Ketone Ester Effects on Biomarkers of Brain Metabolism and Cognitive Performance in Cognitively Intact Adults 55 Years Old or Older

Background: In Alzheimer s disease (AD) the brain cannot use glucose as a fuel. The brain can use ketones as a fuel instead of glucose. Researchers want to test a supplement, Ketone Ester (KE). It may improve brain metabolic function and cognition in normal people and, perhaps, down the road, in patients with AD. Objective: To study the change in brain ketone levels in people after 28 days of taking KE compared with baseline and placebo. Also, to study changes in cognitive performance. Eligibility: People 55 years old or older with metabolic syndrome and no cognitive impairment Design: Participants will have 4 visits. Participants will be screened at Visit 1 with: Medical history Physical exam Blood and urine tests Cognitive testing Participants will be randomly assigned to receive either the study supplement or a placebo with same amount of calories. Neither they nor the researchers will know which they receive. Visit 2 will include repeats of some screening tests. It will also include: Stool sample (brought from home) MRI/MRS: Participants will lie on a table that slides in and out of a scanner. A coil will be placed over their head. They may be asked to perform leg exercises. First dose of study supplement or placebo About 2 weeks after Visit 2, Visit 3 will include blood and urine tests and a questionnaire. About 2 weeks after Visit 3, Visit 4 will include repeats of the Visit 2 tests. Participants will drink the study supplement or placebo 3 times per day during the study. They will keep a daily log of each dose. They will bring the log to Visits 3 and 4. Participants will by contacted by phone once per week during the study to see how they are doing. ...