One papaya of medium size is a storehouse of various vitamins, minerals, antioxidants and other healthy nutrients. It yields about 120 calories, from about 30g of carbohydrates. Of this, 5g is comprised of fiber and 18g sugar. There are only 2g of protein, but many vitamins, such as folate, vitamin A, magnesium, copper, and pantothenic acid, as well as the B complex, including the carotenes (alpha and beta), lutein and zeaxanthin pigments, tocoferols, lycopene and vitamin K. It is also rich in calcium and potassium.

Papaya: Health Benefits (news-medical.net)