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]