21 Mar Neither Vitamin E or Selenium Found To Prevent Dementia
MedicalResearch.com Interview with:
Dr. Richard Kryscio
Richard J. Kryscio, Ph.D.
Statistics and Chair, Biostatistics and Sanders-Brown Center on Aging
Sanders-Brown Center on Aging
University of Kentucky
MedicalResearch.com: What is the background for this study?
Response: At the time the trial was initiated (2002), there was ample evidence that oxidative stress is an important mechanism in brain aging. Research showed that protein oxidation is linked to the brain’s response to the abnormal proteins seen in Alzheimer disease (amyloid beta plaques in particular) leading to inflammation, DNA repair problems, reduced energy production, and other cellular changes that are identified mechanisms in the Alzheimer brain.
Both vitamin E and selenium are antioxidants. Antioxidants, either through food or supplements, are believed to reduce oxidative stress throughout the body. In the brain, they may reduce the formation of amyloid beta plaques, reduce brain inflammation, and improve other brain processes. Studies in humans support these hypotheses. The Rotterdam study in the Netherlands, as an example, showed that initial blood levels of vitamin E could predict dementia risk. Those people with higher vitamin E levels were 25% less likely to develop dementia. Also, selenium deficiency results in cognitive difficulties and several population-based studies have shown an association between selenium level and cognitive decline (lower selenium levels are linked to thinking changes in the elderly).
MedicalResearch.com: What are the main findings?
Response: We enrolled 7,540 dementia free men in our randomized trial exposing the subjects to 5.4 years use of the supplements. A subset of these men (3,786) were followed for up to an additional six years. The men were randomly assigned to either vitamin E, or selenium, both or placebo. We found that the incidence of dementia (about 4.4%) did not differ among the four groups. We concluded that neither supplement prevented dementia.
MedicalResearch.com: What should readers take away from your report?
Response: There is likely a difference between taking a supplement to boost antioxidant levels in the body and having the levels increased due to an antioxidant rich diet like that found in the Mediterranean diet. Since overuse of supplements could pose problems, use should be monitored by a person’s physician.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: We need to find a way to prevent dementia since we have not been successful to date in treating the disease. Conducting a primary prevention trial like ours is difficult due to its length and issues encountered while conducting the study. Key issues encountered include determining the length of time a person would take a supplement, the dose of the supplement, the type of supplement chosen, and recruiting a large enough sample to detect a small effect.
No disclosures
Since this is a team effort, we need to acknowledge all of our team. This includes Dr. Gregory Jicha (Department of Neurology, College of Medicine, University of Kentucky, Lexington, KY 40536, USA) and Dr. Gregory Cooper (Baptist Health Lexington) who were part of our team and our authors:
Richard J. Kryscio, Ph.D.1,2,3,4, Erin L. Abner, Ph.D.1,2,3,5, Allison Caban-Holt, Ph.D.1,2, Mark Lovell, Ph.D. 1,2,6, Phyllis Goodman, M.S.7, Amy K. Darke, M.S.7, Monica Yee, B.A.8, John Crowley, Ph.D.8, and Frederick A. Schmitt, Ph.D. 1,2,9
1 Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536, USA
2 Alzheimer’s Disease Center, University of Kentucky, Lexington, KY 40536, USA
3 Department of Biostatistics, University of Kentucky, Lexington, KY 40536, USA
4 Department of Statistics, University of Kentucky, Lexington, KY 40536, USA
5 Department of Epidemiology, University of Kentucky, Lexington, KY 40536, USA
6 Department of Chemistry, University of Kentucky, Lexington, KY 40536, USA
7 SWOG Statistical Center, Seattle, Fred Hutchinson Cancer Research Center, WA, USA
8 SWOG Statistical Center, Seattle, Cancer Research and Biostatistics, WA, USA
9 Department of Neurology, College of Medicine, University of Kentucky, Lexington, KY 40536, USA
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Citation:
Richard J. Kryscio, Erin L. Abner, Allison Caban-Holt, Mark Lovell, Phyllis Goodman, Amy K. Darke, Monica Yee, John Crowley, Frederick A. Schmitt. Association of Antioxidant Supplement Use and Dementia in the Prevention of Alzheimer’s Disease by Vitamin E and Selenium Trial (PREADViSE). JAMA Neurology, 2017; DOI: 10.1001/jamaneurol.2016.5778
Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.
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Last Updated on March 21, 2017 by Marie Benz MD FAAD