Turmeric is a widely used tropical herb in the ginger family. Its stalk is used both in food and medicine, yielding the familiar yellow ingredient that colors and adds flavor to curry. In the traditional Indian system of herbal medicine known as Ayurveda, turmeric is believed to strengthen the overall energy of the body, relieve gas, dispel worms, improve digestion, regulate menstruation, dissolve gallstones, and relieve arthritis, among other uses.
Modern interest in turmeric began in 1971 when Indian researchers found evidence suggesting that turmeric may possess anti-inflammatory properties. Much of this observed activity appeared to be due to the presence of a constituent called curcumin. 1 Curcumin is also an antioxidant. 2 Many of the studies mentioned in this article used curcumin rather than turmeric.
What Is Turmeric Used for Today?
Turmeric's antioxidant abilities make it a good food preservative, provided that the food is already yellow in color, and it is widely used for this purpose.
Turmeric has been proposed as a treatment for dypepsia. Dyspepsia is a catchall term that includes a variety of digestive problems such as stomach discomfort, gas, bloating, belching, appetite loss, and nausea. Although many serious medical conditions can cause digestive distress, the term "dyspepsia" is most often used when no identifiable medical cause can be detected.
In Europe, dyspepsia is commonly attributed to inadequate bile flow from the gallbladder. While this has not been proven, turmeric does appear to stimulate the gallbladder. 8 More importantly, one double-blind, placebo-controlled study suggests that turmeric does reduce dyspepsia symptoms. 9 /tnp/testtubestudy
Other proposed uses of turmeric or curcumin have little supporting evidence. Based on test tube and animal studies, and human trials too preliminary to provide any meaningful evidence 3,17,18 curcumin and turmeric are frequently described as anti-inflammatory drugs and recommended for the treatment of such conditions as osteoarthritis and menstrual pain. Some advocates go so far as to state that curcumin is superior to standard medications in the ibuprofen family, because, at standard doses, it does not appear to harm the stomach. 4 However, until turmeric is actually proven to meaningfully reduce pain and inflammation, such a comparison is rather premature. Not only that, high doses of curcumin might in fact increase the risk of ulcers. 5
Contrary to some reports, turmeric does not appear to be effective for treating ulcers. 6,7
Animal and test tube studies suggest (but definitely do not prove) that turmeric might help prevent cancer. 19-26
Some researchers have reported evidence that curcumin or turmeric might help protect the liver from damage. 28-31 However, other researchers have failed to find any liver protective effects, and there are even some indications turmeric extracts can damage the liver when taken in high doses or for an extended period. 32,33
On the basis of even weaker evidence, curcumin or turmeric have also been recommended for preventing cataracts, and treating high cholesterol, multiple sclerosis, fungal infections, Alzheimer's disease, and chronic anterior uveitis (an inflammation of the iris of the eye). 12,34-39
What Is the Scientific Evidence for Turmeric?
Dyspepsia
A double-blind placebo controlled study performed in Thailand compared the effects of 500 mg curcumin 4 times daily against placebo, as well as against a locally popular over-the-counter treatment. A total of 116 people were enrolled in the study. After 7 days, 87% percent of the curcumin group experienced full or partial symptom relief from dyspepsia as compared to 53% of the placebo group, and this difference was statistically significant. 9
Dosage
For medicinal purposes, turmeric is frequently taken in a form standardized to curcumin content, at a dose that provides 400 to 600 mg of curcumin 3 times daily.
Safety Issues
Turmeric is on the FDA's GRAS (generally recognized as safe) list, and curcumin, too, is believed to be fairly nontoxic. 1,16 Reported side effects are uncommon and are generally limited to mild stomach distress.
However, there is some evidence to suggest that turmeric extracts can be toxic to the liver when taken in high doses or for a prolonged period of time. 32,33 For this reason, turmeric products should probably be avoided by individuals with liver disease and those who take medications that are hard on the liver.
In addition, due to curcumin's stimulating effects on the gallbladder, individuals with gallbladder disease should use curcumin only on the advice of a physician. However, safety in young children, pregnant or nursing women, and those with severe kidney disease have also not been established.
References
1. Ammon HPT, Wahl MA. Pharmacology of Curcuma longa. Planta Med. 1991;57:1–7.
2. Sreejayan N, Rao MNA. Free radical scavenging activity of curcuminoids. Arzneimittelforschung. 1996;46:169–171.
3. Deodhar SD, Sethi R, Srimal RC. Preliminary study on antirheumatic activity of curcumin (diferuloyl methane). Indian J Med Res. 1980;71:632–634.
4. Srimal RC, Dhawan BN. Pharmacology of diferuloyl methane (curcumin), a non-steroidal anti-inflammatory agent. J Pharm Pharmacol. 1973;25:447–452.
5. Gupta B, Kulshrestha VK, Srivastava RK, et al. Mechanisms of curcumin induced gastric ulcer in rats. Indian J Med Res. 1980;71:806–814.
6. Van Dau N, Ngoc Ham N, Huy Khac D, et al. The effects of a traditional drug, turmeric (Curcuma longa), and placebo on the healing of duodenal ulcer. Phytomedicine. 1998;5:29–34.
7. Kositchaiwat C, Kositchaiwat S, Havanondha J. Curcuma longa Linn. in the treatment of gastric ulcer comparison to liquid antacid: a controlled clinical trial. J Med Assoc Thai. 1993;76:601–605.
8. Rasyid A, Lelo A. The effect of curcumin and placebo on human gall-bladder function: an ultrasound study. Aliment Pharmacol Ther. 1999;13:245–249.
9. Thamlikitkul V, Bunyapraphatsara N, Dechatiwongse T, et al. Randomized double blind study of Curcuma domestica Val. for dyspepsia. J Med Assoc Thai. 1989;72:613–620.
12. Lal B, Kapoor AK, Asthana OP, et al. Efficacy of curcumin in the management of chronic anterior uveitis. Phytother Res. 1999;13:318–322.
14. Ravindranath V, Chandrasekhara N. Absorption and tissue distribution of curcumin in rats. Toxicology. 1980;16:259–265.
16. Shankar TNB, Shantha NV, Ramesh HP, et al. Toxicity studies on turmeric ( Cucurma longa): acute toxicity studies in rats, guinea pigs and monkeys. Indian J Exp Biol. 1980;18:73–75.
17. Ruby AJ, Kuttan G, Babu KD, et al. Anti-tumour and antioxidant activity of natural curcuminoids. Cancer Lett. 1995;79-83.
18. Satoskar RR, Shah SJ, Shenoy SG. Evaluation of anti-inflammatory property of curcumin (diferuloyl methane) in patients with postoperative inflammation. Int J Clin Pharmacol Ther Toxicol. 1986 Dec;24(12):651-654.
19. Afaq F, Adhami VM, Ahmad N, et al. Botanical antioxidants for chemoprevention of photocarcinogenesis. Front Biosci. 2002;7:d784-92.
20. Arbiser JL, Klauber N, Rohan R, et al. Curcumin is an in vivo inhibitor of angiogenesis. Mol Med. 1998;4:376-383.
21. Cheng AL, Hsu CH, Lin JK, et al. Phase I clinical trial of curcumin, a chemopreventive agent, in patients with high-risk or pre-malignant lesions. Anticancer Res. 2001;21:2895-2900.
22. Deshpande SS, Ingle AD, Maru GB. Chemopreventive efficacy of curcumin-free aqueous turmeric extract in 7,12-dimethylbenz(a)anthracene-induced rat mammary tumorigenesis. Cancer Lett. 1998;123:35-40.
23. Dorai T, Gehani N, Katz A. Therapeutic potential of curcumin in human prostate cancer. Curcumin inhibits tyrosine kinase activity of epidermal growth factor receptor and depletes the protein. Mol Urol. 2000;4:1-6.
24. Ireson CR, Jones DJ, Orr S, et al. Metabolism of the cancer chemopreventive agent curcumin in human and rat intestine. Cancer Epidemiol Biomarkers Prev. 2002;11:105-111.
25. Krishnaswamy K, Goud VK, Sesikeran B, et al. Retardation of experimental tumorigenesis and reduction in DNA adducts by turmeric and curcumin. Nutr Cancer. 1998;30:163-166.
26. Li JK, Lin-Shia SY. Mechanisms of cancer chemoprevention by curcumin. Proc Natl Sci Counc Repub China B. 2001;25:59-66.
27. Smith WA, Freeman JW, Gupta RC. Effect of chemopreventive agents on DNA adduction induced by the potent mammary carcinogen dibenzo[a,l]pyrene in the human breast cells MCF-7. Mutat Res. 2001;480-481:97-108.
28. Chuang S, Cheng A, Lin J, Kuo M. Inhibition by curcumin of diethylnitrosamine-induced hepatic hyperplasia, inflammation, cellular gene products and cell-cycle related proteins in rats. Food Chem Toxicol. 2000;38(11):991-995.
29. Deshpande UR, Gadre SG, Raste AS, et al. Protective effect of turmeric (Curcuma longa L) extract on carbon tetrachloride-induced liver damage in rats. Indian J Exp Biol. 1998;36:573-577.
30. Song EK, Cho H, Kim JS, et al. Diarylheptanoids with free radical scavenging and hepatoprotective activity in vitro from Curcuma longa. Planta Med. 2001;67:876-877
31. Venkatesan N. Pulmonary protective effects of curcumin against paraquat toxicity. Life Sci. 2000;66:PL21-28.
32. Deshpande S, et al. Subchronic oral toxicity of turmeric and ethanolic turmeric extract in female mice and rats. Toxicology Letters. 1998;95:183-193.
33. Kandarkar SV, Sawant SS, Ingle AD, et al. Subchronic oral hepatotoxicity of turmeric in mice--histopathological and ultrastructural studies. Indian J Exp Biol. 1998 Jul;36(7):675-679.
34. Babu PS, et al. Hypolipidemic action of curcumin, the active principle of turmeric (Curcuma longa) in streptozocin induced diabetic rats. Mol Cell Biochem. 1997;166:169–175.
35. Rao DS, et al. Effect of curcumin on serum and liver cholesterol levels in the rat. J Nutr. 1970;100: 1307–1316.
36. Srinivasan K, et al. The effect of spices on cholesterol 7 alpha-hydroxylase activity and on serum and hepatic cholesterol levels in the rat. Int J Vitam Nutr Res. 1991;61: 364–369.
37. Lim GP, Chu T, Yang F, et al. The curry spice curcumin reduces oxidative damage and amyloid pathology in an Alzheimer transgenic mouse. J Neurosci. 2001;21:8370–8377.
38. Awasthi S, Srivatava SK, Piper JT, et al. Curcumin protects against 4-hydroxy-2-trans-nonenal-induced cataract formation in rat lenses. Am J Clin Nutr. 1996;64:761-766.
39. Apisariyakul A, Vanittanakom N, Buddhasukh D. Antifungal activity of turmeric oil extracted from Curcuma longa (Zingiberaceae). J Ethnopharmacol. 1995;49:163-169.
http://www.swedish.org/110864.cfm
What Is the Scientific Evidence for Turmeric?
For medicinal purposes, turmeric is frequently taken in a form standardized to curcumin content, to provide 400 to 600 mg of curcumin 3 times daily.
Unfortunately, curcumin is not absorbed well by the body.14 It is often sold in combination with bromelain for the supposed purpose of enhancing absorption. While there is no evidence or even sensible reason to believe that this strategy works, bromelain possesses some anti-inflammatory powers of its own that may add to those of curcumin.
http://www.nutritionresource.com/substance.cfm?id=92
http://healthresources.caremark.com/GetHerbContent.do?primerid=100227016&name...
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