Blueberries, Inflammation, Motivation, and Physical Activity

The investigators will conduct a 14 week, single-site, randomized, double-blind, parallel pilot study in 40 sedentary, older adults with depressive symptoms. Participants will first enter a 2-week washout period where they will avoid consumption of foods high in fiber and anthocyanins (e.g., blueberries) and will also be wearing an activity monitor. Participants will then be randomized to consume either 48 g of freeze-dried blueberry powder (~600 mg of anthocyanins and ~8 g of fiber) or 48 g of a nutritionally matched placebo powder (devoid of anthocyanins and fiber) each day for a total of 12 weeks.

At baseline, participants will be undergo assessments for mood/well-being, relevant symptoms, motivation to engage in physical activity, and provide a blood sample for the evaluation of inflammatory biomarkers. For the entire duration of the study, participants will continue to wear the activity monitor. After 4, 6, 8 and 12 weeks of consuming the powder there will be study visits that assess mood/well-being, relevant symptoms, motivation to engage in physical activity and compliance with the intervention. Additionally, a blood sample for the evaluation of inflammatory makers will be taken after 6 and 12 weeks of the intervention.

Inclusion criteria

• Men and women aged ≥65 years
• Self-reporting ≥ 8 hours of sitting per/day (e.g., sedentary behavior)
• Depressive symptoms (defined as ≥4 and <16 points on the center for epidemiological studies depression-scale)

Exclusion criteria

• Unwilling to follow the study protocol
• A median daily step count >7,500 steps per day (as measured by the ActiGraph), or per discretion of the PI
• Cognitive impairment (defined as Montreal Cognitive Assessment, MoCA <22 points)
• Self-reporting a history of inflammatory bowel disease/syndrome, major depression, bipolar, schizophrenia, or other psychotic disorders, or per discretion of the PI
• Self-reporting type 1 or type 2 diabetes
• Allergic to intervention or control products
• Recent use (within the last 3 months) of antibiotics, or per discretion of the PI
• Recent use (within the last 3 months) of pro-biotics, or per discretion of the PI
• Current substance use disorder (Drug Abuse Screening Test, DAST-10>2 points)
• Current alcohol use disorder (Alcohol Use Disorders Identification Test - Consumption, AUDIT-C≥4 points)
• Unstable anti-depressant use (e.g., change in medication within last 3-6 months), or per discretion of the PI
• Current homicidal or suicidal ideation (assessed via the P4 Suicidality Screener)
• Current psychosis (via the Psychosis and Hallucinations Questionnaire, PHQ>12 points)
• Manic symptoms (assessed by the Mood Disorder Questionnaire, MDQ >5 points)