A survey done by Chinese scientists found traces of milk more than 3,000 years old at a site of ancient ruins in Namling county of the Tibet autonomous region.

The milk residue was discovered in the Gongthang Ruin and shows that milk was consumed by ancient people on the Tibetan Plateau.

The information was presented in a thesis — Early milk consumption on the Tibetan Plateau — which was published in Science Bulletin on Jan 20.

The research notes that compensating for energy loss and oxidative stress, the Tibetan people developed unique dietary traditions that are different from the plains areas.

Meat products, such as beef and mutton, were common foods on the plateau, providing abundant protein and fats for the human body to maintain its metabolism.

It also notes that dairy foods from cattle and goats relieved the hardening of arteries caused by excessive meat consumption and replenished antioxidants, probiotics and various nutrients.

In prehistoric times, dairy products could have been part of the daily diet in pastoral communities. However, no direct evidence of dairy products during prehistoric times has yet been found in the high-elevation areas, except for some clues in the form of visible food remains, the research found.

Yang Xiaoyan, a professor from Lanzhou University who is responsible of the scientific expedition, said human development of storable dairy products technology promoted the formation and development of nomadic industry.

"The time of the milk remains detected at the Gongthang Ruin site was similar to the time emergence of domestic herbivores, agriculture and animal husbandry at the Qugong site in Lhasa and Bangga site in the region's Lhokha city," Yang said.

"It implies that the development of milk as a secondary product occurred at the same time as the utilization of primary animal products, such as meat."

The research was jointly conducted by several Chinese academic institutes, including the Institute of Tibetan Plateau Research of the Chinese Academy of Sciences, Lanzhou University, the University of Science and Technology of China, the Cultural Relics Conservation Institute of the Tibet autonomous region, Northwest University and the Institute of Archaeology of the Chinese Academy of Social Sciences.