Screening (Phone and Visit 1): Subjects are screened for eligibility by telephone for major exclusion criteria. They then attend a screening visit. At the start of the visit subjects must meet pre-test requirements (fasting ≥ 10 h, no alcohol ≥ 10 h, no exercise ≥ 10 h, no cannabis products ≥ 10 h). During this visit, consent is obtained, followed by a medical history interview, a physical assessment (including vital signs, body weight, and waist circumference) and fasting blood samples are collected for screening analysis of: clinical chemistry, hematology, lipid profile, thyroid hormones. A clean catch urine sample is also collected for urinalysis. Subjects eligible and willing to take part in the study are randomized to take one of the two ketone ester serving sizes (12.5 g , 25 g) for the ketone kinetics visit (Visit 2). Subjects will be given a stool sample collection kit to take home for at-home sample collection up to 3 days before Visit 2, the stool sample will be returned to investigators using a prepaid mailer.
Ketone Kinetics Visit (Visit 2): Subjects must meet pre-test requirements (as above). A BTQ (Beverage Tolerability Questionnaire) is used to observe the tolerability of ketone drinks before and after their consumption. Blood glucose and ketone levels are measured from a finger stick sample of a ketone meter at baseline, and at 30, 60, 90,120,180, 240-minute timepoints. Subjects are then randomized to their experimental group ketone ester or placebo for the remainder of the visits (Visit 3-5). Subjects will be given a stool sample collection kit to take home for at-home sample collection up to 3 days before Visit 3; samples are returned by mail.
Baseline Visit (Visit 3- Week 0): Subjects must meet pre-test requirements (as above). Fasted blood samples are collected for screening analysis of: clinical chemistry, hematology, lipid profile, thyroid hormones. A clean catch urine sample is collected for screening analysis and urinalysis and additional plasma is banked for future aging biomarker analysis. Subjects will undergo an interview for Katz's Activities of Daily Living (ADL), and Lawton's Instrumental Activities of Daily Living (IADLs), and CSHA Frailty Score (Canadian Study of Health and Aging). Subjects also complete the following paper questionnaires: Profile of Mood States (Short form), The Sexual Quality of Life Questionnaire (Male or Female Version), Short Form Health Survey-36, Pittsburgh Sleep Quality Index, Pittsburgh Fatiguability Scale and Geriatric Depression Scale. Physical and cognitive measures are assessed through the following tests: Montreal Cognitive Assessment, Digit Symbol Substitution Task and Trails A and B. Subjects also complete physical function testing at baseline (Visit 3) and final visit (Visit 5): Short Physical Performance Battery, 1 rep max leg press, sub maximal leg press repetitions to failure, 6-minute walk test and grip strength.
At the end of the testing, a continuous glucose and ketone monitor is applied (lasting 2 weeks). Subjects will be given a stool sample collection kit to take home for at-home sample between Week 1 and 2; samples are returned by mail. Subject will be given a month's supply of study product to take home. Subjects will be reminded of study instructions (for study beverage consumption, daily Study Log completion, and to maintain habitual exercise, meal/diet, and medication/supplementation use).
At home procedures (Week 0 - 12): Each day at home, subjects should consume their first meal of the day at a similar time and consume the study product within 5 minutes of finishing their first meal. Subjects will complete the Study Log immediately before they consume their second meal of the day or a snack (3 - 6 h after the study beverage). For Days 1 - 14 the Study Log will query the presence of specific symptoms with a beverage tolerance questionnaire (BTQ) and will confirm that subjects consumed their study product. From Day 15 onwards, the Study Log records study product consumption, but a full BTQ is not completed; however, any symptoms can be noted to assess tolerance by interview for the previous 2-week interval; at Visit 4- Week 4, during phone check-ins (Week 5, 8, and 10) and at Visit 5. At Week 8, subjects will be mailed the final mont's supply of study product, a continuous glucose and ketone sensor to apply at home (Week 10), and a stool sample collection kit for at-home sample collection up to 3 days before Visit 5 (Week 12), samples are returned by mail.
Intermediate Visit (Visit 4- Week 4): Subjects must meet pre-test requirements (as above). Fasted blood samples are collected for screening analysis of: clinical chemistry, hematology, lipid profile, thyroid hormones. A clean catch urine sample is collected for screening analysis and urinalysis and additional plasma is banked for future aging biomarker analysis. Tolerance of the study beverage and Adverse Events are assessed by interview. Subjects will be given a month's supply of study product to take home. Subjects will be given a stool sample collection kit to take home for at-home sample collection up to 3 days after Visit 4; samples are returned by mail.
Final Visit (Visit 5- Week 12): Follows identical testing procedures to Baseline Visit (Visit 3, Week 0).
