UNIVERSITY PARK, Pa. (WTAJ) — During the mid-14th Century, the Black Death swept through Europe, killing a large portion of the population. Now, researchers out of Penn State are finding a link between that plague and some modern-day chronic illnesses.

“The microbiome, these healthy microbial communities that exist in all of us as part of what makes us human, were really potentially shaped and changed after what we call the Second Plague Pandemic or when the Black Death arrived for the second time in London in the UK,” Laura Weyrich, Professor of Anthropology and Bioethics at Penn State said.

The study found that these microbes, now associated with obesity, cardiovascular disease, allergies and poor mental health became more common after the Second Plague Pandemic.

“We actually went in and cleaned the teeth of ancestors that lived in ancient London and picked out the bacteria that was stuck between their teeth in calcified dental plaque,” Weyrich said. “We then sequenced the DNA that was preserved or residing in that dental calculus and we were then able to reconstruct the types of bacteria that people had, both before and after that time period.”

Weyrich said the increase can be traced back to better dental hygiene after the plague and changes in diet.

“Increases in sugar in our diet and milk consumption as well as meat,” Weyrich said.

Now, Weyrich said the team is looking to use this research to develop new technologies that could improve the health of people suffering from chronic diseases in the future.