Biotin what is it good for
Biotin Ц Vitamin B7
Biotin is an important component of enzymes in the body that break down certain substances like fats, carbohydrates, and others. There isn't a good laboratory test for detecting low biotin levels. Mar 08, †Ј With that said, itТs always a good idea to eat a balanced, healthy diet of nonprocessed or minimally processed foods for your optimal health. Shop online for biotin supplements. Last medically.
You may recognize vitamin B7 by its popular name what is it what is it worth biotin.
It is a water-soluble B vitamin found naturally in some foods and also in supplements. Biotin plays a vital role in assisting enzymes to break down fats, wha, and proteins in food. It also helps to regulate signals sent by cells and the activity of genes. An RDA Recommended Dietary Allowance does not exist for biotin because there is not enough evidence to suggest a daily amount needed by most healthy people.
Instead, there is an AI Adequate Intake level, which is assumed to ensure nutritional adequacy. AI: The AI for biotin for men and women 19 years and older and for pregnant women is 30 micrograms bitin.
Lactating women biotln 35 micrograms daily. There is no UL for biotin due to a lack of reports showing negative effects from very high intakes. Biotin supplements are often glamorized as a treatment for hair loss and to promote healthy bioton, skin, and nails. Although a deficiency of biotin can certainly lead to hair loss and skin or nail problems, evidence showing a benefit of supplementation is giotin.
A handful of case reports and small trials have shown a benefit, but the study designs had weaknesses:. Despite the inconclusive evidence, biotin supplements remain popular.
Between andthe proportion of supplement users increased by nearly thirtyfold. Food and Drug Administration FDA issued a warning based on reports of biotin supplements interfering with laboratory blood tests, causing incorrect results. High doses have produced either falsely elevated or decreased blood levels, depending on the test. This has affected lab results of certain hormones, such as thyroid-stimulating hormone and vitamin Froas well as a biomarker for heart attacks called troponin.
The FDA recommends biotin what is it good for people inform their doctors at each visit of all supplements and doses they are taking. A biotin deficiency in the U. Alcoholism can increase the ogod of biotin deficiency and many other nutrients as alcohol can block their absorption, and also because alcohol abuse is generally associated with a poor dietary what do rats eat in nature. About a third of pregnant women show a mild biotin deficiency despite eating adequate intakes, though the exact reason is not clear.
No evidence in humans has shown a toxicity of biotin even with high intakes. Because it is water-soluble, any excess amount will leave through the urine. There is no established upper limit or toxic level for biotin.
Those who frequently enjoy raw eggs in recipes for mayonnaise, Caesar dressing, or eggnog may want to reconsider. A protein in raw eggs called avidin can bind to biotin, preventing its absorption. Cooked eggs are not an issue because avidin is broken down when heated. B Vitamins Vitamins and Minerals. The contents of this website are for educational purposes and are not intended to offer personal medical advice.
You should seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
The Nutrition Source does not recommend or endorse any products. Skip to content The Nutrition Source. Harvard T. The Nutrition Source Menu. Search for:. Vitamin B7 and Health Biotin supplements are often glamorized as a treatment for hair loss and to promote healthy hair, skin, and nails.
A handful of case reports and small trials have shown a benefit, but the what does l eau mean in english designs had weaknesses: The diagnoses of the type of hair conditions varied or were not cited at all. Researchers have also noted that certain hair loss whxt like alopecia can resolve spontaneously without treatment, so it is not clear that biotin supplements specifically caused the regrowth.
Some research suggests what is xfs file system biotin supplements may be of most benefit in people who have a deficiency of the nutrient; however, again, there is a lack of studies that biotin what is it good for measured biotin levels before and during supplementation to confirm this conclusion. Did You Know? Biotin: Fact Sheet for Health Professionals. Journal of the American Academy of Dermatology. Lipner SR. Rethinking biotin therapy for hair, nail, and skin disorders.
Lipner S. A review of the use of biotin for hair loss. Skin appendage disorders. Food and Drug Administration. Bernard Lown, visionary cardiologist, activist, inventor, teacЕ. RT HarvardChanSPH : Eating two servings of fruit and three servings of vegetables every day is the right mix for longevity, according to aЕ. Bernard Lown created the first effective heart defibrillator, and was awarded how to make blog website Nobel Peace Prize for his work to eЕ.
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Sep 25, †Ј УWe find biotin to be very helpful for hair disorders,Ф says dermatologist Wilma Bergfeld, MD. УIt also makes nails thicker, and oral biotin is exceedingly safe, even in large doses.Ф. Biotin, also called vitamin B 7, is one of the B vitamins. It is involved in a wide range of metabolic processes, both in humans and in other organisms, primarily related to the utilization of fats, carbohydrates, and amino acids. The name biotin derives from the Greek word УbiosФ (to live) and the suffix У-inФ (a general chemical suffix used in organic chemistry). Oct 21, †Ј Biotin is widely found in food, and good dietary sources include egg yolk, liver, whole-grain cereal, and some vegetables. (More information) Long-term anticonvulsant (anti-seizure) therapy may increase the dietary requirement for biotin because anticonvulsants can interfere with the intestinal absorption and renal re-absorption of biotin and.
Biotin is a water-soluble vitamin that is generally classified as a B-complex vitamin. After its initial discovery in , 40 years of additional research was required to unequivocally establish biotin as a vitamin 1. Biotin is required by all organisms but can be synthesized by some strains of bacteria , yeast, mold, algae, and some plant species 2.
Biotin functions as a covalently bound cofactor required for the biological activity of the five known mammalian biotin-dependent carboxylases see below. Such a non- protein cofactor is known as a "prosthetic group. The term "biotinylation" refers to the covalent addition of biotin to any molecules, including apocarboxylases and histones. HCS catalyzes the post-translational biotinylation of the epsilon amino group of a lysine residue at the active site of each apocarboxylase, converting the inactive apocarboxylase into a fully active holocarboxylase Figure 1a.
Particular lysine residues within the N-terminal tail of specific histones , which help package DNA in eukaryotic nuclei , can also be biotinylated 3. Biotinidase is the enzyme that catalyzes the release of biotin from biotinylated histones and from the peptide products of holocarboxylase breakdown Figure 1b.
Five mammalian carboxylases that catalyze essential metabolic reactions:. ACC1 is found in all tissues and is particularly active in lipogenic tissues i.
ACC2 is especially abundant in skeletal muscle and heart 4. Pyruvate carboxylase catalyzes the ATP-dependent incorporation of bicarbonate into pyruvate, producing oxaloacetate; hence, pyruvate carboxylase is anaplerotic for the citric acid cycle Figure 3. Oxaloacetate can then be converted to phosphoenolpyruvate and eventually to glucose.
This biotin-containing enzyme catalyzes the production of 3-methylglutaconyl-CoA from methylcrotonyl-CoA Figure 4a. The conversion of propionyl-CoA to D-malonylmalonyl-CoA is also required in the catabolic pathways of two branched-chain amino acids isoleucine and valine , methionine , threonine, and the side chain of cholesterol Figure 4a and 4b.
In eukaryotic nuclei , DNA is packaged into compact structures to form nucleosomes Ч fundamental units of chromatin.
Another histone, called H1 linker, is located at the outer surface of each nucleosome and serves as an anchor to fix the DNA around the histone core. The compact packaging of chromatin must be relaxed from time to time to allow biological processes, such as DNA replication and transcription to occur.
Chemical modifications of DNA and histones affect the folding of chromatin, increasing or reducing DNA accessibility to factors involved in the above-mentioned processes. Together with DNA methylation , a number of chemical modifications within the N-terminal tail of core histones modify their electric charge and structure, thereby changing chromatin conformation and transcriptional activity of genes.
The various modifications of histone tails, including acetylation, methylation, phosphorylation, ubiquitination, SUMOylation, ADP-ribosylation, carbonylation, deimination, hydroxylation , and biotinylation, have different regulatory functions. Several sites of biotinylation have been identified in histones H2A, H3, and H4 5.
Amongst them, histone H4 biotinylation at lysine K 12 noted H4K12bio appears to be enriched in heterochromatin, a tightly condensed chromatin associated with repeat regions in peri centromeres and telomeres , and with transposable elements known as long terminal repeats 3.
In addition, biotinylation marks co-localize with well-known gene repression marks like methylated lysine 9 in histone H3 H3K9me in transcriptionally competent chromatin 6. For example, H4K12bio can be found at the promoter of the gene SLC5A6 that codes for the transporter mediating biotin uptake into cells, the human sodium-dependent multivitamin transporter hSMVT.
Conversely, in biotin-deficient cells, biotinylation marks in the SLC5A6 promoter are removed such that gene expression can occur, enabling the synthesis of hSMVT and subsequently increasing the uptake of biotin 7. Although overt biotin deficiency is very rare, the human requirement for dietary biotin has been demonstrated in three different situations: prolonged intravenous feeding parenteral without biotin supplementation, infants fed an elemental formula devoid of biotin, and consumption of raw egg white for a prolonged period many weeks to years 8.
Raw egg white contains an antimicrobial protein known as avidin that can bind biotin and prevent its absorption.
Cooking egg white denatures avidin, rendering it susceptible to digestion and therefore unable to prevent the absorption of dietary biotin 5.
Signs of overt biotin deficiency include hair loss alopecia and a scaly red rash around the eyes, nose, mouth, and genital area. Neurologic symptoms in adults have included depression, lethargy, hallucinations, numbness and tingling of the extremities, ataxia , and seizures. The characteristic facial rash, together with unusual facial fat distribution, has been termed the "biotin deficient facies" by some investigators 1.
Individuals with hereditary disorders of biotin metabolism see Inborn metabolic disorders resulting in functional biotin deficiency often have similar physical findings, as well as seizures and evidence of impaired immune system function and increased susceptibility to bacterial and fungal infections 9, Aside from prolonged consumption of raw egg white or total intravenous nutritional support lacking biotin, other conditions may increase the risk of biotin depletion.
Smoking has been associated with increased biotin catabolism The rapidly dividing cells of the developing fetus require biotin for synthesis of essential carboxylases and histone biotinylation; hence, the biotin requirement is likely increased during pregnancy. Research suggests that a substantial number of women develop marginal or subclinical biotin deficiency during normal pregnancy see also Disease Prevention 8 , 12, Additionally, certain 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 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 for more information on biotin and anticonvulsants, see Drug interactions.
There are several ways in which the hereditary disorder, biotinidase deficiency, leads to secondary biotin deficiency. Intestinal absorption is decreased because a lack of biotinidase prevents the release of biotin from dietary protein Recycling of one's own biotin bound to carboxylases and histones is also impaired, and urinary loss of biocytin N-biotinyl-lysine and biotin is increased see Figure 1 above 5. Biotinidase deficiency uniformly responds to supplemental biotin.
Oral supplementation with as much as 5 to 10 milligrams mg of biotin daily is sometimes required, although smaller doses are often sufficient reviewed in Some forms of HCS deficiency respond to supplementation with pharmacologic doses of biotin.
HCS deficiency results in decreased formation of all holocarboxylases at physiological blood biotin concentrations; thus, high-dose biotin supplementation mg of biotin daily is required The prognosis of these two disorders is usually good if biotin therapy is introduced early infancy or childhood and continued for life There has been one case report of a child with biotin transport deficiency who responded to high-dose biotin supplementation Of note, the presence of a defective human sodium-dependent multivitamin transporter hSMVT was ruled out as a cause of biotin transport deficiency.
Abnormally elevated concentrations of the amino acid , phenylalanine, in the blood of PKU -affected individuals may inhibit the activity of biotinidase. Schulpis et al. Four measures of marginal biotin deficiency have been validated as indicators of biotin status: 1 reduced urinary excretion of biotin and some of its catabolites; 2 high urinary excretion of an organic acid, 3-hydroxyisovaleric acid, and its derivative, carnitylhydroxyisovaleric acid, both of which reflect decreased activity of biotin-dependent methylcrotonyl-CoA carboxylase; 3 reduced propionyl-CoA carboxylase activity in peripheral blood lymphocytes 5 ; and 4 reduced levels of holo-methylcrotonyl-CoA carboxylase and holo-propionyl-CoA carboxylase in lymphocytes Ч the most reliable indicators of biotin status These markers have been only validated in men and nonpregnant women, and they may not accurately reflect biotin status in pregnant and breast-feeding women Sufficient scientific evidence is lacking to estimate the dietary requirement for biotin; thus, no Recommended Dietary Allowance RDA for biotin has been established.
The requirement for biotin in pregnancy may be increased Current research indicates that at least one-third of women develop marginal biotin deficiency during pregnancy 8 , but it is not known whether this might increase the risk of congenital anomalies.
Small observational studies in pregnant women have reported an abnormally high urinary excretion of 3-hydroxyisovaleric acid in both early and late pregnancy, suggesting decreased activity of biotin-dependent methylcrotonyl-CoA carboxylase 21, Although the level of biotin deficiency is not associated with overt signs of deficiency in pregnant women, such observations are sources of concern because subclinical biotin deficiency has been shown to cause cleft palate and limb hypoplasia in several animal species reviewed in In addition, biotin depletion has been found to suppress the expression of biotin-dependent carboxylases, remove biotin marks from histones , and decrease the proliferation in human embryonic palatal mesenchymal cells in culture Impaired carboxylase activity may result in alterations in lipid metabolism , which have been linked to cleft palate and skeletal abnormalities in animals.
Further, biotin deficiency leading to reduced histone biotinylation at specific genomic loci could possibly increase genomic instability and result in chromosome anomalies and fetal malformations While pregnant women are advised to consume supplemental folic acid prior to and during pregnancy to prevent neural tube defects see Folate , it would also be prudent to ensure adequate biotin intake throughout pregnancy.
Biotin-responsive basal ganglia disease, also called thiamin metabolism dysfunction syndrome-2, is caused by mutations in the gene coding for thiamin transporter-2 THTR The clinical features appear around three to four years of age and include sub-acute encephalopathy confusion, drowsiness, and altered level of consciousness , ataxia , and seizures.
A retrospective study of 18 affected individuals from the same family or the same tribe in Saudi Arabia was recently conducted. Early diagnostic and immediate treatment with biotin and thiamin led to positive outcomes The mechanism for the beneficial effect of biotin supplementation has yet to be elucidated. Multiple sclerosis MS is an autoimmune disease characterized by progressive damages to the myelin sheath surrounding nerve fibers axons and neuronal loss in the brain and spinal cord of affected individuals.
The progression of neurologic disabilities in MS patients is often assessed by the Expanded Disability Status Scale EDSS with scores from 1 to 10, from minimal signs of motor dysfunction score of 1 to death by MS score of ATP deficiency due to mitochondrial dysfunction and increased oxidative stress may be partly responsible for the progressive degeneration of neurons in MS Given its role in intermediary metabolism and fatty acid synthesis required for myelin formation see Function , it has been hypothesized that biotin might exert beneficial effects that would limit or reverse MS-associated functional impairments In addition, the preliminary results from a multicenter, randomized , placebo -controlled trial in subjects with progressive MS indicated that 13 out of patients randomized to receive daily oral biotin mg for 48 weeks achieved a composite functional endpoint that included a decrease in EDSS scores.
In comparison, none of the 51 patients randomized to the placebo group showed significant clinical improvements Overt biotin deficiency has been shown to impair glucose utilization in mice 29 and cause fatal hypoglycemia in chickens. Overt biotin deficiency likely also causes abnormalities in glucose regulation in humans see Function.
One early human study reported lower serum biotin concentrations in 43 patients with type 2 diabetes mellitus compared to 64 non-diabetic control subjects, as well as an inverse relationship between fasting blood glucose and biotin concentrations A more recent double-blind , placebo-controlled study by the same research group showed that the same biotin regimen lowered plasma triglyceride concentrations in both diabetic and nondiabetic patients with hypertriglyceridemia In this study, biotin administration did not affect blood glucose concentrations in either patient group.
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 However, administration of chromium picolinate alone has been shown to improve glycemic control in diabetic subjects see the article on Chromium As a cofactor of carboxylases required for fatty acid synthesis , 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 also appeared to trigger the secretion of insulin in the pancreas of rats and improve glucose homeostasis Yet, reduced activity of ACC1 and ACC2 would be expected to reduce fatty acid synthesis and increase fatty acid oxidation, respectively.
Not surprisingly, it is currently unclear whether pharmacologic doses of biotin could benefit the management of hyperglycemia in patients with impaired glucose tolerance. Moreover, whether supplemental biotin lowers the risk of cardiovascular complications in diabetic patients by reducing serum triglycerides and LDL - cholesterol remains to be proven The finding that biotin supplements were effective in treating hoof abnormalities in hoofed animals suggested that biotin might also be helpful in strengthening brittle fingernails in humans Three uncontrolled trials examining the effects of biotin supplementation 2.
Although preliminary evidence suggests that supplemental biotin may help strengthen fragile nails, larger placebo -controlled trials are needed to assess the efficacy of high-dose biotin supplementation for the treatment of brittle fingernails. Biotin administration was found to reverse alopecia in children treated with the anticonvulsant , valproic acid see Drug interactions. Yet, 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, either as the free form that is directly taken up by enterocytes or as biotin bound to dietary proteins.
Egg yolk, liver, and yeast are rich sources of biotin. However, US national nutritional surveys have not yet been able to estimate biotin intake due to the scarcity and unreliability of data regarding biotin content of food. Food composition tables for biotin are incomplete such that dietary intakes cannot be reliably estimated in humans.
A study by Staggs et al.
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