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Nutrient Metabolism
Vitamin E
23
Science
Not Applicable
03/13/2010

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Cards

Term
Vit. E food sources
Definition
alpha-tocopherol: plant oils, leaves, green parts of pants, peanut butter, high fat meat
gama-tocopherol: soybean and corn oil
tocotrienols: whole grains
Term
Vit. E and food processing
Definition
easily destroyed during prep, processing, storage, exposure to light, and heat and air
Term
Vit. E digestion: tocotrienols
Definition
have to get emulsified by bile acids, consumed as esters so ahve to be hydrolyzed in micelle by pancreatic and mucosal esterase
Term
Vit. E digestion: tocopherols
Definition
have to get emulsified by bile acids, they are present in free fomr, so don't have to get digested
Term
Vit. E absorption
Definition
primarily in jejunum by non-saturable, passive diffusion
Term
Vit. E in enterocyte
Definition
E is incorporated in chylomicrons for transport
Term
Vit. E transport
Definition
-chylomicron remnants deliver tocopherols and tocotrienols to liver
-alpha tocopherol is incorporated into VLDL by alpha tocopherol transfer protein (only incorporates RRR)
-tocopherol equilibrates among LDL and HDL
-E taken up by receptor mediated endocytosis or lipoprotein lipase mediated hydrolysis
Term
Vit. E genetic mutation
Definition
in ppl with genetic mutation in alpha TTP suffer from E deficiency, so give supplements to increased [RRR alpha tocopherol] in chylomicron
Term
Vit E storage
Definition
no single storage form, unesterified form in fat droplets, stored mostly in adipose tissue, mostly in cell membrane
Term
Vit. E storage with intake
Definition
adipose tissue storage increases lineraly with dosage, very efficient at storing it, related to rate of intake, doesn't release E at significant rates; storage forms other than adipose remain constant; liver and plasma [] provide readily available source; heart and muscle can be used at intermediate rates
Term
Vit E excretion
Definition
major route of absorbed alpha tocopherol is thru bile into feces
minor route is thru sebaceous glands in the skin
Term
Vit. E functions
Definition
1) antioxidant
2) heart disease
3) cancer
4) eye health
5) diabetes
Term
Vit. E: Antioxidant
Definition
helps prevent peroxidation
-PUFA on cell membrane are highly prone to oxidation, which decreases membrane stability; brain, lungs and RBC highly prone
Term
Vit. E: process of oxidative stress
Definition
1)initiation: brought about by free radicals or O2; free radical --> alkyl radical; )2 --> alkyl radical and hydroperoxyl radical
2) propagation - requires alkyl radical, which binds with O2 to from lipid peroxyl radical (reacts with PUFA), then forms more alkyl and lipid hydroperoxide
3)termination- E can neutralize alkyl radical, thereby stopping peroxidation
Term
Vit. E: regeneration
Definition
Gets oxidized in process of being an anitoxidant. Reducing agents are ascorbi acid, reduced glutathione, and NADPH
Term
Vit E: heart disease
Definition
macrophages only recognize oxidized LDL, and E helps prevent LDL from becoming oxidized
Term
Vit. E: cancer
Definition
tocotrienols and tocopherols can suppress tumor growth and cell proliferation; alpha tocopherol inhibits protein kinase C which plays a role in cell growth and differentiation pathways
Term
Vit. E: eye health
Definition
helps prevent oxidative damage to proteins; oxidized proteins get aggregated on lens --> cataracts
Term
Vit. E: diabetes
Definition
have increased peroxidation b/e of high glucose levels, E thought to improve PM structure --> may improve glucose transporter fxn --> improve insulin-dependent cellular glucose uptake
Term
Vit. E: RDA
Definition
adults (including pregnant): 15 mg alpha tocopherol
lactating and smokers need more
Term
Vit. E: deficiency
Definition
-skeletal muscle pain (myopathy)
-hemolytic anemia
-degenerative neurological problems (cereballar ataxia)
Term
Vit. E: toxicity
Definition
UL= 1000 mg alpha tocopherol = 1500 IU RRR alpha tocopherol
high levels cause bleeding
Term
Vit. E: assessment
Definition
1) plasma []- indicates recent intake
2) erythrocyte hemolysis test --> better assessment a) incubate RBC in H2O2 and DI water
b0 see what % of cells rupture, >20% indication of deficiency
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