Milk proteins in Neolithic dental calculus

A new research paper by Sophy Charlton and coworkers looks at calculus on human teeth from several Neolithic-era sites in England, finding that many of the individuals have trace evidence of milk consumption: “New insights into Neolithic milk consumption through proteomic analysis of dental calculus”.

There has long been debate over the origins of dairy consumption within European populations. Whilst it was previously assumed that lactase persistence (LP) was under positive selection following the advent of agriculture, recent genetic studies of prehistoric human remains have revealed LP may have only emerged in Europe in the last 4000 years. These findings stand in contrast to organic residue analysis of Neolithic pottery indicating the utilisation of dairy products, and zooarchaeological mortality profiles consistent with dairying herds at Neolithic sites. The recent discovery of the milk protein β-lactoglobulin (BLG) within human dental calculus presents a new method via which to explore dairy product consumption in the archaeological past. Here, we apply shotgun proteomic analysis to dental calculus samples from three British Neolithic sites, revealing the earliest identification of BLG in human dental calculus to date. The presence of BLG peptides in individuals who are unlikely to possess LP provides new insight into dairying in the British Neolithic, suggesting the potential processing of milk by Neolithic populations to reduce the lactose content of dairy products.
Additionally, organic residue analysis of pottery from Hambledon Hill has indicated the presence of both porcine and ruminant fats, and ruminant adipose and dairy fats (Copley et al. 2003, 2005a, b, 2008). The presence of dairy fats in > 25% of potsherds analysed has been suggested to indicate that ‘dairying was a very important element of animal husbandry at Hambledon Hill’ (Copley et al. 2008, p. 535).

It’s nice to have confirmation that milk trace residues in pottery co-occur with milk trace residues in human dental calculus. More and more sites where these data show a pattern will help us to understand the big picture – both by helping us to interpret sites where preservation is not as good, and by looking at smaller-scale shifts in diet.

It is no surprise that people in Britain started relying upon animal milk before lactase persistence was common in northern European populations. That’s how natural selection works. The environment changes, creating different survival and fertility conditions. Only then can genes that are adaptive in the new environment proliferate due to selection in the population.