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7/23/2002

Vitamin E May Slow Cognitive Decline

Kate Traynor

Vitamin E from food and supplements may slow age-associated cognitive decline, report researchers from Chicago's Rush-Presbyterian-St. Luke's Medical Center.

Using a system that involved combining the results of four common cognitive tests, the researchers calculated that, on average, the cognitive skills of seniors who participated in the study fell by 0.05 standardized units each year. The decline was greatest—0.067 units per year—among seniors who consumed the least vitamin E. In contrast to this group, the mental state of seniors who took in the most vitamin E declined 36 percent more slowly, at a rate of 0.047 units per year.

Despite the overall trend toward cognitive decline, the research team noted that 39 percent of the study participants had no decline in their mental state during the study, and some seniors' cognitive scores improved. The report, which appeared in the July issue of Archives of Neurology, did not include a separate analysis vitamin E intake among seniors whose cognitive scores did not decline.

The study's findings were published Seniors for whom study data were obtained had enrolled in the Chicago Health and Aging Project (CHAP), which involved 6,158 people 65 years and older who lived in Chicago's south side. The 2,889 participants in the current project had completed a food frequency questionnaire within 2.5 years of enrolling in CHAP and had undergone cognitive testing at baseline and three years later.

The research team divided the seniors' vitamin E intake into quintiles. Half of the people in the lowest fifth took in 6.3 IU of vitamin E per day, and half of those in the highest fifth consumed 11.7 IU of vitamin E each day.

Both dietary vitamin E and supplements containing the vitamin counted toward the daily total intake. The cognitive scores of people who consumed large amounts of vitamin E from food were similar to the scores of those who used a supplement containing the vitamin. But people who consumed little dietary vitamin E and did not use a supplement scored less well than supplement users regardless of their dietary vitamin E intake.

In contrast to the findings on vitamin E, vitamin C and carotene intake did not appear to influence the study participants' cognitive state.

A report published in the Journal of the American Medical Association (JAMA) last month by the same research team and additional colleagues examined the effect of vitamin E intake on the development of Alzheimer's disease among CHAP participants. This study found that vitamin E from foods but not supplements may protect against Alzheimer's disease among people who lack the apolipoprotein E4 allele, which is associated with an increased risk for some types of Alzheimer's disease. To explain this unexpected finding, the research team speculated that the negative effects of the apolipoprotein E4 allele are too severe to be overcome by the beneficial effects of vitamin E.

Researchers in the Netherlands reported in the same issue of JAMA that high levels of dietary vitamin E and vitamin C may lower the risk for Alzheimer's disease regardless of a person's apolipoprotein E4 genotype.