Short-Term (-)-Hydroxycitrate Ingestion Increases Fat Oxidation during Exercise in Athletes.

Abstract

Summary(-)-Hydroxycitrate (HCA) is known to inhibit increasing malonyl CoA con centration during endurance exercise. Furthermore, a short-term administration of HCA enhances endurance exercise performance in mice. Therefore we investigated the short term administration of HCA on the exercise performance of athletes. Subjects were adminis tered 250mg of HCA or placebo as a control (CON) for 5 d, after each time performing cycle ergometer exercise at 60% VO2max for 60min followed by 80% VO2max until exhaustion. Blood was collected and expired gas samples analyzed at rest and every 15min. The respira tory exchange ratio was significantly lower in the HCA trial than in the CON trial (p<0.05). Fat oxidation was significantly increased by short-term administration of HCA, and carbo hydrate oxidation was significantly decreased (p<0.05) during exercise, presumably result ing in increasing the cycle ergometer exercise time to exhaustion after 1h of 60% VO2max exercise (p<0.05). These results suggest that a short-term administration of HCA enhances endurance performance with increasing fat oxidation, which spares glycogen utilization during moderate intensity exercise in athletes.

(-)-Hydroxycitric Acid Ingestion Increases Fat Utilization During Exercise in Untrained Women

“…Acute ingestion of HCA did not affect energy sub strate utilization, especially in fat oxidation (7,21). However, the short-term administration of HCA lowers RER and increases fat oxidation in trained subjects (13). In untrained subjects, HCA ingestion significantly decreased RER after 30min of exercise as shown in the present study (Fig.…”

“…These two intensities showed the effects of glycogen sparing during prolonged endurance exercise performance. The fat oxidation rate during the latter stage of exercise increased in trained subjects (13) and increased slightly in untrained sub jects in the present study (data not shown).…”

“…However, Van Loon et al, (20) reported that the lactate concentration was decreased by acute ingestion of HCA during exercise, although not signifi cantly, as in the present study. These findings suggest that short-term ingestion of HCA might delay the lac tate threshold since HCA has an inhibiting effect on carbohydrate oxidation (11,13). Plasma FFA concen trations were not significantly affected by HCA inges tion.…”

“…2P). However, the effects were lower than those of trained subjects (12,13), because train ing might enhance the fat oxidation rate. Our experi ment was designed to test two different exercise intensi ties, 40% and 60% VO2max.…”

“…A previous study regarding controlled HCA ingestion was performed with only trained subjects (13). There fore, in the present study we investigated how HCA affects energy substrate utilization and endurance exer cise performance in untrained women.…”