Vitamin B7 (Biotin) - Sources - Symptoms of Deficiency vs Excess - Diet and Nutrition Series

Summary

This educational video delves into the importance of Vitamin B7, also known as biotin. It explains how biotin acts as a cofactor for carboxylation reactions, crucial for protein synthesis, cell replication, and energy production. The video highlights the rarity of biotin deficiency and its symptoms, such as dermatitis and enteritis. It also addresses the impact of consuming raw egg whites, which contain avidin that binds biotin and inhibits its absorption. Furthermore, it covers the role of biotin in various biochemical pathways, including fatty acid synthesis and gluconeogenesis, and the potential issues arising from its deficiency.

Takeaways

• 🥚 The enzyme sphingomyelinase is deficient in Niemann-Pick disease, one of the lysosomal storage diseases.
• 💊 Vitamins are essential nutrients that must be obtained through diet and act as cofactors for enzymes.
• 🅱️ Biotin (Vitamin B7) is a water-soluble vitamin that acts as a cofactor for carboxylation reactions, adding CO2 to molecules.
• 🥚 Egg whites contain avidin, which binds to biotin and can inhibit its absorption, but egg yolks do not have this issue.
• 🍳 Cooking deactivates avidin, so consuming cooked eggs is essential for biotin absorption.
• 🥬 Biotin is found in various foods, including vegetables, egg yolks, milk, and some fortified foods.
• 🔄 Biotin plays a crucial role in multiple carboxylase enzymes, affecting processes like gluconeogenesis and fatty acid synthesis.
• 🚫 Biotin deficiency is rare but can lead to dermatitis, alopecia, and enteritis.
• 💊 High doses of biotin can interfere with thyroid function tests, potentially mimicking Graves' disease.
• 🌐 The script is part of a biochemistry playlist aiming to educate on the importance and functions of vitamins in the body.

Q & A

What is the disease caused by a deficiency of the enzyme sphingomyelinase?

The disease caused by a deficiency of the enzyme sphingomyelinase is called Niemann-Pick disease, which is one of the sphingolipid storage diseases and a type of lysosomal storage disease.

What is the role of vitamin B7 (biotin) in the body?

Vitamin B7, also known as biotin, is a water-soluble vitamin that acts as a cofactor for carboxylation reactions, helping to add CO2 to various substrates. It is essential for protein synthesis, cell replication, gluconeogenesis, fatty acid synthesis, and fatty acid oxidation.

Why is biotin deficiency rare?

Biotin deficiency is rare because it is widely available in food, and the body requires only small amounts of it. Additionally, the avidin protein in raw egg whites, which binds biotin and inhibits its absorption, must be consumed in large quantities to cause a deficiency.

How does cooking affect the bioavailability of biotin in eggs?

Cooking deactivates the avidin protein in egg whites, which is responsible for binding and inhibiting the absorption of biotin. Therefore, cooked eggs do not pose a risk of biotin deficiency.

What are the direct and indirect benefits of biotin?

Direct benefits of biotin include treating biotin deficiency and multiple carboxylase deficiency, a genetic disease. Indirect benefits come from its role as a cofactor in carboxylation reactions, which are essential for various metabolic processes like protein synthesis and fatty acid metabolism.

What are the sources of biotin?

Biotin can be found in vegetables, egg yolks, milk, and some food products that are fortified with it. It is also available in vitamin B-complex supplements.

What are the enzymes that require biotin as a cofactor?

The enzymes that require biotin as a cofactor include pyruvate carboxylase, propionyl-CoA carboxylase, and acetyl-CoA carboxylase. These enzymes are involved in carboxylation reactions.

How does biotin participate in the TCA cycle?

Biotin, as part of the enzyme succinyl-CoA carboxylase, helps in the conversion of succinyl-CoA to malate in the TCA cycle, which is essential for energy production.

What is the role of biotin in fatty acid synthesis?

Biotin is necessary for the carboxylation step in fatty acid synthesis, where it helps convert acetyl-CoA to malonyl-CoA, a key substrate for the fatty acid synthase complex.

What happens in the body during biotin deficiency?

During biotin deficiency, there is a decreased function of carboxylase enzymes, leading to decreased gluconeogenesis, fatty acid synthesis, and other metabolic processes. Symptoms can include dermatitis, alopecia, and enteritis.

How can biotin deficiency be diagnosed and treated?

Biotin deficiency can be diagnosed through blood and urine tests that measure decreased levels of vitamin B7. Treatment involves administering biotin supplements to the patient.