Butter is the dairy product made from churning milk or cream. The churning process separates the butterfat (the solids) from the buttermilk (the liquid). The butter we most often buy is made from cow's milk, although other varieties — made from the milk of sheep, goat, yak, or buffalo — are also available.
Butter contains very small amounts of other nutrients, including riboflavin, niacin, calcium, and phosphorus. Butter is high in calories and fat but also contains several important nutrients, including vitamins A and E.