Biotin

By: Chinwe Coretta, Elizabeth Bowers, Tiffany Cox, Rebekah Jewell, Brant Johnson, David Overman, Jay Thakkar, Cristina Alcaraz, Katherin Davis

 

The discovery of biotin has a similar history to that of many other vitamins in which no one single person can be accredited to its identification. The full function and structure of biotin, also known as Vitamin H or Vitamin B7, was not completely understood until the first few decades of the 1990s. In 1916, W.G. Bateman became one of the first notable contributors to the discovery of biotin after finding toxic levels of the vitamin within an organism following the addition of excess raw egg white to a nutritionally adequate diet. It was not until 1935, however, that scientists Fritz Kogl and Paul Gyory suggested the name “biotin” for the pure vitamin concentrations that they derived.

 

The dietary sources of biotin are numerous and varied. By far the best sources of the vitamin in the human diet are from organ meats, such as kidney and liver. There are many other food sources of biotin including; egg yolks, cooked oats, bananas, soybeans, brewer’s yeast, rice bran, nuts, milk, and wheat. Natural bacteria that live in the small intestines in humans also produce supplemental biotin. When considering dietary sources of biotin, sources that lower its amount must also be taken into account. Egg whites have a chemical that binds to biotin very tightly preventing its uptake in the body’s bloodstream. Also because of the micro flora that produce biotin in the human intestines, prolonged use of antibiotic medication can lower the amount of biotin within the body.

 

Biotin deficiency is extremely rare in the US because the population gets an enough of the vitamin from their food sources. A deficiency is usually associated with either a predisposed disease or with the consumption of excessive amounts of raw egg whites over a period of months to years. Some of the diseases associated with biotin deficiency have to do with the absorption of enzymes in the small intestines. Diabetics are also at risk for biotin deficiency because they often have problems absorbing enzymes. Consuming mass amounts of raw egg whites (approximately 20 a day) can lead to a deficiency because the protein Avidin, found in raw egg whites, binds to biotin and makes it impossible for the small intestines to absorb the vitamin. Also, pregnant women commonly undergo a biotin deficiency during a normal pregnancy because the developing fetus requires large amounts for growth. The main symptoms of biotin deficiency are brittle nails, hair loss, muscle pain, nausea, fatigue, anemia and dry skin. This deficiency can be treated with a biotin supplement, which is more commonly used for cosmetic purposes since biotin is known for increasing nail and hair growth. Also, eating more biotin-rich foods, such as meat, grapefruit, yeast, and cooked eggs, can treat biotin deficiency.

 

Side effects from having an overdose of biotin are rare. Because it is so easily excreted in urine and feces, the body can simply get rid of any excess. If there is an overdose of biotin in the body, there may be a noticeable increased need to urinate or abnormal sweating frequency. In rare cases, an overdose of the vitamin can be life threatening. When biotin is taken in excess along with vitamin B5, it is possible to develop a condition called eosinophilic pleuropericardial effusion. In mice, excess biotin resulted in a decreased size of the placenta leading to an increased rate of miscarriages and birth defects. Nonetheless, this side effect has not been observed in pregnant women. Another benign consequence of an excess of the vitamin is also rapid nail and hair growth.

 

According to both the American Journal of Clinical Nutrition and the U.S. National Library of Medicine, the diet requirements for biotin are not known. In his article in the American Journal of Clinical Nutrition, Hamid Said explains that this lack of scientific information is due to “a lack of analytic tools to quantitate biotin in body fluids and the metabolic disturbances caused by biotin deficiency and a lack of experimental validation of putative indexes of biotin status.” Although there is no recommended dietary allowance established for biotin, safe and adequate intakes have been suggested (Said). The adequate intakes for biotin are 7 mcg for infants 0-12 months, 8 mcg for children 1-3 years, 12 mcg for children 4-8 years, 20 mcg for children 9-13 years, 25 mcg for adolescents 14-18 years, 30 mcg for adults over 18 years and pregnant women, and 35 mcg for breast-feeding women (U.S. National Library of Medicine).

  

Although biotin is produced in excess by the intestinal bacteria of the body, it is found artificially in many hair, nail, and shampoo products because the vitamin is essential for proper hair and nail growth. Considering that biotin cannot be readily absorbed through neither the hair or the skin, companies who promise hair and skin improvement through superficial application of biotin produce inefficient products. Biotin is used to treat cradle cap (Seborrheic dermatitis), which is a common inflammatory skin condition that causes flaky and/or scaly skin in infants. It is also believed to treat premature graying of hair in individuals with low biotin levels. Uncombable hair syndrome in children can also be treated with Biotin supplementation. It is also believed to help maintain control of blood sugar levels in people suffering from type 1 and type 2 diabetes although no concrete evidence has been shown to prove this theory.

 

 

 


 

References

 

    http://www.buzzle.com/articles/too-much-biotin.html

    "Biotin." Medline Plus. U.S. National Library of Medicine, 30 Sep 2010. Web. 7 Oct 2010. <http://www.nlm.nih.gov/medlineplus/druginfo/natural/313.html>.

    Said, Hamid. "Biotin: the forgotten vitamin." American Journal of Clinical Nutrition. 75.2 (2002): 179-180. Print.

    http://www.vitamins-supplements.org/biotin-sources.php

    http://www.vitaminsdiary.com/vitamins/vitamin-b8.htm

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    "Vitamin Basics: Biotin." Vitamin Basics: Homepage. Web. 08 Oct. 2010. <http://www.vitamin-basics.com/index.php?id=52>.

    http://www.orentreich.org/Biotin.pdf

    http://www.vitamin-basics.com/index.php?id=61

    B Wolf, RE Grier, JR Secor McVoy, GS Heard. Biotinidase deficiency: A novel vitamin recycling defect. 1985. Volume 8. 53-58. Journal of Inherited Metabolic Disease.