One generous slice of watermelon (about 1/16th of a melon) contains large amounts of vitamin C and beta-carotene which may help protect against various forms of cancer due to their antioxidant properties. Watermelon is also high in potassium which helps regulate heart functions and normalize blood pressure. It is a good source of fiber which helps maintain bowel regularity and works to prevent colon and rectal cancer.
Watermelon seeds contain cucurbocitrin to aid in lowering blood pressure and improve kidney function. The sweet watermelon surprisingly has only half the sugar content (5 percent) of an equivalent-sized apple. It tastes sweeter because the sugar is its main taste-producing agent. Two cups of watermelon has only 80 calories, no fat, and no cholesterol.