The human stomach is full of bacteria, archaea, and fungi that make up the microbiome, which helps digest food, fight disease, and regulate the body’s immune system. But our microbiomes have changed over the years, and many microbial genomes have gone extinct.
That’s why researchers were so excited to get their hands on some ancient fecal matter that contains microbial genomes from generations past. These ancient fungi, bacteria, and fungi could be the secret to regulating chronic illness.
Unlocking the Secrets of Ancient Poop
Research shows that the microbiomes living in our ancestors’ stomachs vary greatly from those living inside us today. Pre-industrialized diets tend to feature greater diversity in the gut microbiome, potentially resulting in lower rates of chronic illness.
For this reason, researcher Aleksandar Kostic of the Joslin Diabetes Center in Boston and his team set out to find if these ancient microbes could be used to reduce the rate of chronic disease.
There are few well-preserved samples from the pre-industrialized era, which makes this type of research nearly impossible to conduct, but Kostic and his team were able to get their hands on eight human feces samples collected along the Mexico, Southwest U.S. border. Researchers believe the poop is anywhere between 1,000 to 2,000 years old.
Kostic said the feces were “exquisitely preserved” thanks to the desert region’s extreme aridity. The team reconstructed the 498 microbial genomes found in the feces, 161 of which seemed to come from ancient humans. Of those, 61 had never been seen before.
They compared the ancient microbiomes to today’s, including those of people who live in industrialized and non-industrialized societies, and found that the ancient microbiomes are much closer to those found in non-industrialized populations, based on samples collected from Fiji, Madagascar, Peru, Tanzania and the Mazahua, an indigenous community in Mexico.
According to the study, now published in Nature, a non-industrialized lifestyle is “characterized by consumption of unprocessed and self-produced foods, limited antibiotic use and a more active lifestyle.”
Both the ancient and modern non-industrialized microbiomes contain more enzymes used to break up starches. That’s because ancient humans and non-industrialized people tend to eat more complex carbohydrates compared to those living in present-day industrialized societies.
Researchers said that some microbes simply disappear over time, changing human beings for good. “When they’re gone, we’re missing a key piece of what makes us us,” Kostic said.
Treating Chronic Illness with Ancient Microbes
Kostic and his team hope to use these ancient microbes to reduce the rate of chronic illnesses here in the U.S., including diabetes, obesity, and even autoimmune diseases.
“We could reseed people with these human-associated microbes,” he said.
He adds that fecal microbiota transplants are currently working their way through the approval process under the Food and Drug Administration.
Next, the researchers plan to find out if the same ancient microbes are present in today’s non-industrialized populations. They will then insert them into the digestive systems of animals to see if they have a positive effect.
Kostic and his team plan on pinpointing exactly which microbes can be introduced to humans. They will then use technology to create synthetic versions that could potentially reduce the rate of chronic illness.
However, he adds that more research and samples are needed to see whether there is “a unified human microbiome that used to exist,” he added.
Unfortunately, there’s nothing Kostic and his team can do to recreate ancient microbes that have gone the way of the dinosaur. The only thing they can do is hope to find more samples intact.
However, the study shows that humans can increase the diversity of their gut microbiomes by eating more fiber and complex carbohydrates, including peas, beans, whole grains, and vegetables, and fewer simple carbs, like pasta and white bread. Kostic also says exercising regularly and coming into contact with soil and animals may help restore the gut microbiome as well.
These ancient microbes tell a story of what life was like for our ancestors. They were clearly eating healthier, staying more active, and benefiting from living off the land. Hopefully, we will one day be able to reconstruct the ancient human microbiome to keep chronic illness at bay.