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Gut MicrobiotaNCT03266055

Effects of Blueberry on Gut Microbiota and Metabolic Syndrome

A study testing 50 g of blueberry powder, taken daily for 8 weeks in people with Gut Microbiota and Metabolic Syndrome, run by Laval University at 1 site in Canada.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

There is growing evidence that nutritional intervention with dietary polyphenols can positively modulate the gut microbiota to improve cardiometabolic health. Whether the beneficial effects of blueberries on obesity and the metabolic syndrome can be linked to their potential impact on the gut microbiota and intestinal… Read more about this study

Who is it for?
Ages 18 to 55 yearsHealthy volunteers can take part
Conditions the study is for
Gut Microbiota, Metabolic Syndrome
What is being tested?
50 g of blueberry powder, taken daily for 8 weeks
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
59 participants
Where
1 siteCanada
Study dates
1 Sep 2017to Dec 2028
Phase
Interventional
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 55 years
  • All sexes
  • Healthy volunteers accepted
  • Adult

Who may be able to join

  • Men and premenopause women in good health
  • Caucasians
  • At least one of the following : BMI between 25 and 40 kg/m2 or Waist circumference ≥ 80 cm for women and ≥ 94 cm for men
  • At least one of the following : TG ≥ 1.35 mmol/L or fasting insulinemia ≥ 42 pmol/L

Who cannot join

  • Metabolic disorders (hypertension, diabetes, hypercholesterolemia)
  • Regular use of medication affecting study parameters
  • Use of natural health product in the last 3 months
  • Use of antibiotics in the last 3 months
  • Nicotine users
  • Allergy or intolerance for blueberries
Show all 11Show fewer
  • Blueberry taste aversion
  • More than 2 alcohol drinks par day
  • Particular dietary habits (vegetarism, gluten-free diet, cetogenic diet...)
  • Weight change of more than 5% in the last 3 months
  • Surgery in the last 3 months or planed during the study

Trial locations and contacts

1 site in 1 country.

Canada1 site
  • Laval University

    Québec, G1V0A6

Other trials in Canada

About this study

Official title: Prebiotic Effects of Blueberry in Overweight/Obese Individuals: Potential Role of the Gut Microbiota in Alleviating the Metabolic Syndrome.

There is growing evidence that nutritional intervention with dietary polyphenols can positively modulate the gut microbiota to improve cardiometabolic health. Whether the beneficial effects of blueberries on obesity and the metabolic syndrome can be linked to their potential impact on the gut microbiota and intestinal integrity remains speculative at this time. Moreover, the mechanisms of action underlying health benefits associated to blueberry consumption are still unknown. The investigators are thus proposing to combine the study of metagenomics, transcriptomics and metabolomics to test whether a prebiotic activity of highbush blueberries can play a role in the prevention of obesity-linked metabolic syndrome in a clinical setting.

Being tested
50 g of blueberry powder, taken daily for 8 weeks, 50g of placebo blueberry powder, taken daily for 8 weeks
Keywords
Blueberry, Diet
Medical subject headings
Metabolic Syndrome

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • 50 g of blueberry powder, taken daily for 8 weeksDietary supplement

    Subjects will consume blueberry powder during 8 weeks to test the possible effects of blueberries on gut microbiota composition and on metabolic syndrome parameters.

  • 50g of placebo blueberry powder, taken daily for 8 weeksDietary supplement

    Subjects will consume blueberry placebo powder to test if there is a significant difference on the impact on gut microbiota composition and metabolic syndrome parameters between this treatment and the active treatment (blueberry powder).

Study groups in NCT03266055
Study groupRoleWhat they receive
Blueberry powderExperimentalNot described
Receives: Dietary Supplement: 50 g of blueberry powder, taken daily for 8 weeks
Blueberry placebo powderPlacebo comparatorNot described
Receives: Dietary Supplement: 50g of placebo blueberry powder, taken daily for 8 weeks

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Changes in plasma insulin/glucose of overweight/obese men and women taking either blueberry powder or placebo blueberry powder

    Measured: 12 months

  2. Changes in plasma lipids/lipoproteins of overweight/obese men and women taking either blueberry powder or placebo blueberry powder

    Measured: 12 months

Secondary outcomes (6)
  1. Changes in gene expression in overweight/obese men and women taking either blueberry powder or placebo blueberry powder

    Measured: 3-6 months

  2. Changes in metabolites concentration in overweight/obese men and women taking either blueberry powder or placebo blueberry powder

    Measured: 3-6 months

  3. Changes in the gut microbiota composition in overweight/obese men and women taking either blueberry powder or placebo blueberry powder

    Measured: 3-6 months

  4. Changes in blood pressure of overweight/obese men and women taking either blueberry powder or placebo blueberry powder

    Measured: 12 months

  5. Changes in intestinal integrity of overweight/obese men and women taking either blueberry powder or placebo blueberry powder

    Measured: 12 months

  6. Changes in inflammation biomarkers of overweight/obese men and women taking either blueberry powder or placebo blueberry powder

    Measured: 12 months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted29 Aug 2017
  2. Study start1 Sep 2017
  3. Primary completion14 Jan 2019
  4. Study completionDec 2028 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Prevention
Allocation
Randomised
Intervention model
Parallel groups
Masking
Single blind
Who is masked
Participant
Enrolment
59 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT03266055
Sponsor's protocol ID
BLEUET 2017-135
Status last verified
Sep 2026
First submitted
6 Jul 2017
Last updated
8 Sep 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No

Publications

  • Rousseau M, Horne J, Guenard F, de Toro-Martin J, Garneau V, Guay V, Kearney M, Pilon G, Roy D, Couture P, Couillard C, Marette A, Vohl MC. An 8-week freeze-dried blueberry supplement impacts immune-related pathways: a randomized, double-blind placebo-controlled trial. Genes Nutr. 2021 May 17;16(1):7. doi: 10.1186/s12263-021-00688-2.

    PubMed 34000994

Questions about this trial

What is this clinical trial studying?

A study testing 50 g of blueberry powder, taken daily for 8 weeks in people with Gut Microbiota and Metabolic Syndrome, run by Laval University at 1 site in Canada.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: under way, not looking for participants, as of the sponsor's last update on 8 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Changes in plasma insulin/glucose of overweight/obese men and women taking either blueberry powder or placebo blueberry powder (time frame: 12 months). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT03266055, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 Sep 2026.

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