The VITAL trial showed a positive effect of B-vitamin treatment in slowing cognitive decline on the Alzheimer Disease Assessment Scale (ADAS-cog) [13] and on the Mini-Mental State Examination (Fig. 7 in ref. [7]) for patients with mild AD. B-vitamin supplements are available over-the-counter at very low cost, in contrast to long-term more expensive stra- tegies that aim to increase education attainment or physical activity.