Cardiometabolic Effects of Sweet Cherry Juice

This study aims to determine the effects of consuming sweet cherry juice on cardiovascular function, glucose regulation, and lipid status in overweight human subjects. The investigators hypothesize that sweet cherry juice consumption will improve metabolic and physiological status in overweight persons compared to a placebo.

The investigators will conduct a randomized, cross-over study lasting 14 weeks and including 1 week for screening/enrollment, 1 week baseline assessment, and two intervention periods of 6 weeks each for the cherry juice and placebo interventions. Two test visits, 3 to 7 days apart, will occur before the start of intervention (baseline, or week 0) and then at weeks 6 and 12. Participants will be randomized to consume either the cherry juice or placebo beverage first, and will cross over to the alternate intervention immediately following the end of the first 6 weeks. Test Visit 1 will include measures of blood pressure, vascular tone, liver fat and stiffness, post-prandial metabolic response to the study beverage, cardiovascular activity and function, and nervous system control of cardiovascular activity and tone. Acute effects of study beverages will be measured, as will the chronic effects of study beverage consumption after 6 weeks. At Test Visit 2, participants will take a standard 75 gram oral glucose tolerance test (OGTT). Participants will be equipped with physiological monitoring devices, which will monitor cardiovascular activity and function and nervous system control of cardiovascular activity and tone, and continuously measure blood pressure. A series of cognitive function tasks will be administered, and a mental stress test will be conducted. The Test Visit 1 and 2 will be repeated at week 6 and week 12 following each intervention with cherry juice or the placebo beverage.

Sweet cherry juice concentrate will be consumed twice daily for 6 weeks, followed by consumption of placebo beverage twice daily for 6 weeks.

Placebo beverage will be consumed twice daily for 6 weeks, followed by consumption of sweet cherry juice concentrate twice daily for 6 weeks.

FruitSmart® Cherry Concentrate: Dark Sweet Cherry Juice Concentrate produced from dark sweet cherries to retain the characteristic color and flavor of the whole fruit.

Cherry flavored placebo beverage prepared from commercially available cherry syrup with food coloring and thickener to match the color and viscosity of the cherry concentrate.

Peripheral arterial tone (PAT) determined using the EndoPAT expressed as the reactive hyperemia index (RHI)

Liver fat assessed from the Controlled Attenuation Parameter (CAP) computed from the liver stiffness measurement using the Fibroscan®

Assessed using Cambridge Gambling Task (CGT), from Cambridge Neuropsychological Test Automated Battery (CANTAB)

Measured by Stanford Brief Physical Activity questionnaire. Scale is categorical for two subscales: work physical activity and leisure time activity.

Perceived stress measured using the Perceived stress scale (PSS). Scores on the PSS can range from 0 to 40 with higher scores indicating higher perceived stress. Responses for individual questions are summed to a total score.

Chronic stress measured using the Wheaton Chronic Stress Questionnaire. Individual scores range from 0 to 102, with higher scores indicating higher chronic stress.

Mood assessed using the Profile of Mood States (POMS) Standard Score. Total Mood Disturbance (TMD) score is found from the difference between "negative" subscales - "positive" subscales. Individual scores on the POMS range from -32 to 200 with higher scores indicating higher mood disturbance.

Inclusion Criteria: Men aged 20 - 65 years Post-menopausal women aged 45 - 65 years Body Mass Index ≥25 and <40 kg/m2 Systolic blood pressure >120 and <140 mmHg or diastolic blood pressure >80 and <90 mmHg Exclusion Criteria: Diagnosed metabolic disorder Diabetes mellitus Thyroid disease Cardiovascular disease Poly-cystic ovary syndrome Vasoconstrictive diseases (e.g. Raynaud's phenomenon or Raynaud's disease) Digestive disorder (e.g. Crohn's, irritable bowel syndrome, colitis) History of gastrointestinal surgery affecting digestion and/or absorption Use of medications for hypertension, hyperlipidemia, glycemic control, or weight loss Use of medications such as steroids, statins, or non-steroidal anti-inflammatory agents Routine use of over-the-counter medications Weight change >5% in the past 6 months Performing exercise greater than 60 minutes/day Presence of a pacemaker or other internal electronic device controlling rhythm or pacing of heart excludes participant from MindWare procedure Presence of atrial fibrillation or other arrhythmia excludes participant from MindWare procedure