Dr oz said banana helps prevent cancer. i thought it was just to replace potassium after loss.?

You may be right: Bananas have many healthy nutrients and are part of a healthy diet. A healthy diet helps you maintain a strong immune system that can destroy fledgling cancers caused by random cell mutations. However, thereis no basis to single out bananas as a superior cancer prevention fruit over many others. Don't take medical advice from dr. Oz and other doctors who don't know your personal health history.