A small but informative clinical trial by Johns
Hopkins investigators shows that a pill combining chemicals
found in turmeric, a spice used in curries, and onions
reduces both the size and number of precancerous lesions in
the human intestinal tract.
In the study, published in the August issue of
Clinical Gastroenterology and Hepatology, five
patients with an inherited form of precancerous polyps in
the lower bowel known as familial adenomatous polyposis, of
FAP, were treated over an average of six months with
regular doses of curcumin, the chemical found in turmeric,
and quercetin, an antioxidant in onions. The average number
of polyps dropped 60.4 percent, and the average size
dropped by 50.9 percent, according to a team led by
gastroenterologist Francis M. Giardiello, a professor
at the School of Medicine, and Marcia Cruz-Correa, a
visiting professor from the University of Puerto Rico
School of Medicine.
"We believe this is the first proof of principle that
these substances have significant effects in patients with
FAP," Giardiello said.
Familial adenomatous polyposis is a disorder that runs
in families and is characterized by the development of
hundreds of colorectal adenomas (polyps) and eventual colon
cancer. Recently, nonsteroidal anti-inflammatory drugs,
known as NSAIDs, have been used to treat some patients with
this condition, but these compounds often produce
significant side effects, including gastrointestinal
ulcerations and bleeding.
Previous observational studies in populations that
consume large amounts of curry, as well as laboratory
research on rodents, have strongly suggested that curcumin
— a relatively innocuous yellow pigment extracted
from turmeric, the powdered root of the herb curcuma longa
and one of the main ingredients in Asian curries —
might be effective in preventing and/or treating cancer in
the lower intestine, according to Cruz-Correa. Curcumin has
been given to cancer patients, she said, and previous
studies have demonstrated that it is well tolerated at high
Similarly, quercetin — a member of a group of
plant-derived polyphenolic anti-oxidant substances known as
flavanoids (found in a variety of foods including onions,
green tea and red wine) — has been shown to inhibit
growth of colon cancer cell lines in humans and abnormal
colorectal cells in rodents.
Although these substances were administered together,
Giardiello said that due to their relative dose levels, he
believes that curcumin is the key 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, since turmeric only contains on average 3
percent to 5 percent curcumin by weight," Giardiello said.
Because of this, he cautions that simply consuming curry
and onions may not have the same effect as was produced in
In the trial, five patients were selected from the
Cleveland Clinic Florida. All had previously had their
colons surgically removed; four of the five retained the
rectums, whereas the remaining patient had had both colon
and rectum removed and part of the small intestine adapted
to serve as colon and rectum. All patients had five or more
adenomas in their lower intestinal tract. None of the
patients had taken NSAIDS for more than one week during the
three months leading up to the study.
Participants were examined using a flexible
sigmoidoscope before treatment was initiated and at
three-month intervals (range three to nine months) during
treatment. Number and size of polyps were examined at each
Each patient received 480 milligrams of curcumin and
20 milligrams of quercetin orally three times a day for six
months and was told not to use NSAIDs for the duration of
the study. Three patients followed treatment as prescribed.
One patient did not follow the scheduled treatment doses
between months three and six and was continued on therapy
until the ninth month. Another patient dropped out of the
study after the third month.
A decrease in polyp number was observed in four of the
five patients at three months and four of the four patients
at six months.
Side effects were minimal. One patient reported slight
nausea and a sour taste within a couple of hours of taking
the pill, an effect that went away within three days, and a
second patient had mild diarrhea for five days.
"This study showed for the first time that curcumin
treatment was efficacious in decreasing the number of
polyps in patients with FAP, similar to what has been seen
with the use of synthetic NSAID agents but with minimal
side effects. Furthermore, we saw that adenomas found in
the small intestine of our patients also responded to
curcumin," Cruz-Correa said.
A randomized clinical trial involving more patients
will be conducted at Johns Hopkins and the University of
Puerto Rico Comprehensive Cancer Center, she said. No date
has been set for this trial.
This study was supported by a grant from the National
Institutes of Health. Additional researchers who
contributed to this study are Daniel A. Shoskes, Patricia
Sanchez, Rhongua Zhao and Steven D. Wexner, all of the
Cleveland Clinic Florida; and Linda M. Hylind, of the Johns
Hopkins School of Medicine.