Biotin is part of the water-soluble B-complex vitamins. As a group, the B-complex vitamins help the body convert carbohydrates into fuel used for energy. They help metabolize fats and proteins, and aid in proper function of the nervous system. The B vitamins are necessary for healthy skin, hair, eyes and liver.
Function of Biotin
Biotin, also called vitamin H, works as a coenzyme in the metabolism of protein, fats and carbohydrates. There are five biotin-dependent enzymes involved in the energy cycle. Biotin is important for embryonic growth, making it a crucial nutrient during pregnancy. As a supplement, biotin is used for preventing and treating biotin deficiency resulting from pregnancy, long-term tube feeding, malnutrition and rapid weight loss. Cosmetically, biotin is used for healthy hair, nails and skin.
Adequate Intake and Food Sources
Biotin is found in a variety of food sources, but it is not as abundant as other water-soluble vitamins. Egg yolk, liver, yeast and soybeans are good sources of biotin. In 1998, the Food and Nutrition Board of the Institute of Medicine established an "Adequate Intake" for biotin. This was done because there was insufficient evidence to calculate a Recommended Dietary Allowance. The AI varies with age and health conditions. The AI for healthy men and women over the age of 19 is 30 mcg per day
Biotin Toxicity and Side Effects
Biotin is not known to be toxic. As a water-soluble vitamin, excess biotin is excreted by the kidneys through urine. There is one reported case of eosinophilic pleuropericardial effusion in an elderly woman taking a combination of 10,000 mcg per day of biotin -- and 300 mg per day of pantothenic acid -- for two months. Eosinophilic pleuropericardial effusion is a life-threatening disease in which blood and air fill the pleural space surrounding the lungs, causing an infection.
According to the Linus Pauling Institute, dosages of up to 5,000 mcg per day in healthy individuals -- taken for two years -- were not associated with adverse affects. In individuals with hereditary biotin metabolism disorders, dosages of 200,000 mcg per day were well tolerated. People on anti-convulsant and sulfa medication might experience biotin deficiency. Little is known about the amount of biotin needed to promote optimal health. Consult your physician prior to starting a biotin supplement.