Late Bronze Age cultural origins of dairy pastoralism in Mongolia

Dairy products provide a substantial part of the food energy intake for many populations around the world. Fresh milk is an important source of many proteins (whey β-lactoglobulin and caseins), fats, vitamin D, calcium, and electrolytes—but it has only a single carbohydrate, lactose (1). We can all digest lactose as newborns but, after weaning, only some of us continue to express the lactase enzyme in our small intestine that digests lactose into glucose and galactose. Individuals with lactase persistence (LP) are thus lactose tolerant. Conversely, in lactase-nonpersistent individuals, the undigested lactose reaches the large intestine, where it undergoes bacterial fermentation, leading to a range of harmful symptoms, including diarrhea, flatulence, and constipation (2). The preparation of cheese and several milk beverages involves lactose fermentation, which is why lactose-intolerant persons can still benefit from the nutritional virtues of milk without suffering strong symptoms after consumption. With time, such food products have become part of the culinary identity of several countries, such as French cheese, Greek yogurt, and fermented mare’s milk known as kumis in Kazakhstan and airag in Mongolia. Archaeological evidence shows that dairy consumption came soon after the domestication of ruminants. Cattle-specific β-lactoglobulin and casein peptides have been detected in ∼8,000-y-old vessel sherds from Çatalhöyük in Turkey, only two millennia after taurine cattle were first domesticated (3). In Europe, lipid signatures indicative of cheese making were found in ∼7,400- to 6,800-y-old strainer vessels (4) [the earliest cheese ever found was preserved in an Egyptian jar for ∼3,300 y (5)]. In the central Asian steppe, the isotopic content of fatty acids in pottery has suggested that dairy consumption accompanied the early stages of horse domestication, some ∼5,500 y ago (6, 7). In contrast, the early origins of dairy consumption in the eastern Eurasian steppe, east of the Altai (or … [↵][1]1Email: ludovic.orlando{at}univ-tlse3.fr. [1]: #xref-corresp-1-1