P4–395: The impact of 2y B‐vitamin supplementation on cognitive performance: The B‐PROOF study. (1st July 2013) - van der Zwaluw, Nikita; van Wijngaarden, Janneke; Dhonukshe‐Rutten, Rosalie; Brouwer‐Brolsma, Elske; in 't Veld, Paulette; Kessels, Roy; ,; ,; de Groot, Lisette