Clinical trial NCT03572296: Effect of Drinks Containing Fruit Polyphenol Extracts and Fibre on Postprandial Glycaemia. (Glu-MIX)
Official title: Effect of Drinks Containing Fruit Polyphenol Extracts and Fibre on Postprandial Glycaemia. The Glu-MIX Study
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Postprandial Period
Keywords: Blackcurrant
Polyphenols
Pulp
Fibre
Glucose
Postprandial
Metabolism
Cognition
Lead sponsor: Lucozade Ribena Suntory
Sponsor class: INDUSTRY
Collaborators: name: King's College London
First posted: 2018-06-28
Enrollment: 38
Sex: ALL
Minimum age (years): 18
Maximum age (years): 70
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: Cross-over design. Each participant receives placebo plus 2 treatments.
Primary purpose: PREVENTION

Brief summary: Postprandial glycaemia refers to the transient rise in blood glucose levels that occurs after consuming a meal. Large fluctuations in blood glucose levels, experienced on a frequent basis, may impair the functioning of pancreatic beta cells, and thus elevate the risk of developing type 2 diabetes mellitus (T2DM) and cardiovascular disease. Our group has previously shown that consuming a drink containing fruit polyphenols immediately before a meal, may reduce postprandial glycaemia. Importantly, other fruit components, namely soluble fibres, also impact on carbohydrate digestion by slowing gastric emptying rates. Combining fruit polyphenols and fibre in a drink may, potentially, have additive or synergistic effects on reducing postprandial glycaemia.

This study will investigate the effects of drinks containing blackcurrant polyphenol extract combined with pulp (source of fibre), and pulp alone, on postprandial outcomes and cognitive function following a mixed carbohydrate (starch and sucrose) test meal.

Detailed description: Intake of carbohydrate-rich foods transiently increases blood glucose levels (known as postprandial glycaemia). Repeated, high, postprandial glucose responses are evidenced to impair pancreatic beta cell function, thus increasing the risk of developing type-2 diabetes mellitus and cardiovascular disease. Therefore, meals that elicit a reduced, or more gradual, rise in blood glucose levels are desirable.

Previous studies have shown that consuming a drink containing fruit polyphenols, such as those from blackcurrants (BC), immediately before a high carbohydrate meal, reduced the postprandial glycaemic response. Importantly, other fruit components, namely soluble fibres, also impact on carbohydrate digestion by slowing gastric emptying rates. It is not yet known the effect of combining fibre and polyphenols on postprandial glycaemia. Although limited, there is a growing body of evidence showing beneficial acute effects of polyphenols in cognitive function which is of great interest in many work and academic environments where fast cognitive enhancement is wanted to perform a task or an exam.

This study will investigate the effects of drinks containing BC polyphenol extract combined with pulp (source of fibre), and pulp alone, on postprandial outcomes and cognitive function following a mixed carbohydrate (starch and sucrose) test meal.

Study design: A randomised, controlled, double-blind, cross-over study, of the healthy adult UK population, will be conducted. All subjects will receive the placebo drink, pulp only drink and the pulp with polyphenol drink in a random order. Baseline (fasted) blood samples will be taken before consuming the test drink (T0 min). Immediately following consumption of the drink, a mixed carbohydrate test meal will be consumed. Further blood samples will be collected at regular times until T150 min. Blood samples will be analysed for plasma glucose, insulin, glucose-dependent insulinotropic peptide (GIP) and C-peptide. Subjects will also perform a 30 min computer based cognitive performance test at baseline (T-45 min) and endpoint (T165 min). Visual analogue scales will be used to assess the effect of the test drinks on a range of sensory characteristics e.g. palatability, satiety and subjective mood feelings. Finally, an ad libitum pasta meal at the end of the study visit (T 215 min) will be used to assess the effects on energy intake.

Eligibility criteria: Inclusion Criteria:

* Age: 18-70 years
* Men and women
* 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 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 breastfeeding
* 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/ high fibre foods for 48 h before the study
* Weight change \>3 kg in preceding 2 months
* 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). 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.

Primary outcomes:
measure: Postprandial glycaemia (iAUC 0-30 min)
timeFrame: 30 min
Secondary outcomes:
measure: Postprandial glycaemia: iAUC 0-120 min
timeFrame: 120 min
measure: Postprandial glycaemia: iAUC 0-150 min
timeFrame: 150 min
measure: Postprandial glycaemia: iCmax
timeFrame: 150 min
measure: Postprandial glycaemia: Tmax
timeFrame: 150 min
measure: Postprandial glycaemia: absolute concentrations at specific time points
timeFrame: 150 min
measure: Postprandial insulinemia: iAUC 0-30 min
timeFrame: 30 min
measure: Postprandial insulinemia: iAUC 0-120 min
timeFrame: 120 min
measure: Postprandial insulinemia: iAUC 0-150 min
timeFrame: 150 min
measure: Postprandial insulinemia: iCmax
timeFrame: 150 min
measure: Postprandial insulinemia: Tmax
timeFrame: 150 min
measure: Postprandial insulinemia: absolute concentrations at specific time points
timeFrame: 150 min
measure: Postprandial C-peptide: iAUC 0-30 min
timeFrame: 30 min
measure: Postprandial C-peptide: iAUC 0-120 min
timeFrame: 120 min
measure: Postprandial C-peptide: iAUC 0-150 min
timeFrame: 150 min
measure: Postprandial C-peptide: iCmax
timeFrame: 150 min
measure: Postprandial C-peptide: Tmax
timeFrame: 150 min
measure: Postprandial C-peptide: Absolute concentrations at specific time points
timeFrame: 150 min
measure: Postprandial blood glucose-dependent insulinotropic peptide (GIP): iAUC 0-30 min
timeFrame: 30 min
measure: Postprandial blood glucose-dependent insulinotropic peptide (GIP): iAUC 0-120 min
timeFrame: 120 min
measure: Postprandial blood glucose-dependent insulinotropic peptide (GIP): iAUC 0-150 min
timeFrame: 150 min
measure: Postprandial blood glucose-dependent insulinotropic peptide (GIP): iCmax
timeFrame: 150 min
measure: Postprandial blood glucose-dependent insulinotropic peptide (GIP): Tmax
timeFrame: 150 min
measure: Postprandial blood glucose-dependent insulinotropic peptide (GIP): Absolute concentrations at specific time points
timeFrame: 150 min
measure: Cognitive function test scores
timeFrame: Before and after 150 min blood collection
Other outcomes:
measure: 7-d food diary (estimated/unweighed)
timeFrame: 7-days
measure: 100 mm visual analogue scale (VAS) measures of the palatability of the study drink
timeFrame: 10 min following the test drink
measure: 100 mm visual analogue scale (VAS) measures of mood, satiety and digestive comfort
timeFrame: 150 min
measure: Ad libitum energy intake
timeFrame: 15 min
measure: 100 mm visual analogue scale (VAS) measures of the palatability of the ad libitum meal
timeFrame: 15 min following the ad libitum meal
measure: Buccal mouth swab
timeFrame: One off sample, collected at the first 1 day of study visit
Locations:
city: London
country: United Kingdom
facility: Metabolic Research Unit
Study officials:
affiliation: King's College London
name: Wendy L Hall, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Castro-Acosta ML, Smith L, Miller RJ, McCarthy DI, Farrimond JA, Hall WL. Drinks containing anthocyanin-rich blackcurrant extract decrease postprandial blood glucose, insulin and incretin concentrations. J Nutr Biochem. 2016 Dec;38:154-161. doi: 10.1016/j.jnutbio.2016.09.002. Epub 2016 Sep 14.