Effect of Blueberries on Immunity (Blueberry)

February 2, 2026 updated by: Loma Linda University

Immune Benefits of Blueberry Consumption in Overweight Older Men and Postmenopausal Women: A Randomized Trial

This research study will test the effects of Blueberries on immune functions in overweight older men and postmenopausal women

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This study will examine the effects of Blueberries on clinically relevant markers of immune function. Eligible and selected participants will be randomized to one of two groups at the baseline clinic visit. The Blueberry group participants will consume blueberries (2 packets of blueberry freeze-dried powder equivalent to 2 cups of fresh blueberries) added to the habitual diet and the Control group participants will abstain from blueberries (with instructions to limit the consumption of other berries and polyphenol rich foods) but otherwise continue their habitual diet. During the study, clinic visits will occur at 4-week intervals (baseline, weeks 4, 8 and 12) for a total of 4 visits at the Loma Linda University Nutrition Research Center. Blood samples taken at baseline and at week 12 will be assayed for changes in immune function and inflammatory markers.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
52

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

  • Name: Joan Sabate, DrPH
  • Phone Number: 47238 095584300
  • Email: jsabate@llu.edu

Study Locations

  • United States
    • California
      • Loma Linda, California, United States, 92350
        • Loma Linda University School of Public Health

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

50 years to 70 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Older men and post-menopausal women aged 50-70 year
  2. Have BMI of 25-32
  3. Able to commute to Loma Linda University
  4. Consuming a typical American Diet low in polyphenols

Exclusion Criteria:

  1. Intolerance or allergy to Blueberries
  2. Regular intake of Blueberries and other berried (>2 ounces/week)
  3. Immune system insufficiency or disease
  4. Using immune boosting supplements
  5. Exposure to antibiotics and corticoids immediately prior to study
  6. Uncontrolled chronic diseases and relevant psychiatric illness, including major depression
  7. Flu vaccination and or Covid Vaccination less than 3 months ago from the start of the study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Blueberry powder group
Participants in the blueberry powder group will receive freeze dried blueberries in form of a powder
Dietary supplement: Blueberry powder group
Participants in the blueberry powder group will receive freeze dried blueberries in form of a powder
Dietary supplement: Placebo powder group
Participants in the placebo powder group will receive an isocaloric placebo powder
Placebo Comparator: Placebo powder group
Participants in the placebo group will receive an isocaloric placebo powder.
Dietary supplement: Blueberry powder group
Participants in the blueberry powder group will receive freeze dried blueberries in form of a powder
Dietary supplement: Placebo powder group
Participants in the placebo powder group will receive an isocaloric placebo powder

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
changes in lymphocyte populations
Time Frame: baseline to 12 weeks
Immunophenotyping will be performed by flow cytometry to measure the number of T helper, T cytotoxic, Naïve and memory cells and B cells
baseline to 12 weeks
changes in natural killer (NK) cell activity
Time Frame: baseline to 12 weeks
The NK degranulation assay will be performed on blood samples. The test will be conducted using a modified flow cytometry method that measures the expression of CD107a
baseline to 12 weeks
changes in serum inflammatory cytokine concentration
Time Frame: baseline to 12 weeks
Changes in the concentrations of the inflammatory cytokines will be performed on serum using enzyme-linked immunoassay (ELISA)
baseline to 12 weeks
changes in complete blood count (CBC)
Time Frame: baseline to 12 weeks
changes in the complete blood count will be performed on whole blood with the use of an automated hematology analyzer at a certified clinical facility
baseline to 12 weeks
changes in cytokine production
Time Frame: baseline to 12 weeks
PBMC cells will be separated from blood, activated and cultured using phytohemagglutinin (PHA). Inflammatory cytokine production will be measured in the resulting supernatant using ELISA
baseline to 12 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
changes in neutralizing antibody titers against hemagglutinin and neuraminidase of the vaccine strain
Time Frame: week 8 to week 12
Neutralizing antibody titers in the serum against the hemagglutinin and neuraminidase of the vaccine strain will be measured using the standard commercial ELISA kits
week 8 to week 12
changes in the viral load in response to vaccination
Time Frame: week 8 to week 12
viral load in blood will be measured using a quantitative polymerase chain reaction
week 8 to week 12

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Loma Linda University

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
U.S. Highbush Blueberry Council

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Joan Sabate, DrPH, Loma Linda University
  • Principal Investigator: Sujatha Rajaram, PhD, Loma Linda University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
October 12, 2022

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 12, 2023

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 12, 2023

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 6, 2022

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 8, 2022

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 10, 2022

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 4, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 2, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 5220098

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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