WATERCRESS MIGHT CUT CANCER RISK IN SMOKERS

(The following is an edited article from the Associated Press originally released on March 27, 1996)

A substance found in watercress, Chinese cabbage, and turnips might be able to cut lung cancer risk in smokers, a preliminary study suggests. The substance can prevent a particular compound in cigarette smoke from causing lung cancer in rats and the study of smokers who ate watercress found evidence it might do the same in people.

The study was conducted by Dr. Stephen Hecht, a researcher with the American Health Foundation of Valhalla, New York. Hecht's goal is to develop a pill for smokers who can't kick the habit. Such a pill would contain the watercress substance and others that would block lung cancer by several chemical pathways. Hecht presented his findings recently at a seminar in San Francisco sponsored by the American Cancer Society. Hecht's study, which received no funding from the tobacco industry, focused on a substance called PEITC. In rats, it blocks lung cancer caused by a substance called NNK that is found in tobacco smoke. NNK causes cancer only after it has been chemically activated in the body. PEITC blocks this process.

To test PEITC's effects in people, Hecht and colleagues tracked what happened when smokers ate watercress. Eleven smokers ate two ounces of watercress at each meal for three days while keeping their cigarette consumption constant. Scientists looked in urine samples before and afterwards to study chemical signs of how the smokers' bodies were handling NNK. Results showed that during the watercress period, the output of two substances that result from breakdown of NNK rose about 30 percent. According to Hecht, that indicates that the dangerous activation of NNK was being blocked, leaving more NNK to be handled by other chemical processes. This effect appeared in 7 of the 11 smokers.

Dr. Hecht's study was received with skepticism by Dr. Yasmin Thanavala of the Roswell Park Cancer Institute in Buffalo, New York. He pointed out that the right message to be sending is "not to smoke." He claimed that studies such as Dr. Hecht's were counterproductive to the overall health of society: "Once it is ingrained in the public's mind that there is a pill to counteract the destructive properties of smoking, it will be even harder and harder to convince people to stop smoking. It will ultimately mean that the public will come to expect a pill to fix virtually all of the activities and habits that stand in the way of public health."

Dr. Peter Greenwald, director of cancer prevention and control at the National Cancer Institute, however, praised Hecht's efforts. He maintained that Hecht's work is important because it shows in people that the idea of preventing cancer with certain substances is plausible.