The Effects of Wild Blueberries on Depressive Symptoms in Young Adults

Study Overview
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Brief Summary
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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
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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.

Official Title
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The Effects of Wild Blueberries on Depressive Symptoms in Young Adults: a Randomized, Double-blind, Placebo-controlled Trial

Conditions
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Depression, Anxiety, Anhedonia

Intervention / Treatment
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* Dietary Supplement: Wild blueberry powder
* Dietary Supplement: Placebo powder


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 24 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Blueberry powder<br> | Dietary Supplement: Wild blueberry powder<br>* 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.<br>|
| Experimental: Placebo powder<br> | Dietary Supplement: Placebo powder<br>* 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.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Beck Depression Inventory-II (BDI-II) | 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. | 6 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Patient Health Questionnaire-9 (PHQ-9) | A self-rated scale of depressive symptoms. The scale ranges from 0 to 27 points with higher scores indicating more severe depression. | 6 weeks | 
| Generalized Anxiety Disorder 7-item Scale (GAD-7) | A brief self-rated scale of generalized anxiety. The scale ranges from 0 to 21 points with higher scores indicating more severe anxiety. | 6 weeks | 
| Snaith-Hamilton Pleasure Scale (SHAPS) - modified version | 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. | 6 weeks | 
| Perceived Stress Scale (PSS-10) | 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. | 6 weeks | 
| Composite Quality of Life Index | 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. | 6 weeks | 
| Positive affect as measured by PANAS-X | 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. | 2 hours post-ingestion | 
| Positive affect as measured by PANAS-X | 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. | 6 weeks | 
| Negative affect as measured by PANAS-X | 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. | 2 hours post-ingestion | 
| Negative affect as measured by PANAS-X | 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. | 6 weeks | 
| Cognitive flexibility | 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%). | 2 hours post-ingestion | 
| Cognitive flexibility | 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%). | 6 weeks | 
| Brain-derived neutrophic factor (BDNF) in serum | Serum levels of BDNF will be analyzed using enzyme-linked immunosorbent assay (ELISA). | 6 weeks | 
| Interleukin-6 (IL-6) in serum | Serum levels of IL-6 will be analyzed using enzyme-linked immunosorbent assay (ELISA) as a marker of systemic inflammation. | 6 weeks | 
| C-reactive protein (CRP) in serum | Serum levels of CRP will be measured using an automated chemistry analyzer as a marker of systemic inflammation. | 6 weeks | 
| Uric acid in serum | Serum levels of uric acid will be measured using an automated chemistry analyzer. | 6 weeks | 
| Serum total antioxidant capacity (TAC) | The total antioxidant capacity (TAC) of serum will be measured to assess systemic antioxidant status. | 6 weeks | 
| Serum superoxide dismutase (SOD) | Serum levels of superoxide dismutase (SOD) will be measured as an indicator of oxidative stress. | 6 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Blueberry, Anthocyanins