THURSDAY, March 16, 2006 (HealthDay News) -- Capsaicin, the component that gives jalapeno peppers their heat, may also kill prostate cancer cells, a new study suggests.
Initial experiments in cancer cells and mice show that capsaicin causes prostate cancer cells to undergo a kind of suicide. Researchers speculate that, in the future, pills containing capsaicin might be used as therapy to prevent prostate cancer's return.
According to their report, capsaicin caused almost 80 percent of prostate cancer cells in the mice to die. In addition, prostate cancer tumors treated with capsaicin were about one-fifth the size of tumors in untreated mice.
"Capsaicin inhibits the growth of human prostate cancer cell in Petri dishes and mice," said lead researcher Dr. H. Phillip Koeffler, director of hematology and oncology at Cedars-Sinai Medical Center and a professor of medicine at the University of California, Los Angeles. Based on the findings, Koeffler believe the next step is a trial to see if it works in patients with prostate cancer.
The report appears in the March 15 issue of Cancer Research.
Capsaicin probably has several effects, Koeffler said. Most noticeable is its effect in blocking NF-kappa Beta, a molecular mechanism that promotes cancer cell growth, he noted.
In addition, capsaicin also was effective against leukemia, and might be effective in slowing or preventing the growth of other cancers as well, he added.
But it's still too early to reach for the chili sauce, Koeffler said.
"I am not recommending that people increase their consumption of peppers," he said. "Our calculation is that you would have to eat 10 habanera peppers three times a week, which would be equivalent to the amount of capsaicin we gave to the mice."
The researcher believes capsaicin could someday gain a place in adjuvant prostate cancer therapy. For example, it might be used after prostate surgery to kill cancer cells in patients whose blood PSA levels start to rise, indicating the presence of tumors too small to be seen, he said.
The study does highlight the crossover that can occur between conventional and alternative therapies. "We should take note of herbal medicines and then use modern-day techniques to find what the active compounds are and bring them into clinical trials," Koeffler said.
One expert thinks it's too early to know if capsaicin will ever be an effective prostate cancer treatment, however.
"Since large amounts of capsaicin have never been given to people, we don't know what the side effects might be," cautioned Dr. Len Lichtenfeld, deputy chief medical officer at the American Cancer Society. "We don't know about the right dose or anything."
Lichtenfeld believes that any trial should be done in patients who are not responsive to other standard therapies. "We are ways away from a clinical trial," he said. "We need more basic research before we start treating patients."
Another expert concurred.
"This study does not prove that capsaicin will prove effective in the treatment of prostate cancer in humans," said Dr. David L. Katz, an associate professor of public health and director of the Prevention Research Center at Yale University School of Medicine. "Nor does it tell us that eating peppers rich in the substance will help prevent such cancer, or forestall its growth. But it provides a compelling argument for clinical study of capsaicin in human prostate cancer to put these questions to the test."
"This paper should serve to remind us that herbal remedies and pharmacotherapy are often of common origins, differing only in our capacity to identify, purify and package the active ingredients," Katz said. "This work suggests that the conventional medical community should turn a discriminating eye, rather than a jaded eye, toward time-honored herbal treatments. Many will doubtless prove ineffective when put to the test of high-quality research. But some will pass that test, and we must meticulously distinguish between them."
For more on prostate cancer, head to the National Cancer Institute.