An RS4-type
resistant starch is a chemically modified
starch that shows reduced availability in comparison to the corresponding unmodified
starch. Hydroxypropylated distarch
phosphate (HDP) is an RS4-type
resistant starch that increases energy expenditure and prevents high-fat diet-induced
obesity through increased hepatic
fatty acid oxidation. The aim of this study was to clarify the acute effects of HDP from tapioca
starch (HPdTSP) on physical performance in mice. Male C57BL/6J mice were used to examine the effects of a single administration of 2 mg/g
body weight HPdTSP or unmodified tapioca
starch (TS) on postprandial responses in serum metabolic parameters, running endurance capacity on a treadmill, whole-body energy metabolism during exercise, activity of
enzymes involved in
fatty acid oxidation, liver and gastrocnemius muscle
glycogen content, and serum
glucose,
insulin, non-
esterified fatty acid,
lactate, and
triglyceride levels after exercise. Running time to
fatigue was significantly greater in HPdTSP mice than in TS mice. Furthermore, HPdTSP maintained higher fat oxidation and this was associated with a greater activity of
enzymes in
fatty acid oxidation in the muscle during exercise. The blood
lactate and serum
insulin levels after exercise was significantly lower in HPdTSP mice than in TS mice.
Liver glycogen was significantly higher in HPdTSP mice than in TS mice. These results suggest that acute
oral administration of the RS4-type
resistant starch, HPdTSP, maintained higher fat oxidation and reduced
liver glycogen consumption during exercise and increased running endurance capacity in mice.