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CancerQuest > Introduction to Patient Information > Introduction to Cancer Prevention > Cancer Prevention: Plant Products (Phytochemicals) > Cancer Prevention: Vitamin E

Cancer Prevention: Vitamin E

Also called:
alpha-Tocopherol, gamma-Tocopherol

Structure of Alpha-Tococpherol ( a form of vitamin E)

Intro and Background
Vitamin E is a term used to describe a group of eight naturally occurring compounds. ⁽¹⁾ Some of them function as antioxidants in cell membranes. The most abundant form of vitamin E found in dietary sources is the antioxidant alpha-tocopherol. This is also the form of vitamin E with the highest activity in the body. A different, less effective form of vitamin E, gamma-tocopherol, is the type often found in dietary supplements. ⁽²⁾ Vitamin E can be obtained from many foods including wheat germ, nuts, green leafy vegetables, meat, fish, and eggs. ^{(3) (4)} The US Food and Nutrition Board recommends 15mg per day with a maximum intake of 1000 mg per day. ⁽⁵⁾ Vitamin E is thought to inhibit cancer cell growth by preventing metastasis and DNA damage and by inducing apoptosis in cancer cells. ⁽⁶⁾ Alpha-tocopherol may also decrease the sensitivity of cancer cells to growth signals. ⁽⁷⁾ Vitamin E is also being examined for its ability to help prevent Alzheimer's, pulmonary, and cardiac diseases. ^{(8) (9)}

Learn more about apoptosis and metastasis

Scientific Evidence
There are several problems with the studies that have investigated the ability of vitamin E to prevent cancer. The studies varied in the amount of supplement taken and which of the eight possible forms was used. Also, it is difficult for these long term studies to take into account different lifestyles among the participants. ⁽¹⁰⁾ Some researchers believe that too many antioxidants may interfere with the normal immune response that can kill cancer cells. The fact that the most common form of dietary vitamin E is different from that usually found in supplements also increases the difficulty of determing whether vitamin E can or cannot prevent specific cancer types. ⁽²⁾

Studies have shown that vitamin E has the potential to be a cancer fighting agent.  Some of the best results have been obtained with prostate cancer. ⁽⁸⁾ The beta-carotene and retinol efficacy trial (CARET) showed that not getting enough vitamin E (alpha-tocopherol) was associated with a higher risk of prostate cancer. Additionally, one form of the compound (vitamin E succinate) has been shown to significantly decrease the development of prostate cancer, a protective effect that was lost when the subjects stopped taking the vitamin. ⁽¹¹⁾

A long term study recently revealed that dietary or supplemental vitamin E, vitamin C or beta carotene did not prevent prostate cancer. ⁽¹²⁾ After seven years of supplementation, another study revealed that vitamin E had no overall effect on the incidence of all cancers, including prostate cancer. ⁽¹³⁾ Another long term study (SELECT), was conducted with 35,000 North American men investigating the ability of a combination of vitamin E and selenium to prevent several types of cancer and quality of life. The study was stopped after preliminary results showed no benefit of the suplements. ^(6)(14) Participants were told to stop taking the study pills, but they will be followed for 3 more years.

For information about ongoing clinical trials involving vitamin E, please visit our section on Finding Clinical Trials.

US Food and Drug Administration Approval
At this time there is not enough conclusive evidence that any form of vitamin E can effectively prevent cancer. For this reason, vitamin E has not been approved for cancer prevention by the FDA.

References for this page:

1. Meydani M, Koga T, Ali S. Vitamin E deficiency. In: ENCYCLOPEDIA OF LIFE SCIENCES. John Wiley & Sons, Ltd: Chichester http://www.els.net/ [doi:10.1038/npg.els.0006101] [http://www.els.net/ [doi:10.1038/npg.els.0006101] ]
2. Kirsh VA, Hayes RB, Mayne ST, et al. Supplemental and dietary vitamin E, beta-carotene, and vitamin C intakes and prostate cancer risk. J Natl Cancer Inst (2006) 98: 24554 [PUBMED]
3. Garcia-Closas R, et al. Dietary sources of vitamin C, vitamin E and specific carotenoids in Spain. British Journal of Nutrition. (2004) 91: 1005-1011. [PUBMED]
4. "Medical Encyclopedia: Vitamin E." Medline Plus (6-21-2005). Accessed 2 June 2010. [http://www.nlm.nih.gov/medlineplus/ency/article/002406.htm]
5. Institute of Medicine, Food and Nutrition board. Dietary Reference Intakes: Vitamin C, Vitamin E, Selenium, and Carotenoids. National Academy Press, Washington, DC, 2001.
6. Klein EA, Thompson IM, Lippman SM, et al. SELECT: the next prostate cancer prevention trial. Selenium and Vitamin E. Cancer Prevention Trial. J Urol. (2001) 166: 13115. [PUBMED]
7. Jolly CA. Diet manipulation and prevention of aging, cancer and autoimmune disease. Curr Opin Clin Nutr Metab Care. (2005) 8: 382-387. [PUBMED]
8. Duffield-Lillico AJ, Reid ME, Turnbull BW, et al. Baseline characteristics and the effect of selenium supplementation on cancer incidence in a randomized clinical trial: a summary report of the Nutritional Prevention of Cancer Trial. Cancer Epidemiol Biomarkers Prev. (2002) 11:6309. [PUBMED]
9. Virtamo J, Pietinen P, Huttunen JK, et al for the ATBC Study Group. Incidence of cancer and mortality following alpha-tocopherol and betacarotene supplementation: a postintervention follow-up. JAMA. (2003) 290: 47685. [PUBMED]
10. Greenwald P, Anderson D, Nelson SA, Taylor PR. Clinical trials of vitamin and mineral supplements for cancer prevention. Am J Clin Nutr. (2007) 85(1):314S-317S. [PUBMED]
11. Klein EA. Chemoprevention of prostate cancer. Crit Rev Oncol hematol. (2005) 54: 1-10. [PUBMED]
12. Victoria A. Kirsh, Richard B. Hayes, Susan T. Mayne, Nilanjan Chatterjee, Amy F. Subar, L. Beth Dixon, Demetrius Albanes, Gerald L. Andriole, Donald A. Urban, and Ulrike Peters. Supplemental and Dietary Vitamin E, -Carotene, and Vitamin C Intakes and Prostate Cancer Risk. J Natl Cancer Inst. (Feb 2006) 98: 245 - 254 [PUBMED]
13. Lonn E, Bosch J, Yusuf S, Sheridan P, Pogue J, Arnold JM, Ross C, Arnold A, Sleight P, Probstfield J, Dagenais GR. HOPE and HOPE-TOO Trial investigators. Effects of long-term vitamin E supplementation on cardiovascular events and cancer: a randomized controlled trial. JAMA. (2005) 293: 1338-1347. [PUBMED]
14. Lippman SM, Klein EA, Goodman PJ, et al. Effect of Selenium and Vitamin E on Risk of Prostate Cancer and Other Cancers: The Selenium and Vitamin E Cancer Prevention Trial (SELECT). JAMA. 2009; 301(1). [PUBMED]