Vitamins

Question 1

Fat soluble vitamins

Answer 1

Vitamins A,D,E, and K

Question 2

Two water soluble vitamins that are stored in the liver

Answer 2

B12 and folate

Question 3

4 major functions of vitamin A

Answer 3

Antioxidant

Constituent of visual pigments (retinal)

Essential for normal differentiation of epithelial cells

Prevents squamous metaplasia

Question 4

Two conditions that can be treated with vitamin A

Answer 4

Measles and AML, subtype M3

Question 5

Symptoms of vitamin A deficiency

Answer 5

Night blindness, dry skin, keratomalacia, squamous metaplasia

Question 6

Symptoms of vitamin A excess

Answer 6

Arthralgias, fatigue, headaches, skin changes, sore throat, alopecia,

Teratogenic (cleft palate, cardiac abnormalities): pregnancy test and two forms of contraception are needed before isotretinoin is used for severe acne

Question 7

4 enzymes that use vitamin B1 as a cofactor

Answer 7

Pyruvate dehydrogenase (links glycolysis to TCA)
Alpha-ketoglutarate dehydrogenase (TCA)
Transketolase (HMP shunt)
BCAA dehydrogenase

Question 8

3 conditions seen in vitamin B1 deficiency

Answer 8

Wernicke-Korsakoff: confusion, ophthalmoplegia, ataxia (classic triad) + confabulation, personality change, memory loss (permanent)

Dry beriberi: polyneuritis, symmetrical muscle wasting

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

Question 9

Condition seen with chronic thiamine deficiency that affects cerebellum

Answer 9

Alcoholic cerebellar degeneration: loss of Purkinje cells in anterior lobes and vermis

Causes progressive, wide-based gait ataxia, truncal instability, intention tremor

Question 10

Function of vitamin B2 (riboflavin)

Answer 10

Cofactor in oxidation and reduction (e.g. FADH2)

Question 11

Symptoms of B2 deficiency

Answer 11

Cheilosis (inflammation of lips, scaling and fissures at the corners of the mouth), corneal vascularization, magenta colored tongue

Question 12

Function of vitamin B3 (niacin)

Answer 12

Constituent of NAD+ ,NADP+ (used in redox reactions)

Question 13

Amino acid necessary for synthesis of niacin

Answer 13

Tryptophan, also requires vitamin B6

Question 14

Symptoms of niacin deficiency

Answer 14

Glossitis and severe deficiency leads to pellagra (diarrhea, dermatitis, dementia)

Question 15

Conditions where niacin deficiency may be seen

Answer 15

Hartnup’s (decreased tryptophan absorption), malignant carcinoid syndrome (increased tryptophan metabolism), and isoniazid therapy (decreased B6)

Question 16

Symptoms of niacin excess

Answer 16

Facial flushing (can prevent with aspirin pre-treatment)

Question 17

Function of vitamin B5 (pantothenate)

Answer 17

Essential component of CoA (a cofactor for acyl transfers) and fatty acid synthase

Question 18

Symptoms of vitamin B5 defieciency

Answer 18

Dermatitis, enteritis, alopecia, adrenal insufficiency

Question 19

Function of vitamin B6 (pyridoxine)

Answer 19

Cofactor used in transamination reactions, decarboxylation reactions, and glycogen phosphorylase

Question 20

Symptoms of vitamin B6 deficiency

Answer 20

Convulsions, hyperirritability, peripheral neuropathy (seen in isoniazid use), sideroblastic anemias due to impaired hemoglobin synthesis and iron excess

Question 21

Function of vitamin B7 (biotin)

Answer 21

Cofactor for carboxylation enzymes including:

1) pyruvate carboxylase
2) acetyl-CoA carboxylase
3) propionyl-CoA carboxylase

Question 22

Function of vitamin B9 (folic acid)

Answer 22

Converted to THF, a coenzyme for 1 carbon transfers/methylation reactions

Also important for synthesis of nitrogenous bases in DNA and RNA

Question 23

Symptoms of folic acid deficiency

Answer 23

Macrocytic, megaloblastic anemia (no neurologic symptoms), homocysteinemia (increased risk for DVT and atherosclerosis)

Question 24

Function of vitamin B12

Answer 24

Cofactor for homocysteine methyltransferase (transfers methyl groups) and methylmalonyl-CoA mutase

Question 25

Symptoms of B12 deficiency

Answer 25

Macrocytic, megaloblastic anemia with hypersegmented neutrophils (paressthesias, subacute combined degeneration)

Question 26

Cause of B12 deficiency seen with normal urinary excretion of radiolabeled B12

Answer 26

Poor B12 intake

Question 27

Cause of B12 deficiency seen with diminished urinary excretion of radiolabeled B12

Answer 27

Impaired intestinal absorption

Question 28

Cause of B12 deficiency seen with with normal urinary excretion after addition of intrinsic factor

Answer 28

Pernicious anemia

Question 29

Cause of B12 deficiency seen with diminished urinary excretion after addition of intrinsic factor

Answer 29

Malabsorption syndrome such as pancreatic insufficiency, bacterial overgrowth, or short gut syndrome

Question 30

4 functions of vitamin C

Answer 30

Antioxidant

Facilitates iron absorption

Hydroyxlation of proline and lysine in collagen synthesis

Necessary for dopamine hydroxylase which converts DA to NE

Question 31

Symptoms of vitamin C deficiency

Answer 31

Scurvy: swollen gums, bruising, hemarthrosis, anemia, poor wound healing, weakened immune response

Collagen synthesis defect

Question 32

Symptoms of vitamin C excess

Answer 32

N/V, diarrhea, fatigue, sleep problems

Can increase risk of iron toxicity in predisposed people (those with transfusions, hereditary hemochromatosis)

Question 33

Function of vitamin D

Answer 33

Increases intestinal absorption of calcium and phosphate, and increases bone mineralization

Question 34

Symptoms of vitamin D deficiency

Answer 34

Rickets (children, bone pain and deformities) and osteomalacia (adults, bone pain and weakness), hypocalcemic tetany

Breast milk has low vitamin-D (must supplement in dark-skin peopled)

Question 35

Symptoms of vitamin D excess

Answer 35

Hypercalcemia, hypercalciuria, loss of appetite, stupor

Question 36

Disease that can cause vitamin D excess

Answer 36

Sarcoidosis: increases activation of vitamin D by epithelioid macrophages

Question 37

Function of vitamin E

Answer 37

Antioxidant (protects RBCs and membranes from free-radical damage)

Question 38

Symptoms of vitamin E deficiency

Answer 38

Increased fragility of RBCs (hemolytic anemia), muscle weakness, posterior column and spinocerebellar tract demyelination, infertility

Question 39

Symptoms of vitamin E excess

Answer 39

Potential hemorrhage in warfarin patients

Question 40

Function of vitamin K

Answer 40

Catalyzes gamma-carboxylation of glutamic acid residues on various proteins associated with blood clotting

Question 41

Symptoms of vitamin K deficiency

Answer 41

Neonatal hemorrhage with prolonged PT and aPTT but normal bleeding time