Some of our gut microbiota predates the human-Neanderthal split

Feb. 5 (UPI) -- Some of the same microbes still found in the human gut today were present in the intestines of Neanderthals some 50,000 years ago.

DNA from Neanderthal fecal remains, recovered from an archaeological site in Spain, suggests microbiota in the human gut predates the split between Neanderthals and modern humans.

Neanderthals and modern humans diverged between 700,000 and 800,000 years ago. Around 40,000 years ago, Neanderthals died out.

The latest research, published Friday in the journal Communications Biology, suggests that when humans and their closest relatives split, the two lineages carried their microbial heritage with them.

"These results allow us to understand which components of the human gut microbiota are essential for our health, as they are integral elements of our biology also from an evolutionary point of view," study leader Marco Candela said in a news release.

"Nowadays there is a progressive reduction of our microbiota diversity due to the context of our modern life: this research group's findings could guide us in devising diet- and lifestyle-tailored solutions to counteract this phenomenon," said Candela, a professor of biotechnology at the University of Bologna in Italy.

The millions of microbes that constitute the human gut microbiome play a variety of important roles in supporting human health, aiding digestion, regulating metabolism and governing the immune system.

Over the last decade or so, researchers have discovered important links between the human gut microbiome and a variety of health problems, including mental health disorders, such as anxiety and depression.

But untangling the links between diet, lifestyle and human gut health remains a complicated task.

Some researchers have hypothesized that modern diets and lifestyle changes have divorced the human gut microbiome from ancient microbiota lineages, yielding increases in certain health maladies.

"The process of depletion of the gut microbiota in modern western urban populations could represent a significant wake-up call," said study first author Simone Rampelli.

"This depletion process would become particularly alarming if it involved the loss of those microbiota components that are crucial to our physiology," said Rampelli, a researcher at Bologna.

In Europe and the United States, health researchers have noted a marked increase in the prevalence of several chronic inflammatory diseases, including inflammatory bowel disease, metabolic syndrome and type 2 diabetes. Likewise, colorectal cancer diagnoses among young people are rising rapidly.

The authors of the latest study contend that by better understanding what the human microbiota looked like thousands of years ago, researchers can better appreciate what's been lost.

DNA signatures recovered from the ancient Neanderthal feces revealed many of the same kinds of bacteria that populate the intestines of modern humans -- including Blautia, Dorea, Roseburia, Ruminococcus and Faecalibacterium.

These bacteria help balance metabolism and immune responses in the human body by converting dietary fiber into short-chain fatty acids.

Researchers also found evidence of some of the bacteria strains that researchers call "old friends" -- microbes that once populated human guts but have been lost over time.

Though the latest findings don't offer clarity on the health implications of this lost microbiota diversity, the discovery confirms that the human gut today isn't what it used to be.

"In the current modernization scenario, in which there is a progressive reduction of microbiota diversity, this information could guide integrated diet- and lifestyle-tailored strategies to safeguard the micro-organisms that are fundamental to our health," Candela said.

"To this end, promoting lifestyles that are sustainable for our gut microbiota is of the utmost importance, as it will help maintain the configurations that are compatible with our biology," Candela said.