Curcumin latest hopeful element to fight diseaseSpice in curry may be therapy for major illnesses
Tom Blackwell, National Post
Tumeric may be useful to fight such diseases as Alzheimer's. Chuck Kennedy, Krt Files
Canadian researchers have discovered another potentially remarkable health benefit of the spice that gives Indian curry its distinctive yellow hue, adding to a growing but controversial body of evidence around cur-cumin's disease-fighting possibilities.
Treatment with the key ingredient in tumeric prevented diabetes-related damage to kidneys in rats, the University of Western Ontario scientists found, pointing to a possible therapy for a leading cause of disease and death in Canada.
Other researchers have found curcumin attacks cancer, stymies heart failure and curbs the effects of Alzheimer's -- at least in animals -- and appears to have no toxic side effects. Some of the results have been replicated in human trials, although the evidence is far from conclusive.
"Curcumin is so safe and so cheap," said Bharat Aggarwal, a professor at the University of Texas's respected M. D. Anderson Cancer Center, and one of the ingredient's main boosters. "I really think it is a win-win situation all the way."
It is difficult, however, to find funding for the larger-scale studies of actual patients needed to prove the compound's efficacy, as corporations are reluctant to invest in a commonplace, inexpensive substance they cannot patent, said Prof. Aggarwal, a biochemist.
Other experts, meanwhile, warn against reading too much into the findings so far, noting that other, once-promising natural-health products, such as vitamin E, turned out to be medicinal duds when tested in human trials involving hundreds or thousands of people.
"We see time and time again that something looks promising in the laboratory or in animal studies and ends up not being effective in the human body, because the physiology is so complex," said Heather Chappell, a senior manager at the Canadian Cancer Society.
Still, curcumin, the yellow pigment in the spice tumeric, has generated considerable research and some intriguing results. The theory is that its anti-oxidant and anti-inflammatory properties can essentially turn off some of the molecular triggers responsible for a variety of illness.
In the latest study, Western scientists induced diabetes in rats, then treated them for a month with injections of concentrated curcumin. The spice prevented or curbed various types of kidney damage seen in diabetics, says a paper just published in the journal Nutrition.
"It has got good potential," said Dr. Subrata Chakrabarti, the UWO pathologist and diabetes researcher who led the work. Kidney complications caused by diabetes are one of the chief causes of renal failure leading to dialysis, kidney transplant or death.
Dr. Chakrabarti said he and his colleagues would now like to repeat the experiment in diabetes patients.
Last year, a team at Toronto's University Health Network released a study of mice that found curcumin prevented and dramatically reversed enlargement of the heart, which can lead to heart failure.
There have been similarly promising results in animals for breast, ovarian, pancreatic and other cancers, Alzheimer's disease, bowel disease such as Crohn's and diabetes, said Prof. Aggarwal.
Numerous small human trials have been completed or are underway, with some positive findings. In a Cleveland Clinic trial published in 2006, for instance, five patients saw their pre-cancerous colorectal polyps decreased in size and number under curcumin treatment, with better results than a drug approved for such treatment.
Dr. Aggarwal also points to circumstantial evidence from India, where tumeric is a dietary staple. Even after adjusting statistics for age in a country where many people die before reaching the peak years for developing cancer, the rates of most cancers are tenfold to 50-fold lower than in the United States, says a 2004 paper he co-authored.
Prof. Aggarwal acknowledges that large, blinded trials that compare curcumin to other treatments and placebos are needed to truly establish its effectiveness and safety. But he is sufficiently convinced by the existing evidence that he recommends people take 500 mg. a day in supplement form as a preventive measure.
Canadian patient groups, however, are much more skeptical and do not recommend patients turn to what they consider a still-unproven therapy.
"We unfortunately see a lot of these things that come and go," said Dr. Vincent Woo, chairman of the Canadian Diabetes Association's clinical and scientific section, which helped fund the UWO study. "We don't want to give false hope to our patients."
As a cautionary tale, scientists point to vitamin E, which laboratory, animal and some human studies suggested was a fighter against cancer and heart disease.
Huge, sophisticated trials published in recent months, though, found that vitamin E did not protect against cancer, cardiovascular disease or stroke in middle-aged men and women.
A major thrust of medical science lately has been to isolate substances from the fruits and vegetables shown to be protective against many chronic diseases, and see if they could act as more powerful medicines in a concentrated form, noted Dr. Neil Fleshner, head of urology at Toronto's Princess Margaret Hospital.
"Unfortunately, the vast majority don't pan out," he said.
tblackwell@nationalpost.com
http://www.nationalpost.com/news/canada/story.html?id=1387998
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