Ground from the root of a plant (Curcuma longa L.) of the ginger family, found wild in the Himalayas and grown across South Asia, turmeric powder is surprisingly bland, not hot, tangy or peppery. The powder tastes a little sour. The first time I put some on my tongue I suspected my jar, purchased from a supermarket, was stale. Turmeric is pungent, bitter and astringent, not sweet like ginger. Fresh root, which goes well in snacks and main meals, as yet may be hard to find outside of stores in Asian neighborhoods. Turmeric capsules are sold through a number of suppliers.
But why make this spice part of the diet? Let's not romanticize South Asian nutrition today. Although India is doing relatively well, 47% of children there are underweight (Nutrition for Health Development, chart). South Asia's nutritional crises and disparities are harsh. Centuries of charcoal fires for home and industry have contributed to deforestation. Clean water, a cure for malaria, vaccinations and reproductive health care, not more spices, are what most of the citizens of those lands need to improve their health. Yet the very survival of peoples in South Asia must at times have depended on informed use of a wide array of stored dried plants including turmeric root.
A Little Dab
Most North Americans consume only miniscule traces of turmeric, say, by way of mustard lavished on meats of iffy provenance. Bright yellow mustards like French's "classic American" contain, labels say, "no more than 2 per cent" turmeric, paprika and other spices (as if more would adulterate the product). Mustard itself is medicinal. But that gaudy, store-bought, hot-dog-stand glow comes from curcumin, the intense yellow pigment in turmeric. And curcumin protects the stomach against tainted foods. According to University of Chicago scientists, curcumin inhibits a cancer-provoking bacteria (H. pylori) associated with gastric and colon cancer (Magad GB, Anticancer Res. 2002 Nov-Dec;22(6C):4179-81).
On the margins, so some biologists say, eco-diversity sprouts. Today curcumin is on a margin between ancient food customs and cutting-edge medicine. In suburban cuisine it can brighten and glorify nutritious foods (cauliflower, white fish ). At ballpark, beach and food mall a dab of "hidden" curcumin helps carnivore bellies lower risks from gorging on over-handled broiled oddments. In Asia the root and powder are used in cooking, home remedies and medicine: to gild and help preserve festive dishes and in drinks, ointments and poultices to treat sore throat, sprains, inflammation and wounds. In the lab, scientists are dosing rats with curcumin to measure its effects on cancer.
Prostate Cancer Patients Go For the Gold
Turmeric lore in recent decades drifted outwards from Asian diaspora communities in European cities like Leicester, UK. Local researchers and cancer patients listened up. Clusters of men on Internet prostate cancer support groups (notably Don Cooley's lists) began seriously experimenting with turmeric to cope with a troublesome side-effect of androgen-suppression therapy, gynecomastia (sore swollen breasts). Most men who take antiandrogen drugs like Flutamide (Eulexin) or Casodex experience this breast swelling, which can be painful. Gynecomastia can occur also with use of finasteride(Proscar), prescribed for BPH (benign growth of the prostate) and now under discussion as a chemo-preventive for prostate cancer. Before starting Casodex some patients opt to receive a brief course of radiation to the breasts. Others have tried low-dose tamoxifen, which raises levels of circulating estradiol. Then there are the turmeric warriors, who report that dietary intake of turmeric (in salads, soups and sandwiches made with fresh root) and use of curcumin paste externally brings some relief.
Still more intriguingly, University of Leicester began investigating dietary agents including curcumin, genistein, and the vitamin A analogue 13-cis retinoic acid for tumor-suppressing properties (Br J Clin Pharmacol 1998 Jan;45(1):1-12;update Toxicol Lett 2000 Mar 15;112-113:499-505). They observed that curcumin slows the rate at which hormone-responsive prostate cancer cells become resistant to hormonal therapy.
Antioxidant, anti-inflammatory and anti-carcinogenic properties of turmeric and curcumin are undergoing intense research. Tests in Germany, reported July 2003,found that "All fractions of the turmeric extract preparation exhibited pronounced antioxidant activity...." Turmeric extract tested more potent than garlic, devil's claw, and salmon oil [ J Pharm Pharmacol. 2003 Jul;55(7):981-6].
Biochemists in China reported January 2007 that month that curcumin “downregulates homeobox gene NKX3.1 in prostate cancer cell LNCaP” and could also dampen the androgen receptor's sensitivity to this gene. Independent studies have found that the Nkx3.1 homeobox gene has a key role in the prostate and may be implicated in startup of prostate cancer.
Does this mean, the more the better? Not necessarily. Some studies find no ill effects from large doses while others (listed in references below) disagree. Of note, a study of curcumin to prevent cataracts found, unexpectedly, that in rats low doses indeed did lower cataract rates but heavy doses raised the rate of cataracts (Molecular Vision 2003; 9:223-230, full text free online). Another study found that rats fed large amounts of turmeric for 14 days developed enlarged, damaged livers.
Several studies indicate that curcumin slows the development and growth of a number of types of cancer cells. In Japan this year researchers defined curcumin as a broad-spectrum anti-cancer agent. Its induction of "detoxifying enzymes," the researchers say, indicate its "potential value ... as a protective agent against chemical carcinogenesis and other forms of electrophilic toxicity. The significance of these results can be implicated in relation to cancer chemopreventive effects of curcumin against the induction of tumors in various target organs" (Iqbal M, et al. Pharmacol Toxicol. 2003 Jan;92(1):33-8).
Since India won a claim against two US scientists who shamelessly patented turmeric (see sidebar), the tide of interest may naturally be driven in part by Asian pride in phytomedicinal heritage. But as scientists at M. D. Anderson, Texas, wrote in January 2003: "Extensive research over the last 50 years has indicated [curcumin] can both prevent and treat cancer. The anticancer potential of curcumin stems from its ability to suppress proliferation of a wide variety of tumor cells, down-regulate transcription factors NF-kappa B, AP-1 and Egr-1; down-regulate the expression of COX2, LOX, NOS, MMP-9, uPA, TNF, chemokines, cell surface adhesion molecules and cyclin D1; down-regulate growth factor receptors (such as EGFR and HER2); and inhibit the activity of c-Jun N-terminal kinase, protein tyrosine kinases and protein serine/threonine kinases." In their latest of a series of reports the M. D. Anderson say: "Curcumin can suppress tumor initiation, promotion and metastasis. Pharmacologically, curcumin has been found to be safe. Human clinical trials indicated no dose-limiting toxicity when administered at doses up to 10 g/day. All of these studies suggest that curcumin has enormous potential in the prevention and therapy of cancer." [Aggarwal, BB et al,Anticancer Res. 2003 Jan-Feb;23(1A):363-98].
Several breast tumor cell lines, "including hormone-dependent and -independent and multidrug-resistant (MDR) lines," respond to antiproliferative effects of curcumin. Aggarwal et al examined cell lines "including the MDR-positive ones," and found they were all "highly sensitive to curcumin. The growth inhibitory effect of curcumin was time- and dose-dependent.... Overall our results suggest that curcumin is a potent antiproliferative agent for breast tumor cells and may have potential as an anticancer agent." (Anticancer Drugs. 1997 Jun;8(5):470-81). Other laboratories offer varying explanations but confirm the activity level of curcumin against breast , prostate and other cancers. See e.g., Ramachandran C, Miami 1999; Hidaka H, Japan, 2002(human pancreatic cells lines); Elattar TM, University of Missouri-Kansas City, 2000(oral cancer cell-line).
Some researchers say curcumin inhibits angiogenesis, i.e. formation of new blood vessels, which tumors use to nourish themselves as they spread (Mol Med 1998 Jun;4(6):376-83). As an anti-inflammatory, turmeric triggers heat-shock stress response (see Wiki Online Encyclopedia for heat-shock). Heat shock proteins stimulate the immune system. "The mechanism of the stimulation by curcumin of
the stress responses," Japanese researchers say (Cell Stress Chaperones 1998
Sep;3(3):152-60), "might be similar to that of salicylate [active in aspirin and similar drugs derived from willow bark], indomethacin [a nonsteroidal antiinflammatory drug] and
nordihydroguaiaretic acid [an anti-oxidant, antiflammatory, lipoxegenase inhibitor found in chapparel, that interferes with arachidonic acid metabolism].
To sum up -- regular healthy folks may benefit from adding turmeric to the spice rack and using it more liberally on adult and children's foods. Kids love bright colors. And turmeric is an ideal brightener for rice and for steamed or gently fried tofu.
For cancer patients, until curcumin has been shown in well-designed, well-conducted human clinical trials to have measurable effects on existing disease, it remains just another interesting home remedy with a lot of promise. Research at Memorial Sloan-Kettering a few years back indicates that it makes sense to drink green tea along with a meal spiced with turmeric for double-boosted anti-cancer protective effects: "EGCG and curcumin, were noted to
inhibit growth by different mechanisms, a factor which may account for their
demonstrable interactive synergistic effect." For new developments with curcumin, M. D. Anderson is another place to watch.
If you are taking medications or undergoing radiotherapy or
chemotherapy to treat cancer, be extremely cautious about possible
interactions and effects of turmeric/curcumin on your liver and other
organs. Talk to your oncologist and oncology nurse. A
recent study, available free online, finds that curcumin inhibits desired
effects of chemotherapy for breast cancer:
Research 62, 3868-3875, July 1, 2002, Dietary Curcumin Inhibits Chemotherapy-induced Apoptosis in Models of Human Breast Cancer Sivagurunathan Somasundaram et al, The Lineberger Comprehensive Cancer Center and the Department of Medicine [R. Z. O.], Division
of Hematology/Oncology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
- Curcumin downregulates homeobox gene NKX3.1 in prostate cancer cell LNCaP1. Acta Pharmacologica Sinica 2007 March; 28 (3): 423-430
- "Spicing up" of the immune system by curcumin. (J Clin Immunol. 2007 Jan;27(1):19-35 ).
- On tumor cells in a lab dish, curcumin prevents or slows prostate and lung cancer. But dietary consumption of turmeric, researchers report, so far shows no effect on those organs and failed to inhibit tobacco-induced tumors (Cancer Lett 1999 Apr 1;137(2):123-30).
- Recent studies found that curcumin has a dose-dependent chemopreventive effect in rats during promotion/progression stages of colon cancer (Cancer Res 1999 Feb 1;59(3):597-601). It has similar preventive effects against skin cancer, Oral cancer and forestomach and other intestinal tumors (J Surg Res 2000 Apr;89(2):169-75).
- Tufts researchers say "a mixture of curcumin and isoflavonoids is the most potent inhibitor against growth of human breast tumor cells. These data suggest that combinations of natural plant compounds may have preventive and therapeutic applications against the growth of breast tumors induced by environmental estrogens" (Environ Health Perspect 1998 Dec;106(12):807-12)
- Curr Pharm Des. 2002;8(19):1695-706. Chemotherapeutic potential of curcumin for colorectal cancer. Chauhan DP.
Division of Gastroenterology, Department of Medicine, The University of California, San Diego, CA 92093-0688, USA.
- Turmeric compares with soy, licorice, red clover, and thyme in binding to progesterone and estrogen receptors in breast cancer cells (Proc Soc Exp Biol Med 1998 Mar;217(3):369-78).
- Kentucky researchers report curcumin "inhibited proliferation of a variety of B lymphoma cells" (Clin Immunol 1999 Nov;93(2):152-61).
- Curcumin may or may not protect against cellular damage from radiation, perhaps depending on dose. It appears to protect against damage to certain organs brought about by some chemotherapy agents. In hamsters it protects the kidneys from Adriamycin (Br J Pharmacol 2000 Jan;129(2):231-4). If you are taking radiation or chemotherapy, it is very important to discuss your diet and use of any antioxidants with your oncologist.
- Typical dietary amounts of turmeric have an antioxidant effect that protects rats from cataracts. But in one study rats heavily dosed developed more cataract signs (Molecular Vision 2003. 9:223-230).
- Curcumin protects rats from liver-damage caused by toxins (J Pharm Pharmacol 2000 Apr;52(4):437-40; Carcinogenesis 2000 Feb;21(2):331-5)
But in one experiment, mice fed anti-cancer doses of curcumin for 14 days developed enlarged, damaged livers.
- Dosing mice with curcumin for 14 days damaged their livers.
- Curcumin prevents formation of some tumors: J Cell Biochem Suppl 1997;27:26-34
Inhibitory effects of curcumin on tumorigenesis in mice. Huang MT, Newmark HL, Frenkel K Department of Chemical Biology, College of Pharmacy, Rutgers-State University of New Jersey, Piscataway, NJ 08854-8020, USA.
- Arousal of the human system through "heat shock" response: Curcumin induces the stress response.
- Drink green tea with a meal spiced with turmeric for double-boosted anti-cancer protective effects: "EGCG and curcumin, were noted to
inhibit growth by different mechanisms, a factor which may account for their
demonstrable interactive synergistic effect." Memorial Sloan- Kettering researchers, 1998
- Curcumin and genistein protect breast cells against DDT and other pesticides Tufts School of Medicine, 1997
- More reading: Lipooxygenase Inhibitors as Potential Anti-Cancer Drugs Ted Holman, Chemistry & Biochemistry
content last modified February 2007
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