 Explanations for population variation in adult milk digestion depend on evolutionary histories with dairying and milk usage.  So, it is essential to know what consumption practices were like in the past, especially among populations with high frequencies of lactase persistence.  We do know that milk consumption becomes much more common in the late 19 th century in Europe and the United States, but why?

 Earliest domestication of dairy animals was ~8,000 years ago in the Middle East  Milk may have been one of the earliest uses for these animals, who were also used for other purposes  Cows (Bos taurus and Bos indicus) were important sources of milk in Europe and South Asia, respectively  Goats and sheep were more common in the Mediterranean  Lactase persistence co-evolved with milk usage in Europe, Africa, and South Asia. © 2011 Taylor and Francis

 Evidence from household budgets, rations for poorhouses, representations in art, culinary traditions  Probably not – more frequently used to produce cheese, butter, buttermilk. Whey used in porridge  Beer or wine more common as beverages for both adults and children © 2011 Taylor and Francis

 Coffee, tea, and chocolate, which were all products imported from European colonies, were often consumed with milk.  This reduced bitterness and gave rise to an increase in milk consumption in Europe in conjunction with these commodities.  These were often consumed by workers as a cheap stimulants and “hunger-killers” (See Sidney Mintz, Sweetness and Power) © 2011 Taylor and Francis

 No domestic source of milk – had to purchase from the market  Concern over “putrefication” – i.e. traditional modes of fermentation of milk products  More women working in factories – in need of a breastmilk substitute for infants  Urban women lost their social network for wet nursing and cows milk became the wet-nurse substitute as well © 2011 Taylor and Francis

 Cows kept in close confinement outside of cities – spread of disease  Cows poorly nourished and fed “swill,” the remains of alcohol fermentation  No means to keep milk cold while it was transported to urban consumers  Milk contaminated with pathogens – contributed to infant and child mortality © 2011 Taylor and Francis

A ghoulish figure selling swill milk to a mother and her sickly child in New York City (Source: Harpers Weekly (1878)). Correlation of trends in child deaths from diarrheal disease and spread of pasteurization in Massachusetts (Source: Drawn from data in Crumbine and Tobey (1929)).

 Louis Pasteur – heating destroys microbes that induce fermentation or that cause disease.  Robert Koch – germ theory of disease (1882)  Concerns about milk’s safety led to pasteurization of milk supply to cities in late 19 th - early 20 th century  Questions about milk as an appropriate food, especially for children, were framed in terms of safety; it was assumed that milk drinking was the “natural” state of affairs  Ensuring a safe milk supply was seen as a way of solving some of the social problems of city life in the 19 th century.  Refrigerated transport allowed broader distribution of pasteurized milk. © 2011 Taylor and Francis

 With increased production of milk, need for larger market  Children (older than infants) became the target market for milk  National Dairy Council formed in 1915 to promote milk  Child health equated with milk drinking  Milk promoted as key to child growth © 2011 Taylor and Francis

Milk promotion emphasizing milk’s value for child growth (Source: Ladies Home Journal (June 1904)). U.S. Bureau of Education recommendations for schoolchildren (Source: Reaney (1922)).

© 2011 Taylor and Francis Trends in fluid milk and cheese consumption in the United States (Source: Drawn from data from United States Department of Agriculture (2008)). Milk consumption peaked during WWII and has been declining ever since and is well below levels from the early 20 th century Cheese consumption has continued to climb Does this represent a return to pre-industrial forms of milk/dairy consumption?