Vitamin E–Rich Foods May Reduce Long-Term Risk for Dementia
Allison Gandey
July 22, 2010 — Vitamin E may play a modest role in altering the course of dementia, say researchers. Compared with participants with the lowest intake, investigators found that those patients with higher vitamin E intake were 25% less likely to develop dementia.
"When beta-amyloid — a hallmark of pathologic Alzheimer disease — accumulates in the brain, an inflammatory response is likely evoked that produces nitric oxide radicals and downstream neurodegenerative effects," report investigators led by Elizabeth Devore, ScD, from the Erasmus Medical Center in Rotterdam, the Netherlands.
"Vitamin E is a powerful fat-soluble antioxidant that may help to inhibit the pathogenesis of dementia."
Number of Alzheimer cases by dietary vitamin E intake.
The results appear in the July issue of the Archives of Neurology and suggest that dietary antioxidants affect the early stages of dementia.
Vitamin E is found in whole-grain foods, eggs, milk, nuts, seeds, avocado, spinach, and unheated vegetable oils. The Rotterdam Study previously found that higher dietary intakes of vitamins E and C were associated with a lower risk for dementia and Alzheimer's disease.
In this new long-term follow-up of the Rotterdam Study, investigators followed participants for 9.6 years. The population-based prospective cohort study included 5395 people free of disease at baseline.
A total of 465 people developed dementia. Of these, 365 were diagnosed with Alzheimer's disease. The investigators found that higher dietary intake of vitamin E, but not vitamin C, beta carotene, or flavonoids, was associated with lower long-term risk for dementia.
These results conflict with previous findings, which suggested a link between vitamin C intake and dementia risk. "The result was modest in our analysis," note the investigators, who reported a hazard ratio of 0.66 (95% confidence interval, 0.44 - 1.00). "Chance is the most likely explanation," they add. "Alternatively, vitamin C intake could be important exclusively at later stages of dementia development, but this is less likely because results of previous studies suggest that dietary antioxidants affect early stages of dementia pathogenesis."
Long-Term Prospective Study
The investigators adjusted for age, education, apolipoprotein E ε4 genotype, total energy, alcohol intake, smoking habits, body mass index, and supplement use. They found that higher vitamin E intake at study baseline was associated with lower long-term risk for dementia (P = .02 for trend).
Asked by Medscape Medical News to comment, Maria Carrillo, PhD, senior director of medical and scientific relations at the Alzheimer's Association, pointed out the National Institutes of Health have been calling for long-term prospective studies such as this one. "These are important studies, and this one was conducted by a fantastic, internationally renowned group."
Dr. Carrillo acknowledged the finding is preliminary — it is still too early for specific recommendations on vitamin E intake, and excessive use can have negative cardiovascular effects, she said.
"Future studies should continue to evaluate dietary intake of antioxidants relative to dementia risk," note the investigators, "including different points at which antioxidant intake might modulate risk."
This study was supported by the Netherlands Organization for Scientific Research, the National Institutes of Health, and a US Fulbright Fellowship to the Netherlands. The researchers have disclosed no relevant financial relationships.
Arch Neurol. 2010;67:819-825. Abstract
High levels of vitamin E in the blood reduce the risk of developing Alzheimer's disease in old age, says a new study. Italian and Swedish researchers found that several components of vitamin E helped prevent cognitive deterioration in people 80 years of age and older.
"Vitamin E is a family of eight natural components, but most studies related to Alzheimer's disease investigate only one of these components, tocopherol," Dr. Francesca Mangialasche, who led the study, said in a statement. "We hypothesized that all the vitamin E family members could be important in protecting against AD. If confirmed, this result has implications for both individuals and society, as 70 percent of all dementia cases in the general population occur in people more than 75 years of age, and the study suggests a protective effect of vitamin E against AD in individuals aged 80 plus."
The researchers studied 232 people who were 80 years or older and were free of dementia at the beginning of the study. After six years, they identified 57 cases of Alzheimer's disease.
At the beginning of the study, the blood levels of all eight natural components of vitamin E were measured. People with higher blood levels were compared with those subjects who had lower blood levels. The scientists found that seniors with the higher blood levels of all the forms of vitamin E reduced their risk of developing Alzheimer's by 45 to 54 percent, depending on the levels of specific components.
Mangialasche noted that the protective effect of vitamin E appears to be related to the combination of the different forms. Along this line, another recent study suggested that supplements containing high doses of the tocopherol component of vitamin E may increase mortality, indicating that such dietary supplements, if not balanced in the body, may be more harmful than previously thought.
"Elderly people as a group are large consumers of vitamin E supplements, which usually contain only tocopherol, and this is often at high doses," says Mangialasche. "Our findings need to be confirmed by other studies, but they open up the possibility that the balanced presence of different vitamin E forms can have an important neuroprotective effect."
According to the Alzheimer's Association, 5.3 million Americans have the disease, and it is the seventh leading cause of death. |
