A team of international scientists has made the groundbreaking discovery of an ancient ecospecies of stomach bacteria that hints at our ancestors’ diets – meat-heavy with little to no vegetables.
Led by Professor Daniel Falush from the Shanghai Institute of Immunity and Infection of the Chinese Academy of Sciences, the research analyzed nearly 7,000 helicobacter pylori genomes from across the globe. Helicobacter pylori, notorious for causing around one million stomach cancer cases annually as well as other life-threatening gastric diseases, has been a resident in the human stomach for over 100,000 years.
In a surprising twist, the researchers uncovered the Hardy ecospecies, a unique variant of helicobacter pylori that emerged hundreds of thousands of years ago and spread worldwide alongside humans. They suggest that this ecospecies thrives in the stomachs of individuals whose diets are predominantly meat or fish, indicating that the genetic variations in our stomach bacteria today can reveal insights into our ancestors’ eating habits.
So far, the Hardy ecospecies has been identified only in humans from indigenous populations in places such as Siberia and Northern Canada. It has also been found in tigers and cheetahs in zoos, thanks to an ancient host jump. With key genetic differences that allow it to adapt to the conditions in a carnivore’s stomach, the Hardy ecospecies poses intriguing questions about human dietary history.
Ti Gong
Helicobacter’s journey from Africa in human stomachs.
“Our analysis suggests that both ecospecies accompanied humans since our species originated in Africa more than 200,000 years ago,” Falush said. “If the Hardy ecospecies is indeed adapted to carnivores, it implies that humans who spread across the world often didn’t consume much plant matter, even when it was available.”
The researchers conclude that the first modern humans were infected by two distinct types of helicobacter pylori: Hardy and Ubiquitous. Both spread out of Africa during early human migrations. While the Ubiquitous ecospecies is found in all sampled human populations, the Hardy ecospecies has only been identified in a small number of indigenous populations, hinting that it may have gone extinct in many locations during its migration path.
Understanding why the ecospecies coexist in some populations but not others could provide valuable insights into our prehistory and the significant burden of gastric diseases we still face today.
Other scientists who participated in the study include Professor Yoshio Yamaoka from Oita University in Japan, and Assistant professor Kaisa Thorell from Gothenburg University in Sweden. The research was published in the journal Nature.
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