Acute Study of Anthocyanin-rich Bilberry and Polyphenol-rich Apple Extracts on Postprandial Glycaemic Response
Trial Snapshot
- Phase
- Not Applicable
- Sponsor
- University of Aberdeen
- Enrollment
- 24
- Locations
- 1
- Primary Endpoint
- Glucose
Study Overview
Brief 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.
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)
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Treatment
- Masking
- None
Eligibility Criteria
- Ages
- 40 Years to 70 Years (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •Healthy men or post-menopausal women
- •Aged ≥40 and ≤ 70 years old.
- •BMI > 25.0kg/m2
- •HbA1c <6.5%
Exclusion Criteria
- •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
- •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)
Arms & Interventions
OGTT session
Oral Glucose Tolerance test (OGTT)
Intervention: Fruit bar with addition of polyphenols (Dietary Supplement)
Fruit bar
Fruit bar Plus Oral Glucose Tolerance test (OGTT)
Intervention: Fruit bar with addition of polyphenols (Dietary Supplement)
Fruit bar with bilberry
Fruit bar with addition of 600 mg bilberry anthocyanins Plus Oral Glucose Tolerance test (OGTT)
Intervention: Fruit bar with addition of polyphenols (Dietary Supplement)
Fruit bar with bilberry and apple
Fruit bar with addition of 600mg bilberry anthocyanins and 1200mg apple polyphenols Plus Oral Glucose Tolerance test (OGTT)
Intervention: Fruit bar with addition of polyphenols (Dietary Supplement)
Outcomes
Primary Outcomes
Glucose
Time Frame: Over 3 hours post OGTT
Changes postprandial blood glucose
Insulin
Time Frame: Over 3 hours post OGTT
Changes postprandial blood glucose
Secondary Outcomes
No secondary outcomes reported