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Biotin: an essential B vitamin

Published: January 19, 2018

Cranberries are a good source of biotin
Cranberries are a good source of biotin

Biotin belongs to the B vitamin family, and may also be referred to as vitamin B7, vitamin H and coenzyme R.

Along with the other members of this family (thiamin, niacin, riboflavin, folate, vitamin B6, vitamin B12, and pantothenic acid), Biotin is water soluble and is considered an essential vitamin despite being synthesised by your gut bacteria.
The amount of biotin synthesised by your gut bacteria that is absorbed into your body from your large intestine, may not be sufficient to meet your biotin requirements.
Hence the need for a daily dietary source of biotin.
Functions
Biotin’s primary function is as part of several coenzymes involved in various metabolic processes. Biotin may also be involved in gene expression and cell cycle although biotin’s role in these non-coenzyme roles is not yet fully understood.
Biotin’s coenzyme roles include:

  • Biotin and pyruvate carboxylase: Energy metabolism particularly the replenishment of oxaloacetate a key molecule in the Krebs cycle which maintains energy metabolism. This metabolic reaction also requires magnesium.
  • Biotin and acetyl CoA carboxylase: Fatty acid synthesis and the formation of malonyl CoA from acetate.
  • Biotin and Propionyl CoA carboxylase: Metabolism of amino acids (isoleucine, threonine, methionine) and odd-numbered chain fatty acids through the conversion of propionyl CoA to methylmalonyl CoA. This metabolic reaction requires magnesium.
  • Biotin and beta-methylcrotonyl CoA carboxylase: Catabolism of leucine and some isoprenoid compounds through the conversion of beta-methylcrotonyl CoA to beta-methylglutaconyl CoA. This metabolic reaction requires magnesium.
  • Gluconeogenesis: Biotin is required for the synthesis of glucose from a non-carbohydrate source such as an amino acid or glycerol.

Biotin is also involved in hair, nail and skin growth, and may help stabilise blood-glucose levels in people with non-insulin diabetes.

The chemical structure of biotin
The chemical structure of biotin
AI or Adequate Intake
An RDA (recommended dietary intake) has not been determined for biotin, but the AI although more tentative than an RDA is thought to be sufficient to use as a goal for dietary intake.
AI for biotin:

  • Up to 5 months    = 5 mcg/day

Follow the link to the full article to continue learning about biotin.

Related Topics

Diet  Health  Metabolism  Vitamins  Your Body 

References

1.
Gropper, S.S., Smith, J.L. & Groff, J.L. (2005). Advanced Nutrition and Human Metabolism (4thEd.). Belmont, CA: Thomson Wadsworth.
2.
Whitney, E. & Rady Rolfes, S. (2005). Understanding Nutrition. Belmont, CA: Thomson Wadsworth
3.
Dieticians of Canada