New study suggests the fruit may improve symptoms of depression and anxiety
A new study published in US journal Nutrients suggests that individuals with depression, anxiety or both may potentially see an improvement in their symptoms with the addition of blueberries to their diet.
A group of scientists from Louisiana State University, led by Joseph Francis, PhD, explored whether supplementing the diet with about a cup of blueberries per day could improve symptoms of depression and anxiety in individuals from a rural population who were diagnosed with major depressive disorders (MDD) or generalised anxiety disorder (GAD) and were undergoing standard of care for these symptoms.
Specialised health care may be limited in rural communities and this is one of the first randomised clinical trials to be conducted using rural health centres as a study site.
The (n=23) participants consumed either freeze-dried whole blueberry powder (equivalent to 1 cup of fresh blueberries) or a placebo powder similar in colour, taste and calories every day for 12 weeks. At the beginning, midpoint and end of the 12-week period, study participants completed a Major Depression Inventory (MDI) and a Generalised Anxiety Disorder 7-Item Questionnaire (GAD-7).
In addition, at the beginning and end of each study period, a clinician performed a diagnostic interview of patients, seeking input on symptoms and the severity of their depression based on the Hamilton Depression Rating Scale (HDRS). The research was conducted as a double-blind, randomized study, so neither the participants nor the research team knew which powder was being consumed.
After consuming 24g of freeze-dried blueberry powder for 12 weeks, there was a reduction in clinical symptoms of depression and anxiety compared to that seen when a placebo powder was consumed. There were no changes in C-reactive protein or inflammatory cytokine levels, although serum metabolite measurements between the two groups did indicate differences.
“This study suggests that something as simple as adding blueberries to the diet may have meaningful benefits for mental health, highlighting the powerful connection between nutrition and emotional well-being,” said Francis.
Commenting on the research, the US Highbush Blueberry Council said: “The link between diet and mental well-being is attracting increasing attention. While the effect of blueberry consumption on cognitive health has been a subject of previous research, this study specifically investigates the impact on mood. With 23 participants, this study was small, but it demonstrated that similar studies could be conducted in a rural health setting”.
Despite the difficulties in conducting a study in a rural clinic as compared to an urban setting, the authors feel that studies performed in these locations provide access and data from participants who might not normally be studied.
“To provide further evidence for the role of blueberries in depression and anxiety, this type of study should be replicated in larger and more diverse populations, with additional data collected on usual diet intakes and biomarkers to provide information for a proposed mechanism for the effect of blueberries,” the Council said.
“Blueberry supplementation was never presented as a substitute or replacement for regular medication and psychiatric care, but this study demonstrated potential promising effects of daily blueberry consumption on depression and anxiety symptoms in a rural Louisiana population.”
