Issue #60 : A-Z of Nutrition: Biotin
Biotin is the eighth and final true B vitamin that was first discovered as the factor that protected against the toxicity of raw egg whites. Subsequently, a biotin-binding factor was found in egg white - the effect of which was overcome by adding biotin to the diet.
What does it do?
Like many of the other B vitamins, biotin is involved in the intermediary metabolism of carbohydrates, energy and fats. It is of central importance in lipogenesis (fat manufacture), gluconeogenesis (glycogen manufacture) and branched chain amino acid metabolism.
What are the deficiency signs?
Biotin deficiency is rare in human adults except in those who have consumed large amounts of raw eggs. The symptoms then show themselves as fine scaly dermatitis and hair loss. More extreme experimental depletion of biotin leads to anorexia, nausea, depression and hallucinations. All these symptoms are reversible upon injection of biotin. Biotin deficiency is more common in babies and leads to the skin conditions seborrhoeic dermatitis and desquamating erythroderma (Leiner's disease).
Is it toxic?
Biotin has been administered to infants in dosages of up to 40 mg without side effects, and is regarded as a perfectly safe vitamin even at extremely high levels.
Who should supplement?
Biotin may give relief to those with seborrhoeic dermatitis and Leiner's disease (1).
Biotin supplements are sometimes recommended to candida albicans sufferers because it is thought that biotin may prevent Candida from changing into its invasive fungal form.
Biotin has also been shown to be of value in the treatment of brittle fingernails, acne, hair fragility and alopecia (2).
Intake levels: Micrograms (µg)
RDA: 150
Upper Safe Level:
Long term 2500
Short term 2500
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Which foods?
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Micrograms(µg/100g)
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Brewer's yeast
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0.08
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Pig's kidney
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0.032
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Yeast extract
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0.027
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Pig's liver
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0.027
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Wheat bran
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0.014
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Eggs, cooked (each)
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0.012
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Chicken
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0.010
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References
- Soini Y et al. Aberrant accumulation of p53 associates with Ki67 and mitotic count in benign skin lesions. Br J Dermatol, 131;4:514-520, 1994.
- "Handbook of Dietary Supplements", Pamela Mason, Blackwell Science, 1995
- Vitamin and Mineral Safety Council for responsible nutrition: 1997.
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