Vitamins

Question 1

Vitamin A

Answer 1

Retinol

Fat soluble (A, D, E, K)

Function: antioxidant, constituent of visual pigments (retinal), used to treat measles and AML

Deficiency: night blindness, alopecia, immune suppression

Excess: Arthralgias, cerebral edema, teratogenic effects

Question 2

Vitamin B1

Answer 2

Thiamine

Function: cofactor for pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, transketolase, and branched-chain ketoacid dehydrogenase (ATP-B)

Deficiency: impaired glucose breakdown w/ ATP depletion, highly aerobic tissues are affected first (brain, heart)

Question 3

Wernicke-Korsakoff syndrome

Answer 3

Deficiency in thiamine (B1), alcoholism

Presents w/ confusion, opthalmoplegia, ataxia, confabulation, and personality/memory changes

Question 4

Beriberi

Answer 4

Deficiency in thiamine

Dry: polyneuritis, symmetrical muscle wasting

Wet: high output cardiac failure (dilated cardiomyopathy), edema

Question 5

Vitamin B2

Answer 5

Riboflavin

Function: cofactor in redox reactions, component of FAD

Deficiency: cheilosis (inflammation of lips, fissure at corners of mouth), corneal vascularization

Question 6

Vitamin B3

Answer 6

Niacin

Function: constituent of NAD and NADP, derived from tryptophan, used to treat dyslipidemia

Deficiency: glossitis, pellagra (diarrhea, dementia dermatitis), malignant carcinoid syndrome

Excess: facial flushing, hyperglycemia

Question 7

Vitamin B5

Answer 7

Pantothenate

Function: essential component of coenzyme A and fatty acid synthesis

Deficiency: dermatitis, enteritis, alopecia, adrenal insufficiency

Question 8

Vitamin B6

Answer 8

Pyridoxine

Function: cofactor used in transamination, decarboxylation reaction, synthesis of neurotransmitters such as serotonin, norepi, epi, dopamin, and GABA

Deficiency: convulsions, hyperirritability, peripheral neuropathy, sidoblastic anemia

Question 9

Vitamin B7

Answer 9

Biotin

Function: cofactor for carboxylation

Deficiency: dermatitis, enteriti, caused by antibiotic use or excessive ingestion of raw egg whites

Question 10

Vitamin B9

Answer 10

Folic acid

Function: converted to tetrahydrofolate (THF), a coenzyme for 1 carbon transfer/methylation, important for synthesis of nitrogenous bases in DNA and RNA

Found in leafy green vegetables, absorbed in jejunum

Deficiency: macrocytic anemia, glossitis, no neurological symptoms as opposed to B12, can be caused by several drugs such as phenytonin and methotrexate

Need to supplement early in pregnancy to avoid neural tube defects

Question 11

Vitamin B12

Answer 11

Cobalamin

Function: cofactor for homocysteine methyltransferase and methymalonyl CoA mutase

Found in animal products, large reserve in liver

Deficiency: macrocytic anemia, subacute combined neural degeneration due to abnormal myelin, caused often by lack of intrinsic factors (pernicious aneima, gastric bypass), or absence of terminal ileum

Question 12

Vitamin C

Answer 12

Ascorbic acid

Function: antioxidant, facilitate iron absorption, hydroxylation of proline in collagen synthesis, necessary for dopamine beta-hydroxylase which converts dopamine to NE

Found in fruits and vegetables

Deficiency: scruvy (swollen gums, bruising, anemia, poor wound healing), weakened immune response

Excess: nausea, vomiting, diarrhea, fatigue

Question 13

Vitamin D

Answer 13

Fat soluble

Function: intestinal absorption of calcium and phosphate, bone mineralization

Found in milk

Deficiency: rickets, osteomalacia, hypocalcemic tetany

Excess: hypercalcemia, loss of appetite, stupor, often seen in sarcoidosis (increased activation of vitamin D by epthelioid macrophages)

Question 14

Vitamin E

Answer 14

Tocopherol

Fat soluble

Function: antioxidant (protect erythrocytes and membranes from free radical damage)

Deficiency: hemolytic anemia, muscle weakness

Question 15

Vitamin K

Answer 15

Fat soluble

Function: cofactor for carboxylation of proteins for blood clotting, synthesized by intestinal flora, necessary for the activation of factors 9, 10, 7, 2 and proteins C and S (warfin vitamin K antagonist)

Deficiency: hemorrhage w/ increased PT

Question 16

Zinc

Answer 16

Function: essential for activity of 100+ enzymes, important for zinc fingers (transcription factor motif)

Deficiency: delayed wound healing, hypogonadism

Question 17

Ethanol metabolism

Answer 17

NAD is the limiting agent w/ alcohol dehydrogenase operates in a zero-order kinetics (ethanol –> acetaldehyde –> acetate)

Ethanol metabolism increases NADH/NAD ratio in liver, causing lactic acidosis, fasting hypoglycemia, and hepatosteatosis

Fomepizole inhibits alcohol dehydrogenase and is an antidote for methanol and ethylene glycol poisoning

Disulfiram inhibits acetaldehyde dehydrogenase (2nd step)

Question 18

Kwashiorkor

Answer 18

Protein malnutrition

Presents w/ skin lesions, edema, liver malfunction

Commonly presents as small child with swollen belly

Question 19

Marasmus

Answer 19

Calorie malnutrition

Presents w/ muscle wasting, loss of subcutaneous fat, and variable edema