Biotin and its Role in Human Physiology

What is Biotin?

Biotin, also known as vitamin B7 or vitamin H, is a water-soluble B vitamin that plays a crucial role in various metabolic processes. It acts as a coenzyme for carboxylase enzymes, which are involved in the metabolism of fatty acids, carbohydrates, and amino acids.

Biotin's Functions in the Body

• Carbohydrate Metabolism: Supports the breakdown of glucose for energy.
• Fatty Acid Synthesis: Essential for the production of fatty acids.
• Amino Acid Metabolism: Aids in the processing of amino acids, the building blocks of protein.
• Gluconeogenesis: Assists in the production of glucose from non-carbohydrate sources.

Biotin Deficiency

Biotin deficiency is relatively rare due to its presence in a variety of foods and its production by gut bacteria. However, certain conditions or factors can increase the risk of deficiency, including:

• Genetic disorders: Biotinidase deficiency is a rare inherited disorder that impairs the body's ability to release biotin from proteins.
• Prolonged use of antibiotics: Can disrupt gut bacteria that produce biotin.
• Consumption of raw egg whites: Avidin, a protein found in raw egg whites, binds to biotin and inhibits its absorption. Cooking eggs denatures avidin.
• Certain medical conditions: Such as Crohn's disease.

Symptoms of deficiency can include hair thinning, skin rash, neurological symptoms, and brittle nails.

Dietary Sources of Biotin

Biotin is found in a wide range of foods, including:

• Meat (organ meats, especially liver)
• Eggs
• Nuts and seeds (almonds, peanuts, sunflower seeds)
• Sweet potatoes
• Salmon
• Avocados
• Yeast

Biotin Supplementation and Reported Effects

Biotin supplements are available over-the-counter. While often marketed for improving hair, skin, and nail health, rigorous scientific evidence supporting these claims, particularly in individuals without a deficiency, is limited. Studies have shown some benefit in individuals with underlying biotin deficiencies or specific conditions like brittle nail syndrome.

It is important to note that biotin supplementation can interfere with certain laboratory tests, leading to falsely elevated or decreased results. Individuals taking supplements should inform their healthcare provider before undergoing blood tests.

Recommended Dietary Intake

Since research is ongoing, there isn't a definitive consensus. However, adequate intake (AI) levels have been established. These values represent the amount assumed to ensure nutritional adequacy. The AI typically recommended for adults is 30 micrograms per day.