Curcumin – the active ingredient in turmeric spice – is sometimes touted as having ‘miracle’ medicinal qualities for those who consume it.
But the largest study done to date on human patients shows curcumin is “no better than nothing” in preventing inflammation and complications in patients undergoing elective surgery for aortic aneurysm repair, according to a large randomized controlled trial with results published Monday in the CMAJ (Canadian Medical Association Journal).
“Turmeric has been used for thousands of years in Indian and Chinese medicine, and curcumin continues to gain popularity today as a natural health supplement,” said lead author Dr. Amit Garg, Professor of Medicine at Western’s Schulich School of Medicine and Dentistry and a researcher at Lawson Health Research Institute.
“In this randomized trial, the largest to date, perioperative oral curcumin did not ameliorate the complications of elective abdominal aortic aneurysm repair.”
Despite the increasing popularity of curcumin, and many animal studies showing benefit, few rigorous clinical trials have looked at its effects in humans.
This study at 10 hospitals enrolled 606 patients, all scheduled for elective surgery to repair abdominal aortic aneurysms, to test the hypothesis that curcumin reduces inflammation and improves outcomes of surgery.
The patients received either high-dose oral curcumin (2000 mg twice a day over four days) or placebo before surgery.
Compared with a placebo, curcumin did not reduce inflammation; and in secondary analysis, patients in the cucumin group had an increased risk of post-surgical kidney damage .
“Our findings emphasize the importance of testing turmeric and curcumin in rigorous human clinical trials before espousing any health benefits, as is currently done in the popular media,” caution the authors.
The study was funded by the Canadian Institutes of Health Research (CIHR).
In a related editorial, CMAJ deputy editors Kirsten Patrick and Matthew Stanbrook write, “No one should be shocked by the findings of the study by Garg and colleagues. This is how science works. It’s deeply disappointing when a promising compound is shown to be no better than nothing. But it happens every day.”
Natural health products are not subject to the same rigorous evaluation as pharmaceutical products, and we need studies that evaluate these products. Many people assume that natural products are safe, but many natural substances, such as caffeine and tobacco, can be harmful, they said.
“With natural health products, the marketing most often comes first – usually based on few small, nonrandomized and unblinded studies at best – and the good science usually fails to follow,” they said.
“Natural health products should be subject to a high standard of scientific testing, journals should publish and promote these high-quality studies for the public good, and purveyors of natural health products need to be as willing – or should be regulated to be as willing –to admit that their health claims are wrong when good science demonstrates them to be so,” they concluded.