29/07/2023
There are two distinct categories of milk consumption: all infant mammals drink milk directly from their mothers’ bodies, and it is their primary source of nutrition; and humans obtain milk from other mammals for consumption by humans of all ages, as one component of a varied diet.
Nutrition for infant mammals
Further information: Breastfeeding and Lactation
Breastfeeding to provide a mother's milk
A goat kid feeding on its mother's milk
In almost all mammals, milk is fed to infants through breastfeeding, either directly or by expressing the milk to be stored and consumed later. The early milk from mammals is called colostrum. Colostrum contains antibodies that provide protection to the newborn baby as well as nutrients and growth factors.[13] The makeup of the colostrum and the period of secretion varies from species to species.[14]
For humans, the World Health Organization recommends exclusive breastfeeding for six months and breastfeeding in addition to other food for up to two years of age or more.[15] In some cultures it is common to breastfeed children for three to five years, and the period may be longer.[16]
Fresh goats' milk is sometimes substituted for breast milk, which introduces the risk of the child developing electrolyte imbalances, metabolic acidosis, megaloblastic anemia, and a host of allergic reactions.[17]
Food product for humans
The Holstein Friesian cow is the dominant breed in industrialized dairy farms today
A bowl of milk for the shaman rite; Buryatia, Russia
In many cultures, especially in the West, humans continue to consume milk beyond infancy, using the milk of other mammals (especially cattle, goats and sheep) as a food product. Initially, the ability to digest milk was limited to children as adults did not produce lactase, an enzyme necessary for digesting the lactose in milk. People therefore converted milk to curd, cheese, and other products to reduce the levels of lactose. Thousands of years ago, a chance mutation spread in human populations in northwestern Europe that enabled the production of lactase in adulthood. This mutation allowed milk to be used as a new source of nutrition which could sustain populations when other food sources failed.[18] Milk is processed into a variety of products such as cream, butter, yogurt, kefir, ice cream, and cheese. Modern industrial processes use milk to produce casein, whey protein, lactose, condensed milk, powdered milk, and many other food-additives and industrial products.
Whole milk, butter, and cream have high levels of saturated fat.[19][20] The sugar lactose is found only in milk, and possibly in forsythia flowers and a few tropical shrubs.[21] Lactase, the enzyme needed to digest lactose, reaches its highest levels in the human small intestine immediately after birth, and then begins a slow decline unless milk is consumed regularly.[22] Those groups who continue to tolerate milk have often exercised great creativity in using the milk of domesticated ungulates, not only cattle, but also sheep, goats, yaks, water buffalo, horses, reindeer and camels. India is the largest producer and consumer of cattle milk and buffalo milk in the world.[23]
