What did this study look at?
It is well-established that nutritional strategies allowing to increase exogenous carbohydrate oxidation without causing gastrointestinal distress, can be ergogenic in endurance exercise events lasting > 60 min. Thus, compared with the ingestion of glucose-based carbohydrates only, isocaloric glucose-fructose mixtures elevate the rate of oral carbohydrate oxidation, which often translates into improved performance because of improved O2-efficiency.
It has been claimed by some in a commercial context that the addition of pectin and sodium alginate to such glucose-fructose mix, by facilitating gastric emptying, stimulates carbohydrate oxidation and performance in endurance exercise. However, convincing scientific evidence to underpin such claim is lacking.
Therefore, Barber and his co-workers from the universities of Bath and Birmingham in the UK, investigated whether the addition of pectin and sodium alginate to a glucose-fructose mixture, indeed, could stimulate exogenous carbohydrate oxidation during a 2h moderate-intensity (60% VO2max) running bout. The subjects ingested sports drinks delivering 1.5g carbohydrates per kg bw per hour, either in the form of maltodextrin-glucose mixture (1.4:1.0 ratio), or in the form of a 1.4:1.0 maltodextrin-fructose mixture, or an identical maltodextrin-fructose mixture with pectin and sodium alginate added (Maurten, Gothenburg, Sweden).
What did the study show?
The study showed that the rate of oral carbohydrate oxidation during the 2h exercise bout on average was ~20% higher with the ingestion of maltodextrin + fructose than for the isocaloric maltodextrin + glucose intake. However, the addition of pectin and sodium alginate did not add to the stimulation of carbohydrate oxidation during exercise. Gastrointestinal symptoms as well as perception of fatigue also were similar between the conditions.
What is the importance of this finding for sports performance?
This study once more confirms that glucose-fructose mixtures can establish higher rates of exogenous carbohydrate oxidation during prolonged moderate intensity exercise than purely glucose-based sports drinks. Higher rate of carbohydrate oxidation is an important mechanism underlying the ergogenic effect of carbohydrate-containing sports drinks to stimulate performance in prolonged endurance exercise.
However, based on available research data it is reasonable to state that so-called special formulation ‘hydrogel sports drinks’ containing pectin and sodium alginate, do not yield a benefit over traditional glucose-fructose based sports drinks.