Effectiveness and safety of turmeric for the treatment of COVID-19: An updated systematic review and meta-analysis of randomized controlled trials

Abstract

We conducted a comprehensive and updated systematic review and meta-analysis (SR-MA) to determine the effectiveness and safety of turmeric in patients with coronavirus disease 2019 (COVID-19). Multiple databases were searched from inception to July 31, 2024, for randomized controlled trials (RCTs) assessing turmeric in mild to severe COVID-19. This SR-MA uniquely includes recent trials conducted alongside modern antiviral-based regimens and explores effect modifiers by disease severity, comorbidity, formulation, and treatment duration. Twenty-three RCTs with 1407 participants were included, making this the largest synthesis to date. Most studies (17/23, 73.9 %) enrolled hospitalized patients; over half involved mild to moderate cases. The most common intervention was nano-curcumin 160–240 mg/day (39 %), used as an adjunct to standard care. Nine studies were rated high risk of bias (ROB). Meta-analysis showed turmeric significantly reduced all-cause mortality (Relative risk (RR) = 0.39; 95 % confidence interval (95 %CI): 0.23–0.67; I ² = 0 %; n = 8 RCTs; moderate certainty), suggesting a 61 % reduction in risk of death. It also reduced the need for intubation/mechanical ventilation (RR = 0.35; 95 %CI: 0.17–0.72) and clinical deterioration (RR=0.36; 95 %CI: 0.22–0.59), while improving overall symptom resolution (RR = 1.36; 95 %CI: 1.16–1.59). These results remained robust after excluding high ROB studies. Adverse events, mostly mild gastrointestinal symptoms, were comparable to placebo. In conclusion, turmeric, particularly bioavailability-enhanced nano-curcumin, provides meaningful clinical benefits and favorable safety profile as adjunctive therapy for COVID-19. Further large-scale, high-quality, multicenter RCTs are warranted to confirm its therapeutic potential, particularly in resource-limited settings.