Hate brain aging as much as I do? Eat a few servings of vegetables a day to slow your rate of cognitive decline.
CHICAGO - Eating vegetables, not fruit, helps slow down the rate of cognitive change in older adults, according to a study published in the October 24, 2006, issue of Neurology, the scientific journal of the American Academy of Neurology.
In determining whether there was an association between vegetables, fruit and cognitive decline, researchers from Rush University Medical Center studied 3,718 residents in Chicago, Illinois, who were age 65 and older. Participants completed a food frequency questionnaire and received at least two cognitive tests over a six-year period.
“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, said study author Martha Clare Morris, ScD, associate professor at Rush University Medical Center in Chicago, Illinois. “This decrease is equivalent to about 5 years of younger age.”
Of the different types of vegetables consumed by participants, green leafy vegetables had the strongest association to slowing the rate of cognitive decline. The study also found the older the person, the greater the slowdown in the rate of cognitive decline if that person consumed more than two servings of vegetables a day. Surprisingly, the study found fruit consumption was not associated with cognitive change.
Maybe vitamin E makes vegetables more beneficial for the brain than fruits.
“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.”
Then again, maybe other compounds in vegetables protect the brain.
"This is a sound paper and contributes to our understanding of cognitive decline," said Dr. Meir Stampfer of Harvard's School of Public Health.
"The findings specific for vegetables and not fruit add further credibility that this is not simply a marker of a more healthful lifestyle," said Stampfer, who was not involved in the research.
Some of the commentary about this study answers a curiosity question I've had of late: Most people eat few berries and so population studies on the health effects of fruit consumption do not capture the effects of berry consumption on aging.
Matt Kaeberlein, who conducts research on the biochemical processes of aging at the University of Washington, was surprised the study didn't show any beneficial effect of eating fruit on cognitive decline.
Studies in animals, he said, show that berries—particularly blueberries, strawberries and cranberries—seem to protect memory in aging animals. And a diet high in fruits and vegetables has been linked to protection against heart disease, cancer, stroke, diverticulosis, diabetes and obesity.
Morris agreed that animal research indicates that berries may help preserve memory but that too few people in the study consumed berries regularly to determine if they helped preserve memory and other cognitive functions.
I'm going to keep eating a few bags of dried cranberries every week.
Brain aging is the worst kind of aging. Death of brain cells amounts to the death of part of who you are. Decline in cognitive function is the worst sort of decline in an economy where brain work keeps rising in value while physical work declines in value.
Even worse, brain rejuvenation is going to be the hardest part of body rejuvenation. 20 or 30 years from now if your kidneys or liver or lungs get too old the technology will be available to grow replacements. Or if your heart has lost a lot of muscle cells then stem cell therapies might be able to repair the heart in place. But the brain is a much tougher problem.
The study author Martha Clare Morris above has previously found other dietary factors that influence the rate of brain aging. See my posts Fish In Diet Slows Rate Of Cognitive Decline and Faster Brain Decline With More Fat And Copper In Diets.
Vitamin E is not the only plausible vitamin in green leafy vegetables that might be responsible for the brain protective effects reported above. Also see my post Folic Acid Slows Cognitive Decline With Age. To get lots of folic acid eat greens and beans.
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