New research finds a link between the nutrient lutein and "crystallized intelligence," the ability to use the skills and knowledge acquired during one’s life.
The older I get, the more I nod knowingly with an audible “mmm hmm” when I hear the adage, “Youth is wasted on the young.” On the flipside, of course, is that maturity brings with it all of the wisdom picked up along the way. Now if only we could just remember everything we learned and put it to use. Therein lies the rub.
But now research brings to light a way in which “crystallized intelligence” – the ability to use learned knowledge and experience – might be preserved in older adults. The discovery? That the plant pigment lutein may be playing a role.
We get lutein primarily by eating leafy green vegetables (kale tops the USDA list for lutein content), cruciferous vegetables such as broccoli, or egg yolks (thanks to the diet of chickens). It's also worth noting that many studies have previously shown that lutein and its partner zeaxanthin reduce the risk of chronic eye diseases, including age-related macular degeneration (AMD) and cataracts.
According to study leader Marta Zamroziewicz from the University of Illinois and professor Aron Barbey, lutein accumulates in the brain, embedding in cell membranes, where it likely plays "a neuroprotective role.”
"Previous studies have found that a person's lutein status is linked to cognitive performance across the lifespan," Zamroziewicz says. "Research also shows that lutein accumulates in the gray matter of brain regions known to underlie the preservation of cognitive function in healthy brain aging."
Participants in the new study included 122 healthy adults between the ages of 65 to 75 who solved problems and answered questions on a standard test of crystallized intelligence. Researchers then looked at blood samples for blood serum levels of lutein and analyzed the participants' brains using MRI to measure the volume of different brain structures.
The researchers found that participants with higher blood serum levels of lutein tended to do better on tests of crystallized intelligence. Serum lutein levels reflect only recent dietary intakes, notes the study's press release, but are associated with brain concentrations of lutein in older adults, which reflect long-term dietary intake. Those with higher serum lutein levels also tended to have thicker gray matter in the parahippocampal cortex, a brain region that, like crystallized intelligence, is preserved in healthy aging.
"Our analyses revealed that gray-matter volume of the parahippocampal cortex on the right side of the brain accounts for the relationship between lutein and crystallized intelligence," Barbey says. "This offers the first clue as to which brain regions specifically play a role in the preservation of crystallized intelligence, and how factors such as diet may contribute to that relationship."
So the moral of the story could be: Youth is wasted on the young, but it doesn’t have to be wasted on the old? Or in other words … eat your vegetables.
For more, see the journal Frontiers in Aging Neuroscience.