Milk is the whitish liquid secreted by specialised cells in the mammary glands of mammals for the nourishment of their young after birth.
Milk provides a complete food for the young animals until their digestive system develops enough for them to begin eating an adult diet.
Humans have incorporated milk from other animals - especially cows and goats - into their diet for thousands of years, because of its high nutritional value: it contains some of all the food groups and, for most people, is easy to digest.
Vitamins and minerals in milk include vitamin A, vitamin B, vitamin C (destroyed if the milk is pasteurised, or raw milk is heated in cooking) vitamin D (very small amounts), Calcium and Phosphorus.
Milk does not, however, contain dietary fibre.