"Eat the fruit" seems to be the message of research findings from scientists at the University of Illinois at Urbana-Champaign and Ohio State University. The study comparing lycopene supplements to the whole food (in the study's case, powdered tomato) suggests that pills containing key nutritional elements are neither as effective in promoting health nor protective against disease as simply eating the whole food.
"Our findings strongly suggest that risks of poor dietary habits cannot be reversed simply by taking a pill," said Steven K. Clinton, PhD, MD, one of the researchers. "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."
Foods Contain More than a Single Compound
Lycopene – a carotenoid in tomatoes that has been linked to a lowered risk of prostate cancer – apparently does not act alone. Its effect is stronger in combination with other phytochemicals in the fruit.
Lycopene is an antioxidant and the pigment that provides the red color to foods such as tomatoes, pink grapefruit, guava, papaya, and watermelon. Many people purchase lycopene-based supplements because of its protective role against prostate and other cancers. Results from this study suggest that a combination of the bioactive compounds might offer the best anti-cancer effect. In other words: Lycopene might be effective only in synergy with other compounds.
"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 Jr., PhD, a professor of food science and human nutrition and of internal medicine 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."
Study Specifics
In the study, researchers in Erdman's laboratory at the University of Illinois randomly assigned 194 male rats (that were treated with a carcinogen to induce prostate cancer) to diets containing whole tomato powder, pure lycopene, or a control.
Four weeks later, the rats were divided into two groups, with one having unlimited access to food and the second consuming 80 percent of the first group's average daily intake. At the conclusion of the study, researchers found that the rats that had consumed the tomato powder had a 26 percent lower risk of prostate cancer death than control rats, after controlling for diet restriction. The rats fed pure lycopene had a risk of prostate cancer similar to control rats.
In the end, prostate cancer had claimed the lives of 80 percent of the control group, 72 percent of the lycopene-fed rats and 62 percent of the rats fed tomato powder. Rats on the restricted diet had an even lower risk of developing prostate cancer, independent of their diets. The researchers suggest that tomato products and diet restriction might have independent additive benefits.
"Tomato powder consumption clearly extended the life and reduced the cancer in this particular model," Erdman said. "Lycopene was a little better than the control group but not as good as the tomato powder group."
Animal-based studies, such as this one involving rats, Erdman said, expand on the epidemiologic findings regarding reduced cancer risks and could pave the way for human clinical trials using tomato products or extracts to protect against the development of prostate cancer. |
