Supplements containing the antioxidant lycopene may be ineffective at warding off prostate cancer, researchers said Tuesday.
While tomatoes have been shown to have impressive prostate cancer-fighting properties, early speculation that their potency stems from lycopene has now been called into question by a 14-month study of rats.
Scientists at the University of Illinois and Ohio State University who dosed rats with a prostate cancer-causing carcinogen found that the subjects given a lycopene supplement were not nearly as likely to survive the cancer as rats given pure tomato powder.
"It has been unclear whether lycopene itself is protective. This study suggests that lycopene is one factor involved in reducing the risk of prostate cancer," said John Erdman, study co-author and a professor at Illinois. "This also suggests that taking lycopene as a dietary supplement is not as effective as eating whole tomatoes. We believe people should consume whole tomato products -– in pastas, in salads, in tomato juice and even on pizza."
Dr. Erdman's research team randomly assigned the 194 male rats to diets containing whole tomato powder, a supplement of lycopene only or to a control group. The rats were later divided into another two groups, with one having unlimited access to food and the second being given four-fifths of the first group's average daily intake.
The majority of the rats died by the time the study concluded, but the mortality rates between the groups showed sharp differences.
Eighty per cent of the rats in the control group died, compared to 72 per cent of the rats given lycopene and 62 per cent of the rats given pure tomato. Rats in the group whose diet was restricted had even further reduced death rates.
The research team says that there work is important because studies linking tomatoes with a reduction in prostate cancer have led to the development of dietary supplements containing lycopene.
“Poor dietary habits cannot be reversed simply by taking a pill,” said Ohio State's Steven Clinton, a medical doctor with a doctorate of nutritional sciences. “We shouldn't expect easy solutions to complex problems. We must focus more on choosing a variety of healthy foods, exercising and watching our weight.”
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