Central European dairy farming communities were responsible for the evolution of the digestion of milk sugar lactose some 7,500 years ago, new research shows. Writing in the journal Public Library of Science (PLoS) Computational Biology, German and British scientists shed light on how the genetic change helped early Europeans drink milk without becoming ill. Researchers in the past thought that only northern Europeans were able to drink milk without suffering adverse effects, because they needed vitamin D in their diet due to the lack of sunlight in the region. For this latest study, the scientists used a computer simulation model to investigate the spread of lactase persistence (i.e. lactose tolerance), dairy farming, other food gathering practices and genes in Europe. 'Most adults worldwide do not produce the enzyme lactase and so are unable to digest the milk sugar lactose,' explains Professor Mark Thomas from University College London Department of Genetics, Evolution and Environment. 'However, most Europeans continue to produce lactase throughout their life, a characteristic known as lactase persistence.' The researchers found that lactase persistence is linked with a single genetic change, giving people a huge boost in their survival. Adults began consuming fresh milk only after animals were domesticated. According to the researchers, lactase persistence most probably co-evolved with the cultural practice of dairying (dairy farming). However, researchers were unclear as to when it first emerged in Europe or what factors drove its rapid spread. The authors explained: 'Our study simulated the spread of lactase persistence and farming in Europe, and found that lactase persistence appears to have begun around 7,500 years ago between the central Balkans and central Europe, probably among people of the Linearbandkeramik Culture [Linear Pottery Ceramic Culture; named by German archaeologist Friedrich Klopfleisch (1831-1898) for the first true farming communities in central Europe].' 'But contrary to popular belief, we also found that a need for dietary vitamin D was not necessary to explain why lactase persistence is common in northern Europe today.' Why is the consumption of fresh milk so advantageous? Researchers have said that milk can compensate for insufficient sunlight and the synthesis of vitamin D in skin at more northern latitudes. Vitamin D is needed for calcium absorption and milk provides a good dietary source of both nutrients, according to the experts. Milk is also a good source of protein and is rich in calories. Data also suggest that dairying was present in south-eastern Europe once farming activity got off the ground. 'Overall, by considering the results from our simulations and archaeological, archaeozoological, and archaeometric findings, it seems very plausible to connect the geographic origin of the spread of lactase persistence to the increasing emergence of a cattle-based dairying economy during the sixth millennium BC,' the research shows. More particularly, the authors noted, 'The geographic region of origin of the Linearbandkeramik - in modern-day north-west Hungary and south-west Slovakia - certainly correlates well with our results.' Researchers from Johannes Gutenberg University in Germany and the University of Reading in the UK also contributed to the findings.
Germany, United Kingdom