"Compared to people who consumed less than one serving of vegetables a day, people who ate at least 2.8 servings of vegetables a day saw their rate of cognitive change slow by roughly 40 percent," study author Martha Clare Morris of Rush University Medical Center in Chicago said in a press release.
"This decrease is equivalent to about five years of younger age."
Researchers followed the eating habits of 3718 senior citizens over a six-year period and found that consumption especially of green leafy vegetables were linked to a slowing of cognitive decline. They also found that the older the person, the greater the impact of eating more than two servings of vegetables a day.
Researchers meanwhile said they were surprised that eating fruit showed no link to reducing memory loss.
"This was unanticipated and raises several questions," said Morris. "It may be due to vegetables containing high amounts of vitamin E, which helps lowers the risk of cognitive decline. Vegetables, but not fruits, are also typically consumed with added fats such as salad dressings, and fats increase the absorption of vitamin E. Further study is required to understand why fruit is not associated with cognitive change."
The study is published in the October 24, 2006, issue of Neurology, the scientific journal of the American Academy of Neurology.