Vitamins

Question 1

Mention the function and clinical manifestation of Vitamin B1 (Thiamine)

Answer 1

Function: Coenzyme thiamine pyrophosphate plays a key role in carbohydrate and amino acid intermediary metabolism

Clinical Manifestation Deficiency: Wet beriberi; dry beriberi; Wernicke- Korsakoff syndrome.

Question 2

Mention the function and clinical manifestation of Vitamin B2 (Riboflavin)

Answer 2

Function: Component of FAD and FMN and is essential in a variety of oxidation-reduction processes

Clinical Manifestetion of Deficiency: Cheilosis; corneal vascularization; glossitis; dermatitis

Question 3

Mention the function and clinical manifestation of Vitamin B3 (Niacin):

Answer 3

Finction: Component of NAD and NADP, essential to glycolysis, the citric acid cycle, and to a variety of oxidations (can be synthesized from tryptophan); deficiency requires diet lacking both niacin and tryptophan

Clinical Manifestation Deficiency: Pellagra

Question 4

Mention the function and clinical manifestation of Vitamin B6 (pyridoxine)

Answer 4

Function: Required for transamination, porphyrin synthesis, synthesis of niacin from tryptophan

Clinical Manifestation: Cheilosis; glossitis; sideroblastic anemia; convulsions in infants; neurologic dysfunction

Question 5

Mention the function and clinical manifestation of Vitamin B12 (Cobalamin)

Answer 5

Function: 1-Carbon transfers required for folate synthesis and activation of FH4; N5,10-methylene FH4 is required for conversion of dUMP to dTMP in DNA synthesis

Clinical Manifestation of Deficiency: Megaloblastic anemia; neurologic dysfunction

Question 6

Mention the function and clinical manifestation of Vitamin B9 (Folic Acid)

Answer 6

Function: 1-Carbon transfers in a number of metabolic reactions; N5,10-methylene FH4 required for DNA synthesis

Clinical Manifestation of Deficiency: Megaloblastic anemia; neurologic dysfunction is not a feature (as it is in vitamin B12 deficiency)

Question 7

Mention the function and clinical manifestation of Vitamin C (Ascorbic Acid)

Answer 7

Function: Required for:

• Hydroxylation of proline and lysine, which are essential for collagen synthesis
• Hydroxylation of dopamine in synthesis of norepinephrine
• Enhances maintenance of reduced state of other metabolically active agents, such as iron and FH4

Clinical Manifestation of Deficiency: Scurvy, defective formation of mes- enchymal tissue and osteoid matrix; defective wound healing; hemorrhagic phenomena

Question 8

Mention the function and clinical manifestation of Vitamin A

Answer 8

Function: Precursor in rhodopsin synthesis; important in glycoprotein synthesis; regulator of epithelial differentiation

Clinical Manifestation of Deficiency: Night blindness; squamous metaplasia in many tissues, most importantly in eyes, where blindness may result

Question 9

Mention the function and clinical manifestation of Vitamin D (Calciferol)

Answer 9

Function: Active form 1α,25-dihydroxy-cholecalciferol (1,25-(OH)2D3, calcitriol) promotes intestinal calcium and phosphorus absorption and stimulates parathyroid hormone-mediated renal tubular reabsorption of calcium; thus maintains physiologic concentration of serum calcium; enhances calcification of bone

Clinical Manifestation of Deficiency: Rickets in children; osteomalacia in adults

Question 10

Mention the function and clinical manifestation of Vitamin E (a-tocopherol)

Answer 10

Function: Antioxidant; maintenance of cell membranes, probably by modulation of lipid peroxidation

Clinical Manifestation of Deficiency: Possible neurologic dysfunction

Question 11

Mention the function and clinical manifestation of Vitamin K

Answer 11

Function: Glutamyl carboxylation required for synthesis of γ-carboxyglutamyl residues of active serine proteases (e.g., clotting factors II, VII, IX,
and X)

Clinical Manifestation of Deficiency: Hemorrhagic diatheses, such as hemorrhagic disease of the newborn