What do ginger, a Chinese medicinal herb called Bahn Zhi Lian, and green tea have in common? New research shows that they all help prevent specific types of cancer.
Scientists at the Phoenix, Arizona, conference of the American Association for Cancer Research report that common spices and herbs contain ingredients that may prevent the formation of major tumors.
Take the ginger family, for instance. For thousands of years, it has been used to treat and prevent various illnesses, including nausea and digestive problems. It has even been thought to have anti-cancer properties.
Now, University of Minnesota researcher Ann Bode and colleagues have found that the chemical that makes ginger spicy is effective in preventing and treating colon cancer in mice.
They implanted human colon cancer cells in a strain of mice without immune systems, so they could not reject the cells. Ms. Bode says mice fed an alcohol-water mixture three times a week before and after the injection of the cancer developed tumors much faster than mice given the ginger compound called 6 gingerol. "The tumor growth was monitored, and what we found was that the mice that received the 6 gingerol had a very marked depression of human colon cancer growth," she said.
Two weeks after the Bode team implanted the cancers, the mice fed with the ginger extract developed only about one third the number of tumors than the other group, 13 compared to four. It also took about 35 percent longer for all of them to develop tumors than for the non-ginger-consuming animals, 38 days versus 28.
Ms. Bode does not know how ginger fights cancer, but suggests two possible ways. "It could be directly acting on the colon cancer cells by inducing cell death specifically of those cancer cellsm" she said. "Or it could be also working directly on proteins called transcription factors, such as Activator Protein One, which is a known tumor promoter."
Ms. Bode is planning human trials with the ginger extract.
The herb Bahn Zhi Lian has long been used in Chinese medicine to treat cancers of the liver, lung and rectum. A scientific study by researchers from Union College in Nebraska has found that it also slows the advance of prostate tumors in mice.
Study leader Brian Wong, a Hong Kong native, says the animals were genetically engineered to develop a form of prostate cancer that mimics the human variety. They were fed either eight milligrams or 16 milligrams of a liquid extract of the herb, or merely water. "We found out that feeding the herbs to the animals actually delayed the onset of cancer about four to five weeks," he said. "That translated to be a delay in the onset of prostate cancer in humans of about five years."
Mr. Wong and his associates also found that the herbal extract induced death in 90 percent of human and mice prostate cancer cells in test tubes. To get the same effect seen in mice, Mr. Wong says a person would need 2.5 grams of Bahn Zhi Lian a day.
But Ms. Bode cannot say how much ginger a person should take to stave off colon cancer. "In the popular literature and scientific literature, the doses of ginger root for humans have varied anywhere from two to eight grams three times a day with no toxic effect," she said. "I'm not saying I recommend that, but it does seem to be highly variable. Many people eat a lot of ginger, and it doesn't seem to have any toxicity that's been reported at least."
Other findings reported at the Phoenix cancer research meeting show that drinking green tea helps the body retain an enzyme that inhibits formation of certain types of tumors and lesions, that eating fruits and vegetables reduces breast cancer risk, that a low carbohydrate diet rather than one low in fats may halt the progression of prostate cancer, and that the antioxidant chemicals in grapes and wine decrease the chances of developing skin cancer from exposure to ultraviolet radiation.
Conference organizers hail the results as important in helping understand ways of preventing cancer that do not require extraordinary measures.