Molecular and isotopic evidence for milk, meat, and plants in prehistoric eastern African herder food systems

Abstract

The development of pastoralism transformed human diets and societies in grasslands worldwide. The long-term success of cattle herding in Africa has been sustained by dynamic food systems, consumption of a broad range of primary and secondary livestock products, and the evolution of lactase persistence (LP), which allows digestion of lactose into adulthood and enables the milk-based, high-protein, low-calorie diets characteristic of contemporary pastoralists. Despite the presence of multiple alleles associated with LP in ancient and present-day eastern African populations, the contexts for selection for LP and the long-term development of pastoralist foodways in this region remain unclear. Pastoral Neolithic (c. 5000 to 1200 BP) faunas indicate that herders relied on cattle, sheep, and goats and some hunting, but direct information on milk consumption, plant use, and broader culinary patterns is rare. Combined chemical and isotopic analysis of ceramic sherds (n = 125) from Pastoral Neolithic archaeological contexts in Kenya and Tanzania, using compound-specific δ13C and Δ13C values of the major fatty acids, provides chemical evidence for milk, meat, and plant processing by ancient herding societies in eastern Africa. These data provide the earliest direct evidence for milk product consumption and reveal a history of reliance on animal products and other nutrients, likely extracted through soups or stews, and plant foods. They document a 5,000-y temporal framework for eastern Africa pastoralist cuisines and cultural contexts for selection for alleles distinctive of LP in eastern Africa.

Ancient proteins provide evidence of dairy consumption in eastern Africa

“…BP and three sherds at Ngamuriak (GuJf6) and Luxmanda in SW Kenya/ northern Tanzania after c. 3000 cal. BP 40 , these data point to milk consumption having been a widespread and persistent component of early herder lifeways. Together, these studies provide strong, multi-proxy evidence that people were regularly relying on access to animal milk throughout the expansion of pastoralism from the Sahara through eastern Africa with no detectable regional or temporal gaps.…”

“…Lipid residue analysis has been applied to investigate the inception and development of pastoral economies in northern and eastern Africa, finding that dairy products were used or stored in ceramic vessels 37 , 38 , 40 , 67 . Models for interpreting lipid residue results in European studies 68 may suggest that the very low detection rate for milk lipids from African ceramics indicates minimal contributions of milk to African herder diets.…”

“…bp in Sudan 38 , 39 . A recent lipid residue study of ceramics ( n = 40) from early herder sites in the Lake Turkana Basin identified one sample with a Δ 13 C value consistent with ruminant milk fats, suggesting some use of dairy products by 5000 bp in eastern Africa 40 . The lipid analysis also returned three other positive results (and one possible positive result) for milk fats from c. 3000-year-old ceramics ( n = 85) from southern Kenya and northern Tanzania 40 .…”

“…This concern is heightened when recovery rates are low. While the recent eastern African lipid study 40 appears to confirm early pastoralist use of milk, it remains unclear what the very low recovery rates of lipids with Δ 13 C values within the range of milk fats mean in terms of consistency or frequency of milk consumption in the past. Ceramic lipid residue analysis is also unable to link milk consumption to particular individuals in a population that may have had mixed LP frequencies.…”

Lipid residues in pottery from the Indus Civilisation in northwest India

“…However, the ratios of palmitic/stearic acid in the study samples were not suggestive of plant products (SI 3). Despite this, plant products cannot be ruled out as they are often rendered ‘invisible’ due to their low-fat content ( Hendy et al, 2018 ; Grillo et al, 2020 ).…”