Vitamin C Flashcards
person who conducted trials to cure scurvy in 1746
James Lind
weak sulfuric acid
vitriol
Albert Szent-Gyorgyi identified ____ factor
antiscorbutic
what are the 2 roles of Vit C?
1) cofactor 2) antioxidant
what is the EAR set on?
antioxidant role
which enzyme do we lack that prevents us from making our own vit c?
L-gulonolactone oxidase
in almost all animals, vit C is made from ___
D-glucose
intakes that prevent scurvy we absorb all by ___ transport; intakes close to usual we absorb __% by ___ transport; intakes at megadoses absorb __% by ___transport
active; 70, active; 16, passive
what is the criterion for UL?
diarrhea
what is storage in cells referred to as?
vitamin C pool
high concentrations of vitamin C in ___
adrenal glands, brain
pool maximum is at ____mg
1500
scurvy begins as pool is
300
dioxygenases need vitamin C to make this
collagen (lysine–>OHLys, Proline–>OHPro)
ascorbate is a good ___ agent
reducing
Fe2+ is called ___, Fe 3+ is called ___
ferrous; ferric
vitamin C acts on ___ when involved with neurotransmitters and ___ synth
copper; stress hormone
Vitamin C donates ___ electrons in antioxidant reaction
2
which enzyme converts dehydroascorbic acid back to ascorbic acid?
dehydroascorbate reductase
What does GSH stand for?
glutathione (tripeptide)
what is glutathione made up of?
glycine, cysteine, glutamate
what does ROS stand for?
reactive oxygen species
Vitamin C increases ___ absorption
iron
Fe2+ is reactive and can generate free radicals through the _____ reaction
Fenton
vitamin C has role to regenerate vit. ___
E
food sources of vitamin C?
fruit+veg (citrus, peppers, broccoli, kiwi), human breast milk, raw organs
intake = [ ] x ____?
frequency of use
food sources of vit. C for aboriginal groups?
willow leaf/white cedar tea
Vit C is destroyed by:
heat, light, oxidation, alkaline solutions
how is vitamin C status assessed?
plasma lvls, urine excretion (indirect), neutrophil levels (antioxidant lvl)
vitamin C is stable in ___ conditions
acidic
what is the RDA for vit. C?
90mg for M; 75mg for F
how does RDA change for smokers?
+35mg
how is EAR set for Vit C?
near-max neutrophil concentration w/ min. urinary excretion
What are the 4 Hs of Scurvy?
hemorrhagic, hyperkeratosis, hypochondria, hematologic abnormalities
synthetic form of Vit C in hot dogs/soft drinks?
D-erythorbic acid
what is purpose of erythorbic acid?
use as reductant/antioxidant, work with nitrites (replace sulfites) in cured meats, prevent carcinogens
psychological probs due to v neurotrans (vit C role in nerve synth)
hyperchondria
pallor is because of _____
anemia
deficiency cause changes in ______
tongue, gum, limbs, legs
guy who promoted megadoses:
Linus Pauling
Vit C often used as alternative to ____; concerns raised because acts as _____ when injected at high doses
chemotherapy; pro-oxidant
ascorbate added to surface of ___ prevent formation of ___
nitrated meat; nitrosamines
Vitamin C helps with these conditions:
cold, cancer, cardiovascular, stress
The UL, set at ___mg, is based on _____
2; osmotic diarrhea
high levels vit C cause ___ because of production of crystallized ___ acid
kidney stones; oxalic
