Abstract
- Objectives
Preclinical investigations utilizing animal models have consistently demonstrated that dietary blueberry supplementation can effectively improve cognitive performance and neuronal function in aged subjects, while establishing direct associations between these neurobiological benefits and active anthocyanin intake. Preliminary human clinical trials likewise suggest potential cognitive enhancements in older adult cohorts, although direct in vivo evidence demonstrating the enhancement of human brain function has remained lacking. This randomized controlled trial was specifically designed to investigate the acute and sustained effects of daily blueberry supplementation on task-related regional brain activation patterns in older adult human subjects identified as being at risk for dementia.
- Methods
A rigorous, randomized, double-blind, placebo-controlled clinical trial was conducted. Functional magnetic resonance imaging (fMRI) was performed both pre- and post-intervention while participants executed a standardized working memory task to evaluate the physiological impact of blueberry supplementation on blood oxygen level-dependent (BOLD) signal responses. The study cohort comprised older adults diagnosed with mild cognitive impairment (MCI), representing a well-established clinical risk condition predisposing to dementia.
- Results
Following 16 weeks of daily nutritional supplementation, participants in the blueberry-treated arm exhibited statistically significant increases in BOLD activation within specific neuroanatomical regions—namely the left pre-central gyrus, left middle frontal gyrus, and left inferior parietal lobe—during heightened working memory load conditions (corrected $P < 0.01$). Despite these robust neurofunctional enhancements, standardized performance metrics indicated no direct, overt behavioral enhancement of working memory associated with the blueberry intervention. Dietary tracking and food records confirmed that there were no significant between-group differences regarding external dietary anthocyanin consumption outside of the controlled intervention protocol.
- Discussion
These empirical findings demonstrate, for the first time in human clinical research, an enhanced neuronal response during a working memory challenge among blueberry-treated older adults experiencing cognitive decline. These neuroimaging outcomes align consistently with prior clinical trials documenting neurocognitive benefits following blueberry supplementation in this vulnerable, at-risk population.
https://pmc.ncbi.nlm.nih.gov/articles/PMC6093614/