CU Boulder-led research seeks to understand the connection between microbiome and aging

If our bodies could talk, they’d tell stories about our childhoods, our working conditions, our exercise regimens, our diets, even our neighborhoods.

Now, researchers at the University of Colorado Boulder and the University of North Carolina Chapel Hill hope to unlock even more secrets about the environmental factors that affect our health by studying the microbiome, the diverse collection of bacteria, viruses, fungi and other microbes that live on and inside the human body. 

This research, recently awarded five years of funding from the National Institute on Aging, aims to create a “microbiome age clock,” that could help identify people whose bodies are aging faster because of environmental stressors.

In the future, doctors could look at a patient’s microbiome to search for clues to premature aging caused by factors like a poor diet or unhealthy stress levels, then make recommendations to help prevent or even reverse these effects. Beyond individual care, the research has the potential to inform how communities and policymakers think about and address the social, economic and environmental factors that lead to poor health and contribute to premature aging. 

“Microbiome is the new frontier,” said Kathleen Mullan Harris, co-investigator on the project and professor of sociology and public policy at the University of North Carolina Chapel Hill. “We know the microbiome is extremely responsive to the environment. We’re hoping to gain some new insights about how the environment affects health as it operates through the microbiome.”

The researchers are using data from the Add Health study, known more formally as the National Longitudinal Study of Adolescent to Adult Health, a project led by Harris.

Since 1994, Add Health researchers have been following a nationally representative group of 20,000 people who began the study when they were teenagers. Over the last 26 years, the researchers have checked in with participants five separate times to gather demographic, socioeconomic, behavioral, cognitive, psychosocial, familial and health data.

Soon, they’ll ask more than 10,000 of these participants, who are now in their 40s, to send in saliva and stool specimens so researchers can catalog their oral and gut microbiomes. 

The researchers will be able to compare the microbiomes across groups of people, the first effort with such a large and representative sample of the population.

“This is going to be one of the first studies to be able to really characterize the microbiome across race, ethnicity, gender, age, geography and so on,” Harris said. “We don’t know how the microbiome varies by those fundamental kinds of demographic differences. Even just describing the microbiome from a nationally representative sample and how it varies in the South and the Northeast and the West is going to be fascinating.”

Because Add Health has collected so much rich data from participants over the last 2 1/2 decades of their lives, researchers also hope to connect people’s early experiences with the current makeup of their microbiomes. 

“We’re interested in how early life exposures are related to your microbiome in adulthood—the mode of (birth) delivery, whether or not you were breastfed, the early life social and economic conditions of your family, your involvement in risky behavior like drug use, whether or not you have any health conditions,” Harris said.

Long term, this microbiome characterization data could ultimately help communities make changes to help improve the health of residents, such as building more parks or providing greater access to healthy foods. 

“If we can demonstrate geographic clustering of microbiome variation that correlates with social or built environmental features, then what appears to be an individual-level process is linked to the places in which people live, work and go to school,” said Jason Boardman, CU Boulder professor of sociology and a co-investigator on the project. “It takes an otherwise biological process and makes it social.”

The researchers also hope to connect the microbiome to biological markers of aging, such as inflammation and changes to the immune system. 

Doing so means that doctors could someday use the microbiome to help prevent disease and extend their patients’ lives.

“Instead of studying people when they have a disease, we’re actually able to identify these predisease markers. People who have high inflammation, for example, that’s pretty asymptomatic. They don’t know they have it but it’s a marker of future disease,” Harris said. “One of the values of our study is we’re going to be able to identify people who are on a pathway to disease in the future and even premature mortality.” 

Other researchers on the project include Matt McQueen, an associate professor of integrative physiology, and Ken Krauter, a professor of molecular, cellular and developmental biology, from CU Boulder; Allison Aiello from the University of North Carolina Chapel Hill; and Jennifer Beam Dowd from the University of Oxford.