The Effects of a Single Dose of Wild Blueberries on Mood and Cognition in Healthy Young Adults

Cognition Clinical Trial

Official title:

The Effects of a Single Dose of Wild Blueberries on Mood and Cognition in Healthy Young Adults: a Randomized, Double-blind, Placebo-controlled, Crossover Study

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT04935099
• Other study ID #: 21/09
• Status: Completed
• Phase: N/A
• Start date: May 26, 2021
• Est. completion date: August 27, 2021

Study information

• Verified date: September 2021
• Source: University of Reading
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

This study aims to investigate whether consuming a drink containing powdered blueberries (equivalent to 150 g fresh fruit) can improve mood and cognition in healthy young adults. Blood biomarkers of inflammation and neurotransmitter turnover will be analyzed as well as responses to computer-based cognitive tasks designed to measure verbal memory, executive function, and emotional processing.

Description:

The present study will examine the psychological effects of a single dose of freeze-dried wild blueberries using a randomized, double-blind, placebo-controlled, counterbalanced, crossover design. A total of 30 healthy young adults will consume two drinks: one containing 22 g blueberry powder and the other containing 22 g matched placebo powder in counterbalanced order one week apart. The investigators will assess changes in transient mood, cognitive-emotional function, and serum biomarkers of inflammation, neuroplasticity, and monoamine metabolism from baseline to 2 hours post-ingestion.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 33
• Est. completion date: August 27, 2021
• Est. primary completion date: August 27, 2021
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 25 Years

Eligibility

Inclusion Criteria:

• 18 to 25 years of age

• Willingness to provide blood samples

Exclusion Criteria:

• Allergy to blueberries or any other Vaccinium species

• Diagnosis or symptoms of anxiety, depression, or other mental health conditions

• Any medically significant condition (e.g. anemia, gastrointestinal disorders, diabetes)

• Use of psychoactive medication or recreational drugs in the last two weeks

• Current use of medication that could interact with the intervention (e.g. antibiotics)

• Obesity or underweight

• Participation in other interventional studies in the last month

• Pregnancy or lactation

Related Conditions & MeSH terms

• Affect
• Cognition
• Mood

Intervention

Dietary Supplement:
• Wild blueberry powder
22 g freeze-dried wild blueberry (Vaccinium angustifolium) powder, mixed with 250 ml water, and served in an opaque container.
• Placebo powder
22 g placebo powder matched for macronutrients and flavor, mixed with 250 ml water, and served in an opaque container.

Locations

Country	Name	City	State
United Kingdom	School of Psychology and Clinical Languages, University of Reading	Reading	Berkshire

Sponsors (2)

Lead Sponsor	Collaborator
University of Reading	Wild Blueberry Association of North America (WBANA)

Country where clinical trial is conducted

United Kingdom, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Other	Recognition memory on RAVLT	In the final task of the Rey Auditory Verbal Learning Test, participants need to recognize the 15 words from List A from a list of 50 words. Recognition memory is defined as the number of correctly recognized words out of the total number of words.	baseline
Other	Recognition memory on RAVLT	In the final task of the Rey Auditory Verbal Learning Test, participants need to recognize the 15 words from List A from a list of 50 words. Recognition memory is defined as the number of correctly recognized words out of the total number of words.	2 hours post-ingestion
Primary	Global transient mood as measured by PANAS-X	The Positive and Negative Affect Schedule - Expanded Form (PANAS-X) is a validated, self-rated measure of affective state, encompassing two general dimensions (positive and negative affect). These will be calculated separately by adding the values of the individual items (21 positive and 25 negative items). Thus, the scales will range from 0 to 84 points for positive affect and from 0 to 100 for negative affect, with a higher score indicating greater positive or negative affect. Positive affect will be considered the primary measure.	baseline
Primary	Global transient mood as measured by PANAS-X	The Positive and Negative Affect Schedule - Expanded Form (PANAS-X) is a validated, self-rated measure of affective state, encompassing two general dimensions (positive and negative affect). These will be calculated separately by adding the values of the individual items (21 positive and 25 negative items). Thus, the scales will range from 0 to 84 points for positive affect and from 0 to 100 for negative affect, with a higher score indicating greater positive or negative affect. Positive affect will be considered the primary measure	2 hours post-ingestion
Primary	Negative interpretation bias	A negative interpretation bias is defined as a tendency to interpret ambiguous information in a consistently threatening or negative manner, thus serving as an objective indicator of affective state. In this task, participants will be asked to categorize facial expressions of anger, happiness, and surprise as either positive or negative. Interpretation bias will be operationalized as the percent of trials in which surprised faces were rated as negative, out of the total number of surprise trials (48 trials).	baseline
Primary	Negative interpretation bias	A negative interpretation bias is defined as a tendency to interpret ambiguous information in a consistently threatening or negative manner, thus serving as an objective indicator of affective state. In this task, participants will be asked to categorize facial expressions of anger, happiness, and surprise as either positive or negative. Interpretation bias will be operationalized as the percent of trials in which surprised faces were rated as negative, out of the total number of surprise trials (48 trials).	2 hours post-ingestion
Primary	Cognitive flexibility (accuracy on post-switch trials)	A task-switching test will be used to assess cognitive performance when switching between two predictable tasks requiring simple numerical decisions. The main outcome of interest is the average accuracy of responses to post-switch trials (those immediately following a switch to a new task).	baseline
Primary	Cognitive flexibility (accuracy on post-switch trials)	A task-switching test will be used to assess cognitive performance when switching between two predictable tasks requiring simple numerical decisions. The main outcome of interest is the average accuracy of responses to post-switch trials (those immediately following a switch to a new task).	2 hours post-ingestion
Primary	Delayed verbal memory on RAVLT	The Rey Auditory Verbal Learning Test (RAVLT) is a standard neuropsychological assessment designed to evaluate verbal memory. The participant hears a list of 15 words and is asked to recall as many words as possible. This procedure is repeated five times. The main outcome of interest is the number of correctly recalled words 20 minutes after the last presentation of the list of words (Trial A7).	baseline
Primary	Delayed verbal memory on RAVLT	The Rey Auditory Verbal Learning Test (RAVLT) is a standard neuropsychological assessment designed to evaluate verbal memory. The participant hears a list of 15 words and is asked to recall as many words as possible. This procedure is repeated five times. The main outcome of interest is the number of correctly recalled words 20 minutes after the last presentation of the list of words (Trial A7).	2 hours post-ingestion
Primary	Serum brain-derived neurotrophic factor (BDNF)	Serum levels of BDNF will be analyzed using enzyme-linked immunosorbent assay (ELISA).	baseline
Primary	Serum brain-derived neurotrophic factor (BDNF)	Serum levels of BDNF will be analyzed using enzyme-linked immunosorbent assay (ELISA).	2 hours post-ingestion
Secondary	Distinct affective states as measured by PANAS-X subscales	The following affective states will be examined separately as defined by the PANAS-X subscales: Joviality (Happiness), Self-Assurance, Attentiveness, Fatigue, Serenity. Higher scores will indicate greater intensity of the respective affective state.	baseline
Secondary	Distinct affective states as measured by PANAS-X subscales	The following affective states will be examined separately as defined by the PANAS-X subscales: Joviality (Happiness), Self-Assurance, Attentiveness, Fatigue, Serenity. Higher scores will indicate greater intensity of the respective affective state.	2 hours post-ingestion
Secondary	Reaction time to positive stimuli	The average reaction time to correctly categorized happy faces in the facial expression task.	baseline
Secondary	Reaction time to positive stimuli	The average reaction time to correctly categorized happy faces in the facial expression task.	2 hours post-ingestion
Secondary	Reaction time to negative stimuli	The average reaction time to correctly categorized angry faces in the facial expression task.	baseline
Secondary	Reaction time to negative stimuli	The average reaction time to correctly categorized angry faces in the facial expression task.	2 hours post-ingestion
Secondary	Attentional bias to emotional information	Attentional bias to emotional information will be operationalized as the average reaction time to correctly categorized angry faces divided by the average reaction time to correctly categorized happy faces. Thus, a higher value indicates a tendency to attend to and process positive information over negative information.	baseline
Secondary	Attentional bias to emotional information	Attentional bias to emotional information will be operationalized as the average reaction time to correctly categorized angry faces divided by the average reaction time to correctly categorized happy faces. Thus, a higher value indicates a tendency to attend to and process positive information over negative information.	2 hours post-ingestion
Secondary	Cognitive flexibility (accuracy on remaining trials of task-switching test)	The average accuracy (in %) of responses to the remaining trials of the task-switching test will be measured as a secondary outcome. In this task, participants have to switch between two predictable tasks requiring simple numerical decisions.	baseline
Secondary	Cognitive flexibility (accuracy on remaining trials of task-switching test)	The average accuracy (in %) of responses to the remaining trials of the task-switching test will be measured as a secondary outcome. In this task, participants have to switch between two predictable tasks requiring simple numerical decisions.	2 hours post-ingestion
Secondary	Choice reaction time (post-switch trials)	The average reaction time of correct responses to post-switch trials of the task-switching test.	baseline
Secondary	Choice reaction time (post-switch trials)	The average reaction time of correct responses to post-switch trials of the task-switching test.	2 hours post-ingestion
Secondary	Choice reaction time (remaining trials of task-switching test)	The average reaction time of correct responses to remaining trials of the task-switching test.	baseline
Secondary	Choice reaction time (remaining trials of task-switching test)	The average reaction time of correct responses to remaining trials of the task-switching test.	2 hours post-ingestion
Secondary	Final acquisition on RAVLT (Trial 5)	The number of correctly retrieved words on Trial 5 (List A) of the Rey Auditory Verbal Learning Test.	baseline
Secondary	Final acquisition on RAVLT (Trial 5)	The number of correctly retrieved words on Trial 5 (List A) of the Rey Auditory Verbal Learning Test.	2 hours post-ingestion
Secondary	Recall of interference list on RAVLT	The number of correctly retrieved words from the interference list (List B) of the Rey Auditory Verbal Learning Test.	baseline
Secondary	Recall of interference list on RAVLT	The number of correctly retrieved words from the interference list (List B) of the Rey Auditory Verbal Learning Test.	2 hours post-ingestion
Secondary	Immediate recall on RAVLT	The number of correctly recalled words on the Rey Auditory Verbal Learning Test 2 minutes after the final presentation of List A (and following the presentation and recall of List B).	baseline
Secondary	Immediate recall on RAVLT	The number of correctly recalled words on the Rey Auditory Verbal Learning Test 2 minutes after the final presentation of List A (and following the presentation and recall of List B).	2 hours post-ingestion
Secondary	Proactive interference on RAVLT	Proactive interference on the Rey Auditory Verbal Learning Test is defined as the number of correctly recalled words from the interference List B divided by the number of correctly recalled words on Trial 1 of List A (B1/A1). A higher score indicates less proactive interference.	baseline
Secondary	Proactive interference on RAVLT	Proactive interference on the Rey Auditory Verbal Learning Test is defined as the number of correctly recalled words from the interference List B divided by the number of correctly recalled words on Trial 1 of List A (B1/A1). A higher score indicates less proactive interference.	2 hours post-ingestion
Secondary	Retroactive interference on RAVLT	Retroactive interference on the Rey Auditory Verbal Learning Test is defined as the number of correctly recalled words on Trial 6 of List A (the free recall trial after the interference List B) divided by the number of correctly recalled words on Trial 5 of List A (A6/A5). A higher score indicates less retroactive interference.	baseline
Secondary	Retroactive interference on RAVLT	Retroactive interference on the Rey Auditory Verbal Learning Test is defined as the number of correctly recalled words on Trial 6 of List A (the free recall trial after the interference List B) divided by the number of correctly recalled words on Trial 5 of List A (A6/A5). A higher score indicates less retroactive interference.	2 hours post-ingestion
Secondary	Retention on RAVLT	Retention on the Rey Auditory Verbal Learning Test is defined as the number of correctly recalled words on Trial 7 of List A (the delayed recall trial at 20 minutes) divided by the number of correctly retrieved words on Trial 6 of List A (A7/A6). Thus, a higher score indicates a higher retention rate.	baseline
Secondary	Retention on RAVLT	Retention on the Rey Auditory Verbal Learning Test is defined as the number of correctly recalled words on Trial 7 of List A (the delayed recall trial at 20 minutes) divided by the number of correctly retrieved words on Trial 6 of List A (A7/A6). Thus, a higher score indicates a higher retention rate.	2 hours post-ingestion
Secondary	Serum monoamine oxidase B (MAO-B) inhibition	The activity of the enzyme MAO-B in serum will be analyzed using a fluorometric assay.	baseline
Secondary	Serum monoamine oxidase B (MAO-B) inhibition	The activity of the enzyme MAO-B in serum will be analyzed using a fluorometric assay.	2 hours post-ingestion
Secondary	Serum 3,4-dihydroxyphenylglycol (DHPG)	Serum levels of DHPG will be analyzed using liquid chromatography-mass spectrometry (LS-MS) to indirectly determine monoamine oxidase A (MAO-A) activity.	baseline
Secondary	Serum 3,4-dihydroxyphenylglycol (DHPG)	Serum levels of DHPG will be analyzed using liquid chromatography-mass spectrometry (LS-MS) to indirectly determine monoamine oxidase A (MAO-A) activity.	2 hours post-ingestion
Secondary	Serum interleukin-6 (IL-6)	Serum levels of IL-6 will be analyzed using enzyme-linked immunosorbent assay (ELISA) as an indication of systemic inflammation.	baseline
Secondary	Serum interleukin-6 (IL-6)	Serum levels of IL-6 will be analyzed using enzyme-linked immunosorbent assay (ELISA) as an indication of systemic inflammation.	2 hours post-ingestion
Secondary	Serum C-reactive protein (CRP)	Serum levels of CRP will be analyzed using enzyme-linked immunosorbent assay (ELISA) as an indication of systemic inflammation.	baseline
Secondary	Serum C-reactive protein (CRP)	Serum levels of CRP will be analyzed using enzyme-linked immunosorbent assay (ELISA) as an indication of systemic inflammation.	2 hours post-ingestion