Multiple Sclerosis

Liuting Zeng et al. (2022) · Frontiers in immunology

This systematic review and meta-analysis pooled 31 randomized controlled trials (34 study records, roughly 1,583 participants) exploring curcumin and Curcuma longa (turmeric) extract across 10 autoimmune diseases — conditions where the immune system mistakenly attacks the body's own tissue. Autoimmune disease covers more than 120 named conditions; this review focused on ankylosing spondylitis, Behçet's disease, Crohn's disease, multiple sclerosis, oral lichen planus, psoriasis, rheumatoid arthritis, systemic lupus erythematosus, Takayasu arteritis, and ulcerative colitis. Curcumin is the main active compound in turmeric, long used in Chinese medicine, and is studied here for its ability to regulate immune cells and reduce inflammation. Researchers searched English and Chinese databases plus the Cochrane Library and ClinicalTrials.gov through February 2022, screening 2,991 records down to 31 RCTs that tested curcumin or Curcuma longa extract against placebo or usual care. Trial count per disease varied widely: 9 RCTs for ulcerative colitis and 6 for oral lichen planus, but only 1 each for ankylosing spondylitis, Behçet's disease, and Takayasu arteritis. Doses ranged from 60 mg to 6,000 mg daily, taken orally, or in some trials applied as a gel, mouthwash, or enema, for 2 to 96 weeks. Disease activity was tracked with condition-specific scales (PASI for psoriasis, DAS28 for rheumatoid arthritis, EDSS for multiple sclerosis, and others) alongside blood markers like ESR and CRP. Where enough trials existed to combine statistically, curcumin performed well. In psoriasis, it roughly tripled the rate of major skin-clearance (PASI75: RR=3.01, p=0.008—meaning patients getting curcumin were about three times as likely to see substantial improvement). In ulcerative colitis, it raised clinical remission more than twofold (RR=2.28, p=0.0005) and lowered inflammatory markers ESR and CRP. In rheumatoid arthritis, it reduced the DAS28 disease-activity score (WMD=-1.10, p=0.0002—a clinically noticeable drop in joint disease activity), though results varied considerably between the five trials. Oral lichen planus, despite being studied in six trials, did not show a significant benefit on its pooled lesion-severity score (p=0.17). None of the pooled analyses found more side effects with curcumin than with placebo. The other six diseases each had just one or two small trials reporting improvement, too few to combine or confirm. These findings support curcumin as a reasonably safe adjunct for psoriasis, ulcerative colitis, and rheumatoid arthritis specifically, where the evidence is strongest and most consistent; for the seven other diseases, results are preliminary and should not yet guide treatment decisions. Curcumin's poor absorption from the gut remains a practical obstacle to reliable dosing. The authors call for larger, multi-center trials, especially for the thinly studied conditions, before broader clinical recommendations can be made.

Zeng L et al. (2022) · Frontiers in Immunology

This systematic review and meta-analysis evaluates the efficacy and safety of curcumin and Curcuma longa extract across five types of arthritis: rheumatoid arthritis (RA), osteoarthritis (OA), ankylosing spondylitis (AS), juvenile idiopathic arthritis (JIA), and gout/hyperuricemia. Twenty-nine randomized controlled trials involving 2,396 participants were included, drawn from 11 countries. For RA (6 RCTs), curcumin significantly reduced disease activity (DAS28), ESR, CRP, and rheumatoid factor compared to controls. For OA (20 RCTs), curcumin reduced pain (VAS and WOMAC-pain), improved physical function, and decreased stiffness compared to placebo. Notably, curcumin showed comparable efficacy to NSAIDs (ibuprofen, diclofenac) with significantly fewer adverse events. For AS, a single RCT of nanocurcumin showed increased regulatory T cells and decreased IL-6. Two JIA trials found curcumin improved disease activity scores in children. Doses ranged from 120 to 1,500 mg daily for 4-36 weeks. The mechanisms of action include inhibition of NF-kB signaling, COX-2 suppression, NLRP3 inflammasome inhibition, and modulation of the RANK/RANKL/OPG system. Safety was favorable across all studies, with no serious adverse events attributed to curcumin. However, the evidence is limited by small sample sizes, short follow-up periods, high heterogeneity, and potential industry funding bias.