While cognitive abilities naturally decline with age, eating one serving of leafy green vegetables a day may aid in preserving memory and thinking skills as a person grows older, according to a study by researchers at Rush University Medical Center in Chicago. The study results were published in the December 20, 2017 issue of Neurology, the medical journal of the American Academy of Neurology.
“Adding a daily serving of green leafy vegetables to your diet may be a simple way to help promote brain health,” said study author Martha Clare Morris, ScD, a nutritional epidemiologist at Rush. “There continue to be sharp increases in the percentage of people with dementia as the oldest age groups continue to grow in number. Effective strategies to prevent dementia are critically needed.”
The study results suggest that people who ate one serving of green, leafy vegetables had a slower rate of decline on tests of memory and thinking skills than people who rarely or never ate them. The study results also suggest that older adults who ate at least one serving of leafy green vegetables showed an equivalent of being 11 years younger, cognitively.
The study enlisted volunteers already participating in the ongoing Rush Memory and Aging Project, which began in 1997 among residents of Chicago-area retirement communities and senior public housing complexes.
This study involved these 960 people, who at the study start were an average age of 81 and did not have dementia. They had their thinking and memory skills tested every year and were followed for an average of 4.7 years.
The participants also completed the food frequency questionnaire, which assessed how often and how many half-cup servings they ate of either spinach; kale/collards/greens; or a one-cup serving of lettuce/salad.
The study divided the participants into five groups based on how often they ate green leafy vegetables, and compared the cognitive assessments of those who ate the most (an average of about 1.3 servings per day) and those who ate the least (0.1 servings per day).
Overall, the participants’ scores on the thinking and memory tests declined at a rate of 0.08 standardized units per year. Over 10 years of follow-up, the rate of decline for those who ate the most leafy greens was slower by 0.05 standardized units per year than the rate for those who ate the least leafy greens. This difference was equivalent to being 11 years younger in age, according to Morris.
The results remained valid after accounting for other factors that could affect brain health, such as seafood and alcohol consumption, smoking, high blood pressure, obesity, education level and amount of physical and cognitive activities.
The results need to be confirmed by other investigators in different populations and through randomized trials to establish a cause-and-effect relationship between the eating leafy greens and reductions in the incidence of cognitive decline, Morris said.
Talk about a Christmas present at the perfect time when holiday treats abound wherever we turn.
Years ago, when I first started running, the group I joined was obsessed with weight-loss. The premise was, the lighter you were, the faster and farther you could run. It proved mostly true.
Our post-breakfast diet consisted mainly of pasta (every conceivable format, including pizza, as far as we were concerned) and massive salads, mainly Caesar (and other types consisting of the leafy-green variety). All we cared about was: maximize the carbs, but minimize the calories. That’s where the salads fit in–lots of roughage, but mostly “air” food = no weight gain.
Then along comes this study in the journal Neurology (probably the most respected source of clinical information in the field), suggesting us runners unknowingly were gaining some additional, possibly major cognitive benefit.
What did the Neurology study actually convey (in nonexpert terms)?
Here’s how Forbes parsed it:
“Analysis of the resulting data found that adults who were in the top 20% of leafy green vegetable consumption (a median of 1.3 servings a day) tended to have slower cognitive decline over time, which, in the words of the researchers, was ‘the equivalent of being 11 years younger in age.’”
What struck me with this finding is the magnitude of the apparent cognitive benefit, namely 11 years’ worth of additional brainy “health.” Not 2 years; or even 5. But 11? Seems to me that’s a big number when it comes to time in one’s lifespan.
So, does this mean that in order to prevent dementia the ideal diet should be richer in chard, kale, and spinach and probably not Big Macs? I’ve heard it said that when meat putrefies in the intestine it creates toxic substances, one of them being ammonia, which kills pretty much everything around it.Steve's Take: New study shows that in order to prevent #dementia the ideal diet should be richer in chard, kale, and spinach and probably not Big Macs. Click To Tweet
A 50-year-old person that eats a typical western diet of animal sourced protein (eggs and dairy included) will have produced about 70 kg of ammonia, the equivalent of 3500 liters of Windex. Not great for the friendly microbes in the gut, which also doesn’t contribute to brain health.
Still, we shouldn’t necessarily sprint to conclusions based on this study from Rush (and Tufts) alone. Forbes reminds us to heed the motto in such observational studies: “Associations and correlations do not prove cause-and-effect.”
And adults who eat more veggies could also be living more healthily and practicing brain-stimulating lifestyles in general. While the Rush study did try to factor in some information on other aspects of the subjects’ lives such as education, participation in certain cognitive activities, general physical activity level, smoking habits, and seafood and alcohol consumption, it did not capture every potentially relevant aspect of each person’s life, such as details about his or her social interactions and work situations.
Nonetheless, there are a distinct group of reasons why greens could protect the brain. For example, the nutrients could help prevent or repair damage to brain cells. Or if they reduce the risk or severity of cardiovascular disease, they can in turn prevent small strokes that may lead to dementia.
And if you tend toward daily exercise, you know that being “clogged up” isn’t how you want to feel, and filling up with greens tends to help keep things moving. It also probably means you aren’t consuming as much unhealthy food, such as those high in saturated fat, salt, sugar, and artificial ingredients.
Especially for us boomers, who know we’re not getting any younger upstairs, gaining 11 years of additional cognitive health is definitely worth upping the salad days. As a matter of fact, I think I’ll throw some “power greens,” topped with balsamic vinegar, into a bowl right now.