Short Term, Oral Supplementation with Optimized Curcumin Does Not Impair Performance Improvements Associated with High Intensity Interval Training

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.

Curcumin/turmeric supplementation could improve blood pressure and endothelial function: A grade-assessed systematic review and dose-response meta-analysis of randomized controlled trials

BACKGROUND AND PURPOSE

A number of studies have examined the impact of curcumin/turmeric on blood pressure and the factors allegedly responsible for hypertension. In this systematic review and meta-analysis, we tried to sum up the existing literature on randomized controlled trials (RCTs) investigating this hypothesis.

METHODS

Online databases (PubMed, Scopus, Web of Science Core Collection, Cochrane Library, and Google Scholar) were searched from inception up to October 2022. We used the cochrane quality assessment tool to evaluate the risk of bias. Outcomes of interest included systolic blood pressure (SBP), diastolic blood pressure (DBP), blood levels of vascular cell adhesion molecule-1 (VCAM-1) and intracellular adhesion molecule-1 (ICAM-1), flow-mediated vasodilation (FMD), and pulse-wave velocity (PWV). Weighted mean differences (WMDs) were derived and reported. In case of significant between-study heterogeneity, subgroup analyses were carried out. Significance level was considered as P-values<0.05.

RESULTS

Finally, 35 RCTs out of 4182 studies were included. Our findings suggested that curcumin/turmeric supplementation significantly improved SBP (WMD: -2.02 mmHg; 95 % CI: -2.85, -1.18), DBP (WMD: -0.82 mmHg; 95 % CI: -1.46, -0.18), VCAM-1 (WMD: -39.19 ng/mL; 95 % CI: -66.15, -12.23), and FMD (WMD: 2.00 %; 95 % CI: 1.07, 2.94). However, it did not significantly change levels of ICAM-1 (WMD: -17.05 ng/ml; 95 % CI: -80.79, 46.70), or PWV (WMD: -79.53 cm/s; 95 % CI: -210.38, 51.33).

CONCLUSION

It seems that curcumin/turmeric supplementation could be regarded as a complementary method to improve blood pressure and endothelial function. However, further research is needed to clarify its impact on inflammatory adhesion molecules in the circulation.

Antioxidant and anti-inflammatory effects of curcumin/turmeric supplementation in adults: A GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials

Turmeric and its prominent bioactive compound, curcumin, have been the subject of many investigations with regard to their impact on inflammatory and oxidative balance in the body. In this systematic review and meta-analysis, we summarized the existing literature on randomized controlled trials (RCTs) which examined this hypothesis. Major databases (PubMed, Scopus, Web of Science, Cochrane Library and Google Scholar) were searched from inception up to October 2022. Relevant studies meeting our eligibility criteria were obtained. Main outcomes included inflammatory markers (i.e. C-reactive protein(CRP), tumour necrosis factorα(TNF-α), interleukin-6(IL-6), and interleukin 1 beta(IL-1β)) and markers of oxidative stress (i.e. total antioxidant capacity (TAC), malondialdehyde(MDA), and superoxide dismutase (SOD) activity). Weighted mean differences (WMDs) were reported. P-values < 0.05 were considered significant. Sixty-six RCTs were included in the final analysis. We observed that turmeric/curcumin supplementation significantly reduces levels of inflammatory markers, including CRP (WMD: -0.58 mg/l, 95 % CI: -0.74, -0.41), TNF-α (WMD: -3.48 pg/ml, 95 % CI: -4.38, -2.58), and IL-6 (WMD: -1.31 pg/ml, 95 % CI: -1.58, -0.67); except for IL-1β (WMD: -0.46 pg/ml, 95 % CI: -1.18, 0.27) for which no significant change was found. Also, turmeric/curcumin supplementation significantly improved anti-oxidant activity through enhancing TAC (WMD = 0.21 mmol/l; 95 % CI: 0.08, 0.33), reducing MDA levels (WMD = -0.33 µmol /l; 95 % CI: -0.53, -0.12), and SOD activity (WMD = 20.51 u/l; 95 % CI: 7.35, 33.67). It seems that turmeric/curcumin supplementation might be used as a viable intervention for improving inflammatory/oxidative status of individuals.