The Effects of Wild Blueberries on Depressive Symptoms in Young Adults (BluMood)

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

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.

Study Overview

• Status: Recruiting
• Conditions: Depression; Anhedonia; Anxiety
• Intervention / Treatment: Dietary supplement: Wild blueberry powder; Dietary supplement: Placebo powder

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.

• Study Type: Interventional
• Enrollment (Anticipated): 60
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Berkshire
    • Reading, Berkshire, United Kingdom, RG6 6AL
      • Recruiting
      • School of Psychology and Clinical Languages, University of Reading
      • Sub-Investigator: Carien van Reekum, Professor

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 24 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Blueberry powder	Dietary supplement: Wild 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.
Experimental: Placebo powder	Dietary supplement: Placebo 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.

What is the study measuring?

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

Collaborators and Investigators

• Sponsor: University of Reading
• Collaborators: Wild Blueberry Association of North America (WBANA)
• Investigators: Principal Investigator: Claire Williams, Professor, University of Reading

Study record dates

Study Major Dates

• Study Start (Actual): April 6, 2022
• Primary Completion (Anticipated): September 20, 2022
• Study Completion (Anticipated): September 20, 2022

Study Registration Dates

• First Submitted: October 21, 2020
• First Submitted That Met QC Criteria: November 22, 2020
• First Posted (Actual): November 30, 2020

Study Record Updates

• Last Update Posted (Actual): April 26, 2022
• Last Update Submitted That Met QC Criteria: April 20, 2022
• Last Verified: April 1, 2022

More Information

Terms related to this study

• Keywords: Blueberry; Anthocyanins
• Additional Relevant MeSH Terms: Behavioral Symptoms; Nervous System Diseases; Neurologic Manifestations; Neurobehavioral Manifestations; Depression; Anhedonia
• Other Study ID Numbers: 20/13

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Yes
• IPD Plan Description: Anonymized data may be made available on a platform such as Open Science Framework (www.osf.io) or a data repository linked to academic journals, in accordance with Open Science principles.
• IPD Sharing Supporting Information Type: Study Protocol; Statistical Analysis Plan (SAP)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No