Meta-analysis of the effect of curcumin supplementation on skeletal muscle damage status.

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• Curcumin supplementation has been shown to improve creatinine kinase (CK) levels, muscle soreness, IL-6 and range of motion (ROM).
• These findings suggest that both dosage and timing play an important role in determining its efficacy.
• To help improve muscle soreness and ROM, a low-dose daily supplement (< 0.5g) one week in advance of physical endurance activity may be most effective.
• To help reduce CK and IL-6 levels, a low-dose supplement taken immediately post-exercise may provide the best results.

Introduction: A meta-analysis was conducted to examine the effect of curcumin supplementation on key markers of skeletal muscle damage, aiming to propose an optimal intervention program.

Method:

• A systematic search of multiple databases including Web of Science, ScienceDirect, China National Knowledge Infrastructure (CNKI), PubMed, and Wanfang was conducted.
• The computerised search focused on randomised controlled trials (RCTs), with adult subjects, using curcumin or a curcumin-based supplement as the focus.
• Primary outcome assessments included creatine kinase (CK), muscle soreness, interLeukin-6 (IL6), and range of motion (ROM).

Results:

• 14 studies encompassing 334 participants met the inclusion criteria.
• A pooled analysis of 12 studies demonstrated that curcumin supplementation significantly alleviated sore muscles (MD=-0.61,Cl:-0.81,-0.41: p<0.00001).
• Curcumin intake was associated with a reduction in CK levels, indicating decreased muscle damage (MD=-137.32,Cl: -238.82,-35.82, p<0.008).
• Data from three studies found that curcumin supplementation significantly enhanced ROM (MD=4.10,Cl:1.45,6.75, p=0.0002).
• Analysis of five studies found that curcumin supplementation lowered IL-6, suggesting anti-inflammatory effects (MD=-0.33, Cl: -0.56,-0.09,p<0.007).
• Subgroup analysis based on supplement timing revealed that the most pronounced reduction in muscle soreness occurred at the 96-hour post exercise (MD=1.24, p<0.0001).
• Intervention duration analysis showed that supplementation for more than one week yielded the greatest effect (MD=-0.83, p<0.00001).
• Dose-dependent analysis indicated the most significant reduction in CK levels occurred in the group that received <0.5g of curcumin (MD=-243.27, p=0.002).

Conclusion: This meta-analysis suggests that curcumin supplementation may effectively reduce muscle soreness, lower CK and IL-6 levels, and enhance range of movement.

Curcumin is known for its anti-inflammatory properties, acting by downregulating cytokines, prostaglandins and histamine. Curcumin may serve as an adjunctive supplement for managing exercise-induced muscle damage (EIMD), helping to lower CK levels and reduce inflammatory markers (IL-6) post-exercise. For Muscle Soreness and ROM: Low-dose supplementation (<0.5g/day) for at least a week before exercise is reported to be most effective. For Reducing CK and IL-6 Levels: supplementation of 0.5–1.5g/day immediately post-exercise may yield the best results.

• Further research is needed to understand the impact of inflammatory markers on post-training inflammation and curcumin supplementation.
• Future studies should aim to investigate bioavailability-enhanced formulations (e.g., curcumin with piperine) to establish maximum effectiveness in modulating interleukins and other inflammatory markers.
• Dose-response studies are needed to refine the optimal curcumin dosage.
• Further clinical trials in patients with chronic pain and inflammatory muscle disorders could provide additional evidence supporting curcumin supplement’s therapeutic applications.