Anhedonia, Anxiety, Depression
Conditions
Keywords
Blueberry, Anthocyanins
Brief summary
This study aims to investigate the effects of a 6-week dietary intervention of 22 g freeze-dried whole wild blueberry powder. The outcomes include measures of depression, anxiety, anhedonia, cognitive function, and biomarkers of inflammation and oxidative stress.
Detailed description
A randomized, double-blind, placebo-controlled, parallel-design study assessing the effects of a 6-week intervention of wild blueberry powder in young adults with depressive symptoms. A total of 60 participants will be randomly assigned to either 22 g blueberry powder or a matched placebo powder consumed daily with water. The severity of depression, anxiety, anhedonia, perceived stress, and quality of life will be measured at baseline and 6 weeks later. In addition, we will assess changes in cognitive function and transient mood 2 hours after consuming a single dose of blueberries.
Interventions
DIETARY_SUPPLEMENTWild blueberry powder
22 g freeze-dried wild blueberry (Vaccinium angustifolium) powder consumed daily with 250 ml water. The powder is sealed in sachets and stored at -24 °C, except when transported. Participants are asked to store the sachets in a freezer until consumption.
DIETARY_SUPPLEMENTPlacebo powder
22 g placebo powder matched for macronutrients, color, and flavor consumed daily with 250 ml water. The powder is sealed in sachets and participants are asked to store the sachets in a freezer until consumption.
Sponsors
Wild Blueberry Association of North America
University of Reading
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 24 Years
Healthy volunteers
No
Inclusion criteria
* 18 to 24 years of age * Patient Health Questionnaire-9 score ≥ 10 and a score ≥ 2 on the sum of items 1 and 2 * Willingness to provide blood samples
Exclusion criteria
* Any medically significant condition (e.g. diabetes, endocrine or gastrointestinal disorders) * Taking medication (excluding hormonal contraception) * History of mental illness (excluding anxiety and unipolar depressive disorders) * Allergy to blueberries or any other Vaccinium species * Receiving psychotherapy or counselling
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Beck Depression Inventory-II (BDI-II) | 6 weeks | A validated 21-item self-rated scale for assessing depression severity. The scale ranges from 0 to 63 points with higher scores indicating more severe depressive symptomatology. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Generalized Anxiety Disorder 7-item Scale (GAD-7) | 6 weeks | A brief self-rated scale of generalized anxiety. The scale ranges from 0 to 21 points with higher scores indicating more severe anxiety. |
| Snaith-Hamilton Pleasure Scale (SHAPS) - modified version | 6 weeks | A 14-item self-rated scale for measuring anhedonia. Each item has been modified to have five possible responses, which are scored as follows: strongly disagree (4 points), somewhat disagree (3 points), neither agree nor disagree (2 points), somewhat agree (1 point), strongly agree (0 points). Thus, the scale will range from 0 to 56 points with higher scores indicating greater levels of anhedonia. |
| Perceived Stress Scale (PSS-10) | 6 weeks | A validated 10-item questionnaire to measure levels of perceived stress. The scale ranges from 0 to 40 points with higher scores indicating greater stress levels. |
| Composite Quality of Life Index | 6 weeks | A 44-item composite index of quality of life derived by adding 11 facets of the WHOQOL-100 Questionnaire (General Health and Life Satisfaction, Pain and Discomfort, Energy and Fatigue, Sleep and Rest, Positive Feelings, Cognitive Function, Self-esteem, Negative Feelings, Activities of Daily Living, Work Capacity, and Personal Relationships). The scale ranges from 0 to 176 points with higher scores indicating better quality of life. |
| Positive affect as measured by PANAS-X | 2 hours post-ingestion | Positive affect will be calculated by adding the values of the 21 positive items of the Positive and Negative Affect Schedule-X and the additional item motivated. Thus, the scale will range from 0 to 88 points with higher scores indicating better mood. |
| Negative affect as measured by PANAS-X | 2 hours post-ingestion | Negative affect will be calculated by adding the values of the 25 negative items of the Positive and Negative Affect Schedule-X. Thus, the scale will range from 0 to 100 points with higher scores indicating worse mood. |
| Patient Health Questionnaire-9 (PHQ-9) | 6 weeks | A self-rated scale of depressive symptoms. The scale ranges from 0 to 27 points with higher scores indicating more severe depression. |
| Brain-derived neutrophic factor (BDNF) in serum | 6 weeks | Serum levels of BDNF will be analyzed using enzyme-linked immunosorbent assay (ELISA). |
| Interleukin-6 (IL-6) in serum | 6 weeks | Serum levels of IL-6 will be analyzed using enzyme-linked immunosorbent assay (ELISA) as a marker of systemic inflammation. |
| C-reactive protein (CRP) in serum | 6 weeks | Serum levels of CRP will be measured using an automated chemistry analyzer as a marker of systemic inflammation. |
| Uric acid in serum | 6 weeks | Serum levels of uric acid will be measured using an automated chemistry analyzer. |
| Serum total antioxidant capacity (TAC) | 6 weeks | The total antioxidant capacity (TAC) of serum will be measured to assess systemic antioxidant status. |
| Serum superoxide dismutase (SOD) | 6 weeks | Serum levels of superoxide dismutase (SOD) will be measured as an indicator of oxidative stress. |
| Cognitive flexibility | 2 hours post-ingestion | A task-switching test will be used to assess cognitive flexibility when switching between two predictable tasks requiring simple numerical decisions. The main outcome of interest is the average accuracy (0 to 100%). |
Countries
United Kingdom
Outcome results
None listed