BALTIMORE -- Chemicals in curry and onions may put the heat on colorectal cancer, helping to reduce both the size and number of adenomas in patients genetically prone to them.
BALTIMORE, Aug. 2 -- Chemicals in curry and onions may put the heat on colorectal cancer, helping to reduce both the size and number of adenomas in patients genetically prone to them.
In a small pilot study, pills containing curcumin, a substance found in turmeric (a key ingredient of curry), and quercetin, an anti-oxidant derived from onions, kept the adenomas at bay, according to Francis Giardiello, M.D., of Johns Hopkins here.
In what Dr. Giardiello, described as a proof of principle, he and colleagues treated five patients with familial adenomatous polyposis (FAP) for six months with curcumin and quercetin, they reported in the August issue of the journal Clinical Gastroenterology and Hepatology. Patients with familial adenomatous polyposis develop hundreds of adenomas and eventually colon cancer.
The study found:
Although studies has shown that nonsteroidal anti-inflammatory drugs can cause these adenomatous polyps to regress, Dr. Giardiello said, NSAIDs have significant risks, including gastrointestinal ulcerations and bleeding. Curcumin and quercetin, on the other hand, had been shown to have similar benefits in animal studies and were thought to be relatively innocuous.
The five patients were given 480 mg of curcumin and 20 mg of quercetin orally three times a day for six months. Three patients followed the therapy properly, and one dropped out in the third month of the study.
Interestingly, a fifth patient stopped taking the medication properly in the third month of the study -- at a time when the adenomas had regressed -- and saw the polyps return. The patient was re-instructed about the study protocol and continued on therapy for another three months; the polyps regressed again, Dr. Giardiello said.
Although the two chemicals were given together, Dr. Giardiello thinks that curcumin is the key. "The amount of quercetin we administered was similar to what many people consume daily," he said. "However, the amount of curcumin is many times what a person might ingest in a typical diet."
The turmeric in curry only contains about 5% curcumin by weight, he said, so simply eating curry and onions may not have the same effect as was seen in the study.
Nonetheless, "this study showed for the first time that curcumin treatment was efficacious in decreasing the number of polyps in patients with familial adenomatous polyposis, similar to what has been seen with the use of synthetic NSAID agents, but with minimal side effects," said study Marcia Cruz-Correa, M.D., Ph.D., also of Johns Hopkins, a coauthor.
Dr. Cruz-Correa said the study must be replicated in a larger, placebo-controlled randomized trial. Such a study is planned, she said.