A Potent, Yet Safe Anti-Inflammatory
The volatile oil fraction of turmeric has demonstrated significant anti-inflammatory activity in a variety of experimental models. Even more potent than its volatile oil is the yellow or orange pigment of turmeric, which is called curcumin. Curcumin is thought to be the primary pharmacological agent in turmeric. In numerous studies, curcumin's anti-inflammatory effects have been shown to be comparable to the potent drugs hydrocortisone and phenylbutazone as well as over-the-counter anti-inflammatory agents such as Motrin. Unlike the drugs, which are associated with significant toxic effects (ulcer formation, decreased white blood cell count, intestinal bleeding), curcumin produces no toxicity.
An Effective Treatment for Inflammatory Bowel Disease
Curcumin may provide an inexpensive, well-tolerated, and effective treatment for inflammatory bowel disease (IBD) such as Crohn's and ulcerative colitis, recent research suggests. In this study, mice given an inflammatory agent that normally induces colitis were protected when curcumin was added to their diet five days beforehand. The mice receiving curcumin not only lost much less weight than the control animals, but when researchers checked their intestinal cell function, all the signs typical of colitis (mucosal ulceration, thickening of the intestinal wall, and the infiltration of inflammatory cells)were all much reduced. While the researchers are not yet sure exactly how curcumin achieves its protective effects, they think its benefits are the result of not only antioxidant activity, but also inhibition of a major cellular inflammatory agent called NF kappa-B. Plus, an important part of the good news reported in this study is the fact that although curcumin has been found to be safe at very large doses, this component of turmeric was effective at a concentration as low as 0.25 per cent—an amount easily supplied by simply enjoying turmeric in flavorful curries.
Relief for Rheumatoid Arthritis
Clinical studies have substantiated that curcumin also exerts very powerful antioxidant effects. As an antioxidant, curcumin is able to neutralize free radicals, chemicals that can travel through the body and cause great amounts of damage to healthy cells and cell membranes. This is important in many diseases, such as arthritis, where free radicals are responsible for the painful joint inflammation and eventual damage to the joints. Turmeric's combination of antioxidant and anti-inflammatory effects explains why many people with joint disease find relief when they use the spice regularly. In a recent study of patients with rheumatoid arthritis, curcumin was compared to phenylbutazone and produced comparable improvements in shortened duration of morning stiffness, lengthened walking time, and reduced joint swelling.
Help for Cystic Fibrosis Sufferers
Curcumin, the major constituent of turmeric that gives the spice its yellow color, can correct the most common expression of the genetic defect that is responsible for cystic fibrosis, suggests an animal study published in the Science (April 2004). Cystic fibrosis, a fatal disease that attacks the lungs with a thick mucus, causing life-threatening infections, afflicts about 30,000 American children and young adults, who rarely survive beyond 30 years of age. The mucus also damages the pancreas, thus interfering with the body's ability to digest and absorb nutrients.
Researchers now know that cystic fibrosis is caused by mutations in the gene that encodes for a protein (the transmembrane conductance regulator or CFTR). The CTFR protein is responsible for traveling to the cell's surface and creating channels through which chloride ions can leave the cell. When the protein is abnormally shaped because of a faulty gene, this cannot happen, so chloride builds up in the cells, which in turn, leads to mucus production.
The most common mutation, which is called DeltaF508, results in the production of a misfolded protein. When mice with this DeltaF508 defect were given curcumin in doses that, on a weight-per-weight basis, would be well-tolerated by humans, curcumin corrected this defect, resulting in a DeltaF508 protein with normal appearance and function. In addition, the Yale scientists studying curcumin have shown that it can inhibit the release of calcium, thus allowing mutated CTFR to exit cells via the calcium channels, which also helps stop the chloride-driven build up of mucus. Specialists in the treatment of cystic fibrosis caution, however, that patients should not self-medicate with dietary supplements containing curcumin, until the correct doses are known and any adverse interactions identified with the numerous prescription drugs taken by cystic fibrosis sufferers.
Cancer Prevention
Curcumin's antioxidant actions enable it to protect the colon cells from free radicals that can damage cellular DNA—a significant benefit particularly in the colon where cell turnover is quite rapid, occuring approximately every three days. Because of their frequent replication, mutations in the DNA of colon cells can result in the formation of cancerous cells much more quickly. Curcumin also helps the body to destroy mutated cancer cells, so they cannot spread through the body and cause more harm. A primary way in which curcumin does so is by enhancing liver function. Additionally, other suggested mechanisms by which it may protect against cancer development include inhibiting the synthesis of a protein thought to be instrumental in tumor formation and preventing the development of additional blood supply necessary for cancer cell growth.
Inhibits Cancer Cell Growth and Metastases
Epidemiological studies have linked the frequent use of turmeric to lower rates of breast, prostate, lung and colon cancer; laboratory experiments have shown curcumin can prevent tumors from forming; and research conducted at the University of Texas suggests that even when breast cancer is already present, curcumin can help slow the spread of breast cancer cells to the lungs in mice.
In this study, published in Biochemical Pharmacology (September 2005), human breast cancer cells were injected into mice, and the resulting tumors removed to simulate a mastectomy. The mice were then divided into four groups. One group received no further treatment and served as a control. A second group was given the cancer drug paclitaxel (Taxol); the third got curcumin, and the fourth was given both Taxol and curcumin.
After five weeks, only half the mice in the curcumin-only group and just 22% of those in the curcumin plus Taxol group had evidence of breast cancer that had spread to the lungs. But 75% of the mice that got Taxol alone and 95% of the control group developed lung tumours.
How did curcumin help? "Curcumin acts against transcription factors, which are like a master switch," said lead researcher, Bharat Aggarwal. "Transcription factors regulate all the genes needed for tumors to form. When we turn them off, we shut down some genes that are involved in the growth and invasion of cancer cells.
In another laboratory study of human non-Hodgkin's lymphoma cells published in Biochemical Pharmacology (September 2005), University of Texas researchers showed that curcumin inhibits the activation of NF-kappaB, a regulatory molecule that signals genes to produce a slew of inflammatory molecules (including TNF, COX-2 and IL-6) that promote cancer cell growth. In addition, curcumin was found to suppress cancer cell proliferation and to induce cell cycle arrest and apoptosis (cell suicide) in the lung cancer cells. Early phase I clinical trials at the University of Texas are now also looking into curcumin's chemopreventive and therapeutic properties against multiple myeloma and pancreatic cancer, and other research groups are investigating curcumin's ability to prevent oral cancer.
Improved Liver Function
In a recent rat study conducted to evaluate the effects of turmeric on the liver's ability to detoxify xenobiotic (toxic) chemicals, levels of two very important liver detoxification enzymes (UDP glucuronyl transferase and glutathione-S-transferase) were significantly elevated in rats fed turmeric as compared to controls. The researchers commented, "The results suggest that turmeric may increase detoxification systems in addition to its anti-oxidant properties...Turmeric used widely as a spice would probably mitigate the effects of several dietary carcinogens."
Curcumin has been shown to prevent colon cancer in rodent studies. When researchers set up a study to analyze how curcumin works, they found that it inhibits free radical damage of fats (such as those found in cell membranes and cholesterol), prevents the formation of the inflammatory chemical cyclooxygenase-2 (COX-2), and induces the formation of a primary liver detoxification enzyme, glutathione S-transferase (GST) enzymes. When the rats were given curcumin for 14 days, their livers' production of GST increased by 16%, and a marker of free radical damage called malondialdehyde decreased by 36% when compared with controls. During this two week period, the researchers gave the rats a cancer-causing chemical called carbon tetrachloride. In the rats not fed curcumin, markers of free radical damage to colon cells went up, but in the rats given turmeric, this increase was prevented by dietary curcumin. Lastly, the researchers compared giving turmeric in the diet versus injecting curcumin into the rats' colons. They found injecting curcumin resulted in more curcumin in the blood, but much less in the colon mucosa. They concluded, "The results show that curcumin mixed with the diet achieves drug levels in the colon and liver sufficient to explain the pharmacological activities observed and suggest that this mode of administration may be preferable for the chemoprevention of colon cancer."
Cardiovascular Protection
Curcumin may be able to prevent the oxidation of cholesterol in the body. Since oxidized cholesterol is what damages blood vessels and builds up in the plaques that can lead to heart attack or stroke, preventing the oxidation of new cholesterol may help to reduce the progression of atherosclerosis and diabetic heart disease. In addition, turmeric is a good source of vitamin B6, which is needed to keep homocysteine levels from getting too high. Homocysteine, an intermediate product of an important cellular process called methylation, is directly damaging to blood vessel walls. High levels of homocysteine are considered a significant risk factor for blood vessel damage, atherosclerotic plaque build-up, and heart disease; while a high intake of vitamin B6 is associated with a reduced risk of heart disease.
In research published in the Indian Journal of Physiology and Pharmacology, when 10 healthy volunteers consumed 500 mg of curcumin per day for 7 days, not only did their blood levels of oxidized cholesterol drop by 33%, but their total cholesterol droped 11.63% , and their HDL (good cholesterol) increased by 29%! (Soni KB, Kuttan R).
How Turmeric Lowers Cholesterol
Tumeric's cholesterol-lowering effects are the result of the curry spice's active constituent, curcumin, which research reveals is a messaging molecule that communicates with genes in liver cells, directing them to increase the production of mRNA (messenger proteins) that direct the creation of receptors for LDL (bad) cholesterol. With more LDL-receptors, liver cells are able to clear more LDL-cholesterol from the body.
LDL-receptor mRNA increased sevenfold in liver cells treated with curcumin at a concentration of 10 microM, compared to untreated cells. (Liver cells were found to tolerate curcumin at levels of up to 12. microM for 24 hours). (Peschel D, Koerting R, et al. J Nutr Biochem)
Practical Tips:
Help increase your liver's ability to clear LDL-cholesterol by relying on turmeric, not just for delicious fish, meat or lentil curries, but to spice up healthy sautéed onions, potatoes and/or cauliflower; or as the key flavoring for a creamy vegetable dip. Just mix plain yogurt with a little omega-3-rich mayonnaise and turmeric, salt and pepper to taste. Serve with raw cauliflower, celery, sweet pepper, jicama and broccoli florets. Be sure to choose turmeric rather than prepared curry blends. Recent research indicates the amount of turmeric (and therefore curcumin) in curry blends is often minimal.(Tayyem RF et al.,Nutr Cancer)
For the most curcumin, be sure to use turmeric rather curry powder—a study analyzing curcumin content in 28 spice products described as turmeric or curry powders found that pure turmeric powder had the highest concentration of curcumin, averaging 3.14% by weight. The curry powder samples, with one exception, contained very small amounts of curcumin. (Tayyem RF, Heath DD, et al. Nutr Cancer)
Protection against Alzheimer's Disease
Growing evidence suggests that turmeric may afford protection against neurodegenerative diseases. Epidemiological studies show that in elderly Indian populations, among whose diet turmeric is a common spice, levels of neurological diseases such as Alzheimer's are very low. Concurrently, experimental research conducted recently found that curcumin does appear to slow the progression of Alzheimer's in mice. Preliminary studies in mice also suggest that curcumin may block the progression of multiple sclerosis. While it is still unclear how it may afford protection against this degenerative condition, one theory is that it may interrupt the production of IL-2, a protein that can play a key role in the destruction of myelin, the sheath that serves to protect most nerves in the body.
A number of studies have suggested that curcumin, the biologically active constituent in turmeric, protects against Alzheimer's disease by turning on a gene that codes for the production of antioxidant proteins. A study published in the Italian Journal of Biochemistry (December 2003) discussed curcumin's role in the induction of the the heme oxygenase pathway, a protective system that, when triggered in brain tissue, causes the production of the potent antioxidant bilirubin, which protects the brain against oxidative (free radical) injury. Such oxidation is thought to be a major factor in aging and to be responsible for neurodegenerative disorders including dementias like Alzheimer's disease. Another study conducted jointly by an Italian and U.S. team and presented at the American Physiological Society's 2004 annual conference in Washington, DC, confirmed that curcumin strongly induces expression of the gene, called hemeoxygenase-1 (HO-1) in astrocytes from the hippocampal region of the brain.
Curcumin Crosses Blood-Brain Barrier, May Help Prevent Alzheimer's Disease
Research conducted at UCLA and published in the Journal of Biological Chemistry (December 2004), which has been confirmed by further research published in the Journal of Agricultural and Food Chemistry (April 2006), provides insight into the mechanisms behind curcumin's protective effects against Alzheimer's disease.
Alzheimer's disease results when a protein fragment called amyloid-B accumulates in brain cells, producing oxidative stress and inflammation, and forming plaques between nerve cells (neurons) in the brain that disrupt brain function.
Amyloid is a general term for protein fragments that the body produces normally. Amyloid-B is a protein fragment snipped from another protein called amyloid precursor protein (APP). In a healthy brain, these protein fragments are broken down and eliminated. In Alzheimer's disease, the fragments accumulate, forming hard, insoluble plaques between brain cells.
The UCLA researchers first conducted test tube studies in which curcumin was shown to inhibit amyloid-B aggregation and to dissolve amyloid fibrils more effectively than the anti-inflammatory drugs ibuprofen and naproxen. Then, using live mice, the researchers found that curcumin crosses the blood brain barrier and binds to small amyloid-B species. Once bound to curcumin, the amyloid-B protein fragments can no longer clump together to form plaques. Curcumin not only binds to amyloid-B, but also has anti-inflammatory and antioxidant properties, supplying additional protection to brain cells.
Turmeric Boosts Amyloid Plaque Clearance in Human Alzheimer's Patients
The most active ingredient in turmeric root, bisdemethoxycurcumin, boosts the activity of the immune system in Alzheimer's patients, helping them to clear the amyloid beta plaques characteristic of the disease.
In healthy patients, immune cells called macrophages, which engulf and destroy abnormal cells and suspected pathogens, efficiently clear amyloid beta, but macrophage activity is suppressed in Alzheimer's patients.
Using blood samples from Alzheimer's patients, Drs. Milan Fiala and John Cashman have shown that bisdemethoxycurcumin boosts macrophage activity to normal levels, helping to clear amyloid beta. Fiala and Cashman also observed that bisdemethoxycurcumin was more effective in promoting the clearance of amyloid beta in some patients' blood than others, hinting at a genetic element. Further study revealed the genes involved are MGAT III and Toll-like receptors, which are also responsible for a number of other key immune functions. Bisdemethoxycurcumin enhances the transcription of these genes, correcting the immune defects seen in Alzheimer's patients.
History
Turmeric is native to Indonesia and southern India, where it has been harvested for more than 5,000 years. It has served an important role in many traditional cultures throughout the East, including being a revered member of the Ayurvedic pharmacopeia. While Arab traders introduced it into Europe in the 13th century, it has only recently become popular in Western cultures. Much of its recent popularity is owed to the recent research that has highlighted its therapeutic properties. The leading commercial producers of turmeric include India, Indonesia, China, the Philippines, Taiwan, Haiti and Jamaica.
Tips for Preparing and Cooking
Tips for Preparing Turmeric
Be careful when using turmeric since its deep color can easily stain. To avoid a lasting stain, quickly wash any area with which it has made contact with soap and water. To prevent staining your hands, you might consider wearing kitchen gloves while handling turmeric.
How to Enjoy
A Few Quick Serving Ideas
- Add turmeric to egg salad to give it an even bolder yellow color.
- Mix brown rice with raisins and cashews and season with turmeric, cumin and coriander.
- Although turmeric is generally a staple ingredient in curry powder, some people like to add a little extra of this spice when preparing curries. And turmeric doesn't have to only be used in curries. This spice is delicious on healthy sautéed apples, and healthy steamed cauliflower and/or green beans and onions. Or, for a creamy, flavor-rich, low-calorie dip, try mixing some turmeric and dried onion with a little omega-3-rich mayonnaise, salt and pepper. Serve with raw cauliflower, celery, sweet pepper, jicama and broccoli florets.
- Turmeric is a great spice to complement recipes that feature lentils.
- Give salad dressings an orange-yellow hue by adding some turmeric powder to them.
- For an especially delicious way to add more turmeric to your healthy way of eating, cut cauliflower florets in half and healthy sauté with a generous spoonful of turmeric for 5 minutes. Remove from the heat and toss with olive oil, salt and pepper to taste.
