Vit E 3 pp - Vitamin E Spring 2011 Vitamin E: History Evans...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
Vitamin E Spring 2011 Vitamin E: History • Evans & Bishop discovered – wheat germ oil cured reproductive failure in rats fed rancid fat • Evans isolated vitamin E from wheat germ and named the factor “tocopherol” from Greek “tokos” meaning “offspring” and “pherein” meaning to “bear” Chemical Forms of Vitamin E • Vitamin E name includes 8 different forms • 4 tocophenols and 4 tocotrienols • tocotrienols differ from tocopherols –Unsaturated side chain
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Form that Meets Human Requirement • Food and Nutrition Board defined -tocopherol as only form that meets human vitamin E requirement –only -tocopherol shown to reverse deficiency symptoms Naturally-Occurring Stereoisomer in food is RRR - -tocopherol carbons at the 2, 4, 8 position in R position
Background image of page 2
Synthetic Vitamin E • Chemically synthesized -tocopherol is not identical to naturally occurring form in food • Chemical synthesis produces 8 different stereoisomers – mixture of 8 stereoisomers referred to as mixture of 8 stereoisomers referred to as all-rac - -tocopherol – Only 4 of these are biologically active- stereoisomers- must be 2 R forms RR SR RS SS Biologically Active Forms Synthetic Vitamin E • Chemically synthesized -tocopherol Only half of the stereoisomers in al • Only half of the stereoisomers in all- rac- - tocopherol meet human requirement
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Blood tocopherol response to labeled (d3 and d6) dose of 150 mg each of d3 RRR - -andd6 all rac - -tocopherol Vitamin E: Food Sources •Ma jo r sou r ce s – Vegetable oils –Margarine – Mayonnaise –Wheat germ – Nuts, seeds
Background image of page 4
Stability of Vitamin E • Oxidized easily –light, heat, or metals destruction • Esterification of synthetic form –prevents oxidation/extends shelf life Vitamin E Absorption • Vitamin E absorbed along with fats as component of micelles into intestinal cells – all chemical forms are incorporated into chylomicrons inside intestinal cells • Fat malabsorption can result in vit E deficiency – Cystic fibrosis (pancreatic lipase deficiency) – Cholestasis (decreased bile production) – Celiac disease Vitamin E Transport • Unlike other fat-soluble vitamins, vitamin E does not have a specific transport protein • Transported as a component of plasma lipoproteins • Chylomicron remnants transport to live • Chylomicron remnants transport to liver • Liver exports -tocopherol into plasma as component of VLDL – secretion of -tocopherol into plasma under control of -tocopherol transfer protein ( -TPP) • genetic defect in synthesis of -TPP leads to vitamin E deficiency
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
-Tocopherol Transfer Protein -tocopherol transfer protein ( -TPP) involved in transfer of -tocopherol from liver to lipoproteins • Vitamin E forms are not interconvertible because their plasma concentrations are
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/09/2011 for the course HUN 4445 taught by Professor Sitren during the Spring '08 term at University of Florida.

Page1 / 22

Vit E 3 pp - Vitamin E Spring 2011 Vitamin E: History Evans...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online