Effects of Blueberry Supplementation on Depression and Anxiety Symptoms in a Rural Louisiana Population

Background/Objectives: Blueberries are an important nutraceutical due to their excellent nutritional profile, with particularly high levels of polyphenols and anthocyanins. These compounds can improve mood, cognition, and health. As such, blueberry consumption can potentially benefit those coping with depression and anxiety. In this regard, there is an unmet need for novel, effective, and accessible treatments for these conditions, particularly in rural communities, where specialized health care is often limited. Methods: Therefore, we conducted a double-blind, randomized pilot study in a rural population to assess whether daily blueberry supplementation affected symptoms of anxiety and depression. We employed a crossover design to test the effects of 12 weeks daily ingestion of 24 g of whole freeze-dried blueberry powder versus placebo on symptoms of depression and anxiety in those diagnosed with a depressive or anxiety disorder including major depressive disorder (MDD) and generalized anxiety disorder (GAD). We collected behavioral data (HDRS, GAD-7, MDI) at baseline, mid-, and post-treatment timepoints. We collected blood, serum, plasma, and behavioral data (HDRS, GAD-7, MDI) at baseline, mid-, and post-treatment timepoints. We measured inflammatory cytokines IL-1β, IL-6, TNF-α, IFN-γ, and IL-10 in serum, CRP in whole blood, and performed global metabolomics in plasma. Results: Blueberries significantly reduced symptoms of depression and anxiety compared to placebo. CRP and inflammatory cytokine levels were unaffected. Our global metabolomic measures suggested that different metabolites were differentially affected at the middle and post-intervention timepoints in the study. Conclusions: Overall, this study found potential improvements in symptoms of depression and anxiety following daily blueberry supplementation, although the biochemical mechanisms underlying these behavioral improvements remain unresolved.