Strong genetic mutations noted only in certain populations, including northern Europe, allow the intestinal enzyme which digests lactose during infancy to be produced throughout a lifetime.
     An international team of researchers say that proteins found in the dental plaque of people from Roman and medieval Yorkshire who lived between 1000 and 1550 CE provide "direct evidence" of milk consumption from as early as the Bronze Age. The identification of cattle, sheep and goat whey on teeth supports previous findings from the pottery and cooking utensils of early farming communities. Milk is usually difficult to detect due to its swift disappearance from archaeological remains.
     "Most of the molecular evidence for milk consumption has previously come from residues on ceramics," says Dr Camilla Speller, from the University of York. "This study is very exciting because for the first time we can link milk consumption to specific skeletons and figure out who has access to this important nutritional resource."
     "The study has far-reaching implications for understanding the relationship between human diet and evolution," says Dr Christina Warinner, from the Department of Anthropology at the University of Oklahoma, USA. "Dairy products are a very recent, post-Neolithic dietary innovation, and most of the world's population is unable to digest lactose, often developing the symptoms of lactose intolerance. The discovery of milk proteins in human dental calculus will allow scientists to unite these lines of evidence and compare the genetic traits and cultural behaviours of specific individuals who lived thousands of years ago."

Edited from Culture24 (25 December 2014)