Diets rich in tomato products, such as tomato sauce and ketchup, have long been associated with a reduced risk of various cancers, especially prostate cancer, but the reason for such an action is yet to be found.
Clinical trials have suggested that lycopene, which is found in tomato products and other natural plant nutrients may be effective in preventing prostate cancer and treating the disease in its earliest stages.
Dr. Frederick Khachik, co-author on the study and professor of chemistry and biochemistry at the University of Maryland came forward with the explanation that the combination of these plant nutrients, called phytonutrients, including lycopene, which is highly concentrated in tomato products is responsible for the protective effects against cancer.But the epidemiological studies does not actually prove a cause-and-effect between lycopene and reduced cancer risk.
In their study , the researchers followed 30 men with localized prostate cancer and administered 15 milligrams of lycopene daily to half of them ,while the other half received no intervention for three weeks prior to surgery.Those who were treated had smaller tumors and tumors that were more likely to remain confined to the prostate, as well as lower levels of prostate specific antigen or PSA in serum, a common marker used to detect prostate cancer.
Dr. Edward Giovannucci, professor of Medicine at Harvard Medical School said that as the number is small , it is hard to conclude anything definitive from the study.
Surprisingly, however, people who eat lots of fruits and vegetables do not necessarily have high lycopene levels. A few fruits, such as watermelon, have very low amounts of lycopene. The tomato, however, appears to be unique in its content of lycopene.
The National Cancer Institute is to begin a study soon assessing the effects of pure synthetic lycopene supplements, without other phytonutrients, to distinguish whether it is the lycopene that fights cancer or some other compound.