Monday, 25 June 2012
It is a scientifically accepted fact that humans were, for thousands of years, lactose intolerant. The ability to process and digest dairy products was an evolved trait--most humans lost the ability to digest dairy after the age of five. New research published in Nature finds that dairy first entered the human diet in North Africa close to 7,000 years ago.
Shards of pottery covered with fermented fat from dairy products, which date from 5200 to 3000 B.C., were discovered in Libya's Acacus mountains at the Takarkori rock shelter. The rock shelter had colorful images of cattle being milked; the drawings are unable to be dated. As a result, scientists have dated the dairy to try to find the earliest point at which dairy was introduced into the adult human diet.Biomolecular archaeologist Richard Evershed of the University of Bristol, UK, who led the study with archaeological scientist Julie Dunn, shares that processing milk to lower the lactose content may have made dairy products more digestible since most people at that time had some level of lactose intolerance.
Dunn shared with The New York Times that what North African were making is still unclear. “We can’t tell whether it was butter, cheese or yogurt," she said, "but we can tell they were processing it in the pots,” says Dunn.
These findings are crucial since the ability to digest dairy was a turning point in our history. Mark Thomas, a geneticist at University College London, explained in Nature:"He speculates that mutations that allow adults to digest lactose, or lactase persistence, that arose around 6,000 years ago in Europe and later spread to Africa could have offered a unique benefit in a parching climate. Fresh milk is a reliably uncontaminated source of fluid, and people able to tolerate lactose may have stayed better hydrated than people without the gene."
What do you think of this study? Are you surprised that humans were once lactose intolerant?