Biotin, also known as vitamin B7 or vitamin H, is a water-soluble B-vitamin that the human body cannot produce on its own. As an essential nutrient, it must be obtained through diet or supplements. This vitamin plays a role in various bodily processes. It is necessary for maintaining metabolic balance and supporting the health of different body systems.
Essential Role in Metabolism
Biotin functions as a coenzyme for several carboxylase enzymes, which add a carboxyl group to other compounds. In humans, four biotin-dependent carboxylases exist: pyruvate carboxylase, acetyl-CoA carboxylase, propionyl-CoA carboxylase, and beta-methylcrotonyl-CoA carboxylase. These enzymes are involved in transforming fats, carbohydrates, and proteins into usable energy for the body.
Pyruvate carboxylase is involved in gluconeogenesis, a metabolic pathway that synthesizes glucose from non-carbohydrate sources like amino acids and pyruvate. This process is particularly relevant during periods of fasting, helping to maintain blood glucose levels for the brain and red blood cells. Acetyl-CoA carboxylase plays a role in fatty acid synthesis, converting acetyl-CoA to malonyl-CoA, a step necessary for building new fat molecules.
Propionyl-CoA carboxylase and beta-methylcrotonyl-CoA carboxylase contribute to amino acid catabolism, breaking down amino acids such as isoleucine, leucine, methionine, and threonine. This breakdown helps the body process and utilize these protein building blocks. Biotin’s involvement ensures these metabolic pathways function, supporting the body’s energy production and nutrient utilization.
Biotin’s Influence on Body Systems
Biotin’s metabolic involvement influences various body systems. Its role in the synthesis of fatty acids and amino acids directly contributes to the production of keratin, a fibrous protein. Keratin forms the structural foundation of hair, skin, and nails, providing strength and resilience.
For hair, biotin supports keratin production, contributing to stronger hair strands and potentially reducing breakage. In skin, biotin aids in maintaining a healthy skin barrier by supporting the production of fatty acids, important for skin integrity. This helps protect against environmental damage and maintain skin’s appearance.
Similar to hair, biotin’s contribution to keratin synthesis helps maintain nail integrity and strength, potentially preventing brittleness. Biotin also supports nervous system function. It contributes to nerve signaling and the synthesis of neurotransmitters, chemical messengers in the brain, influencing mood and cognitive processes.
Obtaining Biotin and Deficiency Indicators
Biotin is acquired primarily through dietary intake. Common food sources include egg yolks, nuts, seeds, whole grains, liver, and certain vegetables. Additionally, bacteria residing in the gut can synthesize small amounts of this vitamin, contributing to the body’s supply.
Biotin deficiency is uncommon in individuals who consume a balanced diet, but certain factors can increase the risk. These include rare genetic conditions, such as biotinidase deficiency, where the body struggles to utilize biotin effectively. Consuming large quantities of raw egg whites can also lead to deficiency, as raw egg whites contain avidin, a protein that binds to biotin and prevents its absorption.
Long-term antibiotic use can disrupt the gut bacteria that produce biotin, potentially leading to lower levels. Symptoms of biotin deficiency often appear gradually and can include thinning hair, progressing to hair loss, and a scaly, red rash that often appears around body openings like the eyes, nose, and mouth. Other indicators may involve brittle nails, fatigue, muscle pain, and neurological symptoms such as depression, lethargy, or a tingling sensation in the extremities.