antioxidant properties of vitamin E are effective in
preventing cataracts. Five studies found a protective
effect, while five others found no effect.Precautions
There is a great deal of debate about how much
vitamin E is too much. The UL for healthy adults in
the United States is 1,500 IU daily. However, some
experts feel this is too high, especially since it is based
on research done in the 1950s. They argue that UL
should be lower since the Johns Hopkins study found
that daily amounts over 400 IU increased the death
rate and protective effects of larger doses of vitamin E
are still unproven. In the United Kingdom, the recom-
mended daily limit of vitamin E is 800 UI.
Large doses of vitamin E increase the chance of
bleeding. People who are taking blood-thinning med-
ications such as warfarin (Coumadin), heparin, and
clopidogrel (Plavix) should discuss the use of vitamin
E with their healthcare providers. Other people who
should be wary of taking vitamin E as a dietary supple-
ment are those who arevitamin Kdeficient, who have
liver damage, and those with a history of bleeding
ulcers. Vitamin E supplementation should be stopped
about one month before surgery because of the
increased risk of bleeding. Other possible, but uncom-
mon, side effects of vitamin E supplementation
include nausea, vomiting, diarrhea, damage to the
retina, breast soreness, fatigue, emotional disturban-
ces, and thyroid hormone disturbances.InteractionsVitamin E may interact with the following:
When taken with blood-thinning drugs, vitamin E
may increase the likelihood of bleeding.
When taken with nonsteroidal anti-inflammatory
(NSAIDs) drugs such as ibuprofen (Motrin, Advil)
or naproxen (Aleve, Naprosyn), vitamin E may
increase the likelihood of bleeding.
Cholestyramine (Questran) and colestipol (Colestid)
may decrease vitamin E absorption.
Orlistat (Xenical, Alli) decreases Vitamin E absorption.
Olestra, a fat substitute in foods, decreases the
absorption of vitamin E.ComplicationsNo complications are expected when vitamin E is
used in the recommended amounts. The complications
resulting from insufficient or excess use are discussed
above.Resources
BOOKS
Gaby, Alan R., ed.A-Z Guide to Drug-Herb-Vitamin Inter-
actions Revised and Expanded 2nd Edition: Improve
Your Health and Avoid Side Effects When Using Com-
mon Medications and Natural Supplements Together.
New York: Three Rivers Press, 2006.
Lieberman, Shari and Nancy Bruning.The Real Vitamin and
Mineral Book: The Definitive Guide to Designing Your
Personal Supplement Program,4th ed. New York:
Avery, 2007.
Preedy, Victor R. and Ronald R. Watson, eds.The Ency-
clopedia of Vitamin E.Wallingford, Oxfordshire, UK :
CABI International, 2007.
Pressman, Alan H. and Sheila Buff.The Complete Idiot’s
Guide to Vitamins and Minerals,3rd ed. Indianapolis,
IN: Alpha Books, 2007.
Rucker, Robert B., ed.Handbook of Vitamins.Boca Raton,
FL: Taylor & Francis, 2007.
PERIODICALS
Schardt, David. ‘‘Is Vitamin E Dangerous?’’Nutrition
Action Healthletter32, no.4 (May 1, 2005):12.
ORGANIZATIONS
American Cancer Society. 1599 Clifton Road NE, Atlanta
GA 30329-4251. Telephone: (800) ACS-2345. Website:
http://www.cancer.org.
American Heart Association. 7272 Greenville Avenue, Dal-
las, TX 75231. Telephone: (800) 242-8721. Website:
http://www.americanheart.org.
American Dietetic Association. 120 South Riverside Plaza,
Suite 2000, Chicago, Illinois 60606-6995. Telephone:
(800) 877-1600. Website: http://www.eatright.org/
Linus Pauling Institute. Oregon State University, 571
Weniger Hall, Corvallis, OR 97331-6512. Telephone:
(541) 717-5075. Fax: (541) 737-5077. Website: http://
lpi.oregonstate.edu/
Office of Dietary Supplements, National Institutes of
Health. 6100 Executive Blvd., Room 3B01, MSC 7517,
Bethesda, MD 20892-7517 Telephone: (301)435-2920.
Fax: (301)480-1845. Website: http://dietary-
supplements.info.nih.gov/
OTHER
American Cancer Society ‘‘Vitamin E.’’ American Cancer
Society, June 1, 2005.<http://www.cancer.org/docroot/
ETO/content/ETO_5_3X_Vitamin_E.asp?sitearea=
ETO>.
American Heart Association Nutrition Committee. ‘‘Diet
and Lifestyle Recommendations Revision 2006.’’
American Heart Association, June 19, 2006.<http://
http://www.americanheart.org/presenter.jhtml?identifier=
3040741 >
Higdon, Jane. ‘‘Vitamin E.’’Linus Pauling Institute-Oregon
State University, November 11, 2004.<http://lpi.
oregonstate.edu/infocenter/vitamins/VitaminE>Vitamin E