Lutein & Zeaxanthin Improve Cognition in Teenagers Lutein and zeaxanthin are crucial for cognition, but we often don’t get enough of them in our diet, since many of us don’t eat enough fruits and vegetables. A new study shows that when teenagers supplement those two carotenoids, it has a very positive impact on their cognition. Research shows that supplementing lutein and zeaxanthin improves cognition. A systematic review found that 10 mg of lutein a day leads to improved cognitive function (Nutrients.