II. Background
- Vitamin E is a complex of 8 different fat soluble molecules (4 tocopherols and 4 tocotrienols)
- Of the 8 compounds in Vitamin E, only Alpha Tocopherol is functional in humans
- Antioxidant properties include donating electrons to lipids in their free radical form, reducing their oxidative effects
III. Mechanism
- Vegetable and Seed Oils: gamma-tocopherol
- Antioxidant
- Usual daily intake 15 IU/day
- Supplements: alpha-tocopherol
- May block antioxidant effect of natural foods
- May have pro-Oxidant effect
IV. Preparations: Sources
- Wheat germ
- Fish liver oil
- Nuts
- Vegetable Oil
- Corn oil
- Cottonseed oil
- Sunflower oil
- Soybean oil
- Green vegetables
- Beet greens
- Collard greens
- Spinach
- Asparagus
V. Efficacy: Potential Benefits
- May delay progression of Alzheimer's Disease
- May slow functional decline in mild to moderate Dementia (in those on Cholinesterase Inhibitor)
- Initial studies showed slower functional decline
- Insufficient evidence to recommend by Cochrane
- May boost immune response in elderly
- Study (DBPCT) of those over age 65 years (n=88)
- Measured Antigen produced induration to PPD
- Marked increase induration with 200 mg/day
- Suggested that US RDA (30 mg) may be too low
- References
- Study (DBPCT) of those over age 65 years (n=88)
VI. Adverse Effects: Potential Risks or No Benefit
- Increased overall motality risk
- Associated with consistent dosing >400 IU/day for >1 year
- Does not reduce cancer risk
- Prostate Cancer risk is increased (1 new case in 625 men taking 400 units/day)
- Klein (2011) JAMA 306:1549-56. [PubMed]
- Congestive Heart Failure increased risk
-
Coronary Artery Disease risk
- Initial studies suggested possible benefit
- PPP Study suggests no benefit
- May increase Heart Failure risk
- PPP study shows possibly higher CVA risk
- Studies show slightly higher all cause mortality
- Increased risk of bleeding and Hemorrhagic Stroke
- Interference with Vitamin K metabolism, Antagonizing Vitamin K dependent Clotting Factors
- Interference with Platelet aggregation
- Do not use >800 IU/day in patients on Warfarin or antiplatelet agents
- Schurks (2010) BMJ 341: c5702 [PubMed]
VII. References
- (2011) Presc Lett 18(12): 68
- (2014) Presc Lett 21(2):12
- Stephans (1996) Lancet 347:781 [PubMed]
- (2001) Lancet 357:89-95 [PubMed]
- Lonn (2005) JAMA 293:1338-47 [PubMed]
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Related Studies
Definition (MEDLINEPLUS) |
Vitamin E is an antioxidant. Antioxidants are substances that may protect your cells against the effects of free radicals. Free radicals are molecules produced when your body breaks down food, or by environmental exposures like tobacco smoke and radiation. Vitamin E also plays a role in your immune system and metabolic processes. Good sources of vitamin E are vegetable oils, margarine, nuts, seeds, and leafy greens. Vitamin E is also added to foods like cereals. Most people get enough vitamin E from the foods they eat. People with certain disorders, such as liver diseases, cystic fibrosis, and Crohn's disease may need extra vitamin E. Vitamin E supplements may be harmful for people who take blood thinners and other medicines. Check with your health care provider before taking the supplements. NIH: National Institutes of Health Office of Dietary Supplements |
Definition (NCI) | A natural fat-soluble antioxidant with potential chemopreventive activity. Also known as tocopherol, vitamin E ameliorates free-radical damage to biological membranes, protecting polyunsaturated fatty acids (PUFA) within membrane phospholipids and within circulating lipoproteins. Peroxyl radicals react 1000-fold faster with vitamin E than with PUFA. In the case of oxygen free radical-mediated tumorigenesis, vitamin E may be chemopreventive. (NCI04) |
Definition (NCI_CRCH) | A fat-soluble vitamin which is primarily a chain-breaking antioxidant that prevents the propagation of lipid peroxidation. |
Definition (NCI_NCI-GLOSS) | A nutrient that the body needs in small amounts to function and stay healthy. Vitamin E helps prevent cell damage caused by free radicals (highly reactive chemicals). It is fat-soluble (can dissolve in fats and oils) and is found in seeds, nuts, leafy vegetables, and vegetable oils. Not enough vitamin E can result in infertility (the inability to produce children). It is being studied in the prevention and treatment of some types of cancer. Vitamin E is a type of antioxidant. |
Definition (MSH) | A generic descriptor for all TOCOPHEROLS and TOCOTRIENOLS that exhibit ALPHA-TOCOPHEROL activity. By virtue of the phenolic hydrogen on the 2H-1-benzopyran-6-ol nucleus, these compounds exhibit varying degree of antioxidant activity, depending on the site and number of methyl groups and the type of ISOPRENOIDS. |
Definition (PDQ) | A natural fat-soluble antioxidant with potential chemopreventive activity. Also known as tocopherol, vitamin E ameliorates free-radical damage to biological membranes, protecting polyunsaturated fatty acids (PUFA) within membrane phospholipids and within circulating lipoproteins. Peroxyl radicals react 1000-fold faster with vitamin E than with PUFA. In the case of oxygen free radical-mediated tumorigenesis, vitamin E may be chemopreventive. Check for "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=38321&idtype=1" active clinical trials or "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=38321&idtype=1&closed=1" closed clinical trials using this agent. ("http://nciterms.nci.nih.gov:80/NCIBrowser/ConceptReport.jsp?dictionary=NCI_Thesaurus&code=C942" NCI Thesaurus) |
Concepts | Pharmacologic Substance (T121) , Lipid (T119) , Vitamin (T127) |
MSH | D014810 |
SnomedCT | 37237003, 63822004 |
English | Vitamin E, 3,4-Dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6-ol, 5,7,8-Trimethyltocol, VIT E, E vitamin, vitamin-E, Vitamin E Compound, vitamin E (medication), Vitamin E [Chemical/Ingredient], VITAMIN E, vit e, vitamin E, tocopherol (vit E), tocopherol, 2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)chroman-6-ol, Vitamin E preparation, Vitamin E product, Vitamin E (substance), Vitamin E preparation (product), VIT-E, Vitamin E preparation, NOS, Vitamin E preparation (substance), E Vitamin |
Swedish | Vitamin E |
Czech | vitamin E |
Finnish | Tokoferoli |
Russian | TOKOFEROL, VITAMIN E, ВИТАМИН E, ТОКОФЕРОЛ |
Spanish | producto con vitamina E, vitamina E (producto), preparado con vitamina E (producto), preparado con vitamina E, preparado de vitamina E (sustancia), vitamina E (sustancia), vitamina E, Vitamina E |
Croatian | VITAMIN E |
Polish | Tokoferol, Witamina E |
French | Vitamine E |
German | Vitamin E |
Italian | Vitamina E |
Portuguese | Vitamina E |
Ontology: alpha Tocopherol (C0969677)
Definition (NCI) | A naturally-occurring form of vitamin E, a fat-soluble vitamin with potent antioxidant properties. Considered essential for the stabilization of biological membranes (especially those with high amounts of polyunsaturated fatty acids), d-alpha-Tocopherol is a potent peroxyl radical scavenger and inhibits noncompetitively cyclooxygenase activity in many tissues, resulting in a decrease in prostaglandin production. Vitamin E also inhibits angiogenesis and tumor dormancy through suppressing vascular endothelial growth factor (VEGF) gene transcription. (NCI04) |
Definition (NCI) | A naturally-occurring form of vitamin E, a fat-soluble vitamin with potent antioxidant properties. Considered essential for the stabilization of biological membranes (especially those with high amounts of polyunsaturated fatty acids), d-alpha-Tocopherol is a potent peroxyl radical scavenger and inhibits noncompetitively cyclooxygenase activity in many tissues, resulting in a decrease in prostaglandin production. Vitamin E also inhibits angiogenesis and tumor dormancy through suppressing vascular endothelial growth factor (VEGF) gene transcription. (NCI04) |
Definition (NCI_CRCH) | Tocopherol with three methyl groups on its chromanol ring. |
Definition (MSH) | A natural tocopherol and one of the most potent antioxidant tocopherols. It exhibits antioxidant activity by virtue of the phenolic hydrogen on the 2H-1-benzopyran-6-ol nucleus. It has four methyl groups on the 6-chromanol nucleus. The natural d form of alpha-tocopherol is more active than its synthetic dl-alpha-tocopherol racemic mixture. |
Concepts | Pharmacologic Substance (T121) , Lipid (T119) , Vitamin (T127) |
MSH | D024502 |
SnomedCT | 63822004, 259666007, 350546004, 116776001, 37237003 |
LNC | LP15369-9, MTHU004905 |
English | alpha-Tocopherol, Alpha tocopheryl product, d-Alpha-Tocopherol, (+/-)-alpha-Tocopherol, d-alpha-Tocopherol, (+)-alpha-Tocopherol, d-alpha tocopherol, Alfa tocopherol, Alpha tocopherol, alpha-tocopherols, alpha-tocopherols (medication), (+-)-alpha-Tocopherol, alpha-Tocopherol [Chemical/Ingredient], Alpha-Tocopherol, alpha-tocopherol, ALPHA-TOCOPHEROL, D-, ALPHA-TOCOPHEROL, d-alpha-tocopherol, d alpha tocopherol, dl-alpha tocopherol, alpha tocopherol, ALPHA-Tocopherol, .Alpha.-Tocopherol, .alpha.-tocopherol, 3,4-Dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6-ol, .Alpha.-tocopherol, .ALPHA.-TOCOPHEROL, D-, .ALPHA.-TOCOPHEROL, .Alpha.-Tocopherol, D-, .ALPHA.-Tocopherol, R,R,R-alpha-Tocopherol, Tocopherol, d-alpha, d alpha Tocopherol, d-alpha Tocopherol, Alpha tocopheryl product (product), 2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)chroman-6-ol, .alpha.-tocopherol, d-, D-alpha-tocopherol, alpha-Tocopherol preparation, Alpha-tocopherol, D-alpha-tocopherol (substance), Alpha-tocopherol (substance), alpha Tocopherol |
Swedish | Alfatokoferol |
Czech | alfa-tokoferol |
Spanish | alfa-tocoferol, tocofersolán, preparado con alfa-tocoferol, Alfa Tocoferol, alfa - tocoferol (sustancia), alfa - tocoferol, d - alfa - tocoferol (sustancia), d - alfa - tocoferol, alfa-Tocoferol |
Finnish | Alfatokoferoli |
Russian | AL'FA-TOKOFEROL, АЛЬФА-ТОКОФЕРОЛ |
Japanese | アルファ-トコフェロール, d-α-トコフェロール |
Polish | Alfa-tokoferol |
French | alpha-Tocophérol, Tocophérol alpha |
German | Alpha-Tokopherol |
Italian | Tocoferolo alfa |
Portuguese | alfa-Tocoferol |