Milk and dairy products are a staple to modern day diet but it appears that ancient Europeans did not enjoy as much the goodness and health benefits of milk.
DNA analysis has revealed that the early Europeans were lactose intolerant and that they have started raising domesticated animals such as sheep, goats and cows long before they developed the ability to drink milk from these animals without causing any problem.
Lactose intolerance is characterized by the body not being able to break down lactose, the natural sugar found in the milk of mammals, and absorbs it into the blood and this causes unwanted symptoms that include diarrhea, bloating and flatulence.
For the new study, University College Dublin's Earth Institute professor Ron Pinhasi and colleagues extracted DNA from the remains of 13 individuals who were buried in archaeological burial sites in Central Europe's Great Hungarian Plain, a region where Eastern and Western cultures intersected and which experienced significant cultural and technological transformations that helped shape European prehistory.
The researchers took DNA samples from the skeletons' petrous bones, a hard part of the skull that protects the inner ear. Scientists have found that the inner ear region of the petrous bone is an ideal source of samples for DNA analysis because the bone is well protected from damage.
Researchers said that they can extract 12 to 90 percent human DNA from petrous bones compared with 0 to 20 percent when they obtain samples from fingers, rib bones and teeth.
DNA analysis of the skeletons, whose age span about 5,000 years dating back from 5,700 BC, the last stage of the Stone Age, to 800 BC, the Iron Age, revealed that the ancient Central Europeans appeared to have been intolerant to lactose until the Bronze age, which is about 4,000 year later after they started dairying.
"We observe transition towards lighter pigmentation and surprisingly, no Neolithic presence of lactase persistence," Pinhasi and colleagues wrote in the study. "Genome flux and stasis in a five millennium transect of European prehistory," which was published in journal Nature Communications on Oct. 21.
Artifacts that were previously found suggest that the ancient Europeans began dairying during the Neolithic period.
"This means that these ancient Europeans would have had domesticated animals like cows, goats and sheep, but they would not yet have genetically developed a tolerance for drinking large quantities of milk from mammals," Pinhasi said.
The researcher said that early Europeans may have practiced dairying to consume yogurt and cheese and not to drink milk because the process involved with making these dairy products break down the lactose.