Effect of Drinks Containing Fruit Polyphenol Extracts and Fibre on Postprandial Glycaemia. (Glu-MIX)
Condition: Postprandial Period
Study type: Interventional

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.
    

Intervention name(s): Placebo; Polyphenol and fibre; Fibre
Intervention type(s): Dietary Supplement; Dietary Supplement; Dietary Supplement
Intervention description(s): Drinks will be delivered in random order at 3 separate study visits immediately before a high carbohydrate meal. A minimum of 4 days (ideally 7 days) wash-out period will be required between study days.; Drinks will be delivered in random order at 3 separate study visits immediately before a high carbohydrate meal. A minimum of 4 days (ideally 7 days) wash-out period will be required between study days.; Drinks will be delivered in random order at 3 separate study visits immediately before a high carbohydrate meal. A minimum of 4 days (ideally 7 days) wash-out period will be required between study days.
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Cross-over design. Each participant receives placebo plus 2 treatments.
Masking: Double (Participant, Investigator)
Primary purpose: Prevention
Keywords: Blackcurrant; Polyphenols; Pulp; Fibre; Glucose; Postprandial; Metabolism; Cognition