The Impact of Sucrose Ingestion Post-Exercise on Liver and Muscle Glycogen Repletion.

Carbohydrate is stored in the body as glycogen, which is mainly found in the liver and muscle. During endurance exercise, muscle glycogen is used as fuel for the working muscles and liver glycogen is broken down to provide glucose to maintain blood glucose (sugar) levels. Both liver and muscle glycogen are important for our ability to perform intense/prolonged endurance exercise. Therefore, it is important to replete these stores after an intense/prolonged endurance exercise session in order to recover and perform optimally during a subsequent exercise bout, especially if the next exercise session is within 24h (e.g. stage races such as the Tour de France, tournament-style competitions such as the Olympic games and ultra-endurance events).

Carbohydrate intake has been shown to increase the availability of glycogen in the muscle and liver after exercise. The carbohydrates typically found in sports drinks are glucose and sometimes fructose. It has been observed that the ingestion of glucose will lead to a maximum rate of absorption of approximately ~1 g/min. However, if we also provide a different source of carbohydrate (fructose) then this is absorbed through a different pathway and therefore we can absorb up to ~1.75 g/min of carbohydrate. In addition, both carbohydrate sources are metabolised differently in the human body. By supplementing both glucose and fructose, we can potentially replenish the liver and muscle glycogen stores at a faster rate than ingestion of glucose only.

Sucrose is a naturally occurring sugar that is made up of a single glucose and single fructose molecule. Therefore, theoretically, this can use the two different pathways of absorption and also maximise carbohydrate delivery. It is not yet known however, what impact this has on our liver and muscle glycogen stores post-exercise when supplemented in relatively high amounts. Therefore the aim of this study is to assess whether relative high amounts of sucrose ingestion will improve liver and muscle glycogen repletion after endurance exercise.

Study Overview

• Status: Completed
• Conditions: Liver and Muscle Glycogen Replenishment Post-exercise
• Intervention / Treatment: Dietary supplement: Glucose; Dietary supplement: Sucrose

• Study Type: Interventional
• Enrollment (Actual): 15
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • North East
    • Newcastle upon Tyne, North East, United Kingdom, NE1 8ST
      • Northumbria University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 35 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Male

Description

Inclusion Criteria:

• Healthy
• Endurance trained cyclists/triathletes
• VO2 max ≥ 50 ml/kg/min

Exclusion Criteria:

• Use of medication
• Smoking
• Metabolic disorders

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Sucrose; Sucrose ingestion post-exercise	Dietary supplement: Glucose
Active Comparator: Glucose; Glucose ingestion post-exercise	Dietary supplement: Sucrose

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
change in liver glycogen concentration	The change in liver glycogen content will be determined post-exercise using 13C magnetic resonance spectroscopy	5 h

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in muscle glycogen concentration	The change in muscle glycogen content will be determined post-exercise using 13C magnetic resonance spectroscopy	5 h
Plasma glucose concentration		5 h
Plasma insulin concentration		5 h
Plasma lactate concentration		5 h

Collaborators and Investigators

• Sponsor: Northumbria University
• Collaborators: Newcastle University; Maastricht University; Sugar Nutrition

Study record dates

Study Major Dates

• Study Start: January 1, 2015
• Primary Completion (Actual): May 1, 2015
• Study Completion (Actual): May 1, 2015

Study Registration Dates

• First Submitted: January 16, 2015
• First Submitted That Met QC Criteria: January 16, 2015
• First Posted (Estimate): January 26, 2015

Study Record Updates

• Last Update Posted (Estimate): October 23, 2015
• Last Update Submitted That Met QC Criteria: October 22, 2015
• Last Verified: October 1, 2015

More Information

Terms related to this study

• Other Study ID Numbers: NorthumbriaU