Vit C Flashcards
Dietary Sources
citrus sources, cabbage type,
Destroyed by heat & oxygen & canning
RDA
75mg for females
90mg for males
+35 for smokers-increased free radicals
–due to increased mtb turnover oxidation status
Absorption
Absorption rate decreased w/increased intake
-High intake (6g):16%
-Low intake (<20mg): 190%
Oxidized to dehydroascorbate (DHAA) prior absorption
Active transport
Reduced to ascorbic acid w/in enterocytes
Transport
In plasma - free form -5% bound to albumin Into cells -simple diffusion
Functions
Antioxidant -reducing agent -donate electron -react with free radicals Collagen Synthesis- acting as matrix -most abundant protein found in body -major component of connective tissue ---skin, bone, cartilage, tendons and ligaments **Vit C is required for hydroxylation of lysine & proline residues in collagen synthesis**
Tyrosine Synthesis & MTB
Tyrosine -Phenalalinine Hydroxylase -Requires Vit-C **Tyrosine- nonessential Tyrosine- to actoacetyl CoA Tyrosine- Norepinephrine/ Dopamine
Diseases
Common Cold
Cancer
Interactions
Iron -increased bioavailability -helps incorporate of iron into ferritin (storage form) Heavy Metals -increased excretion - from chelates w/metals Can interfere with copper MTB Folate -helps reduce to active form
Excretion
in urine
- excess Vit C
- Metabolites : DHAA diketoglulonate acid, oxilate acid
Deficiency
Scurvy, poor wound healing:irrability, swelling, bleeding gums, bone joint pain
Tox
> 2,000 g, GI problems, abdominal pain, diarrhea,
Kidney Stones
Hemochromatosis -mutation of chromosome 6, unable to regulate to iron absorption, only cure to take blood out
Assessment
1) Plasma or serum level: most sensitive indicator of deficiency
2) WBC reflects body stores
- change in response to recent dietary Vit C. intake
