Effects of an Apple Extract on Glycaemia: The GLU-Pomme Study (GLU-Pomme)

Dose-response Effect of an Apple Extract on Postprandial Glycaemia: a Randomised Controlled Trial. The GLU-POMME Study.

Postprandial hyperglycaemia can lead to adverse modifications to functional proteins within the body and eventually lead to the development of type 2 diabetes. Previous research by this group has shown that an apple polyphenol extract reduced hyperglycaemia following a high-carbohydrate meal. The aim of this study is to investigate the effects of lower doses of the apple extract on postprandial glycaemia, insulinaemia and plasma gastric inhibitory polypeptide concentrations following a mixed carbohydrate test meal.

Study Overview

• Status: Completed
• Conditions: Prevention of Hyperglycaemia
• Intervention / Treatment: Dietary supplement: Placebo; Dietary supplement: Apple polyphenols

Detailed Description

Introduction:

Sharp peaks in blood glucose levels can lead to adverse modifications to functional proteins, oxidative stress and pancreatic beta cell dysfunction. It is therefore desirable to consume a diet that will allow more gradual rises in blood glucose levels after meals. Fruit polyphenols may help to limit the glucose excursion following a high carbohydrate meal. Previous research by this research group has demonstrated that 1200 mg of apple polyphenols (Appl'In™) inhibited the average incremental area under the curve (T+0 to T+30 min) of plasma glucose by 54% relative to placebo. Possible mechanisms include inhibition of intestinal enzymes and inhibition of intestinal glucose absorption by decreasing SGLT1/GLUT2 transport activity. The literature also suggests that foods rich in polyphenols exert beneficial effects on risk factors of cardiovascular disease such as hypertension, lipid metabolism and vascular function.

Study design:

A randomised, controlled, double-blind, cross-over study will be conducted. Four matched test drinks will be consumed in random order on separate study visits immediately before a mixed-carbohydrate test meal, containing either: 1) 1.2 g, 2) 0.9 g 3). 0.6 g of apple polyphenols, or 4). placebo. Postprandial changes in plasma glucose, insulin, NEFA, GIP, GLP-1 concentrations as well as changes in vascular function will be measured. Twenty-four hour urine samples will be collected for analysis of urinary polyphenol metabolites and glucose. In a sub sample of participants, a paracetamol absorption test will be incorporated via addition of 1.5 g paracetamol into the test drink.

• Study Type: Interventional
• Enrollment (Actual): 34
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • London
    • Waterloo Campus, London, United Kingdom, SE1 9NH
      • Metabolic Research Unit at King's College London

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Age: 18-70 y
• Male and female
• Healthy (free of diagnosed diseases listed in the exclusion criteria)
• Body Mass Index 18-35 kg/m2
• Able to understand the information sheet and willing to comply with study protocol
• Able to give informed written consent

Exclusion Criteria:

• Those diagnosed with Phenylketonuria (PKU)
• Those with known or suspected food and/or paracetamol intolerances, allergies or hypersensitivity
• Women who are known to be pregnant or who are intending to become pregnant over the course of the study
• Women who are breast feeding
• Participation in another clinical trial
• Those who have donated blood within 3 months of the screening visit and participants for whom participation in this study would result in having donated more than 1500 millilitres of blood in the previous 12 months.
• Full Blood Counts and Liver Function test results outside of the normal range.
• Current smokers, or reported giving up smoking within the last 6 months
• History of substance abuse or alcoholism
• Reported history of Cardiovascular disease, diabetes (or fasting glucose ≥ 7.1 mmol/L), cancer, kidney, liver or bowel disease, gastrointestinal disorder or use of drug likely to alter gastrointestinal function
• Unwilling to restrict consumption of specified high polyphenol foods for 48 h before the study
• Weight change >3kg in preceding 2 months and body mass index <18 or >35 kg/m2
• Blood pressure ≥160/100 mmHg
• Total cholesterol ≥ 7.5 mmol/L; fasting triacylglycerol concentrations ≥ 5.0 mmol/L
• Medications that may interfere with the study: alpha-glucosidase inhibitors (acarbose: Glucobay), insulin sensitizing drugs (metformin: Glucophage, Glucophage SR, Eucreas, Janumet; thiazolidinediones: Actos, Competact), sulfonylureas (Daonil, Diamicron, Diamicron MR, Glibenese, Minodiab, Amaryl Tolbutamide), and lipid lowering drugs (statins, nicotinic acid, colestyramine anhydrous, ezetimibe, fibrates); and medications that may react unpredictably with paracetamol: ketoconazole, metoclopramide, carbamazepine, phenobarbital, phenytoin, primidone, warfarin and other products containing paracetamol. Other medications should be reviewed by medical representative from KCL on a case by case basis.
• Nutritional supplements that may interfere with the study: higher dose vitamins/minerals (>200% Recommend Nutrient Intake), B vitamins, Vitamin C, calcium, copper, chromium, iodine, iron, magnesium, manganese, phosphorus, potassium and zinc. Subjects already taking vitamin or minerals at a dose around 100% or less up to 200% of the RNI, or evening primrose/algal/fish oil supplements will be asked to maintain habitual intake patterns, ensuring that they take them every day and not sporadically. They will be advised not to stop taking supplements or start taking new supplements during the course of the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 1.2 g apple polyphenols; 1200 mg apple polyphenols delivered in a low sugar drink.	Dietary supplement: Apple polyphenols; Drinks will be delivered in random order at 4 separate study visits immediately before a high-carbohydrate meal. Seven days wash-out period will be required between study days.
Experimental: 0.9 g apple polyphenols; 900 mg apple polyphenols delivered in a low sugar drink.	Dietary supplement: Apple polyphenols; Drinks will be delivered in random order at 4 separate study visits immediately before a high-carbohydrate meal. Seven days wash-out period will be required between study days.
Experimental: 0.6 g apple polyphenols; 600 mg apple polyphenols delivered in a low sugar drink.	Dietary supplement: Apple polyphenols; Drinks will be delivered in random order at 4 separate study visits immediately before a high-carbohydrate meal. Seven days wash-out period will be required between study days.
Placebo Comparator: Placebo; No polyphenols delivered in a low sugar drink.	Dietary supplement: Placebo

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postprandial Glycaemia	Primary outcome: Area over baseline t+0-30 min for plasma glucose	30 min following the test drink

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postprandial Insulinaemia	Peak postprandial insulin concentrations (Cmax) t +0-30 min and change from baseline data and areas over baseline t+0-30 min and t+0-240 min.	baseline and 10, 20, 30, 45, 60, 75, 90, 120, 150, 180, 240 min following the test drink
Postprandial Glucose-dependent Insulinotropic Polypeptide (GIP) Concentrations	Peak postprandial GIP concentrations (Cmax) t +0-30 min and change from baseline data and areas over baseline t+0-30 min and t+0-240 min.	baseline and 10, 20, 30, 45, 60, 75, 90, 120, 150, 180, 240 min following the test drink
Postprandial Glucagon-like Peptide-1 (GLP-1) Concentrations	Peak postprandial GLP-1 concentrations (Cmax) t +0-30 min and change from baseline data and areas over baseline t+0-30 min and t+0-240 min.	baseline and 10, 20, 30, 45, 60, 75, 90, 120, 150, 180, 240 min following the test drink
Postprandial C-peptide Concentrations	Peak postprandial C-peptide concentrations (Cmax) t +0-30 min and change from baseline data and areas over baseline t+0-30 min and t+0-240 min.	baseline and 10, 20, 30, 45, 60, 75, 90, 120, 150, 180, 240 min following the test drink
Postprandial Non-esterified Fatty Acid (NEFA) Concentrations	Peak postprandial NEFA concentrations (Cmax) t +0-30 min and change from baseline data and areas over baseline t+0-30 min and t+0-240 min	baseline and 10, 20, 30, 45, 60, 75, 90, 120, 150, 180, 240 min following the test drink
Postprandial Triglyceride (TAG) Concentrations	Peak postprandial TAG concentrations (Cmax) t +0-30 min and change from baseline data and areas over baseline t+0-30 min and t+0-240 min.	baseline and 10, 20, 30, 45, 60, 75, 90, 120, 150, 180, 240 min following the test drink
Postprandial Paracetamol Concentrations	Peak postprandial paracetamol concentrations (Cmax) t +0-30 min and change from baseline data and areas over baseline t+0-30 min and t+0-240 min (1.5 g paracetamol will be added to all test drinks in a sub-group of participants).	baseline and 10, 20, 30, 45, 60, 75, 90, 120, 150, 180, 240 min following the test drink
Postprandial Polyphenol Metabolite Concentrations	Peak postprandial polyphenol metabolites concentrations (Cmax) t +0-30 min and change from baseline data and areas over baseline t+0-30 min and t+0-240 min.	baseline and 10, 20, 30, 45, 60, 75, 90, 120, 150, 180, 240 min following the test drink
Vascular Endothelial Function by Flow-mediated Dilation (FMD)	Change in FMD after the consumption of test drink.	baseline and 120, 240, 300 min following the test drink
Vascular Function (Arteriograph Measurement)	Change in augmentation index following the test drink.	Baseline and 60, 90, 120, 180, 240 min following the test drink
Blood Pressure	Change in blood pressure following the test drink.	Baseline and 60, 90, 120, 180, 240 min following the test drink
Urinary Polyphenol Metabolites	Change in urinary polyphenol metabolite concentration following the test drink.	0-4 h, 4-8 h, 8-24 h following the test drink
Urinary Glucose	Change in urinary glucose concentration following the test drink.	0-4 h, 4-8 h, 8-24 h following the test drink

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
7-day Food Diary	Habitual dietary intake analysis	Baseline
Women's Health Questionnaire	Questionnaire to identify menstrual phase	Baseline

Collaborators and Investigators

• Sponsor: King's College London
• Collaborators: DIANA Food

Publications and helpful links

Helpful Links

• Castro-Acosta et al. (2016). Drinks containing anthocyanin-rich blackcurrant extract decrease postprandial blood glucose, insulin and incretin concentrations. The Journal of Nutritional Biochemistry 38: 154-161.

Study record dates

Study Major Dates

• Study Start: January 1, 2017
• Primary Completion (Actual): November 1, 2017
• Study Completion (Actual): February 1, 2018

Study Registration Dates

• First Submitted: October 19, 2016
• First Submitted That Met QC Criteria: October 19, 2016
• First Posted (Estimate): October 20, 2016

Study Record Updates

• Last Update Posted (Actual): June 17, 2020
• Last Update Submitted That Met QC Criteria: June 2, 2020
• Last Verified: March 1, 2018

More Information

Terms related to this study

• Keywords: Hyperglycaemia; Polyphenol; Fruit; Metabolic; Apple
• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Hyperglycemia
• Other Study ID Numbers: GLU-Pomme

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No