Nutritionally, water chestnuts provide 10% each of the daily recommended value in vitamin B6, potassium (350 to 360 mg per ½ cup), copper, riboflavin, and manganese, with a respectable array of smaller amounts of other vitamins and minerals, as well. The corms are a rich source of carbohydrates, which relates itself in a starchy texture. Fiber is another ingredient in very good supply, which is effective for keeping your system running smoothly. However, water chestnut has no cholesterol to speak of or vitamin A at all. Fresh raw water chestnuts contain slightly more fat than the canned variety, but it's the good kind.