vitamins 1 Flashcards
2 main roles of water soluble vitamins
1-cellular metabolism of energy
2-supply of nutrients
niacin is a component of-
NAD+, NADP+
effects of megadoses of niacin
decreased LDL, increased HDL
vasodilation/flushing
increased blood glucose/uric acid
niacin can be synthesized from=
tryptophan, although inefficient
dz caused by niacin deficiency
pellagra- dermatitis, diarrhea, dementia, death
thiamine is required for (2)
- TPP (catabolism)
- nerual transmission
thiamine requirement increases with
increased calories, because of its role in catabolism
beriberi
thiamine def, sx- peripheral neuropathy, mm atrophy, heart failure/edema(wet form)
wernike-korsakoff syndrome
thiamine def due to excess eton that inhibits thiamine absorption
riboflavin found in-
FMN, FAD
riboflavin def sx-
oral lesions, dermatitis
main role of enzymes that require B6 as cofactor
amino acid reactions
increased B6 requirement with-
increased protein in diet and pregnancy
pantothenic acid is involved with-
coenzyme A
“ubiquitious”
biotin is involved with-
reactions involving CO2 (carboxylation) and alters chromatin structure through histones
what is avidin?
component of raw egg white, causes biotin def bc it binds tightly to it and prevents absorption
folic acid is invoked with-
transfer of 1 carbon group, regeneration of Met from homocysteine, aa synthesis
folate def will affect __ first
rapidly dividing cells
contained in the ring structure of B12
cobalt
2 key runs catalyzed by B12
1-homocysteine –> methionine
2-methylmalonic-coA –> succinyl-CoA
test for B12 def
urine test for methylmalonic acid (will be high in def)
risk of treating B12 def with folate
will treat the anemia, but irreversible neurological damage can result
2 def that cause megaloblastic anemia
folate
B12
3 def that cause microcytic anemia
iron, copper, B6
def that causes hemolytic anemia
vit E
vit c hydroxylates ___ in collagen
proline and lysine
vit c enhances the absorption of
iron
__ is used to regenerate ascorbic acid
glutathione (GSH)
too much bit c can cause
diarrhea, kidney stones
pyridoxine-dependent epilepsy is treated by:
vit b6 supplement or GABA
pyridoxine-dependent epilepsy occurs because of-
defect in lysine pathway that causes accumulation of the metabolite that then reacts with B6 and limits its availability
side effect of INH
causes B6 def bc it binds with pyridoxal prior to excretion
cirrhosis can cause decreased levels of-
pyridoxine (B6)
thiamine (B1)
bili lights will destroy-
riboflavin
