The present invention relates to methods of determining if a subject has a decreased risk of suffering from future memory impairment. The methods comprise analyzing at least one plasma sample from the subject to determine a value of the subject's metabolite profile and comparing the value of the subject's metabolite profile with the value of a normal metabolite profile. A change in the value of the subject's metabolite profile, over normal values is indicative that the subject has a decreased risk of suffering from future memory impairment compared to a normal individual.