Vitamin B7: Biotin

Vitamin B7: Biotin

Authored By Murigi

An overview of biotin

Biotin is the other name for vitamin B7. The two terms for the vitamin are used interchangeably throughout this article. Some people also refer to it as vitamin H. This is because, the vitamin is known for its hair strengthening properties. The cosmetic industry has built on this fact to create many hair products with the vitamin as one of the ingredient. Apart from the hair-health improving properties, , biotin possesses many more benefits that support overall health. Vitamin B7 is water soluble and a member of the 8 vitamins that make up the vitamin B-complex. The body’s stores of the vitamin cannot last for any significant period of time and so it must be replenished regularly through diet and nutritional supplements.

Functions of vitamin B7 in the body

Like other vitamins in the B-complex group, vitamin B7 plays a role as a coenzyme in the production of energy from carbohydrates. It exists as free or protein-bound biotin in the body. For it to be available to the body an enzyme called biotinadase has to break the protein bond. This enzyme is also important in the recycling of biotin. Other functions of biotin include:
  • Metabolism of fats
  • Metabolism of proteins
  • Metabolism of amino acids
  • Supports the regulation of chromatins
  • Supports gene expression functions

Symptoms of vitamin B7 deficiency

Obvious signs of biotin deficiency are rare. When these symptoms occur, they may include:
  • Scarce, thin and falling hair
  • Sores at the corners of the mouth (cheilitis)
  • Tongue color changes to magenta
  • Dry eyes
  • Anorexia
  • Lack of sleep
  • Chronic fatigue
  • Mood changes including depression. Other neurological disorders that may occur include:
    • Hallucinations
    • Loss of coordination
    • Seizures
    • Numbness
    • Tingling sensations of the extremities
  • Dry and scaling skin
  • A red and scaly rash may be seen around the eyes, the nose, the genital area and the mouth.
  • Abnormal fat distribution on the face which gives what has been described as biotin deficient faces
  • Poor immunity and susceptibility to infections due to bacteria and fungi.

Who is at risk of developing biotin deficiency?

There are genetic, dietary and lifestyle factors that can increase the risk of developing biotin deficiency. These include:
  • People with an inherited disorder of biotin metabolism. These include biotinadase deficiency and biotin transport deficiency among other disorders.
  • This has been found to increase the breakdown of biotin. One study found this to be a risk factor for pregnant mothers who smoked. It not only exposed them to marginal biotin deficiency, but it also exposed their unborn babies to congenital malformations due to the vitamins deficiency.
  • Prolonged intravenous feeding without biotin
  • Pregnancy increases demand for biotin
  • Babies formula-fed without biotin
  • Liver disease
  • Severe malnutrition
  • Prolonged use of antibiotics interferes with gut friendly microorganisms. Some of these are needed for biotin synthesis in the gut.
  • Low-carbohydrate, high fat diet
  • Excessive alcohol consumption
  • A diet that consists of mainly processed foods
  • Renal disease
  • Prolonged use of some anticonvulsant medications
  • Consumption of raw eggs. Although this may not be an issue to vegans, it is good to know that egg white contain a protein called avidin. This binds biotin making it unavailable to the body. Cooking deactivates this protein.

Sources of biotin

There are three main sources of biotin
  1. From some types of the food we eat
  2. Synthesis by bacteria in the gut
  3. Through biotin nutritional supplements or composite supplements with biotin as one of the ingredients
Food sources of biotin include both plant and animal sources. Here are listed only plant-based sources. They include:
  • Avocado
  • Raspberries
  • Brewer’s yeast
  • Raw cauliflower
  • Nuts such as almonds, walnuts and peanuts
  • Mushrooms
  • Bananas
  • Whole grains
  • Legumes such as beans

Biotin from gut bacteria

Many of the bacteria that colonize the large intestines can synthesize biotin. It is not clear whether the free biotin that they produce gets absorbed into the body or not but a study using gut lining cultured cells suggests that this is possible.

Biotin nutritional supplements

These are available as a sole vitamin B7 supplement or as an ingredient in a vitamin B-complex supplement. On many occasions, it is part of a multivitamin-mineral supplement.

Science backed health benefits of biotin

  1. Supports healthy fetal development
Preliminary animal studies indicate that even marginal biotin deficiency can lead to fetal malformations. If combined with folic acid before and during pregnancy, then many birth defects can be prevented.
  1. May help in healthy glucose metabolism
Many studies have shown that biotin on its own or in combination with chromium helps to normalize blood sugar. One study in China suggests that this comes about through two mechanisms. One way is by encouraging storage of sugar (glycogen) and the other is by reducing the rate of glucose synthesis.
  1. Supports skin health
Good skin health includes healthy hair and nails. A study published in the Journal of Clinical and Aesthetic Dermatology of November 2012, found that biotin supplements helped to increase, hair count, and hair volume and enhanced appearance. It is thought to increase the actual hair growth but available study findings are not yet conclusive about this. Another study found that the vitamin improved brittle fingernails.
  1. Helps to reduce peripheral neuropathy
This may be due to diabetes complications or as a result of dialysis. Neuropathy may also occur due to other causes including nutritional deficiencies.
  1. Supports healthy DNA functions
This helps tin the prevention of fetal malformations and in maintaining healthy tissues.

More benefits of vitamin B7

These include:
  • Prevention of baldness
  • As an adjunct in the management of Parkinson’s disease
  • In the management of Chrohn’s disease
  • May play a role in the treatment of multiple sclerosis disorder
  • Treats neonatal rash called seborrheic dermatitis.

Safety of vitamin B7

When taken within the normal recommended dose, no adverse effects have been observed. Pregnancy and breastfeeding increases the need for biotin and it is considered safe in these groups. Doses of up to 200mg per day for people with the vitamins metabolism disorder have been well-tolerated. In the treatment of multiple sclerosis, doses of up to 600mg have been used for extended periods of time without any ill-effects.

References and further research

Jitrapakdee, S., Maurice, M. S., Rayment, I., Cleland, W. W., Wallace, J. C., & Attwood, P. V. (2008). Structure, Mechanism and Regulation of Pyruvate Carboxylase. The Biochemical Journal, 413(3), 369–387. Tong, L. CMLS, Cell. Mol. Life Sci. (2005) 62: 1784. doi:10.1007/s00018-005-5121-4 Leucine Metabolism in T Cell Activation: mTOR Signaling and Beyond Adv Nutr 2016 7: 798S-805S Institute of Medicine (US) Standing Committee on the Scientific Evaluation of Dietary Reference Intakes and its Panel on Folate, Other B Vitamins, and Choline. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington (DC): National Academies Press (US); 1998. 11, Biotin. Available from: Zempleni, J., Gralla, M., Camporeale, G., & Hassan, Y. I. (2009). Sodium-Dependent Multivitamin Transporter Gene Is Regulated at the Chromatin Level by Histone Biotinylation in Human Jurkat Lymphoblastoma Cells. The Journal of Nutrition, 139(1), 163–166. Food and Nutrition Board, Institute of Medicine. Biotin. Dietary Reference Intakes: Thiamin, Riboflavin, Niacin, Vitamin B6, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, D.C.: National Academy Press; 1998:374-389 Regula Baumgartner, E. and Suormala, T. (1999), Inherited defects of biotin metabolism. BioFactors, 10: 287–290. doi:10.1002/biof.5520100229 Sealey, W. M., Teague, A. M., Stratton, S. L., & Mock, D. M. (2004). Smoking accelerates biotin catabolism in women. The American Journal of Clinical Nutrition, 80(4), 932–935. Magnúsdóttir, S., Ravcheev, D., de Crécy-Lagard, V., & Thiele, I. (2015). Systematic genome assessment of B-vitamin biosynthesis suggests co-operation among gut microbes. Frontiers in Genetics, 6, 148. Said, H. M. (2009). Cell and Molecular Aspects of Human Intestinal Biotin Absorption. The Journal of Nutrition, 139(1), 158–162. Mock DM. Biotin status: which are valid indicators and how do we know? J Nutr. 1999; 129(2S Suppl):498S–503S High doses of biotin in chronic progressive multiple sclerosis: A pilot study Sedel, Frédéric et al. Multiple Sclerosis and Related Disorders , Volume 4 , Issue 2 , 159 - 169


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