Vitamin E is of tremendous dietary importance because it functions as an antioxidant. It goes around the body scavenging free radicals of oxygen and detoxifying them. This is a critical activity in the brain, as it is the body's largest consumer of oxygen and throws off free radicals in the course of the fast and furious metabolic activity that powers every thought, feeling, memory and action you take (and even the ones you only think about) and every dream you dream.

The gradual accumulation of damage from free radicals over the years is thought to be a factor causing the decline in mental faculties often -- but not always -- seen with age. Free radical damage is also now implicated as a cause of Alzheimer's disease. It is widely suspected of being a major contributor to heart disease and cancer as well. What is more, cataracts are thought to result from free radical damage to the eyes. And much of the destructive effect of diabetes is attributed to free radicals.

Although surely the last word on Vitamin E has not been written, a number of studies suggest that the vitamin is essential to mental health particularly as people age.

In one study, reported in the Journal of Nutrition, researchers looked at the vitamin E status of 120 elderly people who were particularly healthy. They also looked at the cognitive performance of the men and women by administering a highly reliable questionnaire assessing intellectual function, and counted the errors the respondents made.

Persons with the lowest levels of Vitamin D made the greatest number of errors. And those who made no errors at all had significantly higher blood levels of Vitamin E than those who made errors. The authors conclude that Vitamin E is essential to cognitive function, and that the vitamin is especially important for those over 65. Or anyone who wants to maintain mental facility, as the vitamin appears to slow mental decline.

Of course, no single food supplies all the nutrients you need for a healthy diet. Vitamin E is a fat-soluble vitamin found in vegetable oils, nuts and green leafy vegetables. It is also found in grains, particularly in whole grains.

The Recommended Dietary Allowance for Vitamin E for adults is 15 mg, or 22 International Units. According to recent surveys of the U.S. Department of Agriculture, the intake of Vitamin E by women between the ages of 19 and 50 averaged less than 90% of the RDA. Men appear to be getting close to 100% of the RDA. However, many researchers believe that the current RDA for Vitamin E is not sufficient to fully protect the body.

The way you store and prepare foods dramatically influences the nutrients they retain and that you actually consume. As with all nutrients, Vitamin E can be lost with exposure to light. It's best to store foods in airtight containers.