Keris KreenHrubec, Diana Zuckerman, PhD, Jacqueline Britz, BA
Updated January 2014
Many people take vitamins, but it’s important to know what positive and negative effects they can have on our health. This article will focus on vitamin E, which is a powerful antioxidant.
Antioxidants help us to stay healthy as we age by getting rid of extra oxygen that can cause damage to our bodies. Research has suggested that having too little vitamin E can harm the ability of your immune system to work properly, and can cause nervous system and eye disorders.1 Many researchers also suspect that taking vitamin E supplements could improve learning, heart disease, eye disorders, and cancer, but the research is not conclusive.1
Research findings on vitamin E’s effect on Alzheimer’s disease have been mixed. Earlier studies published in 1996, 2005, and 2009 found no evidence that vitamin E prevented mental decline or helped patients with Alzheimer’s disease or mild cognitive impairment.2 In contrast, a 2014 study found that vitamin E slowed the progression of mild to moderate Alzheimer’s disease in male military veterans; however, vitamin E taken with the Alzheimer’s drug memantine (brand name Namenda) did not slow down progression of the disease.3 Namenda also had no benefit if taken alone. More research is needed to determine if vitamin E has the same effects on women with mild to moderate Alzheimer’s disease, but these findings suggest that vitamin E may be a more effective, lower-cost treatment than prescription medication.
A study by Yale researcher Dr. Benedetta Bartali indicated that older people who had low amounts of vitamin E in their blood lost more of their physical abilities as they got older.4 The researchers examined 1,155 patients in November 1998, and again in May 2000, to determine any changes in physical ability and of certain vitamins in their system. The patients then received follow-up exams once a year between November 2001 and March 2003 to see how both their abilities and vitamin levels changed. Researchers measured physical abilities in terms of walking, getting out of a chair, and other basic skills. The researchers measured each person’s levels of vitamins B6, B12, D, E, and folate. Only vitamin E significantly correlated with a loss in physical ability. Patients who were over 81 years old had a large decline in physical ability regardless of vitamin E levels, but patients between 70 and 80 only had a large decline in physical ability if they had low vitamin E levels. None of the other vitamins significantly influenced physical ability. This shows that lack of vitamin E could potentially result in poor physical functioning, but not poor mental functioning.4
Other researchers, including Robert J. Glynn, PhD, ScD, and his colleagues from Brigham and Women’s Hospital, have investigated whether taking vitamin E supplements reduces the risk of heart disease.5 Their 2007 study suggested that vitamin E supplements may lower women’s risk of heart disease. A 2008 study, however, showed no correlation between vitamin E intake and men’s risk of heart disease.6 Given these conflicting findings, and the fact that there was only one study of women and one of men, more research is needed to determine whether vitamin E supplements decrease the risk of heart disease in either men or women.
A trial was started in 2001 by the National Cancer Institute to investigate the influence of vitamin E and selenium on prostate cancer and other types of cancer. Researchers expected to show that vitamin E and selenium supplementation would reduce risk of prostate cancer by 25 percent. They were planning to follow up with study participants for a minimum of 7 years and a maximum of 12 years. They decided, however, to end the study in 2008, after only the minimum 7 years, when the independent Data and Safety Monitoring Committee (DSMC) reviewed SELECT study data and determined that there was still no evidence indicating that vitamin E lowers risk of prostate cancer or other diseases.7
Studies on vitamin E and age-related macular degeneration (AMD), an eye disorder that distorts vision, were also inconclusive. One 2007 study reported that there was insufficient data to support the role of dietary supplements in preventing AMD.8
Do these study results mean we should all take or avoid vitamin E? Evidence has shown that health problems can result from not getting enough vitamin E; however, there is not yet enough evidence to show whether or not it is beneficial to take vitamin E supplements to treat or prevent heart disease, mental disorders, eye problems, cancer, or other health problems. Further, extremely high levels of vitamin E can be harmful, as it can prevent blood from clotting, and therefore cause excessive bleeding. The American Heart Association stated in 2004 that taking 400 IU or more per day (approximately 267mg-about 17 times the daily recommended value), can increase the risk of death. The studies cited in this article, however, suggest that it is important to get the recommended daily amount of vitamin E.
The recommended daily amount of vitamin E is 15 mg for the average adult, although the amount varies depending on your age and whether you are a man or a woman, so you might want to check with your doctor.1 Vitamin E is in common foods such as green leafy vegetables, nuts, vegetable oils, and sunflower seeds.
- Vitamin E: Health Professional Fact Sheet. Office of Dietary Supplements. National Institutes of Health, 15 Dec. 2009. Web. 2 Sept. 2010. <http://ods.od.nih.gov/factsheets/vitamine.asp>. ▲
- Farina, N., Isaac, M.G., Clark, A.R., Rusted, J., & Tabet, N. (2012). Vitamin E for Alzheimer’s dementia and mild cognitive impairment In The Cochrane Collaboration (Cochrane review abstract and plain language summary of research). Retrieved from John Wiley and Sons, Ltd website: http://www2.cochrane.org/reviews/en/ab002854.html ▲
- Dysken MW, Sano M, Asthana S, et al. Effect of vitamin E and memantine on functional decline in Alzheimer disease. JAMA; 2014; 311(1):33-44. doi: 10.1001/jama.2013.282834 ▲
- Bartali, Benedetta, et al. (2008, January 23). Serum Micronutrient Concentrations and Decline in Physical Function Among Older Persons. Journal of the American Medical Association, 308-315. Retrieved from http://jama.ama-assn.org/cgi/content/abstract/299/3/308 ▲
- Glenn, R. J., et al. (2007, July 30). Effects of Random Allocation to Vitamin E Supplementation on the Occurrence of Venous Thromboembolism. In American Heart Association (Report From the Women’s Health Study). Retrieved from http://circ.ahajournals.org/cgi/content/short/116/13/1497 ▲
- Sesso, H. D. (2008, November 9). Vitamins E and C in the Prevention of Cardiovascular Disease in Men. Journal of the American Medical Association, 2123-2133. Retrieved from http://jama.ama-assn.org/cgi/content/abstract/300/18/2123 ▲
- Klein, E. A. (2008, December 9). Effect of selenium and vitamin E on risk of prostate cancer and other cancers: the Selenium and Vitamin E Cancer Prevention Trial (SELECT). In SpringerLink (pg. 349-360) (Prostate Cancer Screening ). Retrieved from SpringerLink database. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/19066370 ▲
- Chong, E. W.-T., Wong, T. Y., Kreis, A. J., Simpson, J. A., & Guymer, R. H. (2007, October 8). Dietary antioxidants and primary prevention of age related macular degeneration: systematic review and meta-analysis. British Medical Journal ▲