Supplementation with a flavanol-rich lychee fruit extract influences the inflammatory status of young athletes

Flavanol-rich lychee fruit extract (FRLFE) is a processed lychee fruit extract that is higher in flavanols (monomers, dimers and trimers) than its unprocessed counterpart. FRLFE exerts antioxidant activities in vitro and is expected to protect against inflammation and tissue damage. However, the physiological effects of FRLFE intake have not been explored in vivo. The aim of this study was to examine the effects of FRLFE supplementation on inflammation and tissue damage in young athletes during intense physical training. Twenty healthy male long-distance runners at a university were randomly assigned to receive FRLFE or placebo in a double-blind manner. Blood and serum parameters associated with inflammation, tissue damage and oxidative stress were evaluated before (pre-training), during (mid-training) and after (post-training) a 2-month training period. Some parameters, including the white blood cell count, were significantly modified by FRLFE supplementation. Compared with the placebo group, the change in the serum interleukin-6 level between pre- and mid-training were significantly lower in the FRLFE group, while the change in the transforming growth factor-β level between pre- and post-training was significantly greater in the FRLFE group. These findings suggest that FRLFE supplementation may suppress inflammation or tissue damage caused by high-intensity exercise training.