Take home message
- Milk consumption began in Europe in the Neolithic period. Starting with goat and sheep, milk consumption developed gradually from south (-east) to north (-west) through the countries and regions bordering the Atlantic and North Sea coasts. The further north, the more goat and sheep were replaced by cows, and the more milk people started consuming.
- En passant, European humans developed genetically lactase-persistency as a reward for their life with domesticated cows, goats and sheep.
How to find out, what people ate since the Stone Age? When did milk become part of their diet and to what extent? How fast did milk consumption develop across Europe? There are several methods to gain insight into what people consumed in different regions and in different millennia of development to present-day humans. First, the remains of fats in the pottery used, was this coming from meat (pig, beef, sheep) or was it from milk fat? Then the pots themselves, their shape. Clearly, milk products were often kept in a different type of pottery compared to the ceramic cooking pots. Finally, the bone composition of humans (bones and specifically dentine). Based on so-called isotope ratios of different elements (e.g. carbon as 12C or 13C, calcium as 42Ca or 44Ca), it is possible to interpret the diet.
Frame: stable isotopes
Isotopes are chemical elements with different molecular weights. Mendelejev developed the atomic map, in which you can see, how the chemical elements change and belong together in families. The smallest element is hydrogen (H). Hydrogen has in its nucleus one proton and one neutron. Electrons circulate around each hydrogen nucleus. Together they determine the atomic weight of hydrogen. Carbon has 6 protons and an atomic weight of 12 (6 protons plus 6 neutrons), (= 12C). However, there are two isotopes, including 13C, which are heavier than 'ordinary carbon'. There is also the 14C, which has radioactive properties. Calcium is an important element in our bones. Calcium has 20 protons and an atomic weight of 40 (= 40Ca). Different isotopes exist, including 42Ca and 44Ca. The analysis of stable isotopes gives the possibility to analyse diets, as plant, meat or milk leave different isotope ratios in bones.
The start of agriculture in the fertile Crescent
The transition from hunter-gatherer to farmer took a long time. For it involves a permanent residence, the collection and sowing of (wild) grains and other edible species, the stepwise selection and breeding from grass into grains, and the taming of animals, the ruminants, first for their meat production, later their milk. You don’t become a farmer, and an aurochs is not tame overnight. This taming was accompanied by rearing, housing, feeding these animals, controlling the calving pattern to get milk, not to mention weaning off the offspring, while the mother still had to continue giving milk. A process of 100s to 1000s of years of cultural development and genetic adaptation in the form of human lactase persistence, the ability to continue digesting lactose as adults. To make stone tools with other stones is a laborious process. Not insignificant was the invention of the wheel, to transport goods more easily.
We speak of 11,000 bChr, or 13,000 bP (= before present), the period known as the Neolithic and the cultural phase of the Neolithic revolution: becoming the first farmers in the Stone Age. Periods associated with this are the pre-ceramic and ceramic eras, indicating the introduction of fired pottery, needed for cooking, storing and processing food. As people settled down, it was also necessary to have food for the non-productive seasons.
Dairy consumption through the millennia
Research by Tacail et al. (2021) uses Calcium isotopes in bones and dentin to assess, when early farmers started using milk. Based on present-day people, who never knew milk (products) at all, like the Baka in Cameroon or Melanesians from New Caledonia, the ratio of 44Ca and 42Ca in their bones was assessed. They ate all kinds of things, but did not consume dairy. The same was done in populations that lived on milk and milk products, showing that 50-70% of their daily Calcium came from milk. Consumption of milk lead to a different ratio of both Calcium isotopes in the bones and the ratio reflects the degree of milk consumption over time. It matters for the 44/42Ca ratio, whether you took Calcium from plants, eggs, meat or fish or from dairy.
Based on both the location and age of excavated bone remains and skeletons, Tacail et al. (2021) calculated, how the ratio 44/42Ca shifted over time. In Figure 1, the decrease in the isotope ratio equals the increase of dairy.
The milktour through Europe
Cubas et al., (2020) used the isotope technique to analyse the food remains in earthenware jars. Due to the enormous sensitivity of this laboratory technique, you can make a statement if only traces of food remain are found, from what was cooked or preserved in the stone pot. Over 230 findings could be used, and here the focus was on the fatty acids and the carbon isotopes in the fats, especially the 13C. The combination of the fatty acids C16:0 and C18:0 (palmitic and stearic acids) and the 13C isotope gives a decisive answer as to whether the fat found came from beef, pork or milk fat. Cubas was interested, how milk consumption developed in Europe, how milk consumption spread from the Euphrates and Tigris basin (present-day Iraq), through the Greek islands and Italy, Portugal to the north along the Atlantic coast.
Dairy farming mainly developed in the grassland areas of Euroep. Along the Atlantic coast we find in the South the Iberian Peninsula, namely Portugal and Galicia (Spain), then Normandy and Brittany (France), further along the North Sea coast, Belgium, the Netherlands, northern Germany and Denmark plus in addition the British Isles (England, Scotland, Wales and Ireland), enclosed between Atlantic Ocean and North Sea. The areas are linked to the warm Gulf Stream and excess precipitation. Further large grassland areas were found in the pre-Alpine en Alpine areas, mountenous areas in general.
The researchers found a gradient from south to north along the coast when it comes to the indication of 13C isotope from milk. Stone Age man started in the South of Europe (with goat and sheep) and gradually moved on to central and northern Europe, increasingly based on cow’s milk. As one assessed the later and more northern finds, it became clear, that the importance of milk products in the diet was increasing (more finds) and increasingly cow based. Only in the southern part at the beginning of the Stone Age was there a mix of fats from meat and milk of sheep and goat. The fastest changes in quantity and type of milk consumption took place over a period of 1,500 years, namely between 5,400 bP (south) and 3,500 bP (British Isles).
Analysis of cattle isotopes from Bercy in northern France shows, that the lengthening of their birthing season and early weaning of calves went hand in hand with a certain intensification of dairy farming at the beginning of the 4th millennium bC, coinciding with the arrival of cattle in Britain. Humans were increasingly successful in domesticating cows and breeding them for their milk. Other northern areas (German Schleswig-Holstein, Denmark and the Baltic States) also witnessed the domestication and breeding of cattle around this time (4th millennium bC), as well as the breeding of cultivated plants. With this, man and agriculture reached northern Europe. In northern Europe, this new step is heralded as the Funnel Beaker Culture. Special pottery for storing and processing milk came, narrow cups, bottle-shaped jars and bowls.
Early Neolithic cultures were still lactose intolerant. Adults could not digest milk without getting intestinal problems. However, people of Caucasian background (read: white European man) adapted to the sweet milk in their diet in a relatively short period of time. Multiple genetic adaptations are present, that took modern humans from lactose-intolerant to lactase-persistent, a shift only within a few millennia.
Literature
- Cubas, M., Lucquin, A., Robson, H. K., Colonese, A. C., Arias, P., Aubry, B., … & Craig, O. E. (2020). Latitudinal gradient in dairy production with the introduction of farming in Atlantic Europe. Nature communications, 11(1), 1-9.
- Tacail, T., Martin, J. E., Herrscher, E., Albalat, E., Verna, C., Ramirez-Rozzi, F., … & Balter, V. (2021). Quantifying the evolution of animal dairy intake in humans using calcium isotopes. Quaternary Science Reviews, 256, 106843.
