ROTTERDAM, Netherlands—Ensuring adequate vitamin E intake in the diet may help fight age-related onset of dementia and Alzheimer’s, according to a new study from the Archives of Neurology (2010;67(7):819-825. DOI: 10.1001/archneurol.2010.144). The Rotterdam Study research team from Erasmus Medical Center and Boston’s Harvard University, returned to their original cohort to determine the longer-term impact of dietary antioxidant consumption on dementia and Alzheimer’s disease.
In 2002, the team reported higher dietary intakes of the antioxidant vitamins E and C could reduce the risk of Alzheimer’s disease and dementia over six years of follow-up (JAMA. 2002;287(24):3223-9). In the new study, they looked at information on 5,395 subjects in the prospective cohort, who were free of dementia and provided dietary information at the study baseline, and the connection between dementia or Alzheimer’s risk and intake of vitamin E, vitamin C, beta-carotene and flavonoids.
Over a mean follow-up period of 9.6 years, 465 adults developed dementia, 365 of whom were diagnosed with Alzheimer’s. Higher vitamin E intake at baseline was associated with lower long-term risk of both dementia and Alzheimer’s, reducing the risk by 24 percent and 26 percent, respectively, for subjects in the highest tertile of vitamin E intake (~18 mg/d) compared to those in the lowest tertile. No associations were seen for consumption of vitamin C, beta-carotene or flavonoids. The findings remained unchanged when adjusting for the subjects (n=644) who used supplements, primarily antioxidant supplements, at baseline.
Andrew Shao, Ph.D., senior vice president, scientific and regulatory affairs, Council for Responsible Nutrition (CRN), said the study findings are particularly interesting as they look at the correlation between baseline vitamin E intake and the effects on dementia over a 10-year period. “The vitamin E intake at baseline may not be reflective of their intake over the 10 years, suggesting vitamin E exerts a very strong effect,” he said.
At the same time, the researchers noted their positive findings differed from those found in several randomized clinical trials (RCTs), where supplementation with vitamin E has not been shown to affect dementia or Alzheimer’s risk. They stated, “Our study focused on food-based antioxidants in the context of a Western-type diet, with intakes several-fold lower than supplementation levels in clinical trials. … [and] We studied various antioxidants and total vitamin E (including all eight forms), whereas clinical trials evaluated single-form alpha-tocopherol supplements.”
Shao agreed the fact that the study measured total vitamin E could help explain some of the inconsistencies between the present study’s findings and those generated from recent RCTs. However, he also cited the level of intake, which was just above the U.S. recommended daily allowance (RDA) in the highest tertile. “This suggests there may be a window of benefit in relation to cognitive decline where the effective level is substantially lower than what has been used in some of the RCTs and is typically sold on the market,” he said.
