Biotin (vitamin H)

Chief functions

• Essential for many body processes that manufacture and break down fats, protein, and carbohydrate
• Necessary for metabolism of glucose and formation of certain fatty acids

Possible benefits

• May minimize zinc deficiency symptoms
• Might play a role in gene expression
• Suggested as a treatment for brittle fingernails, particularly in women

Deficiency symptoms

• Rarely occurs—natural deficiency is unknown
• Dermatitis
• Depression
• Conjunctivitis
• Progressive hair loss and color
• Elevated blood cholesterol
• Anemia
• Loss of appetite
• Anorexia
• Nausea
• Lethargy
• Tingling and numbness in hands and feet
• Muscle pain
• Enlargement of liver

Toxicity symptoms

• None known (tested as high as 10 milligrams [mg]/day)

Stability

• Stable to heat
• Most cooking losses are caused by leaching into cooking water

Nutrient-nutrient reactions and absorption

• Incomplete knowledge of bioavailability
• Works with folic acid, pantothenic acid, and vitamin B12

DRI=Dietary Reference Intakes
mcg=microgram

Tolerable upper limits are not defined, because no toxicity symptoms are known with biotin and no data on adverse effects exist.

Dietary sources

• Best—organ meats, egg yolks, corn, tomatoes, and yeast
• Other—oatmeal, soybeans, mushrooms, peanuts, and most vegetables
• Note: In foods that contain wheat, the biotin is almost completely unavailable

Groups at highest risk for deficiency

• Individuals who eat raw egg whites, because this contains the protein avidin, which binds biotin
• Patients receiving long-term parental nutrition void of biotin
• Persons with long-term use of antibiotics
• People with long-term use of certain antiseizure medications

Other facts

• Intestinal bacteria can synthesize biotin
• Biotin is a sulfur-containing vitamin
• The body is able to recycle much of the biotin it has already used

References
Sizer F, Whitney E. Nutrition Concepts and Controversies. 11th ed. Belmont, CA: Thomson & Wadsworth; 2008:219-259.

Somer E. The Essential Guide to Vitamins and Minerals. New York, NY: Harper Collins Publishers; 1992:1-65, 224-246, 287-293.

Schlenker E, Long S. Essentials of Nutrition and Diet Therapy. 9th ed. St Louis, MO: Mosby Elsevier; 2007:107-144.

National Academy of Sciences, Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes: recommended intakes for individuals. Available at: http://fnic.nal.usda.gov/nal_display/index.php?info_center=4&tax_level=3&tax_subject=256&topic_id=1342&level3_id=5140. Accessed July 28, 2008.

Review Date 10/08
G-0802