An Exploratory Study to Compare the Differences in Nutritional Status Between Patients With Mild and Moderate Alzheimer's Disease (AD) and Cognitively Intact Healthy People in an Asian Population

Inclusion Criteria: * Age ≥ 50 years old * Asian ethnicity * Group 1: Cognitively intact healthy volunteers defined by Cumulative Illness Rating Scale for Geriatrics rating of ≤ 2 for all categories except for the category "psychiatric illness" which should have a rating of 0 and a CDR of 0 within 1 year prior to the visit. OR Group 2a: AD patients clinically diagnosed with mild AD (according to the National Institute of Neurological and Communicative Disorders, and Stroke-Alzheimer's Disease and Related Disorders criteria (McKhann et al., 1984)) with Clinical Dementia Rating-1 OR Group 2b: AD patients clinically diagnosed with moderate AD (according to the National Institute of Neurological and Communicative Disorders, and Stroke-Alzheimer's Disease and Related Disorders criteria (McKhann et al., 1984)) with Clinical Dementia Rating-2 \- Written informed consent provided according to local regulations. Exclusion Criteria: * Group 1 only: Current diagnosis of AD or other dementias according to National Institute of Neurological and Communicative Disorders, and Stroke-Alzheimer's Disease and Related Disorders criteria (McKhann et al.,1984 ) * Group 2 only: Change in dose within 2 months prior to visit of AD medication (e.g. donepezil, rivastigmine, galantamine or memantine) Group 1 and 2: * Diagnosis of significant neurological disease (for Groups 2a and 2b: other than AD), including vascular dementia according to National Institute of Neurological and Communicative Disorders, and Stroke-Alzheimer's Disease and Related Disorders criteria, cerebral tumour, Huntington's Disease, Parkinson's Disease, normal pressure hydrocephalus, seizures, major depression, schizophrenia and other entities * Use of vitamins supplements (only vitamins supplements C and D are allowed) for 3 months prior to the visit * Use of vitamin B injections * Alcohol or drug abuse as per investigator's judgement * Investigator's uncertainty about the willingness or ability of the patient to comply with the protocol requirements * Participation in any other studies involving investigational or marketed products concomitantly or within two weeks prior to entry into the study