You Say Tomato, I Say Cancer-Fighter

Carotenoids -- the pigments that give the red, yellow, and orange colors to some fruits and vegetables -- are believed to give tomatoes their cancer-preventive benefits.

Now scientists have developed a tool that will help them understand how this happens.

Researchers at the University of Illinois will use isotopic labeling of three tomato carotenoids (with heavier carbon atoms than are commonly found in nature) to track the carotenoids' absorption and metabolism in the body. Throughout the process, the scientists will look at whether the carotenoids themselves are bioactive or if their metabolic or oxidative products are responsible for their benefits.

They will also look at whether lycopene alone is responsible for the tomato's benefits, or if other carotenoids are also important. "It's work that should move us forward in the fight against prostate cancer," said John W. Erdman, a U of I professor of human nutrition.

"Lycopene (a carotenoid), which gives the fruit its red color, has received a lot of attention -- it's even advertised as an ingredient in multivitamin supplements -- but two little-known colorless carotenoids, phytoene and phytofluene, probably also have benefits," said Nancy Engelmann, a doctoral student who helped develop the method.

University of Illinois researchers and colleagues at Ohio State University are gearing up to use the new method to study carotenoid metabolism in humans.