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Fructose Coingestion Does Not Accelerate Postexercise Muscle Glycogen Repletion
Jorn Trommelen1, Milou Beelen, Philippe J M Pinckaers
1NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastricht, THE NETHERLANDS.
Medicine and Science in Sports and Exercise
|November 26, 2015
Summary
Combining glucose and fructose does not speed up muscle glycogen replenishment in cyclists when sufficient carbohydrates are consumed. However, this combination may reduce gastrointestinal issues during high carbohydrate intake.
Area of Science:
- Exercise Physiology
- Nutritional Science
- Sports Medicine
Background:
- Muscle glycogen repletion post-exercise is primarily dependent on exogenous carbohydrate availability.
- Understanding optimal carbohydrate sources for recovery is crucial for athletes.
Purpose of the Study:
- To investigate the impact of combined glucose and fructose ingestion on muscle glycogen resynthesis.
- To compare the effects of glucose alone versus glucose with fructose or sucrose during post-exercise recovery.
Main Methods:
- Fourteen male cyclists completed three trials involving glycogen-depleting exercise.
- During a 5-hour recovery, participants ingested specific amounts of glucose (GLU), glucose + fructose (GLU + FRU), or glucose + sucrose (GLU + SUC).
- Muscle biopsies were collected to measure glycogen content, alongside blood sampling and gastrointestinal distress assessment.
Main Results:
- While plasma insulin and lactate were higher with combined sugars, muscle glycogen repletion rates did not differ significantly between treatments.
- Muscle glycogen increased significantly over 5 hours in all conditions (P < 0.001).
- No significant differences in muscle glycogen content were observed between GLU, GLU + FRU, and GLU + SUC treatments.
Conclusions:
- Combined ingestion of glucose and fructose does not enhance postexercise muscle glycogen repletion in trained cyclists when carbohydrate intake is sufficient.
- Ingesting glucose with fructose or sucrose may alleviate gastrointestinal discomfort associated with high carbohydrate consumption.
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