Introduction: Oral curcumin decreases inflammatory cytokines and increases muscle regeneration in mice.
Purpose: To determine effects of curcumin on muscle damage, inflammation and delayed onset muscle soreness (DOMS) in humans.
Method: Seventeen men completed a double-blind randomized-controlled crossover trial to estimate the effects of oral curcumin supplementation (2.5 g twice daily) versus placebo on single-leg jump performance and DOMS following unaccustomed heavy eccentric exercise. Curcumin or placebo was taken 2 d before to 3 d after eccentric single-leg press exercise, separated by 14-d washout. Measurements were made at baseline, and 0, 24 and 48-h post-exercise comprising: (a) limb pain (1-10 cm visual analogue scale; VAS), (b) muscle swelling, (c) single-leg jump height, and (d) serum markers of muscle damage and inflammation. Standardized magnitude-based inference was used to define outcomes.
Results: At 24 and 48-h post-exercise, curcumin caused moderate-large reductions in pain during single-leg squat (VAS scale -1.4 to -1.7; 90 %CL: ±1.0), gluteal stretch (-1.0 to -1.9; ±0.9), squat jump (-1.5 to -1.1; ± 1.2) and small reductions in creatine kinase activity (-22-29 %; ±21-22 %). Associated with the pain reduction was a small increase in single-leg jump performance (15 %; 90 %CL ± 12 %). Curcumin increased interleukin-6 concentrations at 0-h (31 %; ±29 %) and 48-h (32 %; ±29 %) relative to baseline, but decreased IL-6 at 24-h relative to post-exercise (-20 %; ±18 %).
Conclusions: Oral curcumin likely reduces pain associated with DOMS with some evidence for enhanced recovery of muscle performance. Further study is required on mechanisms and translational effects on sport or vocational performance.