First isolated in 1936, Biotin is a water soluble vitamin. Biotin plays an important role in carbohydrate metabolism, synthesis of fatty acids, the Citric Acid Cycle (which generates energy during aerobic respiration), gluconeogenesis (the creation of sugar from non-carbohydrates), cell growth, and healthy skin & hair.
Biotin can be produced by gut bacteria, so deficiency is extremely rare. Recommended minimum intake is 30mcg, however the normal American Diet provides approximately 28mcg - 42mcg per day. Deficiency can occur in individuals who have a rare genetic disorder, those on very restrictive biotin deficient diets, patients on intravenous feeding, and anyone eating large amounts of raw egg whites (which contain a biotin binding agent known as Avidin). Symptoms include hair loss, a red rash, anemia, decrease in white blood cell function, high cholesterol, loss of appetite, nausea, lethargy, muscle pain, numbness of the extremities, seborrheic dermititis, intense depression, sleeplessness, hallucinations, and can inhibit retention of lean body mass.
As a water soluble compound Biotin is very difficult to overdose on. 5mg daily intake has been shown to be completely safe, with rare problems occurring at larger doses, though even at 200mg few serious symptoms were encountered. Symptoms can include: Slowed insulin release, increased Vitamin C/B6 requirements, skin eruptions, and increased blood sugar levels. (If you’re looking at the insulin/blood sugar effects and wondering if that’s actually bad thing you’re not alone).
While there are few good studies showing value for healthy individuals in taking increased amounts of Biotin, there is also very little material showing any downside to doing so. It has been shown to improve blood sugar control in diabetics, improve hair condition, strengthen fingernails, and normalize fat metabolism in weight loss programs. The U.S. RDA is 300mcg, though some countries like Australia don’t even have a recommended amount. Personally I’d say that Biotin supplementation is optional, but given it’s potential positive effects on blood sugar & insulin levels I’d probably shoot for an intake between 300mcg and 2mg. That range is likely to provide some benefit with almost no chance of adverse effects.
Common food sources include: Liver, peanuts, chocolate, oatmeal, eggs, peas, cauliflower, mushrooms, hazelnuts, lima beans, molasses, oysters, halibut, bacon, butter, corn, chicken, milk, whole wheat, salmon, bananas, beef, onions, grapefruit, carrots, and cheese.
Sulfa drugs, estrogen, anticonvulsant drugs, and alcohol can raise biotin intake requirements. Biotin can reduce adverse effects from pantothenic acid and zinc deficiencies.
