidation.
- Pyruvate carboxylase is a critical enzyme in gluconeogenesis—the formation of glucose from sources other than carbohydrates, for example, amino acids.
- Methylcrotonyl-CoA carboxylase catalyzes an essential step in thecatabolism of leucine, an essential amino acid.
- Propionyl-CoA carboxylase catalyzes essential steps in the metabolism of certain amino acids, cholesterol, and odd chain fatty acids (fatty acids with an odd number of carbon molecules) (4).
Histones are proteins that bind to DNA and package it into compact structures to form nucleosomes—integral structural components of chromosomes. The compact packaging of DNA must be relaxed somewhat for DNA replication and transcription to occur. Modification of histones through the attachment of acetyl or methyl groups (acetylation or methylation) has been shown to affect the structure of histones, thereby affecting replication and transcription of DNA. Mounting evidence indicates that biotinylation of histones plays a role in regulating DNA replication and transcription as well as cellular proliferation and other cellular responses (5-7).
Although overt biotin deficiency is very rare, the human requirement for dietary biotin has been demonstrated in two different situations: prolonged intravenous feeding (parenteral) without biotin supplementation and consumption of raw egg white for a prolonged period (many weeks to years). Avidin is an antimicrobial protein found in egg white that binds biotin and prevents its absorption. Cooking egg white denatures avidin, rendering it susceptible to digestion and therefore unable to prevent the absorption of dietary biotin (8).
Three measures of biotin status have been validated as indicators of biotin status: (1) high excretion of an organic acid (3-hydroxyisovaleric acid) that reflects decreased activity of the biotin-dependent enzyme, methylcrotonyl-CoA carboxylase; (2) reduced urinary excretion of biotin; and (3) propionyl-CoA carboxylase activity in peripheral blood lymphocytes (4, 9-11).
Signs and symptoms
Signs of overt biotin deficiency include hair loss and a scaly red rash around the eyes, nose, mouth, and genital area. Neurologic symptoms in adults have included depression, lethargy, hallucination, and numbness and tingling of the extremities. The characteristic facial rash, together with unusual facial fat distribution, has been termed the "biotin deficient facies" by some investigators (8). Individuals with hereditary disorders of biotin metabolism resulting in functional biotin deficiency often have similar physical findings as well as evidence of impaired immune system function and increased susceptibility to bacterial and fungal infections (12).
There are several ways in which the hereditary disorder, biotinidase deficiency, leads to biotin deficiency. Intestinal absorption is decreased because a lack of biotinidase inhibits the release of biotin from dietary protein. Recycling of one’s own biotin bound to protein is impaired, and urinary loss of biotin is increased because the kidneys more rapidly excrete biotin that is not bound to biotinidase (5, 8). Biotinidase deficiency uniformly responds to moderate biotin supplementation. Oral supplementation with as much as 5 to 10 milligrams (mg) of biotin daily is sometimes required, although smaller doses are often sufficient. Some forms of holocarboxylase synthetase (HCS) deficiency respond to biotin supplementation with large doses. HCS deficiency results in an enzyme that catalyzes the attachment of biotin to all four carboxylase enzymes (see Function). HCS deficiency results in decreased formation of all holocarboxylases at normal blood levels of biotin; thus, high-dose supplementation (40 mg to 100 mg of biotin/day) is required. The inborn error, biotin transporter deficiency, also responds to high-dose biotin supplementation (13). The prognosis of all three of these disorders is often, but not always, good if biotin therapy is introduced early (infancy or childhood) and continued for life (12).
Aside from prolonged consumption of raw egg white or total intravenous nutritional support lacking biotin, other conditions may increase the risk of biotin depletion. The rapidly dividing cells of the developing fetus require biotin for histone biotinylation and synthesis of essential carboxylases; hence, the biotin requirement is likely increased during pregnancy. Research suggests that a substantial number of women develop marginal or subclinicalbiotin deficiency during normal pregnancy (6, 14). However, the recommended adequate intake does not change for pregnancy (See below). Additionally, some types of liver disease may decrease biotinidase activity and theoretically increase the requirement for biotin. A study of 62 children with chronic liver disease and 27 healthy controls found serum biotinidase activity to be abnormally low in those with severely impaired liver function due to cirrhosis (15). However, this study did not provide evidence of biotin deficiency. Further, anticonvulsant medications, used to prevent seizures in individuals with epilepsy, increase the risk of biotin depletion (16, 17). See Safety for more information on biotin and anticonvulsants.
The Adequate Intake (AI)
In 1998, the Food and Nutrition Board of the Institute of Medicine felt the existing scientific evidence was insufficient to calculate a RDA for biotin, so they set an Adequate Intake level (AI). The AI for biotin assumes that current average intakes of biotin (35 mcg to 60 mcg/day) meet the dietary requirement (1).
|Adequate Intake (AI) for Biotin |
|Life Stage ||Age ||Males (mcg/day) ||Females (mcg/day) |
|Infants ||0-6 months ||5 ||5 |
|Infants ||7-12 months ||6 ||6 |
|Children ||1-3 years ||8 ||8 |
|Children ||4-8 years ||12 ||12 |
|Children ||9-13 years ||20 ||20 |
|Adolescents ||14-18 years ||25 ||25 |
|Adults ||19 years and older ||30 ||30 |
|Pregnancy ||all ages ||- ||30 |
|Breast-feeding ||all ages ||- ||35 |
Research indicates that biotin is broken down more rapidly during pregnancy and that biotin nutritional status declines during the course of pregnancy (6). One study reported that biotin excretion dropped below the normal range during late pregnancy in six out of 13 women, suggesting that their biotin status was abnormally low. Over half of pregnant women have abnormally high excretion of a metabolite (3-hydroxyisovaleric acid) thought to reflect decreased activity of a biotin-dependent enzyme. A study of 26 pregnant women found that biotin supplementation decreased the excretion of this metabolite compared to placebo, suggesting that marginal biotin deficiency may be relatively common in pregnancy (14). In one study, the incidence of decreased lymphocyte propionyl-CoA carboxylase activity (a marker of biotin deficiency) in pregnancy was greater than 75% (18). Although the level of biotin depletion is not severe enough to cause diagnostic signs or symptoms, such observations are sources of concern because subclinical biotin deficiency has been shown to cause birth defects in several animal species (16). Currently, it is estimated that at least one third of women develop marginal biotin deficiency during pregnancy (8). Indirect evidence also suggests that marginal biotin deficiency causes birth defects in humans. On balance, the potential risk for teratogenesis (abnormal development of the embryo or fetus) from biotin deficiency makes it prudent to ensure adequate biotin intake throughout pregnancy. Since pregnant women are advised to consume supplemental folic acid prior to and during pregnancy (see Folic Acid) to prevent neural tube defects, it would be easy to consume supplemental biotin (at least 30 mcg/day) in the form of a multivitamin that also contains at least 400 mcg of folic acid. Toxicity at this level of biotin intake has never been reported (See Safety).
It has been known for many years that overt biotin deficiency impairs glucose utilization in rats (19). In one human study, blood biotin levels were significantly lower in 43 patients with non-insulin dependent diabetes mellitus(NIDDM; type 2 diabetes) than in non-diabetic control subjects, and lower fasting blood glucose levels were associated with higher blood biotin levels. After one month of biotin supplementation (9,000 mcg/day), fasting blood glucose levels decreased by an average of 45% (20). In contrast, a study in ten type 2 diabetics and seven nondiabetic controls reported that biotin supplementation (15,000 mcg/day) for 28 days did not decrease fasting blood glucose levels in either group (21). A more recent double-blind,placebo-controlled study by the same group of investigators found that the same biotin treatment protocol lowered plasma triglyceride levels in both diabetic and nondiabetic patients with hypertriglyceridemia (22). In this study, biotin administration did not affect blood glucose concentrations in either diabetic or nondiabetic subjects. Additionally, a few studies have shown that co-supplementation with biotin and chromium picolinate may be a beneficial adjunct therapy in patients with type 2 diabetes (23-26). However, several studies have reported that administration of chromium picolinate alone improves glycemic control in diabetic subjects (27). See the separate article on chromium.
Reductions in blood glucose levels were found in seven insulin-dependent (type 1) diabetics after one week of supplementation with 16,000 mcg of biotin daily (28). Several mechanisms could explain a possible blood glucose-lowering effect of biotin. As a cofactor of enzymes required for fatty acidsynthesis, biotin may increase the utilization of glucose for fat synthesis. Biotin has been found to stimulate glucokinase, a liver enzyme that increases synthesis of glycogen, the storage form of glucose. Biotin has also been found to stimulate the secretion of insulin in the pancreas of rats, which also has the effect of lowering blood glucose (29). An effect on cellular glucose transporters (GLUT) is currently under investigation. Presently, studies of the effect of supplemental biotin on blood glucose levels in humans are extremely limited, but they highlight the need for further research.
The finding that biotin supplements were effective in treating hoof abnormalities in horses and swine led to speculation that biotin supplements might also be helpful in strengthening brittle fingernails in humans. Three uncontrolled trials examining the effects of biotin supplementation (2.5 mg/day for up to six months) in women with brittle fingernails have been published (29-31). In two of the trials, subjective evidence of clinical improvement was reported in 67-91% of the participants available for follow-up at the end of the treatment period (29, 30). One trial that used scanning electron microscopy to assess fingernail thickness and splitting found that fingernail thickness increased by 25% and splitting decreased after biotin supplementation (31). Although the results of these small uncontrolled trials suggest that biotin supplements may be helpful in strengthening brittle nails, larger placebo-controlled trials are needed to assess the efficacy of high-dose biotin supplementation for the treatment of brittle fingernails.
Although hair loss is a symptom of severe biotin deficiency (see Deficiency), there are no published scientific studies that support the claim that high-dose biotin supplements are effective in preventing or treating hair loss in men or women.
Biotin is found in many foods, but generally in lower amounts than other water-soluble vitamins. Egg yolk, liver, and yeast are rich sources of biotin. Large national nutritional surveys in the U.S. were unable to estimate biotin intake due to the scarcity of data regarding biotin content of food. Smaller studies estimate average daily intakes of biotin to be from 40 to 60 mcg/day in adults (1). The table below lists some rich sources of biotin along with their content in micrograms (mcg) (32). However, a recent publication that employed chemical rather than microbial assays reported quite different content for some common foods (33).
|Food ||Serving ||Biotin (mcg) (32, 33) |
|Yeast ||1 packet (7 grams) ||1.4-14 |
|Bread, whole-wheat ||1 slice ||0.02-6 |
|Egg, cooked ||1 large ||13-25 |
|Cheese, cheddar ||1 ounce ||0.4-2 |
|Liver, cooked ||3 ounces* ||27-35 |
|Pork, cooked ||3 ounces* ||2-4 |
|Salmon, cooked ||3 ounces* ||4-5 |
|Avocado ||1 whole ||2-6 |
|Raspberries ||1 cup ||0.2-2 |
|Cauliflower, raw ||1 cup ||0.2-4 |
*A 3-ounce serving of meat is about the size of a deck of cards.
Most bacteria that normally colonize the small and large intestine (colon)synthesize biotin. Whether the biotin is released and absorbed by humans in meaningful amounts remains unknown. However, a specialized process for the uptake of biotin has been identified in cultured cells derived from the lining of the small bowel and colon (34), suggesting that humans may be able to absorb biotin produced by enteric bacteria—a phenomenon documented in swine.
Biotin is not known to be toxic. Oral biotin supplementation has been well-tolerated in doses up to 200,000 mcg/day in people with hereditary disorders of biotin metabolism (1). In people without disorders of biotin metabolism, doses of up to 5,000 mcg/day for two years were not associated with adverse effects (35). However, there is one case report of life-threatening eosinophilic pleuropericardial effusion in an elderly woman who took a combination of 10,000 mcg/day of biotin and 300 mg/day of pantothenic acidfor two months (36). Due to the lack of reports of adverse effects when the Dietary Reference Intakes (DRI) were established for biotin in 1998, the Institute of Medicine did not establish a tolerable upper level of intake (UL)for biotin (1). Note: 1 mg = 1,000 mcg.
Large doses of pantothenic acid (vitamin B5) have the potential to compete with biotin for intestinal and cellular uptake due to their similar structures(37). In addition, very high (pharmacologic) doses of lipoic acid have been found to decrease the activity of biotin-dependent carboxylases in rats, but such an effect has not been demonstrated in humans (4, 38).
Individuals on long-term anticonvulsant (anti-seizure) therapy reportedly have reduced blood levels of biotin as well as increased urinary excretion of organic acids that indicated decreased carboxylase activity (39). The anticonvulsants primidone and carbamazepine inhibit biotin absorption in the small intestine. Chronic therapy with phenobarbital, phenytoin, or carbamazepine appears to increase urinary excretion of 3-hydroxyisovaleric acid. Use of the anticonvulsant valproic acid has been associated with decreased biotinidase activity in children (17). Long-term treatment with sulfa drugs or other antibiotics may decrease bacterial synthesis of biotin, theoretically increasing the requirement for dietary biotin.
Linus Pauling Institute Recommendation:
Little is known regarding the amount of dietary biotin required to promote optimal health or prevent chronic disease. The Linus Pauling Institute supports the recommendation by the Food and Nutrition Board of 30 micrograms (mcg) of biotin/day for adults. A varied diet should provide enough biotin for most people. However, following the Linus Pauling Institute recommendation to take a daily multivitamin-mineral supplement will generally provide an intake of at least 30 mcg of biotin/day.
Older adults (65 years and older)
Presently, there is no indication that older adults have an increased requirement for biotin. If dietary biotin intake is not sufficient, a daily multivitamin-mineral supplement will generally provide an intake of at least 30 mcg of biotin/day.
Written in June 2004 by:
Jane Higdon, Ph.D.
Linus Pauling Institute
Oregon State University
Updated in August 2008 by:
Victoria J. Drake, Ph.D.
Linus Pauling Institute
Oregon State University
Updated and Reviewed in August 2008 by:
Donald Mock, M.D., Ph.D.
Departments of Biochemistry and Molecular Biology and Pediatrics
University of Arkansas for Medical Sciences
Biotin, also known as vitamin H or B7, is a water-soluble B-complex vitamin which is composed of an ureido (tetrahydroimidizalone) ring fused with at etrahydrothiophene ring. A valeric acid substituent is attached to one of the carbon atoms of the tetrahydrothiophene ring. Biotin is a cofactor in the metabolism of fatty acids and leucine, and it plays a role in gluconeogenesis.
- 1 General overview
- 2 Sources
- 3 Bioavailability
- 3.1 Factors that affect biotin requirements
- 4 Uses
- 4.1 Hair problems
- 4.2 Cradle cap (seborrheic dermatitis)
- 4.3 Diabetes
- 5 Deficiency
- 6 Toxicity
- 7 Biochemistry
- 8 Laboratory uses
- 9 Ruminant nutrition
- 10 See also
- 11 References
- 12 External links
Biotin is necessary for cell growth, the production of fatty acids, and the metabolism of fats and amino acids. It plays a role in the citric acid cycle, which is the process by which biochemical energy is generated during aerobic respiration. Biotin not only assists in various metabolic reactions, but also helps to transfer carbon dioxide. Biotin is also helpful in maintaining a steady blood sugar level. Biotin is often recommended for strengthening hair and nails. Consequently, it is found in many cosmetic and health products for the hair and skin.
Deficiency is extremely rare, as intestinal bacteria generally produce an excess of the body’s daily requirement. For that reason, statutory agencies in many countries (e.g., the Australian Department of Health and Aging) do not prescribe a recommended daily intake.
Biotin is widely distributed in a variety of foods, but most often at low concentrations. Estimates are that the typical U.S. diet provides roughly 40 µg/day. There are only a couple of foods which contain biotin in large amounts, including royal jelly and brewer’s yeast. The best natural sources of biotin in human nutrition are liver, legume, soybeans, Swiss chard, tomatoes, romaine lettuce, and carrots. This includes almonds, eggs, onions, cabbage, cucumber, cauliflower, goat’s milk, cow’s milk, raspberries, strawberries, halibut, oats, and walnuts. The most important natural sources in feeding nonruminant animals are oilseed meals, alfalfa, and dried yeasts. The biotin content of food varies and can be influenced by factors such as plant variety, season, and yield (endosperm-to-pericarp ratio).
Recommended Adequate Intake* for Biotin
| ||Age ||Biotin (µg/day) |
|Infants ||0–6 months ||5 |
| ||7–12 months ||6 |
|Children ||1–3 years ||8 |
| ||4–8 years ||12 |
|Males and Females ||9–13 years ||20 |
| ||14–18 years ||25 |
| ||19–70 years ||30 |
| ||70+ years ||30 |
|Pregnant ||<18-50 ||30 |
|Lactating ||<18-50 ||35 |
- Adequate intake are determined for nutrients when there is insufficient scientific evidence to establish a Recommended Dietary Allowance (RDA). These values are set as goals for individuals to support adequate nutritional status. NOTE: U.S. Food and supplement labels show 30 µg of biotin as providing only 10% DV (Daily Value) because DVs are based on older and in some instances outdated RDAs for nutrients. Thus, the DV for biotin is 300 µg even though there is now consensus that 30 µg is adequate. There is no current Tolerable Upper Limit (UL) set for biotin as research has indicated that high levels of intake by humans has no detrimental effects.
Studies on the bioavailability of biotin have been conducted in rats and in chicks. From these studies, it was concluded that biotin bioavailability may be low or variable depending on the type of food being consumed. In general, biotin exists in food as protein bound form or biocytin . Proteolysis by protease is required prior absorption. This process assists free biotin release from biocytin and protein bound biotin.The biotin present in corn is readily available; however, most grain have about a 20-40% bioavailability of biotin.
A possible explanation for the wide variability in biotin bioavailability is that it is due to ability of an organism to break various biotin-protein bonds from food. Whether an organism has an enzyme with the ability to break that bond will determine the bioavailability of biotin from the foodstuff.
Factors that affect biotin requirements
The frequency of marginal biotin status is not known, but the incidence of low circulating biotin levels in alcoholics has been found to be much greater than in the general population. Also, relatively low levels of biotin have been reported in the urine or plasma of patients who have had partial gastrectomy or who have other causes of achlorhydria, burn patients, epileptics, elderly individuals and athletes. Pregnancy and lactation may be associated with an increased demand for biotin. In pregnancy, this may be due to a possible acceleration of biotin catabolism, whereas in lactation, the higher demand has yet to be elucidated. Recent studies have shown that marginal biotin deficiency can be present in human gestation, as evidenced by increased urinary excretion of 3-hydroxyisovaleric acid, decreased urinary excretion of biotin and bisnorbiotin, and decreased plasma concentration of biotin. Additionally, smoking may further accelerate biotin catabolism in women.
Biotin supplements are often recommended as a natural product to counteract the problem of hair loss in both children and adults. The signs and symptoms of biotin deficiency include hair loss which progresses in severity to include loss of eye lashes and eye brows in severely deficient subjects. Some shampoos are available that contain biotin, but it is doubtful whether they would have any useful effect, as biotin is not absorbed well through the skin.
Cradle cap (seborrheic dermatitis)
Children with a rare inherited metabolic disorder called phenylketonuria (PKU; in which one is unable to break down the amino acid phenylalanine) often develop skin conditions such as eczema and seborrheic dermatitis in areas of the body other than the scalp. The scaly skin changes that occur in people with PKU may be related to poor ability to use biotin. Increasing dietary biotin has been known to improve seborrheic dermatitis in these cases.
Diabetics may also benefit from biotin supplementation. In both insulin-dependent and non-insulin-dependent diabetes, supplementation with biotin can improve blood sugar control and help lower fasting blood glucose levels, in some studies the reduction in fasting glucose exceeded 50 percent. Biotin can also play a role in preventing the neuropathy often associated with diabetes, reducing both the numbness and tingling associated with poor glucose control.
Biotin deficiency is relatively rare and mild, and can be addressed with supplementation. Such deficiency can be caused by the excessive consumption of raw egg whites (20 eggs/day would be required to induce it), which contain high levels of the protein avidin, which binds biotin strongly. Avidin is deactivated by cooking, while the biotin remains intact.
¨Symptoms of overt biotin deficiency include hair loss and a scaly red rash around the eyes, nose, mouth, and genital area. Neurological symptoms in adults have included depression, lethargy, hallucination, and numbness and tingling of the extremities. The characteristic facial rash, together with an unusual facial fat distribution, has been termed the ¨biotin-deficient face¨ by some experts. Individuals with hereditary disorders of biotin deficiency have evidence of impaired immune system function, including increased susceptibility to bacterial and fungal infections.¨
Biotinidase deficiency is not due to inadequate biotin, but rather to a deficiency in the enzymes that process it.
Signs of Biotin Deficiency: In general, appetite and growth are decreased. Dermatologic symptoms include dermatitis,alopecia (hair loss) and achromotrichia (absence or loss of pigment in the hair.) Perosis (a shortening and thickening of bones) is seen in the skeleton. Fatty Liver and Kidney Syndrome (FLKS) and hepatic steatosis also can occur. Genetic defect could also cause biotin deficiency. Holocarboxylase synthetase deficiency is a genetic mutation. It is a severe metabolic disorder. Biochemical and clinical manifestation includes: ketolactic acidosis, organic aciduria, hyperammonemia, skin rash, feeding problems, hypotonie, seizures, development delay, alopecia, and coma. This disease is lethal, however, mentioned manifestation can be reversed by pharmacologic doses of biotin (10-100 mg per day).
Pregnant women tend to have high risk of biotin deficiency. Research as shown nearly half of pregnant women have an abnormal increase of 3-hydroxyisovaleric acid which reflects reduced status of biotin.
Numbers of studies reported that this possible biotin deficiency during the pregnancy may cause infants" congenital malformations such as cleft palate. Mice fed with dried raw egg to induce biotin deficiency during the gestation resulted in up to 100% incidence of the infants" malnourishment. Infants and embryos are more sensitive to the biotin deficiency. Therefore even a mild level of mother’s biotin deficiency which does not reach the appearance of physiological deficiency signs may cause a serious consequence in the infants.
Animal studies have indicated few, if any, effects due to toxic doses of biotin. This may provide evidence that both animals and humans could tolerate doses of at least an order of magnitude greater than each of their nutritional requirements. There are no reported cases of adverse effects from receiving high doses of the vitamin, particularly when used in the treatment of metabolic disorders causing sebhorrheic dermatitis in infants.
Biotin D(+) is a cofactor responsible for carbon dioxide transfer in several carboxylase enzymes:
- Acetyl-CoA carboxylase alpha
- Acetyl-CoA carboxylase beta
- Methylcrotonyl-CoA carboxylase
- Propionyl-CoA carboxylase
- Pyruvate carboxylase
The attachment of biotin to various chemical sites, called biotinylation, can be used as an important laboratory technique to study various processes including protein localization, protein interactions, DNA transcription and replication. Biotinidase itself is known to be able to biotinylate histones, but little biotin is found naturally attached to chromatin. Holocarboxylase synthetase is the mammalian enzyme that covalently attaches biotin to carboxylases.
Biotin binds very tightly to the tetrameric protein avidin (also streptavidin and neutravidin), with a dissociation constant Kd in the order of 10−15 mol/L which is one of the strongest known protein-ligand interactions, approaching the covalent bond in strength. This is often used in different biotechnological applications. Until 2005, very harsh conditions were required to break the biotin-streptavidin bond.
In the biology laboratory, biotin is often chemically linked, or tagged, to a molecule or protein for biochemical assays. This process is called biotinylation. Since avidins bind preferentially to biotin, biotin-tagged molecules can be extracted from a sample by mixing them with beads with covalently-attached avidin, and washing away anything unbound to the beads.
For example, biotin can be attached to a molecule of interest (e.g. a protein), and this modified molecule will be mixed with a complex mixture of proteins. Avidin or streptavidin beads are added to the mixture, and the biotinylated molecule will bind to the beads. Any other proteins binding to the biotinylated molecule will also stay with the beads. All other unbound proteins can be washed away, and the scientist can use a variety of methods to determine which proteins have bound to the biotinylated molecule.
Biotinylated antibodies are used to capture avidin or streptavidin in both the ELISPOT and ELISA techniques.
Ruminal bacteria normally synthesize biotin. Biotin is not extensively metabolized in the rumen and increased intake of dietary biotin results in elevated concentrations of biotin in serum and milk. Unpublished epidemiologic data suggest a negative relationship between serum concentrations of biotin and the incidence of clinical lameness in dairy cattle. Feeding approximately 20 mg/day of supplemental biotin statistically improved measures of hoof health. Currently, insufficient data are available at this time to quantify the requirement for biotin of dairy cattle.
- Merck Index, 11th Edition, 1244.
- Combs, Gerald F. Jr. (2008). The Vitamins: Fundamental Aspects in Nutrition and Health. San Diego: Elsevier, Inc. ISBN 9780121834937.
- McGuire M, Beerman KA. Nutritional sciences: from fundamentals to food. California: Thomson Wadsworth, 2007.
- Gropper S.S., Smith, J.L.,Groff, J.L. (2005). Advanced nutrition and human metabolism. Belmont.
- Bowman, BA and Russell, RM., ed (2006). "Biotin". Present Knowledge in Nutrition, Ninth Edition, Vol 1. Washington, DC: Internation Life Sciences Institute. ISBN 9781578811984.
- Higdon, Jane (2003). "Biotin". An evidence-based approach to vitamins and minerals. Thieme. ISBN 9781588901248.
- Combs, Gerald F. Jr. (1998). The Vitamins: Fundamental Aspects in Nutrition and Health. Ithaca: Elsevier Academic Press. ISBN 0121834921. pg. 360
- Hymes, J; Fleischhauer, K; Wolf, B. (1995). "Biotinylation of histones by human serum biotinidase: assessment of biotinyl-transferase activity in sera from normal individuals and children with biotinidase deficiency.". Biochem Mol Med. 56 (1): 76–83. doi:10.1006/bmme.1995.1059.PMID 8593541.
- Laitinen OH, Hytonen VP, Nordlund HR, Kulomaa MS. (2006). "Genetically engineered avidins and streptavidins.". Cell Mol Life Sci. 63 (24): 2992–3017. doi:10.1007/s00018-006-6288-z. PMID 17086379.
- Holmberg A, Blomstergren A, Nord O et al. (2005). "The biotin-streptavidin interaction can be reversibly broken using water at elevated temperatures". Electrophoresis 26 (3): 501–10. doi:10.1002/elps.200410070. PMID 15690449.
- National Research Council (2001). Nutrient Requirements of Dairy Cattle. 7th rev. ed.. Natl. Acad. Sci., Washington, DC.. ISBN 0309069971.
Biotin is an essential water-soluble B vitamin. The name biotin is taken from the Greek word bios meaning "life." Without biotin, certain enzymes do not work properly and various complications can occur involving the skin, intestinal tract, and nervous system. Metabolic problems including very low blood sugars between meals, high blood ammonia, or acidic blood (acidosis) can occur. Death is theoretically possible, although no clear cases have been reported. Recent studies suggest that biotin is also necessary for processes on the genetic level in cells (DNA replication and gene expression).
Biotin deficiency is extremely rare. This is because daily biotin requirements are relatively small, biotin is found in many foods, and the body is able to recycle much of the biotin it has already used. Significant toxicity has not been reported in the available literature with biotin intake.
ARP [N-(Aminooxyacetyl)-Nˇ-(D-biotinoyl) hydrazine], biocytin, biotin-alkaline phosphate, biotin cadaverine, biotin nitrilotriacetic acid, biotin NTA , biotin-PEO4-amine, Biotin-PEO2-PPO2-amine, biotin-PEO3-maleimide, biotin-PEO4-propionate succinimidyl ester, biotinidase, coenzyme R, D-biotincis-hexahydro-2-oxo-1H-thieno[3,4-d]-imidazole-4-valeric acid, dUTP biotin, factor alpha, tripotassium salt (BNTA), vitamin Bw, vitamin H, W factor.
Note: This review does not cover the use of biotin in radioimmunotherapy (radioactive therapy) or radio-labeling for diagnostic procedures.
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
|Uses based on scientific evidence ||Grade* |
|Biotin deficiencyBiotin deficiency is extremely rare. Some potential causes of biotin deficiency are: long-term use of certain anti-seizure medications; prolonged oral antibiotic use; intestinal malabsorption (for example short gut syndrome); intravenous feeding (total parenteral nutrition/TPN) without added biotin; and eating raw egg whites on a regular basis. Supplementing with biotin appears helpful for the treatment of this deficiency. ||A |
|Biotin-responsive inborn errors of metabolismDisorders such as multiple carboxylase deficiency can cause inborn errors of metabolism that cause a "functional" biotin deficiency. High-dose biotin is used to treat these disorders. Management should be under strict medical supervision. ||A |
|Brittle fingernailsBiotin has been suggested as a treatment for brittle fingernails, particularly in women. There is not sufficient scientific evidence to form a clear conclusion. ||C |
|Cardiovascular disease risk (in diabetics)A combination of biotin and chromium may help lower cholesterol and decrease the risk of developing clogged arteries (called atherosclerosis) in diabetics. However, other research of biotin alone found that biotin did not affect cholesterol, glucose, or insulin levels, but did decrease triglyceride levels. More research with biotin alone is needed. ||C |
|Diabetes mellitus (type 2)In early research, biotin has been reported to decrease insulin resistance and improve glucose tolerance, which are both properties that may be beneficial in patients with types 2 (adult-onset) diabetes. Other research suggests that a combination of biotin and chromium may help improve blood sugar control. However, there is not enough human evidence to form a clear conclusion in this area. ||C |
|Hepatitis (in alcoholics)Antioxidant therapy with biotin, vitamins A-E, selenium, zinc, manganese, copper, magnesium, folic acid, Coenzyme Q10 did not improve survival rates in alcoholics with hepatitis. More research with biotin alone is needed. ||C |
|Pregnancy supplementationMarginal biotin deficiency has been found to commonly occur during pregnancy. Biotin supplementation during pregnancy is not currently standard practice, and prenatal vitamins generally do not contain biotin. However, individual patients may be considered for biotin supplementation by healthcare practitioners on a case-by-case basis. Additional study is needed in this area. ||C |
|Total parenteral nutrition (TPN)Intravenous feeding solutions (TPN) should contain biotin, in order to avoid biotin deficiency in recipient patients. This applies for patients in whom TPN is the sole source of nutrition. More study is needed in this area to make a firm recommendation. ||C |
*Key to grades Uses based on tradition or theory
A: Strong scientific evidence for this use;
B: Good scientific evidence for this use;
C: Unclear scientific evidence for this use;
D: Fair scientific evidence against this use;
F: Strong scientific evidence against this use.
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Alopecia areata (hair loss), antioxidant, basal ganglia disease, cancer, Crohn’s disease, exercise capa