Veggies for brain health.

A six-year study of 3,718 participants aged 65 years and older has found a favorable relationship between regular vegetable consumption and brain health. The Chicago Health and Aging Project, conducted through Rush University Medical Center, asked the subjects to complete "food frequency questionnaires" and then participate in baseline, 3-year, and 6-year cognitive skills tests. The researchers tested immediate memory and delayed recall, and also administered two other tests known as the Mini-Mental State Examination and the Symbol Digit Modalities Test. Subjects were asked to recall stories that had been read to them, as well as perform flashcard-like memory tests using symbols and numbers.

While subjects generally performed worse on the tests over the course of the six years, in models based on the data adjusted for age, sex, race, and education, cognitive decline in regular consumers of vegetables was found to be approximately 40% slower than cognitive decline in subjects with little or no daily vegetable intake. The lowest quintile of vegetable intake was determined to be a median of 0.9 servings per day; the median intake for people in the fourth quintile was 2.8 servings per day; for the fifth quintile, intake averaged 4.1 servings. This last group was found to have a 38% decrease in cognitive decline rates over the six years, while the 3-serving group capped out at 40% as compared to non-vegetable eaters. A serving of vegetables equaled about a half-cup chopped or one cup if the vegetable was raw and leafy.

The researchers said that the results translate practically into about a five-year gain in mental youth among older people who eat over two servings of vegetables daily. Interestingly, fruit consumption was not associated with any cognitive change.

While the association between vegetables and mental sharpness does not decisively imply a direct causal link, the findings also reflect previous research in women only. And the specificity of the results (i.e., the fact that fruits were not similarly helpful) makes it less likely that they were simply due to an overall healthy lifestyle.

Green leafy vegetables including spinach, kale, and collard greens appeared to be the most beneficial. The researchers note that this may be because they contain a good deal of vitamin E. It is widely suggested that this powerful antioxidant staves off cellular damage.

This could help to explain why fruits did not produce similar results, as vegetables tend to contain more vitamin E than fruits. Another possibility is that vegetables are often eaten along with healthy fats, like the oil many people put on salads. Healthy oils help the body absorb vitamin E and other antioxidants. Properly running conduits for oxygenated blood contribute to brain health. The fats from healthy oils can help keep cholesterol low and arteries clear.

Those who ate more vegetables tended to be more physically active as well. And so again modern research confirms the link between taking care of mind and body together, as one seems to follow the other in an inextricable cycle of cause and effect. It's simply what the ancients have touted for millennia: Mens sana in corpore sano.

(Neurology, 2006, Vol. 67, No. 8,pp. 1370-1376)