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Metabolic availability of medium-chain triglycerides coingested with carbohydrates during prolonged exercise
A E Jeukendrup1, W H Saris, P Schrauwen
1Department of Human Biology, University of Limburg, Maastricht, The Netherlands.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|September 1, 1995
Summary
Combining medium-chain triglycerides (MCTs) with carbohydrates (CHOs) enhances MCT oxidation during prolonged exercise in athletes. Ingesting MCTs with CHOs increases their availability as an additional energy source compared to MCTs alone.
Area of Science:
- Sports Nutrition
- Exercise Physiology
- Metabolic Science
Background:
- Medium-chain triglycerides (MCTs) are proposed as an alternative energy source during endurance exercise.
- The interaction between MCT and carbohydrate (CHO) metabolism during prolonged exercise requires further investigation.
- Understanding substrate utilization is crucial for optimizing athletic performance and nutritional strategies.
Purpose of the Study:
- To investigate the metabolic response to ingesting medium-chain triglycerides (MCTs) with or without carbohydrates (CHOs) during prolonged cycling exercise.
- To determine the oxidation rates and metabolic availability of MCTs when consumed alone versus in combination with varying CHO concentrations.
- To assess the potential of MCTs as an additional energy substrate alongside glucose during strenuous physical activity.
Main Methods:
- Eight well-trained athletes completed four 180-minute cycling trials at 50% maximal work rate.
- Ingested solutions included CHO alone, CHO with MCTs, high CHO with MCTs, or MCTs alone.
- Exogenous MCT oxidation was quantified using a [1,1,1-13C]trioctanoate tracer and breath 13CO2 enrichment analysis.
Main Results:
- MCT oxidation was significantly higher when ingested with CHOs (72% of ingested amount) compared to MCTs alone (33%) during the second hour of exercise.
- The rate of MCT oxidation increased more rapidly in trials combining MCTs with CHOs.
- Metabolic availability of MCTs remained high during the latter stages of exercise, with oxidation rates reaching approximately 70% of the ingestion rate when co-ingested with CHOs.
Conclusions:
- Ingesting medium-chain triglycerides (MCTs) in combination with carbohydrates (CHOs) significantly enhances MCT oxidation during prolonged exercise.
- Oral MCTs can serve as an effective supplementary energy source to glucose during endurance activities.
- Combining MCTs and CHOs represents a promising nutritional strategy for athletes seeking to augment fuel availability during prolonged exercise.