Water Soluble Vitamins

Question 1

in what populations do vitamin deficiencies occur in?

Answer 1

alcohol abusers
elderly patients
patients w/ small bowel resections
food faddists
malnourished people

Question 2

what are some general properties of water soluble vitamins

Answer 2

cannot store in body b/c water soluble (lasts a few weeks)

all found in plants (except b12)

precursors of coenzymes involved in intermediary metabolism

Question 3

vitamin B1

Answer 3

thiamine

coenzyme for enzymes involved in:
carbohydrate metabolism (Krebs cycle)
-pyruvate dehydrgenase
-a-ketoglutarate dehydrogenase

deficiency leads to korsakoffs syndrome

Question 4

vitamin b1 deficiency

Answer 4

wernikes encephalopathy

confusion, weakness, ataxia, nystagmous

treated w/ glucose and thiamin

w/ administration of glucose, leads to korsakoffs syndrome

brain takes up glucose but cannot progress through krebs cycle, leading to buildup of lactic acid in brain- neuronal death (mammillary bodies)

Question 5

beriberi

Answer 5

thiamine deficiency

peripheral neuropathy and dilated cardiomyopathy (balloon heart)

flushed, red, sweating- high output heart failure

malnourished from developing world (diet w/ polished rice)

treatment w/ thiamine

Question 6

vitamin b2

Answer 6

riboflavin

precurors of FMN and FAD

generated by ATP:
b2 gets P from ATP for FMN
b2 gets nucleotide from ATP for FAD

Question 7

vitamin b2 deficiency

Answer 7

causes fissuring at the angles of the mouth, dermatitis, and purple tongue

Question 8

vitamin b3

Answer 8

niacin

nicotinic acid or nicotinamide

precursor for NAD or NADP
cofactor for enzymes that catalyze redox rxns

can be synthesized from tryptophan

Question 9

vitamin b3 deficiency

Answer 9

causes pellagra (sour skin)- dermatitis, diarrhea, dementia, and death (sun sensitive skin rash)

Hartnup disease- tryptophan deficiency
carcinoid syndrome- altered tryptophan metabolism

used to lower LDL and VLDL in type IIb hyperlipoproteinemia (inhibits lipolysis)

Question 10

vitamin b5

Answer 10

pantothenic acid

component of coenzyme A

Question 11

vitamin b6

Answer 11

term for pyridoxine, pyridoxal, pyridoxamine

precurors for pyridoxial phosphate

binds to antituberculous drug isoniazid, which causes functional deficiency

isoniazid is administered with vitamin b6

lack of b6 leads to seizures

Question 12

vitamin b7

Answer 12

biotin

coenzyme for carboxylation rxns- covalently binds to lysine residues on enzymes

Question 13

vitamine b7 deficiency

Answer 13

bound by protein avidin- protein found in eggs

can get deficient by eating 20 eggs/day

symptoms- dermatitis, glossitis, nausea, depression

Question 14

vitamin b9

Answer 14

folate

necessary in 1-c metabolism (purine and thymidine synthesis, cell division)

given therapeutically before pregnancy to prevent neural tube defects

supplemented in “enriched foods

Question 15

vitamin b9 deficiency

Answer 15

megoblastic anemia- immature cells in the blood (rather than bone marrow)

occurs b/c of folate deficiency and rapidly dividing cells like RBCs cannot synthsize new DNA effectively

treated with THF directly (leukovorin)

Question 16

vitamin b12

Answer 16

cobalamin

precursor for methylcobalamin, needed to synthesize methionine from homocysteine

precursor for deoxyadenosylcobalamin- need for Fatty acid metabolism in brain

not produced by plants

Question 17

vitamin b12 deficiency

Answer 17

seen in vegans and pts w/ pernicious anemia (lacking intrinsic factor)

causes megoloblastic anemia (used to regenerate THF), dementia, spinal cord degeneration

takes years to present

folate supplements will alleviate anemia, but not the neurologic symptoms (sunacute combined degeneration)

Question 18

vitamin c

Answer 18

ascorbic acid

needed for post translation hydroxylation of proline, especially in collagen (allows for crosslinks between collagen fibers)

anti-oxidant

causes scurvy- bleeding gums, hemorrhages around hair follicles, poor wound healing, bone pain

mega-doses cause kidney stones

Question 19

intrinsic factor

Answer 19

binds b12 and helps it get absorbed

Question 20

how well are fat soluble vitamins stored?

Answer 20

stored well- takes months of inadequate intake to develop deficiency

Question 21

vitamin A

Answer 21

retinol, retinal, retinoic acid

required for reproduction
retinal- protein essential for vision
retinoic acid- differentiates epithelial cells

obtained from animals or B-carotene in plants

used to treat acne

Question 22

vitamin A deficiency

Answer 22

causes permanent blindness- first symptom is night blindness, dry eyes, bitots spots, corneal ulceration, some of which can be alleviated w/ Vitamin A administration

signs- corneal epithelial cell dedifferentiation/keratinization- xeropthalmia and bitots spots (Keratin buildup on eyes)

Question 23

which vitamin should not be given to pregnant women? why?

Answer 23

vitamin A- tetrogenic

Question 24

vitamin d

Answer 24

produced endogenously from skin by UV radiation, or obtained from animals (d3)/plants (d2)

converted to calcitrol by 2 successive hydroxylation rxns (liver first, then kidney/bone/placenta)

increases calcium uptake by intestine

Question 25

vitamin D deficiency

Answer 25

causes bone breakdown (osteomalacia- bone pain, fractures) in adults

kids- rickets and failure for bones to form

Question 26

vitamin D deficiency risk factors

Answer 26

low sun
dark skin
lack of milk

Question 27

down sides of calcitrol therapy

Answer 27

causes hypercalcemia

Question 28

vitamin E

Answer 28

antioxidant that protects lipid membranes

Question 29

vitamine E deficiency

Answer 29

RBC fragility

Question 30

vitamin K

Answer 30

produced by intestinal bacteria

needed for post translational carboxylation of glutamate- required for clotting factors (prothombrin)

administered to premature infants b/c they lack intestinal bacteria, and adults on long term antibiotic therapy

Question 31

vitamin K deficiency

Answer 31

leads to hemorrhage with long prothrombin time

blocked by coumadin (prevents clotting)

Question 32

what patient groups get fatty acid deficiencies?

Answer 32

people w/ intestine resections

people w/ fat breakdown problems (cant break down fats into absorbable units)