Drinking yak butter tea is a daily habit for Tibetans living on the Qinghai-Tibet Plateau. ZHANG YUFENG/XINHUA

LHASA — Chinese researchers have discovered 3,000-year-old residues at an archaeological site in Namling county in Shigatse city, Tibet autonomous region, indicating that milk was consumed there millennia ago.

The research, conducted by the Institute of Tibetan Plateau Research at the Chinese Academy of Sciences, Lanzhou University and the Cultural Relics Conservation Institute of Tibet, among others, was published in the journal Science Bulletin.

According to the study, to compensate for energy loss and lower oxygen levels, Tibetans developed unique dietary traditions that differ from those found on the plains.

Meats, such as beef and mutton, are commonly eaten on the Tibetan Plateau for their abundant proteins and fats that help the body maintain its metabolism.

Dairy products made from cattle and goat milk relieve the hardening of arteries caused by the excessive consumption of meat and replenish antioxidants, probiotics and nutrients, it noted.

The research suggested that in prehistoric times, dairy products could have been the daily staple of pastoral communities on the Tibetan Plateau.

"However, no direct evidence of prehistoric dairy products has been found as yet in high-altitude areas of the Tibetan Plateau, except for clues found in food remains," it stated.

The latest discovery was made at the Gongthang ruins, which is located at an altitude of 4,000 meters on the left bank of one of the tributaries of the Yarlung Zangbo River.

Results from plant remains indicate that the site dates back 3,000 years.

Researchers also discovered shards of pottery and analyzed six of them for lipid residues.

"We found that three had traces of dairy residues," said Zhang Yunan, a researcher at the ITP.

"Through analysis, we also confirmed that the date of the three pieces is consistent with the site, proving that the pottery was indeed used by the inhabitants of the time."

According to Yang Xiaoyan, a professor at Lanzhou University, the date for the milk residues found at Gongthang coincides with the domestication of herbivores, and the rise of agriculture and animal husbandry at the archaeological sites at Qugong in Lhasa and at Bangga in Lhokha city. "This may imply that the development of milk as a secondary animal product (meaning a product that can be continually extracted, as opposed to a primary product like meat, that can only be extracted once) occurred at the same time as the use of primary animal products on the Tibetan Plateau," she said.