Abstract
Isomaltulose (ISO) is a carbohydrate (CHO) with metabolic properties that makes it slowly digested and less likely to raise postprandial blood glucose response. We considered that isomaltulose ingestion was difficult to inhibit fat oxidation during incremental exercise. Here we investigated the effect of isomaltulose ingestion on fat oxidation during incremental exercise on a cycle ergometer in endurance athletes (n=10) who performed an incremental exercise after ISO or sucrose (SUC) ingestion. We measured the fat and CHO oxidation, blood glucose concentration, and blood lactate concentration of the subjects during the incremental exercise. Between the ISO and SUC groups, the fat oxidation was significantly different at 3 min (p<0.05) and CHO oxidation was significantly different at 3, 6, and 12 min (p<0.05). The ISO group's blood glucose concentrations were significantly lower than those of the SUC group at −5, 3, 6, 9, and 12 min (p<0.05). Similarly, the ISO group's blood lactate concentrations were significantly lower than those of the SUC group at −5, 0, 3, 6, 9, and 18 min (p<0.05). These results indicate that isomaltulose ingestion causes only slight fat oxidation inhibition and a slow increase in blood lactate levels compared with sucrose ingestion by a gradual rise in the blood glucose level.
Highlights
The fat and CHO substrates are used for adenosine triphosphate (ATP) synthesis through the tricarboxylic acid cycle and the electron transport chain in mitochondria in the cytosol
It is generally known that saving CHO oxidation and an enhancement of fat oxidation are necessary to maintain an animal or human's endurance exercise capacity, because the CHO energy storage is lower than fat energy storage
We examined the effect of ISO ingestion on fat oxidation in the 10 endurance athletes
Summary
The fat and CHO substrates are used for adenosine triphosphate (ATP) synthesis through the tricarboxylic acid cycle and the electron transport chain in mitochondria in the cytosol. CHO depletion frequently occurs in endurance exercise [1]. CHO depletion leads to a remarkable decrease in endurance exercise performance [2]. It is recognized that CHO ingestion during prolonged exercise promotes endurance exercise performance [4]. This effect of CHO ingestion on endurance exercise capacity has been attributed to a retard of the decrease in CHO accumulation during endurance exercise. CHO ingestion promotes CHO oxidation [5], but it inhibits fat oxidation during exercise [6]. It is suitable a kind of CHO ingestion that does not strongly promote CHO oxidation and slightly inhibits fat oxidation to increase endurance exercise capacity
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