Glucose IntoleranceNCT04004182
Acute Study of Anthocyanin-rich Bilberry and Polyphenol-rich Apple Extracts on Postprandial Glycaemic Response
A study testing Fruit bar with addition of polyphenols in people with Glucose Intolerance and Glucose Metabolism Disorders, run by University of Aberdeen at 1 site in United Kingdom.
Trial summary
Strategies to control chronic postprandial hyperglycaemia by optimizing the functionality of foods would strengthen efforts to reduce the risk of developing T2D in the general population. Read more about this study
- Who is it for?
- Ages 40 to 70 yearsHealthy volunteers can take part
- Conditions the study is for
- Glucose Intolerance, Glucose Metabolism Disorders
- What is being tested?
- Fruit bar with addition of polyphenols
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 24 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 8 Jun 2019to 1 Mar 2023
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 40 to 70 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Healthy men or post-menopausal women
- Aged ≥40 and ≤ 70 years old.
- BMI > 25.0kg/m2
- HbA1c <6.5%
Who cannot join
- Those with any of the following will be excluded from participation:
- Thromboembolic or coagulation disease
- Unregulated thyroid disease
- Kidney disease
- Hepatic disease
- Severe gastrointestinal disorders
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- Pulmonary disease (e.g. chronic bronchitis, COPD, pacemaker implant)
- Nut or date allergy
- Alcohol or any other substance abuse
- Eating disorders
- Women who are lactating or breastfeeding, pregnant
- Allergic/intolerant to foods provided in the study
- Alcohol and/or other substance abuse
- Smoking and the use of e-cigarettes
- Physically active at a competitive level (exercising strenuously on a daily basis for long periods of time)
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
University of Aberdeen Rowett Institute of Nutrition and Health
Aberdeen, AB21 9SB
About this study
Strategies to control chronic postprandial hyperglycaemia by optimizing the functionality of foods would strengthen efforts to reduce the risk of developing T2D in the general population. Polyphenolic constituents, may help to delay starch and disaccharide digestion and glucose absorption following a carbohydrate-containing meal or beverage. In vitro studies suggest that some berry anthocyanins and apple polyphenols are effective inhibitors of digestive enzymes, α-amylases and α-glucosidases. Furthermore, polyphenols found in berries and apples inhibit the action of intestinal glucose transporters. Human data is limited; however, randomized controlled trials (RCTs) have shown that berries and apple products reduced postprandial glucose concentrations following consumption of either starch, glucose or sucrose loads.
The aim of this study is to test the hypothesis that consumption of a fruit bar containing anthocyanin-rich bilberry and polyphenol-rich apple extracts together with a starch and sucrose meal would reduce the postprandial glycemic response.
This study is a randomized cross over study and will aim to recruit 24 overweight (BMI > 25.0), men or post-menopausal women, aged ≥40 and ≤ 70 years who will attend four study sessions. The first study session will be an oral glucose tolerance test (OGTT) and the remaining three will be identical in all respects except for the composition of the fruit bar. Consecutive blood samples will be collected in all 4 study sessions which will be used to measure glucose, insulin, C-peptide, incretins and lipids.
Read the detailed description
This acute intervention study will have a randomised controlled crossover design where the volunteers will return for 4 stand-alone study sessions. All study procedures will be carried out at the Human Nutrition Unit (HNU) of the Rowett Institute.
The first study session will be an oral glucose tolerance test (OGTT). The remaining three will be intervention sessions which will be identical in all respects except for the composition of the fruit bar. There will have a minimum of 1 week washout period. Volunteers will be asked to consume a low polyphenol diet three days prior to each intervention. To ensure compliance, participants will be provided with a list of 'allowed' and 'excluded' foods as well as food diaries to complete over the three day period. The Fruit bars will be made in the HNU kitchens by trained staff.
Table 1. Study sessions Intervention/Meal
Oral Glucose Tolerance test (OGTT) Fruit bar Plus OGTT Fruit bar with addition of 600 mg bilberry anthocyanins Plus OGTT Fruit bar with addition of 600mg bilberry anthocyanins and 1200mg apple polyphenols Plus OGTT
The glucose load for the OGTT in all sessions will be given as carbohydrate meal consisting of white bread, spread, low-polyphenol jam. (meal: 75g carbohydrate total)
Screening session Once the volunteer expresses interest in the study, they will be invited to attend a screening visit lasting approximately 1 h. Informed consent will be obtained from all participants, ensuring that they have fully understood all the study procedures before continuing. A full eligibility assessment (for assessing inclusion and exclusion criteria) will be carried out following consenting. This will include the completion of a health screening questionnaire, anthropometric measurements (height, weight, BMI,). HbA1c will be measured using finger prick blood samples. Volunteers fulfilling all the criteria and who wish to continue will be accepted into the study.
OGTT and Intervention sessions (study sessions 1-3)
At each session the volunteers will return for 2 visits.
Visit 1: Pre - Study Session Day This session will last approximately 1 hour. Volunteers will arrive at the HNU on the day preceding the study session day for the insertion of the continuous blood glucose monitoring (CGM) sensor (iPro 2, Medtronic Ltd, UK). Upon arrival, their weight will be measured for calculating BMI. Waist circumference and body fat composition using bio-impedance will be also be measured. The CGM records interstitial glucose levels at five minute intervals and provides a detailed picture of glucose fluxes. The CGM monitors are widely used by diabetics to monitor blood glucose fluxes and are designed for self-insertion. Their accuracy and level of data detail has also made them a powerful and widely used research tool. The sensor will be inserted into the subcutaneous fat layer (just below the skin surface) in the belly area by a trained researcher or HNU staff member. Insertion will be carried out using a tailor-made inserter provided with the CGM which causes minimum discomfort. Following stabilisation of the sensor a data acquisition unit will be attached to it. The sensor will be calibrated using a finger prick blood sample. Volunteers will be shown how to calibrate the CGM at home using a standard blood glucose meter and finger prick samples, and instructed on the times when they would have to do so. Wearing the sensor (which is about the size of a £2 coin) causes minimum discomfort to the wearer and does not hinder daily activities (including sleeping and having baths). The volunteers will be provided with a list of foods to consume that evening before each session day. We will ask the volunteer to consume the same meal before each session day. No restrictions will be made on water.
Visit 2: study session day This session will last approximately 4 h. The volunteers will return to the HNU the following morning in an overnight fasted state of approximately 10 h. A cannula will be inserted into a vein in the antecubital fossa at the front of an elbow of the left or right arm and kept patent with sterile saline (0.9% NaCl). Baseline fasted blood (10 mL) samples will be collected into K-EDTA tubes (6 mL serum). The plasma blood collection tubes will also contain DPP-4 inhibitors to preserve incretin hormone integrity. Following baseline sample collection, volunteers will consume the fruit bar and then the carbohydrate meal within 10 min. Periodic blood samples 10 mL will be collected into K-EDTA tubes at 15min, 30min, 45min, 1h, 1.5h, 2h, 2.5h, and 3h post fruit bar/carbohydrate meal consumption.
At the end of the 3 h, the cannula will be removed; volunteers will consume a standardised lunch the CGM sensor will be removed and volunteers will be free to leave the HNU.
- Conditions
- Glucose Intolerance, Glucose Metabolism Disorders
- Being tested
- Fruit bar with addition of polyphenols
- Medical subject headings
- Glucose Intolerance, Glucose Metabolism Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Fruit bar with addition of polyphenolsDietary supplement
Fruit bar with addition of 600mg bilberry anthocyanins and 1200mg apple polyphenols
| Study group | Role | What they receive |
|---|---|---|
| OGTT session | Active comparator | Oral Glucose Tolerance test (OGTT) Receives: Dietary Supplement: Fruit bar with addition of polyphenols |
| Fruit bar | Active comparator | Fruit bar Plus Oral Glucose Tolerance test (OGTT) Receives: Dietary Supplement: Fruit bar with addition of polyphenols |
| Fruit bar with bilberry | Experimental | Fruit bar with addition of 600 mg bilberry anthocyanins Plus Oral Glucose Tolerance test (OGTT) Receives: Dietary Supplement: Fruit bar with addition of polyphenols |
| Fruit bar with bilberry and apple | Experimental | Fruit bar with addition of 600mg bilberry anthocyanins and 1200mg apple polyphenols Plus Oral Glucose Tolerance test (OGTT) Receives: Dietary Supplement: Fruit bar with addition of polyphenols |
What is being measured
The primary outcome is the main question the study is designed to answer.
Glucose
Changes postprandial blood glucose
Measured: Over 3 hours post OGTT
Insulin
Changes postprandial blood glucose
Measured: Over 3 hours post OGTT
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Jul 2019
- Study start8 Jun 2019
- Primary completion1 Mar 2023 (estimated)
- Study completion1 Mar 2023 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Glucose IntoleranceStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- This acute intervention study will have a randomised controlled crossover design where the volunteers will return for 4 stand-alone study sessions
- Masking
- None (open label)
- Enrolment
- 24 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Aberdeen
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04004182
- Sponsor's protocol ID
- 2019/ROW_Berry/3
- Other IDs
- The Fruit Bar study
- Status last verified
- Aug 2022
- First submitted
- 27 Jun 2019
- Last updated
- 24 Aug 2022
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: Initially via publication in journal and then via this site
Study at a glance
From the registry record, last updated by the sponsor on 24 Aug 2022. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Acute Study of Anthocyanin-rich Bilberry and Polyphenol-rich Apple Extracts on Postprandial Glycaemic Response
- ClinicalTrials.gov ID
- NCT04004182
- Acronym / sponsor ID
- 2019/ROW_Berry/3
- Conditions
- Glucose Intolerance, Glucose Metabolism Disorders
- Study type
- Interventional
- Recruitment status
- Unknown status
- Enrolment
- 24 participants (estimated)
- Lead sponsor
- University of AberdeenUniversity, hospital or other
- Study start
- 8 Jun 2019 (actual)
- Primary completion
- 1 Mar 2023 (estimated)
- Study completion
- 1 Mar 2023 (estimated)
- First posted
- 1 Jul 2019 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Strategies to control chronic postprandial hyperglycaemia by optimizing the functionality of foods would strengthen efforts to reduce the risk of developing T2D in the general population. Polyphenolic constituents, may help to delay starch and disaccharide digestion and glucose absorption following a carbohydrate-containing meal or beverage. In vitro studies suggest that some berry anthocyanins and apple polyphenols are effective inhibitors of digestive enzymes, α-amylases and α-glucosidases. Furthermore, polyphenols found in berries and apples inhibit the action of intestinal glucose transporters. Human data is limited; however, randomized controlled trials (RCTs) have shown that berries and apple products reduced postprandial glucose concentrations following consumption of either starch, glucose or sucrose loads.
The aim of this study is to test the hypothesis that consumption of a fruit bar containing anthocyanin-rich bilberry and polyphenol-rich apple extracts together with a starch and sucrose meal would reduce the postprandial glycemic response.
This study is a randomized cross over study and will aim to recruit 24 overweight (BMI > 25.0), men or post-menopausal women, aged ≥40 and ≤ 70 years who will attend four study sessions. The first study session will be an oral glucose tolerance test (OGTT) and the remaining three will be identical in all respects except for the composition of the fruit bar. Consecutive blood samples will be collected in all 4 study sessions which will be used to measure glucose, insulin, C-peptide, incretins and lipids.
Detailed description
This acute intervention study will have a randomised controlled crossover design where the volunteers will return for 4 stand-alone study sessions. All study procedures will be carried out at the Human Nutrition Unit (HNU) of the Rowett Institute.
The first study session will be an oral glucose tolerance test (OGTT). The remaining three will be intervention sessions which will be identical in all respects except for the composition of the fruit bar. There will have a minimum of 1 week washout period. Volunteers will be asked to consume a low polyphenol diet three days prior to each intervention. To ensure compliance, participants will be provided with a list of 'allowed' and 'excluded' foods as well as food diaries to complete over the three day period. The Fruit bars will be made in the HNU kitchens by trained staff.
Table 1. Study sessions Intervention/Meal
Oral Glucose Tolerance test (OGTT) Fruit bar Plus OGTT Fruit bar with addition of 600 mg bilberry anthocyanins Plus OGTT Fruit bar with addition of 600mg bilberry anthocyanins and 1200mg apple polyphenols Plus OGTT
The glucose load for the OGTT in all sessions will be given as carbohydrate meal consisting of white bread, spread, low-polyphenol jam. (meal: 75g carbohydrate total)
Screening session Once the volunteer expresses interest in the study, they will be invited to attend a screening visit lasting approximately 1 h. Informed consent will be obtained from all participants, ensuring that they have fully understood all the study procedures before continuing. A full eligibility assessment (for assessing inclusion and exclusion criteria) will be carried out following consenting. This will include the completion of a health screening questionnaire, anthropometric measurements (height, weight, BMI,). HbA1c will be measured using finger prick blood samples. Volunteers fulfilling all the criteria and who wish to continue will be accepted into the study.
OGTT and Intervention sessions (study sessions 1-3)
At each session the volunteers will return for 2 visits.
Visit 1: Pre - Study Session Day This session will last approximately 1 hour. Volunteers will arrive at the HNU on the day preceding the study session day for the insertion of the continuous blood glucose monitoring (CGM) sensor (iPro 2, Medtronic Ltd, UK). Upon arrival, their weight will be measured for calculating BMI. Waist circumference and body fat composition using bio-impedance will be also be measured. The CGM records interstitial glucose levels at five minute intervals and provides a detailed picture of glucose fluxes. The CGM monitors are widely used by diabetics to monitor blood glucose fluxes and are designed for self-insertion. Their accuracy and level of data detail has also made them a powerful and widely used research tool. The sensor will be inserted into the subcutaneous fat layer (just below the skin surface) in the belly area by a trained researcher or HNU staff member. Insertion will be carried out using a tailor-made inserter provided with the CGM which causes minimum discomfort. Following stabilisation of the sensor a data acquisition unit will be attached to it. The sensor will be calibrated using a finger prick blood sample. Volunteers will be shown how to calibrate the CGM at home using a standard blood glucose meter and finger prick samples, and instructed on the times when they would have to do so. Wearing the sensor (which is about the size of a £2 coin) causes minimum discomfort to the wearer and does not hinder daily activities (including sleeping and having baths). The volunteers will be provided with a list of foods to consume that evening before each session day. We will ask the volunteer to consume the same meal before each session day. No restrictions will be made on water.
Visit 2: study session day This session will last approximately 4 h. The volunteers will return to the HNU the following morning in an overnight fasted state of approximately 10 h. A cannula will be inserted into a vein in the antecubital fossa at the front of an elbow of the left or right arm and kept patent with sterile saline (0.9% NaCl). Baseline fasted blood (10 mL) samples will be collected into K-EDTA tubes (6 mL serum). The plasma blood collection tubes will also contain DPP-4 inhibitors to preserve incretin hormone integrity. Following baseline sample collection, volunteers will consume the fruit bar and then the carbohydrate meal within 10 min. Periodic blood samples 10 mL will be collected into K-EDTA tubes at 15min, 30min, 45min, 1h, 1.5h, 2h, 2.5h, and 3h post fruit bar/carbohydrate meal consumption.
At the end of the 3 h, the cannula will be removed; volunteers will consume a standardised lunch the CGM sensor will be removed and volunteers will be free to leave the HNU.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 4
- Model description
- This acute intervention study will have a randomised controlled crossover design where the volunteers will return for 4 stand-alone study sessions
| Arm | Type | Receives |
|---|---|---|
| OGTT session | Active comparator | Dietary Supplement: Fruit bar with addition of polyphenolsOral Glucose Tolerance test (OGTT) |
| Fruit bar | Active comparator | Dietary Supplement: Fruit bar with addition of polyphenolsFruit bar Plus Oral Glucose Tolerance test (OGTT) |
| Fruit bar with bilberry | Experimental | Dietary Supplement: Fruit bar with addition of polyphenolsFruit bar with addition of 600 mg bilberry anthocyanins Plus Oral Glucose Tolerance test (OGTT) |
| Fruit bar with bilberry and apple | Experimental | Dietary Supplement: Fruit bar with addition of polyphenolsFruit bar with addition of 600mg bilberry anthocyanins and 1200mg apple polyphenols Plus Oral Glucose Tolerance test (OGTT) |
Who may qualify
- Ages
- 40 to 70 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Healthy men or post-menopausal women
- Aged ≥40 and ≤ 70 years old.
- BMI > 25.0kg/m2
- HbA1c <6.5%
Key exclusion criteria (15 listed)
- Thromboembolic or coagulation disease
- Unregulated thyroid disease
- Kidney disease
- Hepatic disease
- Severe gastrointestinal disorders
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Fruit bar with addition of polyphenolsFruit bar with addition of 600mg bilberry anthocyanins and 1200mg apple polyphenols | Dietary supplement | Fruit bar, Fruit bar with bilberry, Fruit bar with bilberry and apple, OGTT session |
Primary outcome
Glucose
Time frame: Over 3 hours post OGTT
Changes postprandial blood glucose
Insulin
Time frame: Over 3 hours post OGTT
Changes postprandial blood glucose
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Aug 2022.
- Individual participant dataSharing planned: Undecided. Initially via publication in journal and then via this site
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Fruit bar with addition of polyphenols in people with Glucose Intolerance and Glucose Metabolism Disorders, run by University of Aberdeen at 1 site in United Kingdom.
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 15 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: status not confirmed, as of the sponsor's last update on 24 Aug 2022. 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 United Kingdom. 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. 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?
Results are not available in the source record.
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?
Glucose (time frame: Over 3 hours post OGTT). 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?
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 24 Aug 2022.