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Completed

NCT Number: NCT04647019

The Effects of Wild Blueberries on Depressive Symptoms in Young Adults

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.

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Key information

Conditions

Depression Anhedonia Anxiety Anxiety Disorders Behavior Behavioral Symptoms Mental Disorders Nervous System Diseases Neurobehavioral Manifestations Neurologic Manifestations Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–24 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

School of Psychology and Clinical Languages, University of Reading

Reading, Berkshire, RG6 6AL, United Kingdom

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Wild blueberry powder

Dietary Supplement

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.

Placebo Powder

Dietary Supplement

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.

Primary outcomes

  1. Beck Depression Inventory-II (BDI-II)

    Time frame: 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 outcomes

  1. Patient Health Questionnaire-9 (PHQ-9)

    Time frame: 6 weeks

    A self-rated scale of depressive symptoms. The scale ranges from 0 to 27 points with higher scores indicating more severe depression.

  2. Generalized Anxiety Disorder 7-item Scale (GAD-7)

    Time frame: 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.

  3. Snaith-Hamilton Pleasure Scale (SHAPS) - modified version

    Time frame: 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.

  4. Perceived Stress Scale (PSS-10)

    Time frame: 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.

  5. Composite Quality of Life Index

    Time frame: 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.

  6. Positive affect as measured by PANAS-X

    Time frame: 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.

  7. Positive affect as measured by PANAS-X

    Time frame: 6 weeks

    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.

  8. Negative affect as measured by PANAS-X

    Time frame: 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.

  9. Negative affect as measured by PANAS-X

    Time frame: 6 weeks

    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.

  10. Cognitive flexibility

    Time frame: 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%).

  11. Cognitive flexibility

    Time frame: 6 weeks

    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%).

  12. Brain-derived neutrophic factor (BDNF) in serum

    Time frame: 6 weeks

    Serum levels of BDNF will be analyzed using enzyme-linked immunosorbent assay (ELISA).

  13. Interleukin-6 (IL-6) in serum

    Time frame: 6 weeks

    Serum levels of IL-6 will be analyzed using enzyme-linked immunosorbent assay (ELISA) as a marker of systemic inflammation.

  14. C-reactive protein (CRP) in serum

    Time frame: 6 weeks

    Serum levels of CRP will be measured using an automated chemistry analyzer as a marker of systemic inflammation.

  15. Uric acid in serum

    Time frame: 6 weeks

    Serum levels of uric acid will be measured using an automated chemistry analyzer.

  16. Serum total antioxidant capacity (TAC)

    Time frame: 6 weeks

    The total antioxidant capacity (TAC) of serum will be measured to assess systemic antioxidant status.

  17. Serum superoxide dismutase (SOD)

    Time frame: 6 weeks

    Serum levels of superoxide dismutase (SOD) will be measured as an indicator of oxidative stress.

Sponsors and collaborators

Lead sponsor

University of Reading

Other

Collaborators

  • Wild Blueberry Association of North America

Registry information

Official study title

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

Acronym: BluMood

Important dates

Study start
2021
Primary completion
2022
Study completion
2022
First posted
Nov 30, 2020
Registry last updated
Jan 31, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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