Evaluate and compare the changes in brain ketone and glucose uptake after taking two different MCT oil emulsions (60-40 oil or C8 oil) for one month, in a group of people with Alzheimer's disease and a control group.

Based on a PET/MRI protocol, the aim of this study is to evaluate and compare the response to the dietary supplementation of two different MCT oils (60% C10 + 40% C8 or 100 % C8) in two groups, patients with Alzheimer's disease and healthy elderly people (N=10/group). After a baseline evaluation, participant will test one of the supplements during two successive periods of one month; each period of time ending with 18F-FDG and 11C-acetoacetate PET scans.

Inclusion Criteria:

• Good general health for Control group
• Diagnosis of Alzheimer's disease (NINCDS-ADRDA criteria) for AD group

Exclusion Criteria:

• Depression
• Medical or psychiatric conditions that could interfere with study participation
• Fasting plasma glucose ≥7.0 mM (diabetes or prediabetes)
• Already on MCT supplementation
• Clinically-significant gastrointestinal disease/conditions
• Clinically-significant liver disease/dysfunction
• Clinically-significant renal disease/dysfunction
• Clinically-significant cardiac disease/conditions
• Hypertension
• Uncontrolled dyslipidaemia
• Vitamin B12 deficiency
• Structured physical activity (more than 3 times/week)