Turmeric is widely recognized as the spice that gives curry powder its distinctive color and flavor, but it’s more than a culinary staple. In fact, the golden spice has been used as an herbal medicine for nearly 4000 years.1
In recent decades, researchers have studied turmeric’s main active ingredient, curcumin, to see if it’s a viable treatment option for various prominent disease states. What does science say about turmeric’s potential role in combatting cancer, type 2 diabetes (T2D), depression, and arthritis?
In vitro and animal model studies suggest that curcumin has anticancer properties. The bright yellow chemical is thought to inhibit cell proliferation by decreasing the expression of cell-signaling components that are important for cancer growth.2,3
While high-quality clinical trials are in relative short supply, there have been notable in-human studies on the subject. In a 2016 pilot phase 2 study, researchers evaluated 26 men with progressive chemotherapy-naive metastatic castration-resistant prostate cancer (CRPC) who received curcumin 6 g daily in combination with docetaxel and prednisone for 6 cycles. A prostate-specific antigen (PSA) response of 59% was noted, and 40% of patients experienced a partial response. No adverse events were attributed to curcumin.4
Also in 2016, researchers evaluated the efficacy of curcumin for leukoplakia. In a phase 2 trial, investigators found that curcumin administration resulted in a higher number of clinical responses compared with placebo (67.5% vs 55.3%).5
Bottom Line: While laboratory research and early phase clinical trials show anticancer properties in curcumin, it’s premature to state that its anticancer effects are applicable to humans. Currently, there is a lack of large-scale, well-controlled, late-phase clinical trials on the subject.
Type 2 Diabetes
In 2013, researchers published a systematic review of curcumin and T2D. The investigators found that turmeric may help lower blood glucose levels and other diabetes-related complications. However, many of the findings included were from animal studies. The researchers concluded that clinical trials are needed to confirm curcumin’s potential in limiting diabetes and associated disorders.6
One noteworthy clinical trial was conducted in Thailand. In the randomized, double-blind study, 240 participants with prediabetes were randomly assigned to receive curcumin or placebo capsules for 9 months. After treatment, 16.4% of subjects in the placebo group were diagnosed with T2D mellitus, while none of the people in the curcumin group received the same diagnosis.7
Bottom Line: While there is some evidence to suggest that curcumin can help prevent the onset of T2D, multiple robust clinical trials are needed to verify its effectiveness in this disease state.
There is a growing body of evidence that curcumin may alleviate symptoms of major depressive disorder (MDD). In 2014, researchers conducted a randomized, double-blind study of 56 individuals with MDD. The participants were treated with curcumin 500 mg or placebo twice daily for 8 weeks. In the first 3 weeks, both groups had similar score improvements on the Inventory of Depressive Symptomatology self-rated version (IDS-SR30). However, by the completion of the study, the curcumin group exhibited significantly greater improvements in mood-related symptoms compared with the placebo group.8
In 2017, researchers published a meta-analysis of curcumin for depression. In reviewing 6 clinical trials involving 377 patients, the investigators found evidence to support the clinical efficacy of curcumin in mitigating symptoms of MDD. They also found antianxiety effects in 3 of the trials.9
Bottom Line: Available research shows that curcumin is safe, well tolerated, and effective in reducing depressive symptoms.
Researchers conducted a randomized pilot study to assess the efficacy of curcumin in patients with rheumatoid arthritis (RA). Participants received curcumin, diclofenac sodium, or a combination of both agents. All 3 treatment groups showed statistically significant improvements in Disease Activity Scores (DAS), with the curcumin group showing the greatest improvement.10
Researchers have examined whether patients with osteoarthritis (OA) might also benefit from turmeric. In a multicenter study of 367 people with knee OA, participants were randomly assigned to either ibuprofen or curcumin extracts for 4 weeks. Outcomes were measured using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), which measures pain, stiffness, and function. Both groups improved significantly compared with their baseline values. The WOMAC scores in the turmeric extract group were similar to those of the ibuprofen group, suggesting that the two may be equally effective for knee OA.11
Bottom Line: To this point, research about turmeric as a treatment for RA and OA is promising but scarce. More thorough trials will be needed to verify its benefits.
The Big Takeaway
It’s complicated. Turmeric may be an effective treatment for a laundry list of ailments, but in most cases it’s too early to tell. The challenge moving forward is twofold: collecting ample data in clinical trials and figuring out how to optimize the use of turmeric.
- Cox L. What is turmeric? Live Science. November 15, 2017. Accessed May 1, 2019.
- Allegra A, Innao V, Russo S, et al. Anticancer activity of curcumin and its analogues: preclinical and clinical studies. Cancer Invest. 2017;35(1):1-22.
- Shanmugam MK, Rane G, Kanchi MM, et al. The multifaceted role of curcumin in cancer prevention and treatment. Molecules. 2015;20(2):2728-2769.
- Mahammedi H, Planchat E, Pouget M, et al. The new combination of docetaxel, prednisone and curcumin in patients with castration-resistant prostate cancer: a pilot phase II study. Oncology. 2016;90(2):69-78.
- Kuriakose MA, Ramdas K, Dey B, et al. A randomized double-blind placebo-controlled phase IIB trial of curcumin in oral leukoplakia. Cancer Prev Res. 2016;9(8)683-691.
- Zhang DW, Fu M, Gao SH, Liu JL. Curcumin and diabetes: a systematic review. Evid Based Complement Alternat Med. 2013:636053.
- Chuengsamarn S, Rattanamongkolgul S, Luechapudiporn R, et al. Curcumin extract for prevention of type 2 diabetes. Diabetes Care. 2012;35(11):2121-2127.
- Lopresti AL, Maes M, Maker GL, Hood SD, Drummond PD. Curcumin for the treatment of major depression: a randomized, double-blind, placebo controlled study. J Affect Disord. 2014;167:368-375.
- Ng QX, Koh SSH, Chan HW, Ho CYX. Clinical use of curcumin in depression: a meta-analysis. J Am Med Dir Assoc. 2017;18(6):503-508.
- Chandran B, Goel A. A randomized, pilot study to assess the efficacy and safety of curcumin in patients with active rheumatoid arthritis. Phytother Res. 2012;26(11):1719-1725.
- Kuptniratsaikul V, Dajpratham P, Taechaarpornkul W, et al. Efficacy and safety of curcuma domestica extracts compared with ibuprofen in patients with knee osteoarthritis: a multicenter study. Clin Interv Aging. 2014;9:451-458.