Alternative Therapies: Turmeric
Turmeric (Curcuma domestica, Curcuma longa) is a member of the ginger family (Zingiberaceae) and is thought to be indigenous to the Indian subcontinent. It is grown and harvested commercially in India, China, and many regions of tropical south Asia. Turmeric is best known for its culinary use as a major component of curry powder. In the United States, turmeric is an approved food additive and is commercially available at low cost. It shows up as a coloring agent in items as diverse as pharmaceuticals, yellow mustards, and cosmetics, as well as in dyes for hair and fur. Indigenous systems of medicine, including the Chinese and Ayurvedic systems, have widely used turmeric for centuries in the treatment of many inflammatory conditions and diseases. In India, turmeric has traditionally been used primarily for arthritic and muscular disorders, while in China it has been used as a topical analgesic and for conditions ranging from flatulence, colic, and ringworm to hepatitis and chest pain.

The turmeric constituent curcumin has been used in Europe for the relief of dyspeptic conditions, including loss of appetite, postprandial feelings of fullness, and liver and gallbladder complaints. Curcumin is used internally in the treatment of rheumatoid arthritis and chronic anterior uveitis, as well as topically for conjunctivitis, skin cancer, smallpox, chickenpox, and, when combined with neem (Azadirachta indica), scabies. It is being investigated as a potential adjuvant immunosuppressive agent for the treatment of several types of cancer and as a colon cancer chemoprotectant.

Turmeric's active constituents are yellowish orange volatile oils called curcuminoids. There is currently great interest in the curcuminoid known as curcumin, which has demonstrated antioxidant, antineoplastic, antiviral, and immunosuppressive activity in vitro and in animals. Curcuminoids inhibit leukotriene biosynthesis via the lipoxygenase pathway and decrease prostaglandin formation. Curcumin has caused apoptosis in various cancer cell lines and animal tumor cells and may inhibit angiogenesis. Curcumin has antiseptic and antiparasitic activity. It preferentially inhibits platelet aggregation induced by platelet-activating factor and arachidonic acid.

In rats and mice, dietary curcumin has demonstrated preventive activity against carcinogenesis in the skin, colon, forestomach, and duodenum. Curcumin blocks certain cyclosporine-resistant pathways of T-cell proliferation and thus may be a potential adjuvant immunosuppressive agent for the treatment of cancer. Case reports of decreases in p24 antigen with the ingestion of 2.5 g of curcumin daily for seven days led to a study of curcumin in 60 patients with HIV infection. (The results have yet to be published.)

Curcumin has an estimated bioavailability of 65% after oral administration. It inhibits cytochrome P-450 isoenzyme 1A1 and is metabolized by glucuronidation.

Neither turmeric nor curcumin has been extensively studied in clinical trials. One clinical trial compared curcumin 1200 mg/day with phenylbutazone 300 mg/day in 18 patients with rheumatoid arthritis under double-blind conditions for an unspecified duration. Both curcumin and phenylbutazone improved morning stiffness, walking time, and swelling, but only phenylbutazone improved what the authors termed fatigue time. The investigators assessed both drugs as producing an overall improvement over baseline. However, the patients rated only phenylbutazone as better for controlling symptoms compared with baseline.

In an open clinical trial, curcumin was administered in an oral dose of 375 mg three times daily for 12 weeks to 53 patients with chronic anterior uveitis. Twentyone patients dropped out of the study for various reasons. After 12 weeks of therapy, symptoms improved in about 90% of the patients who complete the trial. In a three-year follow-up, 47% had repeated episodes of anterior uveitis.

A curcumin 0.5% ointment was tested in an open clinical trial in 62 patients with skin and mucous membrane cancers. The patients applied the ointment three times daily for at least four weeks. A total of 68% of the patients responded (reduction in lesion smell [90%], exudates [70%], and pain [50%]). Long-term follow-up did not occur.

Turmeric root combined with neem in the form of a topical paste was successfully used for scabies in a pilot study.

For arthritis, dosages of 8-60 g of fresh turmeric root three times daily or 400-600 mg of curcumin three times daily have been recommended. For dyspepsia, 1.5-3 g of turmeric root is recommended. Preparations of the root should be standardized to contain not less than 3% curcumin and not less than 3% volatile oils.

Curcumin has been used safely as a culinary spice in Asia for centuries. It is estimated that adults in India ingest 80-200 mg of curcumin daily. There are no reported adverse effects of curcumin or turmeric, except rare cases of allergic contact dermatitis. One case occurred as an occupational illness in a miller working in a spice shop. Many Indian women apply turmeric to their skin in an effort to minimize unwanted hair growth, but few experience dermatitis. Of 62 patients completing an 18-month study of the topical use of curcumin to treat skin and mucous membrane cancers, only 1 reported an adverse effect, scalp itching. Some investigators have reported the potential for gastric ulceration with high-dose curcumin on the basis of animal studies, but the data are inconsistent -- with some studies suggesting antiulcerogenic effects. There has been concern about the possibility of additive antiplatelet activity, although there have been no reports of this in humans.

The German Commission E monographs cite no known interactions of curcumin with drugs. Because of the possibility of additive anti-platelet activity, caution should be taken with respect to concurrent use of curcumin with anticoagulants and with medications and dietary supplements known to have antiplatelet activity. Some references have suggested that curcumin decreases the effect of immunosuppressants without providing supporting data.

The American Herbal Products Association classifies turmeric as a menstrual stimulant, and some sources recommend avoiding curcumin in pregnancy. Its use is not recommended during breast-feeding, as effects on breast-feeding infants are unknown. Turmeric should be avoided in patients with bleeding disorders and bile duct obstruction and should be used only under the supervision of a physician in patients with gallstones.

Although the quality of the available clinical studies is questionable, turmeric appears generally safe. Well-designed clinical trials are probably warranted to clarify turmeric's role, if any, in the prevention and treatment of several cancers, as well as in the treatment of rheumatoid arthritis and several ocular conditions.