This study protocol describes a 12-week randomized, double-blind, placebo-controlled pilot trial evaluating the feasibility and preliminary efficacy of freeze-dried blueberry powder supplementation in sedentary adults aged ≥65 with mild depressive symptoms. The intervention provides ~8g/day of fiber and ~600mg/day of anthocyanins, hypothesized to reduce inflammation-driven lack of motivation and increase physical activity.
Forty participants will be randomized to blueberry powder or a nutritionally matched placebo. The primary outcome is physical activity engagement, measured as median daily step count. Secondary outcomes include feasibility (retention and compliance), inflammatory markers (CRP, IL-6, BDNF), and self-reported motivation. A sub-study will explore effects on gut microbiota and depressive symptoms.
The study aims to inform larger-scale interventions targeting inflammation-related motivational deficits in older adults, potentially providing a dietary strategy to combat sedentary behavior and its health risks.