Deficiencies are extremely rare, as intestinal bacteria naturally produce an excess of the body’s daily requirement.
Biotin can be found in a variety of foods that are normally consumed. Estimates are that the typical U.S. diet provides roughly 40 micrograms a day.
There are only a couple of foods that contain biotin in large amounts, including royal jelly, egg yolk, and brewer’s yeast. High levels are also found in milk, liver, and some vegetables like Swiss Chard. Additional sources include tomatoes, romaine lettuce, carrots, almonds, onions, cabbage, cucumber, and cauliflower. Goat’s milk, raspberries, strawberries, halibut, oats, and walnuts also contain some.
There do not appear to be any toxic effects from ingesting unusually large amounts of this nutrient.
The incidence of low circulating biotin levels has been associated with alcoholics, in those with a partial gastrectomy, burn patients, epileptics, the elderly, and athletes. Pregnancy and lactation may also be associated with an increased demand for biotin. Additionally, smoking may further accelerate deficiencies, especially in women.
Signs, symptoms & indicators of Biotin Requirement
Brittle fingernails
Since biotin is known to strengthen hooves in animals, Swiss researchers investigated the use of biotin in strengthening brittle fingernails in humans. An uncontrolled trial of 2.5mg biotin per day found improved firmness and hardness in almost all cases after an average treatment time of 5.5 months. [Z Hautkr 1989;64:pp.41-8]
Risk factors for Biotin Requirement
(High) raw egg white consumption
Biotin is a vitamin that can be bound by avidin, which is found in raw egg white. This binding prevents its absorption from the gastrointestinal tract. The routine consumption of raw egg white may reduce biotin absorption enough to induce a deficiency. Cooking deactivates avidin and makes biotin from other sources available for absorption once again.
Counter Indicators
(High) egg yolk consumption
Whether cooked or raw, egg yolk is so high in biotin that it overcomes the binding effect of avidin that results from consuming raw egg whites.
Recommendations for Biotin Requirement
Key
 | Strong or generally accepted link |
 | Proven definite or direct link |
 | Strongly counter-indicative |
 | Highly recommended |
Glossary
Biotin
An essential coenzyme that assists in the making of fatty acids and in the burning of carbohydrates and fats for body heat and energy. It is also essential for function of red blood cells and hemoglobin synthesis.
Fatty Acids
Chemical chains of carbon, hydrogen, and oxygen atoms that are part of a fat (lipid) and are the major component of triglycerides. Depending on the number and arrangement of these atoms, fatty acids are classified as either saturated, polyunsaturated, or monounsaturated. They are nutritional substances found in nature which include cholesterol, prostaglandins, and stearic, palmitic, linoleic, linolenic, eicosapentanoic (EPA), and decohexanoic acids. Important nutritional lipids include lecithin, choline, gamma-linoleic acid, and inositol.
Metabolism
The chemical processes of living cells in which energy is produced in order to replace and repair tissues and maintain a healthy body. Responsible for the production of energy, biosynthesis of important substances, and degradation of various compounds.
Aerobic
Using oxygen. For example, aerobic exercises such as running, swimming, bicycling or playing tennis use up lots of oxygen and burn up lots of calories and fat.
Bacteria
Microscopic germs. Some bacteria are "harmful" and can cause disease, while other "friendly" bacteria protect the body from harmful invading organisms.
Microgram
(mcg): 1/1,000 of a milligram in weight.
Yeast
A single-cell organism that may cause infection in the mouth, vagina, gastrointestinal tract, and any or all bodily parts. Common yeast infections include candidiasis and thrush.
Lactation
Production of milk; period after giving birth during which milk is secreted in the breasts.
Milligram
(mg): 1/1,000 of a gram by weight.
Gastrointestinal
Pertaining to the stomach, small and large intestines, colon, rectum, liver, pancreas, and gallbladder.
