vitamins Flashcards
fat soluble vitamins
A, D, E, K; toxicity more common that water-soluble b/c accumulate in fat
causes of fat soluble deficiencies
CF, sprue
B1
thiamine: TPP
B2
riboflavin: FAD, FMN
B3
niacin: NAD+
B5
pantothenic acid; CoA
B6
pyridoxine: PLP
B7
biotin
B9
folate
B12
cobalamin
C
ascorbic acid
B12 storage?
liver for 3-4 years
B9 storage?
liver for 3-4 mo.
symptoms of B-complex deficiencies
dermatitis, glossitis, diarrhea
A deficiency
night blindness (nyctalopia); dry, scaly skin (xerosis cutis); corneal degenerations (keratomalacia)
acute A toxicity
nausea, vomiting, vertigo, blurred vision
A teratogenic?
yes - Isotretinoin is derivative - will cause cleft palate and cardiac abnormalities
B1 (thiamine –> thiamine pyrophosphate/TTP) cofactor in what?
pyruvate dehydrogenase (links glycolysis to TCA), a-ketoglutarate dehydrogenase (TCA), transketolase (HMP shunt), branched-chain ketoacid dehydrogenase
how do you make B1 deficiency diagnosis?
look at RBC transketolase activity, will increase following vitamin B1 administration
two diseases caused by B1 deficiency?
Wernicke-Korsakoff and Beri Beri
Dry beriberi
polyneuritis, symmetrical muscle wasting
wet beri beri
high-output cardiac failure (dilated cardiomyopathy), edema
when is B2 a cofactor?
redox reactions (succinate dehydrogenase in TCA cycle)
B2 deficiency?
cheilosis (inflammation of lips, scaling and fissures at the corners of the mouth)
What is B3 derived from?
Tryptophan, synthesis requires B2 and B6
what is B3 used to treat?
dyslipidemia, lowers VLDL and increases HDL
which vitamin is an essential component of CoA?
B5 - pantothenic acid
what is the B6 cofactor?
pyridoxal phosphate (PLP)
what is PLP cofactor used in?
transamination, decarboxylation reactions, glycogen phosphorylase, synthesis of cystathione, heme, niacin, histamine, and neurotransmitters including serotonin, epinephrine, NE, DA and GABA
B5 deficiency
convulsions, hyperirritability, peripheral neuropathy, sideroblastic anemias
B7 cofactor for what reactions?
carboxylations enzymes: pyruvate carboxylase (pyruvate to oxaloacetate), acetyl-CoA carboxylase (acetyl-coA to malonyl-coA), propionyl-coA carboxylase (propionyl-coA to methylmalonyl CoA)
function of B9/folate?
converted to tetrahydrofolic acid (THF), co-enzyme for 1-carbon transfer/methylation reactions; important for synthesis of DNA and RNA
where is folate absorbed?
jejunum
which drugs can cause B9/folate deficiency?
phenytoin, sulfonamid, methotrexate
B9 and B12 deficiency-induced anemias
macrocytic, megaloblastic anemia
B12 function
cofactor for methionine synthase (transfers CH3 groups) and methylmalonyl CoA mutase
causes of B12 deficiency?
malabsorption (sprue, enteritis, diphyllobothrium latum), lack of intrinsic factor (pernicious anemia, gastric bypass), absence of terminal ileum (surgical resection, eg in chron disease), or insufficient intake (veganism)
scurvy sx
swollen gums, bruising, petechiae, hemarthorisis, anemia, poor wound healing, perifollicular and subperiosteal hemorrhages, corkscrew hair, weakened immune system
D function
increase intestinal absorption of Ca and PO4; regulated bone mineralization/resorption (when high, bone resorption)
should breastfed infants receive oral D?
YES, because K and D are not in milk
can E enhance anticoagulant effects of warfarin?
YES
K is necessary for which clotting factors?
II, VII, XI, X
what is a K antagonist?
warfarin
