Curcumin (Turmeric Extract)

Panahi et al. (Annals of Clinical Biochemistry, 2012; PMID 23038702): randomized double-blind trial, 96 veterans with chronic sulfur-mustard-induced pruritus, curcumin 1 g/day reduced serum inflammatory biomarkers. This is the only cited trial isolating curcumin, and its population is narrow. Panahi et al. (Clinical Nutrition, 2015; PMID 25618800) tested a curcuminoid-PIPERINE COMBINATION in metabolic syndrome, so it cannot isolate curcumin. Grade C for this use: every endpoint is a surrogate inflammatory marker, no cited trial reports a clinical outcome, and only one of the two isolates the single agent.

Kuptniratsaikul et al. (Clinical Interventions in Aging, 2014; PMID 24672232): 367 patients with primary knee osteoarthritis randomized to Curcuma domestica extract 1,500 mg/day or ibuprofen 1,200 mg/day for 4 weeks; WOMAC total, pain and function met the pre-specified noninferiority margin against ibuprofen. An earlier trial by the same group (PMID 19678780, n=107) could not establish equivalence. Bannuru et al. (Seminars in Arthritis and Rheumatism, 2018; PMID 29622343): systematic review and meta-analysis, 11 randomized trials, N=1,009, of curcuminoid or Boswellia formulations; curcuminoids were significantly more effective than placebo for pain and function, and showed no significant difference against NSAIDs. Grade C rather than B for three reasons the meta-analysis states about itself: study quality was low overall and most included trials enrolled fewer than 100 participants; the pooled curcuminoid arm combines different formulations, several of them curcuminoid-piperine combinations, so no single product carries the result; and neither head-to-head trial had a placebo arm, so noninferiority to ibuprofen does not by itself establish benefit over no treatment. DOSE NOTE: these trials used 1,500 to 2,000 mg/day of a 75 to 85 percent curcuminoid extract, not an enhanced-bioavailability form at a lower dose.