EVIDENCE ADDED TO LINK BETWEEN VITAMIN E AND MEMORY

INDIANAPOLIS - In the first large scale American study, researchers at the Regenstrief Institute for Health Care and the Indiana University School of Medicine have added evidence to the link between vitamin E and memory recall.

In the study, published in the July 1 issue of the American Journal of Epidemiology, Siu Hui, Ph.D., and colleagues investigated the association between serum antioxidant levels and memory performance in the elderly. This is the first time data from a large multiethnic representative sample of Americans has been studied to determine whether links exist between specific antioxidants and memory. Previous studies, mostly conducted in Europe, focused on a specific ethnic group or on highly educated individuals.

Oxidative stress has been implicated both in the aging process and in the pathological changes associated with Alzheimer's disease. Antioxidants, which have been shown to reduce oxidative stress in laboratory experiments, may represent potentially protective factors for poor memory, a major component of dementing disorders.

This new study analyzed data taken from 4,809 elderly Americans as part of the Third National Health and Nutritional Examination Survey, a national cross-sectional survey conducted between 1988 and 1994.

Memory was assessed using delayed recall (six points from a story and three words). Decreasing serum levels of vitamin E, an antioxidant, were consistently associated with increasing levels of poor memory after adjustment for age and other relevant factors. Only vitamin E was associated with memory. No relationship with memory was found between vitamins A, C or beta-carotine, which are also antioxidants. While not an anti-oxidant, selenium, which is associated with antioxidant enzyme activity, was also studied and similarly found to have no link with memory.

Increasing levels of vitamin E were associated with better memory performance in all ethnic groups included in the sample -- non-Hispanic Whites, non-Hispanic Blacks and Mexican-American elderly. Previous studies have presented mixed results when looking at a possible association of antioxidants with memory and cognition.

"Several factors may explain why our results differ from previous studies," says Dr. Hiu. "Our sample is larger and more diverse both racially and in socioeconomic factors such as education and income levels. In addition we measured blood serum values - the amount of the antioxidants actually in the blood, not dietary intake. And we studied delayed recall, while other studies used other measures of memory."

Other authors of this study are Anthony Perkins, Hugh C. Hendrie, M.B. Ch.B., Christopher M. Callahan, M.D., Sujuan Gao, Ph.D., Frederick W. Unverzagt, Ph..D., Yong Xu, M.D., and Kathleen S. Hall, Ph.D.

Note to the editor:

The best sources of vitamin E are plant products. Wheat germ oil is by far the richest source. Other good sources include almonds, peanut oil, corn oil and olive oil. Animal products are relatively poor sources of vitamin E. Vitamin E is also available as a dietary supplement. This study did not differentiate between sources of vitamin E.

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