Term
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Definition
| humans are incabale of synthesizing vit. C from glucose b/e we lack gulonolactone oxidase |
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Term
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Definition
| citrus, red bell peppers, broccoli, kiwi |
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Term
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Definition
men: 90 mg/day
women: 75 mg/day
smokers: +35 mg/day
pregnant and lactating need more |
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Term
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Definition
| none required, but some ascorbi acid is oxidized to dehydroascorbic acid prior to absorption |
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Term
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Definition
| 70-95% from normal diet; ascorbate taken up by Na+ dependent Vit. C trasporter SVCT 1 and SVCT 2; dehydroascobate competes with glucose for absorption via glucose transporter; absorption decreased with increased intake, and increased intracellular [glucose] decreases absorption |
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Term
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Definition
| Dehydroascorbic acid is converted to ascorbic acid by dehydroascorbate reductase which needs reduced glutathione or NADPH |
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Term
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Definition
| leaves enterocyte thru ion channels, transported as ascorbate ion |
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Term
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Definition
| highest [] in adrenal and pituitary, highest total weight in liver |
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Term
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Definition
1) antioxidant
2) collagen synthesis
3) carnitine synthesis
4) tyrosine synthesis from phenylalanine
5) norepniphrine
6) serotonin synthesis |
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Term
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Definition
| when C gives up electron, it creates free radical semidehydroascorbic acid, and when 2 SDAA come together it produces ascorbic acid and dehydro acid; dehydro acid can get reduce to ascorbic acid; SDAA can also just get reduced to dehydro acid and then ascorbic acid; C is a pro oxidant if there are decreased levels of reduced glutathione, NADPH and NADH |
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Term
| Vit. C in collagen synthesis |
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Definition
skin, bone, tendon
proline --> hydroxyproline by proline hydroxylase
lysine -> hydroxylysine by lysine hydroxylase
HP and HL need ferrous for activity, and C reduces ferric to ferrous |
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Term
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Definition
| P and HP both increase rigidity of collagen fiber, HL serves as site for glycosylation and phosphorylation; HL acted on by lysine oxidase which facilitates cross-linking b/w 3 fibers |
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Term
| norepenephrine synthesis from... |
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Definition
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Term
| seotonin synthesis from... |
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Definition
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Term
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Definition
| Scurvy, and 4H's (prolonged) |
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Term
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Definition
due to impaired HP and HL synthesis
1) bleeding gums
2) pin pt. hemorrhage
3) easy bruising (need vit. C for wound healing) |
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Term
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Definition
1) hyperkeratosis of hair follicles
2) hemorrhage
3) hypochodriasis
4) hematologic abnormalities |
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Term
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Definition
plasma and serum levels -> recent intake
WBC are best indicator of body stores (difficult to perform) |
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Term
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Definition
possible if several large doses are ingested thruout the day
-osmotic diarrhea
increased risk of kidney disease and iron toxicity in pp with kidney disease, and impaired iron metabolism, high C in urine interferes with glucose test |
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