The Impact of Sucrose Ingestion During Exercise on Liver and Muscle Glycogen Concentration.

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 the ability to perform intense/prolonged endurance exercise. Therefore, nutritional strategies which can maximise the availability of glycogen in muscle and liver can benefit endurance exercise capacity.

The carbohydrates typically found in sports drinks are glucose and sometimes fructose. If glucose only is ingested during exercise, then the maximum rate at which can be absorbed from the intestine into the blood stream is ~1 g/min. However, if different sources of carbohydrate (fructose) are used, which are absorbed through a different pathway, absorption of carbohydrate can be up to ~1.8 g/min. With more carbohydrate available as a fuel, this translates into an improvement in performance.

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 during exercise. Therefore the aim of this study is to assess whether sucrose ingestion influences liver and muscle glycogen depletion during endurance exercise.

Study Overview

• Status: Completed
• Conditions: Liver and Muscle Glycogen Use During Exercise.
• Intervention / Treatment: Dietary supplement: Glucose ingestion; Dietary supplement: Sucrose ingestion

• Study Type: Interventional
• Enrollment (Actual): 14
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Tyne and Wear
    • Newcastle upon Tyne, Tyne and Wear, United Kingdom, NE1 8ST
      • Northumbria University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 35 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Male

Description

Inclusion Criteria:

• Healthy
• Male
• 18 - 35 years of age
• Endurance trained cyclist/triathlete
• 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: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Glucose ingestion; Glucose ingestion during exercise at a rate of 1.8 g/min.	Dietary supplement: Glucose ingestion; Glucose ingestion during exercise at 1.8 g/min
Experimental: Sucrose ingestion; Sucrose ingestion during exercise at a rate of 1.8 g/min.	Dietary supplement: Sucrose ingestion; Sucrose ingestion during exercise at 1.8 g/min

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in liver glycogen concentration	The change in liver glycogen concentration will be determined pre-to-post 3 h of exercise using 13C magnetic resonance spectroscopy.	3 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Plasma glucose concentration.	Plasma glucose concentrations will be determined every 30 min during 3 h of exercise.	3 hours
Plasma lactate concentration	Plasma lactate concentrations will be determined every 30 min during 3 h of exercise.	3 hours
Plasma non-esterified fatty acid concentration	Plasma non-esterified fatty acid concentrations will be determined every 30 min during 3 h of exercise.	3 hours
Indirect calorimetry	Measurements of oxygen consumption, carbon dioxide production and respiratory exchange ratio through indirect calorimetry measured every 30 minutes during exercise.	3 hours
Muscle glycogen concentration	The change in muscle glycogen concentration will be determined pre-to-post 3 h of exercise using 13C magnetic resonance spectroscopy.	3 hours
Change in intramyocellular lipid concentration	The change in intramyocellular lipid concentration will be determined pre-to-post 3 h of exercise using 1H magnetic resonance spectroscopy.	3 hours

Collaborators and Investigators

• Sponsor: Javier Gonzalez, PhD
• Collaborators: Maastricht University; University of Newcastle Upon-Tyne; Sugar Nutrition, UK

Publications and helpful links

General Publications

• Gonzalez JT, Fuchs CJ, Smith FE, Thelwall PE, Taylor R, Stevenson EJ, Trenell MI, Cermak NM, van Loon LJ. Ingestion of glucose or sucrose prevents liver but not muscle glycogen depletion during prolonged endurance-type exercise in trained cyclists. Am J Physiol Endocrinol Metab. 2015 Dec 15;309(12):E1032-9. doi: 10.1152/ajpendo.00376.2015. Epub 2015 Oct 20.

Study record dates

Study Major Dates

• Study Start: April 1, 2014
• Primary Completion (Actual): September 1, 2014
• Study Completion (Actual): April 1, 2015

Study Registration Dates

• First Submitted: April 3, 2014
• First Submitted That Met QC Criteria: April 8, 2014
• First Posted (Estimate): April 10, 2014

Study Record Updates

• Last Update Posted (Estimate): August 7, 2015
• Last Update Submitted That Met QC Criteria: August 4, 2015
• Last Verified: August 1, 2015

More Information

Terms related to this study

• Other Study ID Numbers: NUSUCA