Melons are low in calories, with just 64 calories in a 1-cup serving of honeydew balls and fewer calories in cantaloupe, casaba or watermelon balls. At the same time, melons are high in essential vitamins and minerals. They contain almost no fat or saturated fat, making them an excellent choice for snacks or a side dish. Vitamin C Vitamin C is an antioxidant vitamin that plays an important role in the growth and maintenance of all tissues in your body. It functions in wound healing and repair of cartilage, bones and teeth. Adults should receive 90 mg per day of vitamin C. A 1-cup serving of cantaloupe provides 65 mg of vitamin C. One cup of casaba melon provides 37 mg of vitamin C, and honeydew provides 30 mg. Vitamin A Vitamin A is important for healthy teeth, skin, bone and mucous membranes. It helps the vision system by promoting retinal health. Insufficient vitamin A may lead to poor functioning of the immune system. Cantaloupe is high in vitamin A, with more than 25 percent of the recommended daily amount in a 1-cup serving. Potassium Potassium is an important mineral in the maintenance of heart health. Consuming adequate amounts of potassium in your diet may lower blood pressure and reduce the impact of high-sodium foods. Adults should receive 4700 mg of potassium per day. Cantaloupe is high in potassium, with 473 mg in a 1-cup serving. Honeydew contains 403 mg per serving, and other melons have lower levels. Lycopene The red color in watermelon is lycopene, a powerful antioxidant that may help prevent cell damage. Lycopene consumption has been linked to reduced rates of certain cancers and a reduced risk of heart attack. A 1 1/2-cup of raw watermelon contains approximately 9 to 13 mg of lycopene. Watermelon contains about 40 percent more lycopene than a serving of raw tomatoes.