Open Access Research article

Cashew apple juice supplementation enhanced fat utilization during high-intensity exercise in trained and untrained men

Piyapong Prasertsri13, Thapanee Roengrit13, Yupaporn Kanpetta23, Terdthai Tong-un13, Supaporn Muchimapura13, Jintanaporn Wattanathorn13 and Naruemon Leelayuwat13*

Author Affiliations

1 Department of physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand

2 Graduate School, Khon Kaen University, Khon Kaen, 40002, Thailand

3 Exercise and Sport Sciences Development and Research Group, Khon Kaen University, Khon Kaen, 40002, Thailand

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Journal of the International Society of Sports Nutrition 2013, 10:13  doi:10.1186/1550-2783-10-13

Published: 7 March 2013

Abstract

Background

Exercise training is known to increase fat utilization during exercise. Diets containing antioxidants and branch chain amino acids (BCAAs) are also reported to have potential effects on fat utilization. Cashew apple juice (CAJ) comprises many nutritional components including vitamin C and BCAAs. This study aimed to investigate the effect of CAJ supplementation on substrate utilization during high-intensity exercise in trained and untrained subjects.

Methods

Ten trained and ten untrained men were randomly supplemented with either placebo (PLA) or CAJ at 3.5 ml/kg body mass (BM) /day for 4 weeks with a 4-week washout between treatments in a randomized cross-over design. Before and after the 4-week supplementations all subjects performed cycling exercise at 85% of maximal oxygen consumption for 20 minutes. At rest, before, and immediately after the exercise, venous blood samples were taken to determine glucose, insulin and lipid concentrations. Expired air was collected during the 20 minutes of exercise to calculate substrate utilization.

Results

During the exercise in both trained and untrained groups, there were lower carbohydrate (CHO) and higher fat oxidation rates and contributions to total energy expenditure after the CAJ supplementation compared to the PLA supplementation (p<0.05). These values were greater in the trained group than the untrained group except CHO oxidation rates (p<0.05), which were not significantly different. Moreover, in both trained and untrained groups, resting plasma vitamin C concentrations were significantly higher after the CAJ supplementation compared to the PLA supplementation, without any change after the PLA supplementation. These values were greater in the trained group than the untrained group (p<0.05). There were no significant differences in glucose, insulin or lipid concentrations between the groups’ blood samples.

Conclusion

The findings of this study suggest that CAJ supplementation enhanced fat oxidation during exercise may enhance endurance performance, but specific studies are needed to assess this possibility.

Keywords:
Vitamin C; Leucine; Endurance; Fat oxidation rate; Athletes