From Dietitian's Today magazine

It's not news that brown rice is full of fiber, but recent research in the British Journal of Cancer shows that rice bran (the part that's removed from brown rice to make it white) can lower the risk of cancer.  Mice fed the human equivalent of a cup of rice bran daily had a 51% reduction in intestinal tumors.  Researchers believe the fiber in rice bran clears the gut of the growths by creating cancer-fighting compounds and flushing out the carcinogenic ones.