The effect of Cornus mas L. supplementation on the post-exercise inflammation and iron metabolism markers in athletes

Intensive physical training increases oxidative stress and inflammation, resulting in muscle and cellular damage. Moreover, iron deficiency is frequently observed in athletes. The aim of this study was to analyse the effect of dietary supplementation with Cornus mas L. extract on the levels of pro-inflammatory cytokines, hepcidin, and selected markers of iron metabolism in athletes serum. In this randomised control trial, the subjects were divided into two groups: supplement (SUPL) and placebo (PLA) ones. The levels of inflammatory markers (IL-6, TNF- α, IL-6R) and iron metabolism markers (hepcidin, ferritin) were analysed. The SUPL group received C. mas extract, and the PLA group received a placebo for 90 days. Venous blood samples were collected at two time points—before and after the training. After 90 days of supplementation, the intervention group demonstrated no differences compared to the PLA group. There were no differences between the groups before and after the supplementation in circulating hepcidin and ferritin or TNF-α, IL-6 and IL-6R levels, yet athletes showed a significant increase in the level of white blood cells (WBCs) after training. This is the first study to present the regulation of inflammation markers in response to physical activity in athletes supplemented with Cornus mas L. extract, but the verification of this hypothesis still requires further research on the mechanisms through which various components of the Cornus mas L. extract can affect iron metabolic parameters.