Bottom Line: Turmeric demonstrated anti-inflammatory and anticancer activities in lab studies. Recent clinical trial suggests curcumin has biological activity in some cancer patients but more studies are needed to verify its benefits.
Turmeric is a spice that has been used in cooking for centuries. Scientists have determined that turmeric has many biological activities, although they do not fully understand exactly how it exerts these effects. From laboratory experiments, it has been deduced that substances in turmeric (called curcuminoids) prevent inflammation by inhibiting the molecules that mediate inflammatory reactions. Curcuminoids may protect the body in a few ways: they enhance the activity of an important detoxifying enzyme and they also act as antioxidants by neutralizing free radicals (which can cause DNA damage). In rats, turmeric prevented the development of kidney damage from toxins. Turmeric also stimulates the flow of bile in the gastrointestinal tract.
In rats exposed to cancer-causing substances, those that were treated with turmeric were protected from colon, stomach, and skin cancers. Turmeric also stops the replication of tumor cells when applied directly to them in the laboratory, but it is unknown if this effect occurs in the human body. Curcumin has shown biological activity in pancreatic cancer patients and there are ongoing studies to test its effect as an adjuvant in cancer treatment. However, recent experiments have suggested that turmeric might interfere with the activity of some chemotherapy drugs in breast cancer, so the question remains whether this spice is helpful or harmful during chemotherapy.
To prevent cancer Several animal studies suggest that turmeric prevents colon, stomach, and skin cancers in rats exposed to carcinogens, but there is no proof from clinical trials that it can prevent cancer in humans.
To treat infections No scientific evidence supports this use. One clinical trial showed that turmeric does not help lower viral load in HIV positive patients.
To reduce inflammation Laboratory and animal studies suggest that turmeric reduces inflammation, but there is no proof from clinical trials that this effect occurs in humans.
To treat kidney stones No scientific evidence supports this use.
To relieve stomach and intestinal gas No clinical trials have evaluated this use.
To improve gall bladder function Several clinical studies show that turmeric enhances contraction of the gall bladder in humans.
Reduce HIV viral load: The ability of powdered turmeric to reduce HIV viral load was studied in 38 patients. For eight weeks, the patients were randomly assigned to take either a high dose or a low dose of turmeric powder. At the end of the study, there was no difference between the low- and high-dose groups in terms of viral load. Unfortunately, this study did not have a placebo group (not taking turmeric) to compare these results to. Either way, this study does not support the use of oral turmeric powder to treat HIV infection.
This product is regulated by the FDA as a dietary supplement. Unlike approved drugs, supplements are not required to be manufactured under specific standardized conditions. This product may not contain the labeled amount or may be contaminated. In addition, it may not have been tested for safety or effectiveness.
Recent laboratory findings indicate that dietary turmeric may inhibit the anti-tumor action of chemotherapeutic drugs such as cyclophosphamide in treating breast cancer. More research is necessary, but patients undergoing chemotherapy should ask their doctor if they should limit their intake of turmeric and turmeric-containing foods.
You have bile duct obstruction, gallstones, or gastrointestinal disorders such as stomach ulcers and hyperacidity disorders.
You are taking reserpine (Turmeric may lessen its effects).
You are taking indomethacin (Turmeric may lessen its effects).
You are taking warfarin or other blood thinners (Turmeric may increase your risk of bleeding).
You are taking chemotherapy drugs such as camptothecin, mechlorethamine, doxorubicin, or cyclophosphamide (Turmeric inhibits the action of these drugs against breast cancer cells in lab experiments).
Derived from the rhizome and root, this supplement is used as a spice and coloring agent, and in traditional medicine in Asia. The active constituents are thought to be turmerone oil and water soluble curcuminoids, including curcumin. Turmeric may help alleviate symptoms of irritable bowel syndrome (9) as well as quiescent ulcerative colitis (10). Data from an epidemiological study are suggestive of improved cognitive performance in elderly Asians who consume turmeric in the form of curry powder (11); however, no benefits of curcumin supplementation were detected in patients with Alzheimer's (12). In vitro and animal studies suggest antiproliferative and preventative effects of turmeric against cancer (3)(4)(5)(6)(7)(8). Furthermore, curcumin was shown to induce apoptosis in human colon cancer (14) and promyelocytic leukemia cells (15). Curcumin potentiated gemcitabine action in both in vitro and in vivo studies of pancreatic cancer (17). In a phase II trial in pancreatic cancer patients, down-regulation of NF-kappa B and cyclooxygenase-2 were observed (29). Oral administration is well tolerated, but bioavailability is relatively low (1)(2)(29). Following absorption, curcuminoids are rapidly metabolized. Recent animal studies indicate that dietary turmeric may inhibit the antitumor action of chemotherapeutic agents such as cyclophosphamide in treating breast cancer (16). More research is necessary, but it is advisable for cancer patients undergoing chemotherapy to limit intake of turmeric. Patients with gastrointestinal disorders or those predisposed to kidney stone formation (13) should use this supplement with caution.
Turmeric has anti-inflammatory and choleretic actions. Anti-inflammatory action may be due to leukotriene inhibition. Its curcuminoids (curcumin) and volatile oils are both responsible for the anti-inflammatory activity. Curcuminoids induce glutathione S-transferase and are potent inhibitors of cytochrome P450. Turmeric acts as a free radical scavenger and antioxidant, inhibiting lipid peroxidation and oxidative DNA damage. It also inhibits activation of NF-kB 17, 20, c-jun/AP-1 function, and activation of the c-Jun NH2-terminal kinase (JNK) pathway. In vitro and animal models of breast cancer showed that turmeric may inhibit chemotherapy-induced apoptosis via inhibition of the JNK pathway and generation of reactive oxygen species (ROS). The isolated constituent ar-turmerone has been shown to arrest the growth and cytotoxic activity of human lymphocytes, which may contribute to its anti-inflammatory action. In vitro studies suggest that curcumin induces apoptosis in human colon cancer cells independent of p21 expression (14). In addition, in vitro and in vivo studies report that NF-kB-mediated resistance of cancer cells to gemcitabine and ɣ-radiation was repressed by curcumin administration (17)(21). In laboratory tests, curcumin's antitumor actions appear to be due to interactions with arachidonate metabolism and its in vivo antiangiogenic properties (16)(22).
Bioavailability of curcumin is approximately 60-65% following oral administration. Metabolism is primarily via glucuronidation to glucuronide and glucuronide/sulfate metabolites (20). In vitro studies indicate inhibition of Cytochrome P450s (CYPs) such as CYP1A1, CYP1A2, CYP3A4, CYP2D6, CYP2C9, and CYP2B6 (23). Excretion of parent compound is primarily in the feces with metabolites present in the urine (2).
Recent laboratory findings indicate that dietary turmeric may inhibit the anti-tumor action of chemotherapeutic agents such as cyclophosphamide in treating breast cancer. More research is necessary, but it is advisable for cancer patients undergoing chemotherapy to limit intake of turmeric and turmeric-containing foods. (3)
Patients with bile duct obstruction, gallstones, and GI disorders (including stomach ulcers and hyperacidity disorders) should not take this supplement (24).
Anticoagulants / Antiplatelets: Turmeric may increase risk of bleeding (25). Camptothecin: Turmeric inhibits camptothecin-induced apoptosis of breast cancer cell lines in vitro (16). Mechlorethamine: Turmeric inhibits mechlorethamine-induced apoptosis of breast cancer cell lines in vitro (16). Doxorubicin: Turmeric inhibits doxorubicin-induced apoptosis of breast cancer cell lines in vitro (16). Cyclophosphamide: Dietary turmeric inhibits cyclophosphamide-induced tumor regression in animal studies (16).
Baum L, Cheung SK, Mok VC, et al. Curcumin effects on blood lipid profile in a 6-month human study. Pharmacol Res 2007 Dec;56(6):509-14. The effects of curcumin on blood lipid profiles were assessed in this randomized, double-blind study of 36 elderly participants. Subjects were separated into a control or curcumin-treated groups (1 or 4 g/day), and serum lipid profiles were measured at baseline, 1 month, and 6 months. The side effects were similar between the groups. No significant differences in serum lipid profiles were detected upon curcumin administration; however, levels of absorbed curcumin were modestly associated with increased cholesterol concentration. Larger studies are required to determine if curcumin supplementation may increase cholesterol levels.
James J. Curcumin: clinical trial finds no antiviral effect. AIDS Treat News 1996;242:1. A randomized study of 38 patients to either high-dose or low-dose turmeric powder. Following 8 weeks of treatment, there was no demonstrated effect of turmeric on HIV viral load. A small increase in CD4 cells in the high-dose group and a consistent fall of CD4 cells in the low-dose group were documented, but neither result was statistically significant. This report of an abstract presented at the third annual Conference on Retroviruses and Opportunistic Infections demonstrated no efficacy of turmeric in treating HIV.
Animal / In vitro data: Li JK, et al. Mechanisms of cancer chemoprevention by curcumin. Proc Natl Sci Counc Repub China B 2001;25:59-66. Curcumin has shown anti-carcinogenic activity in animals as indicated by its ability to block colon tumor initiation by azoxymethane and skin tumor promotion induced by phorbol ester TPA. Recently, curcumin has been considered by oncologists as a potential third-generation cancer chemopreventive agent, and clinical trials using it have been carried out in several laboratories. Curcumin possesses anti-inflammatory activity and is a potent inhibitor of reactive oxygen-generating enzymes, such as lipoxygenase/cyclooxygenase, xanthine dehydrogenase/oxidase and inducible nitric oxide synthase. Curcumin is also a potent inhibitor of protein kinase C and EGF-receptor tyrosine kinase. It is proposed that curcumin may suppress tumor promotion by blocking signal transduction pathways in the target cells.
Venkatesan N. Curcumin prevents adriamycin nephrotoxicity in rats. Br J Pharmacol 2000;129:231-4. This study investigated the effect of curcumin on Adriamycin (ADR) nephrosis in rats. The results indicate that ADR-induced kidney injury was remarkably well prevented by treatment with curcumin. Treatment with curcumin markedly protected against ADR-induced proteinuria, albuminuria, hypoalbuminemia and hyperlipidemia. Curcumin restored renal function in ADR rats, as judged by the increase in GFR. The data also demonstrate that curcumin protects against ADR-induced renal injury by suppressing oxidative stress and increasing kidney glutathione content and glutathione peroxidase activity. This suggests that administration of curcumin is a promising approach in the treatment of nephrosis caused by ADR.
Kawamori T, et al. Chemopreventive effect of curcumin, a naturally occurring anti-inflammatory agent, during the promotion/progression stages of colon cancer. Cancer Res 1999;59:597-601. This study was designed to investigate the chemopreventive action of curcumin when administered (late in the premalignant stage) during the promotion/progression stage of colon carcinogenesis in male F344 rats. The study also monitored the modulating effect of this agent on apoptosis in the tumors. The results showed that the administration of 0.2% curcumin during both the initiation and post initiation periods significantly inhibited colon tumorigenesis. In addition, administration of 0.2% and of 0.6% synthetic curcumin in the diet during the promotion/progression stage significantly suppressed the incidence and multiplicity of noninvasive adenocarcinomas and also strongly inhibited the multiplicity of invasive adenocarcinomas of the colon.
Rao CV, et al. Chemoprevention of colon carcinogenesis by dietary curcumin, a naturally occurring plant phenolic compound. Cancer Res 1995;55:259-66. This study was designed to investigate the chemopreventive action of dietary curcumin on azoxymethane-induced colon carcinogenesis and the modulating effect of curcumin on the colonic mucosal and tumor phospholipase A2, phospholipase C gamma 1, lipoxygenase, and cyclooxygenase activities in male F344 rats. The results indicate that the administration of curcumin significantly inhibited incidence of colon adenocarcinomas (p<0.004) and the multiplicity of invasive, non-invasive, and total adenocarcinomas. Curcumin also significantly suppressed the colon tumor volume by more than 57% compared to the control diet. Although the precise mechanism by which curcumin inhibits colon tumorigenesis remains to be elucidated, it is likely that the chemopreventive action, at least in part, may be related to the modulation of arachidonic acid metabolism.
