Millions of people look at the nutrition labels on their food and presume that those vitamins and minerals are all there are in the world. But that is just not the case. In fact, there are hundreds of other substances that researchers have identified with essential functions for our bodies and minds.
One such nutrient, Lutein, is found in nuts, eggs, and leafy vegetables, and it plays a pivotal role in the health of, of all things, our eyes. But new research has also indicated that Lutein can provide cognitive benefits, as well.
Beginnings of the Science
Carotenoids, like Vitamin A, are commonly associated with eyesight and eye health. In that regard, research into the carotenoid Lutein has started there. Scientists have formed a definitive link between Lutein and various brain functions related to eyesight and visual processing of information.
From this, large-scale observational studies were conducted, concluding not only that Lutein was the most present carotenoid in the brain, but that it was the most associated with cognitive performance in the elderly.
These data of course led to the next logical step in study, double blind, placebo controlled trials. Again using older participants, researchers found that verbal fluency, memory, and learning were all significantly improved with Lutein intervention.
Next Generation Findings
That may be well and good for the elderly, someone might say; and in fact, a team of researchers took these studies to younger people to determine if the effects held. They did.
Among a cohort of 51 college students, Lutein supplementation led to significantly better attention, spatial memory, and higher reasoning.
All of this has led researchers in the field to conclude that lifetime consumption and long-term supplementation with Lutein can have a positive effect on cognitive function–regardless of age.
These data are supported by further studies of middle-aged people, who saw better visual learning due to Lutein, and an observation study of over 6,000 adults over 50 who saw greater word recall with increased Lutein-rich foods.
Not surprisingly, the primary mechanism of Lutein’s cognitive benefits stem from its interaction with eye health, specifically something called macular pigment optical density, or MPOD. Research tended to find that better MPOD was associated with better cognitive results simply because it led to better eyesight: the better people could see, the better they could process what they saw.
But after dozens of observational and clinical studies, it became clear that something else was at play. This mechanism, whatever it may be, cannot yet be explained, though many of the clinical trials quoted above have noted a link between Lutein, improved MPOD, and increased cognitive function. It could be related to the centers in the brain that control both thought processing and visual processing, which in turn could both be affected by Lutein (as the most prevalent carotenoid), but that research remains to be conducted.
Among the literature reviews I have linked to above, (one from Current Developments in Nutrition and one from the journal Molecules) there are literally dozens of primary studies and clinical trials. All of the data is congruent–Lutein improves MPOD, improves visual processing, and improves cognitive performance.
Some of the data is not statistically significant, and some researchers are more leery of glowing endorsements than others. But the data cannot be denied, and in this case, it appears that Lutein can improve cognitive function.