Vitamin E Flashcards
(30 cards)
How many Vit E vitamers are there
8: 4 tocopherols (tocols) and 4 tocotrienols (trienols)
Describe tocopherols
saturated side chains; a>b>y>g
Describe tocotrienols
unsaturated side chains; only a has significant biological activity
Food sources
leafy and green vegetables, soybeans, bran/germ
What is a low source of Vit E
animal products
What is the most efficient form of Vit E
Alpha-Tocopherol (1mg = a-tcopherol)
How is Vit E found in diet
free or attached to fatty acids
Digestion of Vit E
esterases, bile salts, micelle formation, incorporation into CMs
What % of Vit E is absorbed
20-50%
How is Vit E distributed to tissues
via LDL transport
Where is Vit E located in cells
cell membrane
Where is Vit E stored
adipocytes; liver, lung, heart, muscle, adrenal glands
Main functions of Vit E
- Maintenance of membrane integrity
- Antioxidant function within phospholipids of cellular membranes
Define free radical
atom or group of atoms possessing an unpaired electron
How does vit E eliminate lipid radicals and peroxyl radicals
terminated chain-propagation reactions by donating H to LOO or L
Is Vit E regenerated
yes; by other antioxidants
How does Vit E reduce the risk of heart disease
may reduce oxidation of LDL-C to oxidized LDL; must be a natural form in high intakes
What does oxidized LDL cause
plaque buildup from foam cell formation
What other disease states may Vit E help
Type 2 Diabetes, Cataracts, iron toxicity
Nutrient interactions
Selenium: needed as cofactor in antioxidant reactions
Increased PUFA consumption= increased Vit. E requirements
Vit E protects B-carotene and products
How is Vit. E excreted
oxidation of chromonal ring –> via bile into feces
DRI/RDA
15 mg/d a-tocopherol equivalents
daily value
30 IU = 20mg
