Eating foods with lutein may make you smarter. It is found in leafy greens and egg yolks. Lutein accumulates in the brain, embedding in cell membranes, where it likely plays "a neuroprotective role," she said. "Previous studies have found that a person's lutein status is linked to cognitive performance across the lifespan," Zamroziewicz said. The researchers found that participants with higher blood serum levels of lutein tended to do better on tests of crystallized intelligence.