Turmeric

Selected Scientific Studies

Over the last several years, there has been increasing interest in turmeric and its medicinal properties. This is partially evidenced by the large numbers of scientific studies published on this topic. The active ingredient in turmeric is curcumin, which has been the subject of numerous animal studies—but as of yet, very few studies on people—demonstrating various medicinal properties (1-2). Curcumin has been shown, for example, to stimulate the production of bile and to facilitate the emptying of the gallbladder. It has also demonstrated in animals a protective effect on the liver, anti-tumor action, and ability to reduce inflammation and fight certain infections.

Cancer
There has been a substantial amount of research on turmeric's anti-cancer potential. Evidence from laboratory and animal studies suggests that curcumin has potential in the treatment of various forms of cancer, including prostate, breast, skin, and colon. Human studies will be necessary before it is known to what extent these results may apply to people (3-9).

Prostate cancer
In two recent studies, scientists at New York's Columbia University researched curcumin's therapeutic potential against prostate cancer. In one case last year, the scientists discovered that curcumin had a powerful ability to induce apoptosis and inhibit prostate cell proliferation in vitro by interfering with the cells' protein
signaling pathways that typically begin the growth process.(3) Just recently, the researchers extended those findings to determine if they could achieve similar results in an animal model.(4) In their latest study, the researchers found that prostate cancer cells that had been injected subcutaneously into mice, which had been fed a diet of 2% curcumin for six weeks, were unable to develop extensively and underwent significant apoptosis. "Curcumin could be a potentially therapeutic anti-cancer agent, as it significantly inhibits prostate cancer growth and has the potential to prevent the progression of this cancer to its hormone refractory state," the study authors concluded.

Digestive Disorders
Stomach upset, gas, abdominal cramps: The German Commission E (an authoritative body that determined which herbs could be safely prescribed in that country and for which purpose[s]) approved turmeric for a variety of digestive disorders. Curcumin, for example, one of the active ingredients in turmeric, induces the flow of bile, which helps break down fats. In an animal study, extracts of turmeric root reduced secretion of acid from the stomach and protected against injuries such as inflammation along the stomach (gastritis) or intestinal walls and ulcers from certain medications, stress, or alcohol. Further studies are needed to know to what extent these protective effects apply to people as well (10-11).

Wounds
In animal studies, turmeric applied to wounds hastens the healing process (12).

Liver Disease
Animal studies provide evidence that turmeric can protect the liver from a number of damaging substances such as carbon tetrachloride and acetominophen (also called paracetamol, this medication, used commonly for headache and pain, can cause liver damage if taken in large quantities or in someone who drinks alcohol regularly.) Turmeric accomplishes this, in part, by helping to clear such toxins from the body and by protecting the liver from damage (13).

Osteoarthritis
Because of its ability to reduce inflammation, turmeric may help relieve the symptoms of osteoarthritis. A study of people using an Ayurvedic formula of herbs and minerals containing turmeric as well as Withinia somnifera (winter cherry), Boswellia serrata (Boswellia), and zinc significantly reduced pain and disability. While encouraging for the value of this Ayurvedic combination therapy to help with osteoarthritis, it is difficult to know how much of this success is from turmeric alone, one of the other individual herbs, or the combination of herbs working in tandem (14).

Atherosclerosis
Early studies suggest that turmeric may prove helpful in preventing the build up of atherosclerosis (blockage of arteries that can eventually cause a heart attack or stroke) in one of two ways. First, in animal studies an extract of turmeric lowered cholesterol levels and inhibited the oxidation of LDL ("bad") cholesterol. Oxidized LDL deposits in the walls of blood vessels and contributes to the formation of atherosclerotic plaque. Turmeric may also prevent platelet build up along the walls of an injured blood vessel. Platelets collecting at the site of a damaged blood vessel cause blood clots to form and blockage of the artery as well. Studies of the use of turmeric to prevent or treat heart disease in people would be interesting in terms of determining if these mechanisms discovered in animals apply to people at risk for this condition (15).

Inflammatory activity

Human studies have found some evidence of anti-inflammatory activity of curcumin. The laboratory studies have identified a number of different molecules involved in inflammation that are inhibited by curcumin including phospholipase, lipooxygenase, cyclooxygenase 2, leukotrienes, thromboxane, prostaglandins, nitric oxide, collagenase, elastase, hyaluronidase, monocyte chemoattractant protein-1 (MCP-1), interferon-inducible protein, tumor necrosis factor (TNF), and interleukin-12 (IL-12). CONCLUSIONS: Curcumin has been demonstrated to be safe in six human trials and has demonstrated anti-inflammatory activity. It may exert its anti-inflammatory activity by inhibition of a number of different molecules that play a role in inflammation (16).

Alleviate Cystic Fibrosis

A spice used in curry could help alleviate cystic fibrosis, new research suggests. The tests in mice show that low doses of a component of turmeric can make most of the symptoms disappear.

"It can almost completely correct the measurable defects of the disease," says Michael Caplan at Yale University in New Haven, Connecticut, US, part of the research team. Click here more for detail...

Precautions

The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, contain active substances that can trigger side effects and interact with other herbs, supplements, or medications. For these reasons, herbs should be taken with care, under the supervision of a practitioner knowledgeable in the field of botanical medicine.

Turmeric and curcumin are considered safe when taken at the recommended doses. However, extended or excessive use of curcumin may produce stomach upset and, in extreme cases, ulcers. (Note: normal therapeutic doses of turmeric protect from ulcers – see earlier discussion – but, at very high doses, it may induce ulcers. This is why it is very important to stick with the recommended dose of this herbal remedy.) Turmeric should not be taken by those who have been diagnosed with gallstones or obstruction of the bile passages without explicit direction from a qualified practitioner.

While pregnant women needn't avoid foods containing turmeric, its use as a medicinal herb is not recommended during pregnancy because the effects are not fully known. Studies in pregnant rats, mice, guinea pigs, and monkeys suggest that it is safe for those animals, but safety in pregnant women has not been tested.

References

Ammon H. P. T, et.al., Pharmacology of Curcuma longa. Planta Medica., 57:1-7 (1991). Arbiser J. L., et.al., Curcumin is an in vivo inhibitor of angiogenesis. Mol Med.,4(6):376-383 (1998).
Asai A., et.al., Dietary curcuminoids prevent high-fat diet-induced lipid accumulation in rat liver and epididymal adipose tissue. J Nutr., 131(11):2932-2935 (2001).
Dorai T, Cao YC, Dorai B, Buttyan R, Katz AE. Therapeutic potential of curcumin in human prostate cancer. III. Curcumin inhibits proliferation, induces apoptosis, and inhibits angiogenesis of LNCaP prostate cancer cells in vivo. Prostate, 47(4):293-303 (2001).
Dorai T, Gehani N, Katz A. Therapeutic potential of curcumin in human prostate cancer. II. Curcumin inhibits tyrosine kinase activity of epidermal growth factor receptor and depletes the protein. Mol Urol., 4(1):1-6 (2000).
Gescher A J, Sharma R A, Steward W P. Cancer chemoprevention by dietary constituents: a tale of failure and promise. Lancet Oncol., 2(6):371-379 (2001).
Kawamori T., et. al., Chemopreventive effect of curcumin, a naturally occurring anti-inflammatory agent, during the promotion/progression stages of colon cancer. Cancer Res., 59:597-601 (1999).
Kim M. S., et.al., Inhibition of invasion and induction of apoptosis by curcumin in H-ras-transformed MCF10A human breast epithelial cells. Arch Pharm Res., 24(4):349-354 (2001).
Verma S.P., et.al., Curcumin and genistein, plant natural products, show synergistic inhibitory effects on the growth of human breast cancer MCF-7 cells induced by estrogenic pesticides. Biochem Biophys Res Commun.; 233(3): 692-696, (1997).
Stoner G. D., et.el., Polyphenols as cancer chemopreventive agents. J Cell Biochem Suppl., 22:169-180 (1995).
Blumenthal M, Goldberg A, Brinckmann J. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Integrative Medicine Communications, 379-384 (2000).
Curcuma longa (turmeric). Monograph. Altern Med Rev., 6 Suppl:S62-S66 (2001).
Phan T. T., et.al., Protective effects of curcumin against oxidative damage on skin cells in vitro: its implication for wound healing. J Trauma, 51(5):927-931 (2001).
Luper S., A review of plants used in the treatment of liver disease: part two. Altern Med Rev., 4(3):178-188 (1999).
Kulkarni R. R., et.al., Treatment of osteoarthritis with a herbomineral formulation: a double-blind, placebo-controlled, cross-over study. J Ethnopharmacol.33(1-2):91-95 (1991).
Ramirez-Tortosa M. C.,et al. Oral administration of a turmeric extract inhibits LDL oxidation and has hypocholesterolemic effects in rabbits with experimental atherosclerosis. Atherosclerosis. 147(2):371-378 (1999).
Chainani-Wu N., Safety and anti-inflammatory activity of curcumin: a component of tumeric (Curcuma longa). J Altern Complement Med., 9(1):161-8 (2003).