Collard leaves are rich in calcium (226 mg per cup, cooked), vitamins B1, B2, B9, and C (which may be destroyed by cooking, however), as well as beta-carotene (pro-vitamin A). Each 100 g of leaves provides 46 calories (190 kilojoules) of food energy and contains 4 g of protein, 0.5 grams of fat, 7 g of carbohydrates.