Walnuts are rich in vitamin E, folate, and the omega-3 linolenic acid. Several previous studies have linked antioxidant-rich walnuts with heart health, as the food beneficially impacts blood vessel function.  Peter Pribis, from Andrews University (Michigan, USA), and colleagues enrolled 64 university students in an eight week long study.  Each subject consumed banana bread daily, with one group receiving bread that contained ground walnuts (1/2 cup per day) as well. The subjects performed a number of cognitive tests, including assessments that required inferential reasoning skills. Those subjects who consumed the walnut-recipe bread showed significant improvement in inference, which the researchers point out is necessary for critical thinking and decision-making