New York, Nov 28 (IANS): An international team of researchers has discovered the first evidence of milk consumption preserved in dental plaque of humans in Europe and western Asia.

It shows that milk of all three major dairy livestock - cattle, sheep and goats - has been consumed by human populations for at least 5,000 years.

"The study has far-reaching implications for understanding the relationship between human diet and evolution," explained Christina Warinner, professor at University of Oklahoma, US.

"Dairy products are a very recent dietary innovation and most of the world's population is unable to digest lactose - often developing the symptoms of lactose intolerance," Warinner pointed out.

Understanding how, where and when humans consumed milk products is a necessary link between human consumption and their livestock.

The new findings corroborate previous evidence for milk fats identified on pottery and cooking utensils in early farming communities.

"The discovery of milk proteins in human dental calculus (a mineralised dental plaque) 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," Warinner added.

The study appeared in the journal Nature's Scientific Reports.