Grapes are a source of vitamins, with each cup providing 13.4 micrograms of vitamin K, or 17 percent of the daily value; 3.7 milligrams of vitamin C and 0.09 milligrams of thiamine, or six percent of the daily value for each of the latter two nutrients; and 0.1 milligrams of vitamin B-6, or five percent of the DV.ach one-cup serving of grapes contains 62 calories, 0.6 grams of protein, 0.3 grams of fat and 15.8 grams of carbohydrate, including 0.8 grams of fiber. (See Reference 1) This is about three percent of the daily 25-gram value for fiber for people who eat a 2,000-calorie diet.