Riboflavin & Biotin Lecture Notes

Flashcards covering key concepts related to riboflavin and biotin, essential vitamins in nutrition.

Riboflavin (Vitamin B2)

A water-soluble vitamin essential for energy production and metabolism, exists in coenzyme forms FMN and FAD.

Coenzymes

Molecules that assist enzymes in catalyzing reactions, specifically FMN and FAD for riboflavin.

Flavokinase

An enzyme that catalyzes the conversion of riboflavin to flavin mononucleotide (FMN), regulated by hormones.

Recommended Dietary Allowance (RDA)

The daily dietary intake level sufficient to meet the nutrient requirements of most healthy individuals; for riboflavin: males 1.3 mg, females 1.1 mg.

Sources of Riboflavin

Found in milk/dairy, eggs, meat, legumes, green leafy vegetables, and grains.

Absorption of Riboflavin

95% absorbed from food, aided by bile, and impaired by alcohol.

Flavoproteins

Proteins that contain a flavin cofactor, necessary for oxidation-reduction reactions in metabolism.

Antioxidant Flavoproteins

Proteins containing riboflavin that act to reduce oxidative stress, including glutathione reductase.

Ariboflavinosis

A deficiency condition resulting in symptoms including cheilosis, glossitis, and seborrheic dermatitis.

Biotin (Vitamin B7)

A vitamin that serves as a coenzyme for carboxylases and is involved in fatty acid, glucose, and amino acid metabolism.

Biotinidase

An enzyme required for the recycling of biotin from biocytin, deficiencies can lead to symptoms of biotin deficiency.

Adequate Intake

The recommended daily intake for biotin: 30 mcg for ages 19 and older, 35 mcg during pregnancy.

Synthesis of niacin and vitamin B6

Biotin is essential for synthesizing niacin from tryptophan and vitamin B6 from pyridoxine 5'-phosphate.

Biotin Deficiency Symptoms

Symptoms can include lethargy, depression, red, dry skin, and in severe cases, death if untreated.

Biotin Supplementation Caution

Biotin can interfere with lab tests, leading to misdiagnosis, such as false results for troponin.

Dietary Biotin Cycle

The process by which biotin is obtained from protein-bound sources, requiring digestion to free biotin.