Blueberry consumption and metabolic syndrome
| ISRCTN | ISRCTN47717032 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN47717032 |
| ClinicalTrials.gov (NCT) | Nil known |
| Clinical Trials Information System (CTIS) | Nil known |
| Protocol serial number | Nil known |
| Sponsor | University of Milan |
| Funder | Wild Blueberry Association of North America |
- Submission date
- 28/02/2022
- Registration date
- 03/03/2022
- Last edited
- 13/03/2023
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Nutritional, Metabolic, Endocrine
Plain English summary of protocol
Background and study aims
The metabolic syndrome (MetS) is a constellation of risk factors that include obesity, high blood pressure, high blood lipids, and insulin resistance. MetS is also associated with decreased blood vessel function and alterations in intestinal (gut) permeability.
Increasing evidence indicates that diet and dietary bioactive compounds (e.g., polyphenols) can play a fundamental role in preventing and reversing most risk factors associated with the MetS, suggesting diet as a possible alternative to drug treatment. In particular, polyphenol-rich foods including blueberries may have potential health benefits against the development and progression of MetS. However, these effects need to be confirmed in human studies. At present, few human studies have been conducted evaluating the effect of blueberries on the risk factors associated with the MetS and the results are frequently not significant. No studies have evaluated the impact of blueberries on endothelial (blood vessel lining) permeability as well as intestinal (gut) permeability. The aim of this study is to explore the role of wild blueberries in normalizing MetS factors, improving endothelial function and permeability, and reducing inflammation, in people at high risk for heart disease.
Who can participate?
Men and women aged 40-65 years, overweight (BMI 25-30 kg/m²) and diagnosed with metabolic syndrome
What does the study involve?
Participants will be randomly allocated to drink 240 ml of a wild blueberry or a placebo (dummy) drink for 8 weeks. Blood, urine and feces samples will be collected at the start of the study and after 8 weeks. Blood vessel function markers will be measured at the start of the study, at 2 hours after blueberry/placebo intake, and at the end of the 8-week period, while body measurements and clinical and metabolic parameters will be assessed at the start and at the end of the study.
What are the possible benefits and risks of participating?
The daily intake of blueberry and polyphenols could have an overall beneficial impact on metabolic syndrome markers. In addition, polyphenols may activate the body's defense mechanisms against oxidative stress and inflammation, contributing to the overall health benefit. There are no expected risks.
Where is the study run from?
1. DeFENS, Università degli Studi di Milano (Italy)
2. International Center for Assesment of Nutritional Status (ICANS), Università degli Studi di Milano (Italy)
When is the study starting and how long is it expected to run for?
November 2019 to January 2024
Who is funding the study?
Wild Blueberry Association of North America (USA)
Who is the main contact?
1. Dr Cristian Del Bo’, cristian.delbo@unimi.it
2. Prof. Dorothy Klimis-Zacas, dorothea@maine.edu
3. Prof. Alberto Battezzati, alberto.battezzati@unimi.it
Contact information
Principal investigator
Via G. Celoria 2
Milano
20133
Italy
 ORCID ID |
0000-0001-7562-377X |
|---|---|
| Phone | +39 (0)250316730 |
| cristian.delbo@unimi.it |
Study information
| Primary study design | Interventional |
|---|---|
| Study design | Controlled randomized crossover intervention study |
| Secondary study design | Randomised cross over trial |
| Study type | Participant information sheet |
| Scientific title | The effect of wild blueberries on metabolic syndrome clusters: a new focus on endothelial permeability and functionality |
| Study acronym | BLUMET |
| Study objectives | The present study attempts to test the hypothesis that wild blueberries are able to normalize metabolic syndrome risk factors, improve endothelial function and endothelial permeability, and reduce inflammation, in subjects at high risk for cardiovascular diseases. |
| Ethics approval(s) | Approved 27/01/2022, the Ethics Committee of the University of Milan (Via Festa del Perdono 7, 20122, Milano, Italia; +39 (0)2 503 12667; comitato.etico@unimi.it), ref: 7/22 |
| Health condition(s) or problem(s) studied | Metabolic syndrome |
| Intervention | Thirty-two subjects with risk factors for metabolic syndrome will be enrolled and randomized using a computer random number generator to consume 240 ml/day of a wild blueberry drink (providing at least 560 mg of anthocyanins and 200 mg of chlorogenic acid) or placebo (a drink prepared to match macronutrient and calorie content and to have sensory characteristics similar to the wild blueberry drink but without its bioactives). Each treatment will be 8 weeks long and separated by at least an 8-week wash-out period. At the beginning of each intervention period, an acute study will be performed in which subjects will consume a single portion of the wild blueberry drink. |
| Intervention type | Other |
| Primary outcome measure(s) |
Acute study: improvement of vascular function measured as reactive hyperemia index (by EndPAT2000) at baseline and 2 hours after the intake of blueberry or placebo treatments |
| Key secondary outcome measure(s) |
The following list of markers will be measured at baseline (T0) and after 8 weeks (T8) of blueberry and/or placebo treatment: |
| Completion date | 31/01/2024 |
Eligibility
| Participant type(s) | Healthy volunteer |
|---|---|
| Age group | Adult |
| Lower age limit | 40 Years |
| Upper age limit | 65 Years |
| Sex | All |
| Target sample size at registration | 32 |
| Total final enrolment | 32 |
| Key inclusion criteria | 1. Women and men 2. Aged 40-65 years 3. Body mass index 25-30 kg/m² 4. Waist circumference ≥102 cm in men and ≥88 cm in women 5. High density lipoprotein cholesterol < 1.04 mmol/l in men and <1.30 mmol/l in women 6. Serum triglycerides ≥1.7 mmol/l or treatment with triglycerides-lowering drugs 7. Systolic blood pressure ≥130 mmHg or diastolic blood pressure ≥85 mmHg or treatment with blood pressure lowering drugs 8. Serum glucose ≥6.1 mmol/l or treatment with blood glucose-lowering drugs 9. No smokers |
| Key exclusion criteria | 1. Obesity 2. Uncontrolled diabetes 3. Primary hypercholesterolemia 4. Dysthyroidism 5. Liver and renal disease 6. Gastrointestinal disorders 7. Antibiotic treatment 8. Use of supplements 9. Impaired cognitive function 10. Smokers 11. Allergy to blueberry and their products 12. Vegetarian, vegans, macrobiotic |
| Date of first enrolment | 20/03/2022 |
| Date of final enrolment | 15/10/2023 |
Locations
Countries of recruitment
- Italy
Study participating centre
ICANS: Via Sandro Botticelli 21
Milan
20133
Italy
Results and Publications
| Individual participant data (IPD) Intention to share | Yes |
|---|---|
| IPD sharing plan summary | Available on request |
| IPD sharing plan | Data of the markers analysed will be available upon request at the end of the study from Dr Cristian Del Bo' (cristian.delbo@unimi.it). Data are anonymous and consent was obtained from participants |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Participant information sheet | Participant information sheet | 11/11/2025 | 11/11/2025 | No | Yes |
Editorial Notes
13/03/2023: The following changes have been made:
1. The recruitment end date has been changed from 15/02/2023 to 15/10/2023.
2. The overall trial end date has been changed from 30/06/2023 to 31/01/2024 and the plain English summary updated accordingly.
3. The intention to publish date has been changed from 30/11/2023 to 30/06/2024.
14/09/2022: The recruitment end date was changed from 15/09/2022 to 15/02/2023.
09/05/2022: The recruitment end date was changed from 01/05/2022 to 15/09/2022.
28/02/2022: Trial's existence confirmed by the Ethics Committee of the University of Milan.
