The effect of curcumin supplementation on functional strength outcomes and markers of exercise-induced muscle damage: A systematic review and meta-analysis.

Background: Curcumin is a polyphenol derived from the Curcuma longa L (turmeric) plant and has gained attention through its perceived anti-inflammatory characteristics. The potential interaction with exercise-induced muscle damage (EIMD) and delayed onset muscle soreness (DOMS) has led to investigation of curcumin as a post-exercise strategy that may have the potential to lessen acute reductions in functional strength (FS) following physical activity. Aim: The purpose of this review is to assess the evidence examining curcumin in relation to four outcome measures: FS, EIMD, DOMS and inflammation. Methods: A Medline, SPORTDiscus and CINAHL database search was undertaken with no publication date limit. Sixteen papers met the inclusion criteria and were included in this review. Three meta-analyses were completed for EIMD, DOMS and inflammation, respectively, with FS being excluded due to limited research. Results: Effect sizes were as follows: EIMD (0.15, -0.12, -0.04, -0.2 and -0.61 corresponding to 0, 24, 48, 72 and 96 h post-exercise, respectively), DOMS (-0.64, -0.33, 0.06, -0.53 and -1.16 corresponding to 0, 24, 48, 72 and 96 h post-exercise, respectively) and inflammation (-0.10, 0.26, 0.15 and 0.26 corresponding to 0, 24, 48 and 72 h post-exercise, respectively). A 96 h post-exercise inflammation meta-analysis was not conducted due to limited data. Conclusion: No effect sizes were statistically significant for EIMD (p = 0.644, 0.739, 0.893, 0.601 and 0.134), DOMS (p = 0.054, 0.092, 0.908, 0.119 and 0.074) and inflammation (p = 0.729, 0.603, 0.611 and 0.396). Further research is needed to thoroughly examine whether an effect exists.