Chemicals in curry, onions may shrink colon polyps

NEW YORK (Reuters Health) - Compounds found in curry and onions may help prevent colon cancer in those at risk, according to findings from a small study released this week.

In the study, patients with pre-cancerous polyps in the colon who took a pill containing a combination of curcumin, which is found in the curry spice turmeric, and quercetin, an antioxidant found in onions, experienced a marked reduction in both the size and number of polyps.

"We believe this is the first proof of principle that these substances have significant effects in patients with FAP (familial adenomatous polyposis)," Dr. Francis M. Giardiello of The Johns Hopkins School of Medicine in Baltimore said in a statement.

FAP is an inherited disorder characterized by the development of colorectal polyps and eventually colon cancer.

The potential of curcumin to prevent and/or treat cancer in the lower intestines surfaced in studies in lab rats fed curry, as well as in observational studies of Asian populations that consume a lot of curry. Quercetin has also been shown to have anti-cancer potential.

In their study, Giardiello and colleagues gave five FAP patients who had five or more polyps in their lower intestinal tract with 480 milligrams of curcumin and 20 milligrams of quercetin three times daily.

"All five patients had a decreased polyp number and size from baseline after a mean of 6 months," the team reports in the medical journal Clinical Gastroenterology and Hepatology.

The average number of polyps dropped by 60 percent, and the average size dropped by 51 percent.

Side effects were minimal. One patient experienced nausea and sour taste within a couple of hours of taking the pill, which subsided after three days and did not recur, and another patient reported mild diarrhea.

Of the two compounds, the researchers believe curcumin is the key cancer-fighting agent. "The amount of quercetin we administered was similar to what many people consume daily; however, the amount of curcumin is many times what a person might ingest in a typical diet," Giardiello explained.

The team says larger trials, comparing curcumin-quercetin capsules with dummy "placebo" pills, are needed to confirm these findings.

SOURCE: Clinical Gastroenterology and Hepatology, August 2006.