(PTFS10-03-26) Blueberry Consumption Increases Cerebral Blood Flow in Older Adults: A Double-Blind Randomized Clinical Trial Using 3T MRI

Objectives: Age-related reductions in cerebral blood flow (CBF) contribute to cognitive decline and increased dementia risk. Blueberries are rich in polyphenols that may improve vascular function. We investigated whether daily blueberry consumption increases CBF and brain glutathione (GSH) in older adults.

Methods: In a double-blind randomized clinical trial, older adults (65-89 yrs old) with low berry intake (≤1 serving/week) consumed freeze-dried whole blueberry powder equivalent to one cup of fresh blueberries (n=29) or a matched placebo powder similar in color, flavor and energy content (n=31) daily for 3 months. MRI was performed at baseline and post-intervention. Regional CBF was measured using pseudo-continuous arterial spin labeling MRI, and brain GSH was quantified using multiple quantum chemical shift imaging. Between-group differences in 3-month change were evaluated using ANCOVA adjusted for baseline values and covariates.

Results: Sixty participants completed the intervention with high compliance (92%). Blueberry consumption significantly increased CBF in the anterior cingulate cortex compared with placebo (p=0.03). Within-group analyses showed increases in the blueberry group in the anterior cingulate cortex (+7%, p=0.027), caudate (+7%, p=0.006), and putamen (+6%, p=0.042), while no significant changes occurred in the placebo group. No significant changes in brain GSH were observed following blueberry consumption.

Conclusions: Daily blueberry consumption increased CBF in brain regions involved in executive function and cognitive control that are vulnerable to age-related cognitive decline. These findings suggest that blueberry intake may support brain health in aging through improved cerebrovascular function. In contrast, blueberry consumption did not alter brain GSH levels, indicating that blueberry polyphenols did not appear to measurably affect the cerebral antioxidant system under these conditions.

Funding Sources: U.S. Highbush Blueberry Council