Biotin is a B-complex vitamin needed for different bodily functions and is available in food and via vitamin supplements. Sufficient biotin dosage is dependent upon age and also on health, as some medical conditions can cause a deficiency in this nutrient. Due to the rarity of deficiencies of this vitamin, no recommended daily allowance (RDA) quantities have been established. In the absence of RDA values, the medical community has provided a general guideline called normal daily recommended intake, which are: 10 to 20 micrograms (mcg) for birth to three years of age, 25 mcg for four to six years of age, 30 mcg for seven to 10 years of age, and 30 to 100 mcg for adolescents and adults. Those taking biotin supplements should be familiar with general information regarding it, such as food sources, uses, and possible interactions.
Whenever possible, doctors advise using food sources to obtain an adequate biotin dosage, because food contains other substances that enable vitamins to work. Protein sources of biotin include liver, salmon, and soy flour, while non-protein sources include carrots, bananas, and cauliflower, as well as cereals and yeast. Some amount of this vitamin is lost in the process of cooking and preserving.
Biotin deficiency is the only condition that supplements containing a biotin dosage are considered likely effective for treating. Symptoms of this deficiency include the following: thinning hair; scaly red rash surrounding the eyes, nose, and mouth; and tingling in the arms and legs. Mental signs include depression, listlessness, and hallucinations.
Aside from biotin deficiency, supplements containing a biotin dosage are also sometimes used for treating other conditions. Doctors consider the vitamin to be possibly effective for treating skin rash in infants, known as seborrheic dermatitis. Although evidence is insufficient to rate its effectiveness, preliminary studies show that biotin may be beneficial in treating hair loss, diabetes, and diabetic nerve pain, as well as brittle fingernails and toenails.
Those taking biotin supplements should be aware of adverse effects, along with nutrient or drug interactions. The supplements are considered likely safe for most people and are generally well-tolerated within the recommended dosage limits, but they are considered only possibly safe for women who are pregnant or breastfeeding. Raw egg whites contain an ingredient that prevents biotin from being absorbed in the intestinal tract, and eating two or more daily for several months has produced biotin deficiency. There have been reports that those taking anti-seizure medication have reduced levels of biotin, and also, those on long-term therapy with sulfa or other antibiotics may need to increase their dietary intake of this vitamin.
