WEDNESDAY, May 12, 2021 (HealthDay News) – Not only have humans and their ancestors eaten carbohydrates for longer than was done, but a new study found that these starchy foods may have played a role in the growth of the human brain.
A new study investigating the history of the human oral microbiome found that Neanderthals and ancient humans adapted to eating starchy foods 100,000 years ago, which is much earlier than previously thought.
“We think we see evidence of a really old behavior that could have been a partial encephalization or the growth of the human brain,” said researcher Christina Warinner of Harvard University. “It’s evidence from a new food source that early humans were able to take advantage of in the form of roots, fertile vegetables and seeds.”
The oral microbiome is a community of microorganisms mouth. They help protect against disease and promote health.
The findings are part of a seven-year study that involved more than 50 international scientists.
They reconstructed the oral microbiomes of Neanderthals, primates, and humans, including a 100,000-year-old Neanderthal, in what is believed to be the oldest oral microbiome ever sequenced.
Scientists analyzed the fossilized dental plaque of modern humans and Neanderthals and then compared them to chimpanzees and gorillas, the closest primate relatives of man, and howler monkeys, a more distant relative.
Billions of DNA the fragments preserved in the fossilized plate were genetically analyzed to reconstruct their genome.
The researchers were surprised to find strains of oral bacteria specially adapted to break down starch. These bacteria, of the genus Streptococcus, they have a unique ability to capture digestive starch enzymes from humans saliva and feed. The genetic machinery they use to do this is only active when starch is part of the regular diet.
Neanderthals and ancient humans had these starch-adapted strains on dental plaque, but most primates had almost none.
“It seems to be a very human specific evolutionary trait than ours Streptococcus acquired the ability to do that, “Warinner said in a Harvard press release.
The findings were published on May 10 in Proceedings of the National Academy of Sciences.
The researchers said the finding makes sense because for hunter-gatherer societies around the world, starch-rich foods such as underground roots, tubers such as potatoes and nuts and seeds were important nutritional sources. and reliable.
The human brain needs glucose as a source of nutrients and meat alone is not enough, Warinner said. Starch accounts for approximately 60% of the calories of humans worldwide.
“Its availability is much more predictable throughout the annual season for tropical hunter-gatherers,” said study co-author Richard Wrangham, Ruth B. Moore’s professor of biological anthropology at Harvard. “This new data makes perfect sense to me, reinforcing the newer view of Neanderthals that their diets were more similar to what they knew than previously thought, [meaning] rich in starch and cooked “.
The research also identified 10 groups of bacteria that have been part of the human and primate oral microbiome for more than 40 million years and are still shared today. Relatively little is known about it.
The oral microbiome of Neanderthals and modern humans was almost indistinguishable. The study deals with the analytical power of the tiny microbes that live in the human body.
“It shows that our microbiome encodes valuable information about our own evolution that sometimes gives us clues about things that otherwise leave no trace,” Warinner said.
The Smithsonian National Museum of Natural History has more information old tools and food.
SOURCE: Harvard University, press release, May 10, 2021