Also Known As: Vitamin B7, Biotin
Biotin, also known as Vitamin H or Coenzyme R, is a water-soluble B-complex vitamin (vitamin B7) discovered by Bateman[who?] in 1916[chronology citation needed]. It is composed of a ureido (tetrahydroimidizalone) ring fused with a tetrahydrothiophene ring. A valeric acid substituent is attached to one of the carbon atoms of the tetrahydrothiophene ring. Biotin is a coenzyme in the synthesis of fatty acids, isoleucine, and valine, and it plays a role in gluconeogenesis.
Health and Diet
Diabetics may benefit from biotin supplementation. In both insulin-dependent and non-insulin-dependent diabetics deficient in biotin, supplementation with biotin can improve blood sugar control and help lower fasting blood glucose levels, in one study the reduction in fasting glucose approached 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.
Hair and nail problems
The signs and symptoms of biotin deficiency include hair loss which progresses in severity to include loss of eyelashes and eyebrows in severely deficient subjects, as well as nails that break, chip, or flake easily. Biotin supplements are available in most pharmacies. The recommended dose to treat deficiency for adults varies and can be from 3,000 mcg per day for brittle fingernails up to 7,000 to 15,000 mcg per day for diabetics.
Palmo Plantar Pustulosis
Patients with palmoplantar pustulosis had metabolic derangements of glucose and fatty acids as well as immune dysfunction derived from biotin deficiency, which led to abnormal manifestations of skin, bone and other tissues and organs. All of the clinical, metabolic and immune disorders were improved by biotin administration. These findings indicate that biotin deficiency was implicated in the outbreak and exacerbation of the disease and its complications. Supplementary addition of a probiotic agent to the biotin treatment intensified the therapeutic effect of the vitamin. Additionally, patients with psoriasis vulgaris, systemic lupus erythematosus, atopic dermatitis or rheumatoid arthritis also had biotin deficiency with the subsequent metabolic abnormalities and immune dysfunction, and so the biotin treatment provided beneficial effects in the therapy of the diseases, as in the case of palmoplantar pustulosis.
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.
Biotin is widely used throughout the biotech industry to conjugate proteins for biochemical assays. Biotin's small size means the biological activity of the protein will most likely be unaffected. This process is called biotinylation. Because both streptavidin and avidin bind biotin with high affinity (Kd of 10−14 mol/L to 10−15 mol/L) and specificity, biotinylated proteins of interest can be isolated from a sample by exploiting this highly stable interaction. The sample is incubated with streptavidin/avidin beads, allowing capture of the biotinylated protein of interest. Any other proteins binding to the biotinylated molecule will also stay with the bead and all other unbound proteins can be washed away. However, due to the extremely strong streptavidin-biotin interaction, very harsh conditions are needed to elute the biotinylated protein from the beads (typically 6M Guanidine HCl at pH 1.5), which often will denature the protein of interest. To circumvent this problem, beads conjugated to monomeric avidin can be used, which has a decreased biotin-binding affinity of ~10−8 mol/L, allowing the biotinylated protein of interest to be eluted with excess free biotin.
ELISAs often make use of biotinylated primary antibodies against the antigen of interest, followed by a detection step using streptavidin conjugated to a reporter molecule, such as Horseradish peroxidase.
Animal studies have indicated few, if any, effects due to high level 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, in particular, when used in the treatment of metabolic disorders causing sebhorrheic dermatitis in infants.