This randomized, double-blind, placebo-controlled clinical trial evaluates whether 70 days of daily cranberry juice consumption improves cognitive performance and motor accuracy and reduces psychological and physiological stress responses during a motor-cognitive dual-task multitasking challenge in healthy adults aged 30-55 (Aim 1). It is hypothesized that chronic cranberry juice intake will enhance dual-task performance and attenuate stress reactivity (Hypothesis 1). It is further hypothesized that cranberry juice will mitigate multitasking-related fatigue, mood fluctuations, and cognitive impairment, accompanied by favorable changes in circulating stress biomarkers and stress-regulatory neurochemical pathways (Aim 2/Hypothesis 2). Finally, the study incorporates gut analysis to determine whether cranberry juice induces beneficial shifts in the gut microbiota and microbial metabolites (e.g., SCFAs) and whether these changes are associated with improved cognitive and stress-related outcomes, consistent with a microbiome-gut-brain axis mechanism (Aim 3/Hypothesis 3).
At least 110 pounds
Between 30 and 55 years
BMI between 18.9 and 29.9 kg/m²
A minimum education level of high school or above
Heavy caffeine users (consuming more than 300 mg/day or more than two cups of coffee per day)
Alcohol consumption exceeding three drinks per week
A smoking history of 10 years or more, or current use of cannabis products
Uncontrolled hypertension