Tomatoes are loaded with a substance called lycopene. It gives them their bright red color and helps protect them from the ultraviolet rays of the sun. In much the same way, it can help protect your cells from damage. Tomatoes also have potassium, vitamins B and E, and other nutrients.Lycopene is an antioxidant -- it fights molecules called free radicals that can damage your cells and affect your immune system. Because of that, foods high in lycopene, like tomatoes, may make you less likely to have lung, stomach, or prostate cancer.