title: Oligomerized lychee fruit extract (OLFE) and a mixture of vitamin C and vitamin E for endurance capacity in a double blind randomized controlled trial.
abstract: Antioxidant supplementations are commonly used as an ergogenic aid for physical exercise despite its limited evidence. The study aimed to investigate the effects of a polyphenol mixture and vitamins on exercise endurance capacity. Seventy regularly exercising male participants were randomly assigned to receive oligomerized lychee fruit extract, a mixture of vitamin C (800 mg) and E (320 IU), or a placebo for 30 consecutive days. The study results showed that oligomerized lychee fruit extract significantly elevated the submaximal running time (p = 0.01). The adjusted mean change was 3.87 min (95% CI: 1.29, 6.46) for oligomerized lychee fruit extract, 1.33 (-1.23, 3.89) for the vitamins, and 1.60 (-1.36, 4.56) for the placebo (p = 0.33 in between groups). Oligomerized lychee fruit extract significantly increased the anaerobic threshold by 7.4% (1.8, 13.0). On the other hand, vitamins significantly attenuated VO(2)max by -3.11 ml/kg/m (-5.35, -0.87). Their effects on plasma free radical amount, however, were similar. Our results suggest that a polyphenol-containing supplement and typical antioxidants may have different mechanisms of action and that the endurance-promoting effect of oligomerized lychee fruit extract may not directly come from the scavenging of free radicals but may be attributed to other non-antioxidant properties of polyphenols, which requires further investigation.
authors.affiliation: Institute of Complementary and Integrative Medicine, Medical Research Center, Seoul National University.
authors.forename: Seung Wan
authors.initials: SW
authors.lastname: Kang
authors.forename: Seokyung
authors.initials: S
authors.lastname: Hahn
authors.forename: Jung-Kyu
authors.initials: JK
authors.lastname: Kim
authors.forename: Seung-Min
authors.initials: SM
authors.lastname: Yang
authors.forename: Byung-Joo
authors.initials: BJ
authors.lastname: Park
authors.forename: Sang
authors.initials: S
authors.lastname: Chul Lee