Clinical Trial Details
— Status: Active, not recruiting
Administrative data
| NCT number |
NCT04004182 |
| Other study ID # |
2019/ROW_Berry/3 |
| Secondary ID |
The Fruit Bar st |
| Status |
Active, not recruiting |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
June 8, 2019 |
| Est. completion date |
March 1, 2023 |
Study information
| Verified date |
August 2022 |
| Source |
University of Aberdeen |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical 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. 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.
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.
