A new study provides another reason why we should eat our greens.
As we grow older, our minds tend to lose their edge.
Aging affects us all differently, but, on average, the mind of an 80-year-old will be significantly less adept than that of a 30-year-old.
Because we are living longer, concerns over the impact of this loss of mental agility are growing.
So, despite the fact that there is an inevitability about the creeping shadow of Old Father Time, researchers dedicate their lives to identifying lifestyle choices that might help to keep our noggins ticking over for longer.
Mental agility and diet
One simple intervention that has been considered as an elixir for the mind is the consumption of vegetables. We all know that we should be eating our greens; our mothers told us often enough.
Previous studies have, of course, found a relationship between a nimble mind and a greener dinner plate.
For instance, a paper published in 2005 that followed women's diets and cognitive performance from 1976 to 2001 concluded, "Fruits were not associated with cognition or cognitive decline. However, total vegetable intake was significantly associated with less decline."
Similarly, a paper published in Neurology in the following year, which followed nearly 4,000 65-year-olds over a 6-year period, concluded, "High vegetable but not fruit consumption may be associated with slower rate of cognitive decline with older age."
In both of the studies mentioned above, the food type with the strongest relationship with cognitive protection was green leafy vegetables.
Green leafy veg and cognitive protection
Dr. Martha Clare Morris, of Rush University Medical Center in Chicago, IL, recently reopened the salad bar to take a new look at the power of fresh veg. In this recent experiment, green leafy vegetables were put under particular scrutiny.
In total, 960 participants were recruited. Aged 81, on average, none of them had signs of dementia. They were followed for an average of 4.7 years. Each year, they filled in dietary questionnaires and completed cognitive tests.
They were asked how many of three leafy greens — spinach, collards/kale/greens, and lettuce — that they consumed. This information was then used to split them into five groups by quantity of greens consumed.
The top group ate an average of 1.3 portions per day, and the bottom group just 0.1 per day.
As was expected, an average cognitive decline was seen: 0.08 standardized units per year across the decade. However, there was a difference between the diet groups. Those in the top group for leafy green consumption saw a cognitive reduction 0.05 units slower than those who ate the least.
This difference between the lowest and highest green vegetable consumers is the equivalent of 11 years' worth of cognitive decline. So, those who ate 1–2 portions of greens each day had a brain that performed more than a decade better than those that ate just 0.1 portions.
"Adding a daily serving of green, leafy vegetables to your diet may be a simple way to foster your brain health. Projections show sharp increases in the percentage of people with dementia as the oldest age groups continue to grow in number, so effective strategies to prevent dementia are critical."
Dr. Martha Clare Morris
Of course, a range of factors can impact cognitive decline. The team controlled for many of these, including smoking tobacco, hypertension, obesity, highest level of education, and amount of physical and cognitive activities.
Even after these factors were accounted for, the results were still significant.
However, the authors are quick to mention that the study does not prove cause and effect, it only demonstrates an association. It is also worth noting that the study population was predominantly white, so the findings may not ring true for other races.
Either way, with so many proven health benefits of eating fresh vegetables, you may as well stock up for Christmas; it can't hurt.
Evidence is mounting that spinach and its cohort might protect our brains as we age, but, even if it doesn't, it's still better for you than chocolate, eggnog, and pumpkin pie.