Lipid residue study finds evidence for dramatic change in diet during Neolithic transition
Agriculture reached Britain and Ireland around 4000 BC, but the means by which the transition from hunting, fishing and gathering occurred has been debated for many years. One view is that indigenous Mesolithic people acquired domesticated crops and animals from continental Europe, but retained much of their existing lifestyle. Another is that Neolithic farmers arrived from the continent and spread rapidly. This latter scenario proposes that a rapid acculturation of indigenous Mesolithic people followed.
Previous work has considered stable carbon isotope signatures of bone collagen extracted from Mesolithic and Neolithic human remains. The results suggested that in coastal environments, the Mesolithic diet included a significant amount of marine protein, but that of the Neolithic farmers was predominantly terrestrial-based. However, doubts have been expressed about the sensitivity of the bone collagen stable isotope analysis to low-protein diets; quantities of less than 20 percent marine protein in the diet would be undetectable. Possible Neolithic shell middens from Scotland and Ireland suggest that seafood continued to be eaten.
To address this uncertainty, researchers analysed lipid residues recovered from Neolithic pottery sherds from coastal sites in Britain, the Scottish Isles, and Ireland. To extend the chronological period, material was also included from sites dating to the Bronze Age through to the Viking period. The results confirmed the near-complete absence of marine protein from the Neolithic diet and the strong presence of dairy products. This remained the case during the Bronze Age, and it was not until Viking times did marine protein again become a significant dietary item.
Similar studies in the Baltic region indicate a different pattern. There, hunting, gathering and fishing continued alongside farming. The contrasting patterns occurring at the same time in different regions suggest geographically-distinct ecological, demographic and cultural influences dictating the adoption of agriculture. The rapid shift to an intensive dairy economy is consistent with the low frequency of lactose intolerance among modern inhabitants of northwest European archipelagos. The evolutionary processes driving lactase persistence in adults would have been driven by the increasing importance of dairy products in the diet.
Cramp, L. et al., Immediate replacement of fishing with dairying by the earliest farmers of the northeast Atlantic archipelagos. Proceedings of the Royal Society B 281 (2014).