Watermelon is 90% water, and just one cup of watermelon’s high water content juiciness can refresh you after a warm summer day. Watermelon has a high content of vitamins and minerals: vitamin A, vitamin C, vitamin B6, Potassium, Sodium. Vitamin A is essential for skin and eye health; vitamin B6 helps your body break down the protein you eat. Vitamin C helps strengthen the immune system, and potassium helps lower blood pressure.