Gut microbial health could be key to health disparities

Illustration of bacteria.
Illustration of bacteria. (Credit: iStock)

The old adage “You are what you eat” takes on deeper hues as researchers probe connections between health disparities and bacteria living in a person’s gut.

A diverse set of naturally occurring bacteria species forms a person’s gut microbiome. Some species are acquired during life, and some are inherited. The abundance or lack of certain species may change over time depending upon many different factors.

In fact, the relationship between gut microbes and their host is a two-way street. The gut microbiome plays a pivotal role in many biological processes spanning from metabolism and depression to disease susceptibility. But the gut microbiome is also influenced by factors associated with its host’s lifestyle, socioeconomic status, stress levels, and diet — in short, many of the same factors that influence health disparities.

new paper published in PNAS and coauthored by UF researcher Burton Singer reviews what is known about how the gut microbiome is influenced by its environment and how it influences its host. The forward-looking perspective paper also highlights what science lacks: The need for studies that explore the intersection of the gut microbiome and health inequities.

The gut is a biological pathway that links people’s lived experiences and disease, the authors write. And more research is needed to better understand how the gut microbiome intersects with health disparities, Singer says. Singer is a professor of mathematics in UF’s College of Liberal Arts and Sciences, and a faculty member at UF’s Emerging Pathogens Institute.

Recent research shows that the gut microbiome plays a role in amplifying existing disparities caused by structural racism and poverty, the authors write. So why can’t the process be reversed with strategic interventions?

Gut-immune connection

The paper takes a wide-angle view of links between the gut microbiome and health inequities. But one angle the authors explore peers into connections between the gut microbiome and immunity.

In this line of thought, a healthy gut microbiome promotes a functional immune system; while a gut microbiome that lacks proper nourishment contributes to a more susceptible immune system. This could influence an individual’s susceptibility to infections—even airborne ones such as COVID-19.

“Your gut microbiome influences your immune system,” Singer says. “If you have a poor diet, that makes a difference. Because that will alter how your immune system responds to infection.”

For example, Singer references studies on the effect of famine in Holland in 1944-1945 which have shown how the effects of poor nutrition can span generations. When a mother experiences poor nutrition while pregnant, discernable outcomes can later be measured for offspring’s adult body size and risk of diabetes or schizophrenia. 

“It leaves no doubt there are intergenerational consequences,” Singer says.

Singer and his coauthors speculate that the gut microbiome itself should come to be viewed as an important interventional target for lessening the effects of structural health inequities.

“If you think about it, wealthier neighborhoods tend to have grocery stores with better quality foods and produce, while lower-income neighborhoods tend to have more sugary and refined foods available,” Singer says. “This creates populations of people living near each other with entirely different gut microbiome structures.”

These differences then influence health outcomes and the resilience of an individual’s immune system.

Future trends in gut microbiome research

Prior work in this area has investigated the influence of socioeconomic status, environment, diet, chronic stress and exposure timeframes (early childhood to adulthood) upon persistent biological changes leading to heart disease, stroke, and osteoporosis.

But Singer and his coauthors urge the research community to begin evaluating the plasticity of the gut microbiome—its ability to change and adapt. New insights in this arena could lead to novel interventions aimed at the gut, which could mitigate health inequities amplified by modern structural societal divisions.

“This is a big research opportunity for many people,” Singer says. “It’s not going to go away anytime soon.”

Written by: DeLene Beeland