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vitamin
biotin
Nutrition
definition
Biotin:
» overview:
Water soluble B vitamin which acts as a coenzyme in the making of fatty acids and oxidation of fatty acids and carbohydrates.
Biotin was recognized as a growth factor for microorganisms in 1924. It was originally named Bios II, one of 3 growth factors. The other factors were named vitamin H and coenzyme R. Later, it was found the 3 factors were all the same.
Biotin was synthesized in 1943 and recognized as a compound which protected rats against egg white injury. Rats fed raw egg whites developed eczema and alopecia around the eyes. A substance in egg white, avidin, was found to cause the illness.
» chemistry:
Stable to heat and water soluble, biotin is sensitive to alkalai and oxidation.
» metabolism:
Biotin is rapidly absorbed, chiefly intact, throughout the small intestine.
» Chinese:
Nourishes the Xue (Blood) and the Skin; relaxes the Liver; tonifies the Heart Xue (Blood); calms the Shen (Spirit).
» function:
Biotin is a cofactor required in the synthesis and oxidation of fatty acids.
It is involved in the deamination of amino acids such as serine, aspartic acid, and threonine.
Biotin is essential for carboxylation: the addition and removal of C02 from certain active compounds.
It is required for the synthesis of pancreatic amylase and niacin.
Biotin may be involved in the synthesis and release of insulin.
» requirements:
RDA:
Infants and children: 5 to 20 mg
Adults: 30 mg
Nursing women: 35 mg
Optimal daily intake: 300 mcg
Lab: microbial assay: blood and urine: has a wide variation.
» food sources:
Liver, meat, eggs, legumes, nuts, milk, most vegetables, grapefruit, tomato, watermelon, strawberries, brewer's yeast, unpolished rice, soybeans
Biotin is also normally produced in the intestines if there is sufficient healthy intestinal flora
Best Sources of Biotin:
Food Amount mg
Liver, chicken 3 oz 146
Liver, calf 3 oz 45
Kidney, lamb 3 oz 36
Rolled oats, uncooked 1/2 cup 16
Egg, hard cooked 1 large 10
Haddock 3 oz 5
Milk 1 cup 5
Halibut 3 oz 4
Camembert cheese 2 oz 3
Chicken, dark meat 3 oz 3
Cod 3 oz 3
Salmon 3 oz 3
Tuna, canned 3 oz 3
Orange 1 med 2
Tomato 1 med 2
Whole wheat bread 1 slice 2
(USDA: Composition of Foods. USDA Handbook #8 Washington DC, ARS, USDA, 1976-1986)
» deficiency:
Biotin deficiency causes early changes to occur in the skin.
Signs and symptoms are similar to B1 deficiency.
Dermatitis, characterized by scaliness or hardening, which frequently starts in the region of the eye is often the first symptom.
Other signs and symptoms are anorexia, lassitude, and nausea.
Loss of hair and muscular atrophy follow.
There is evidence that deficiency also results in the elevation of both glucose and cholesterol levels.
» therapeutics:
Seborrheic dermatitis: 5-10 mg in infants
(Nisenson. J. Pediat. 81:630-31,1972)
SIDS: The levels of biotin in the livers of infants who had died of sudden infant death syndrom (SIDS; cot death) were significantly lower than those in livers of infants of similar age, who had died of explicable causes.
(Johnson AR, Hood RL, Emery JL. Nature 1980 May 15;285(5761):159-160.)
Case Study: A baby at age 3 months began to have seizures (around 10/day). Many things were tried. By 14 months, all of her hair had fallen out, even her eyebrows and eyelashes. A red, scaly rash covered her body and her eyes were edematous and inflamed. She became irritable and sleepy as her muscles grew weak and her gait unsteady. Lactic acid levels rose to 2x normal. 12 hours after administering 10mg biotin orally, blood levels of lactic acid dropped to normal. Within 48 hours all blood chemistries returned to normal and, over the next 4 months, her entire development returned to normal.
(Mock DM, et al. N Engl J Med 1981 Apr 2;304(14):820-823.)
Diabetes mellitus
(Coggeshall. Annal N.Y. Acad Sci 447:389-92,1985.)
Cardiovascular disease: Biotin has the effect of lowering cholesterol.
Muscle pains
» drug-related therapeutics:
Uremic patients on dialysis
» dosage:
Maintenance dose: 200 mcg
Therapeutic dose: 300 mcg - 3 mg
» toxicity:
None known to date
» contraindications:
None known to date
» antagonists:
Antibiotics
Avidin
Sulfa drugs
footnotes
Coggeshall. Biotin Satus and Plasma Glucose in Diabetics. Annal N.Y. Acad Sci 447:389-92,1985. Abstract: Patients with insulin-dependant diabetes mellitus were removed from insulin therapy and treatment with biotin 16mg daily or placebo for one week. Fasting blood sugar levels fell significantly in patients on biotin, while they rose as expected in patients on placebo. Since biotin levels typically are elevated in diabetics, the authors speculate that it may be abnormally bound and/or biologically unavailable.
Johnson AR, Hood RL, Emery JL. Biotin and the sudden infant death syndrome. Nature 1980 May 15;285(5761):159-160. Abstract: The livers of SIDS infants contained considerably lower levels of biotin than normal. Researchers in Australia and Great Britain have found that SIDS closely resembles a disorder in which marginally biotin deficient chickens die when subjected to mild stress. The chickens did not display any typical biotin deficient signs and symptoms but had low levels of biotin in their livers.
Kirschmann and Dunne, pp. 36-37
Marz, Russell. Medical Nutrition From Marz. Second Edition. Portland, OR. 1997.
Mock DM, deLorimer AA, Liebman WM, Sweetman L, Baker H. Biotin deficiency: an unusual complication of parenteral alimentation. N Engl J Med 1981 Apr 2;304(14):820-823. Abstract: A baby at age 3 months began to have seizures (around 10/day). Many things were tried. By 14 months, all of her hair had fallen out, even her eyebrows and eyelashes. A red, scaly rash covered her body and her eyes were edematous and inflamed. She became irritable and sleepy as her muscles grew weak and her gait unsteady. Lactic acid levels rose to 2x normal. 12 hours after administering 10mg biotin orally, blood levels of lactic acid dropped to normal. Within 48 hours all blood chemistries returned to normal and, over the next 4 months, her entire development returned to normal.
Nisenson. Treatment of Seborrheic Dermatitis with Biotin and Vitamin B Complex. Letter to Ed. J. Pediat. 81:630-31,1972. Abstract: Infants with extensive seborrheic dermatitis unresponsive to local treatment were fed liver and egg yolk (both of which have very high biotin levels in them; biotin was unavailable at the time). They were fed early in the first month or two of life, with good clinical improvement. Those infants with more widespread involvement improved more rapidly when B complex was added to the regime (1cc 1x or repeated every week).
USDA: Composition of Foods. USDA Handbook #8 Washington DC, ARS, USDA, 1976-1986