- People who belong to historically marginalized groups — whether based on race, gender, or sexual identity — have increased risks of several worse health outcomes.
- The community of microbes in the gut, or gut microbiome, is sensitive to many environmental factors and helps shape health. It may therefore play a role in these disparities.
- Writing in a leading journal, scientists have called for more research to tease apart this complex relationship.
- They believe a greater understanding of how the gut microbiome affects health in minoritized populations can lead to targeted treatments to help redress the balance.
The communities of bacteria, fungi, and viruses that live in our gut, collectively known as the gut microbiome, have multiple effects on health. For example, they can protect the gut from colonization by pathogens, reduce inflammation, and even influence brain function.
A group of scientists led by Northwestern University in Evanston, IL, calls for more research into possible links between the gut microbiome of minoritized populations and worse health.
In an opinion piece in Proceedings of the National Academy of Sciences, they argue that the gut microbiome may respond to and help perpetuate the structural inequities caused by racism and other forms of discrimination.
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High levels of stress and poor sleep quality as a result of discrimination, for example, may change the gut microbiome in ways that are detrimental to health.
In addition, researchers already know that environmental factors linked to lower socioeconomic status adversely affect the composition and diversity of the gut microbiome.
These factors include:
- more cesarean deliveries
- less breastfeeding of infants
- a less healthful diet
- overuse of antibiotics
- poor access to green spaces
“Because the environments that drive [gut microbiome] composition are modifiable, the [gut microbiome] represents an important tool for mitigating the impact of structural inequities and their downstream health consequences,” the authors write.
The scientists also note that race, sexual identity, and gender status are significant predictors of many health outcomes.
For example, after accounting for socioeconomic status, Non-Hispanic Black adults are 1.6 times as likely to receive a diagnosis of diabetes as Non-Hispanic white adults.
According to an older report, gay, lesbian, and bisexual individuals are up to twice as likely as heterosexual individuals to report drug misuse, poor mental health, and smoking.
The authors argue that differences in their gut microbiome may mediate some health inequities in minoritized groups.
“Research has implicated the microbiome in most chronic diseases, and we know that there are disparities in most chronic diseases in which higher morbidity is observed in minoritized populations,” says lead author Katherine Amato, Ph.D., assistant professor of anthropology at the Weinberg College of Arts and Sciences at Northwestern.
She and her co-authors cite evidence that socioeconomic status has associations with distinct gut microbiome features in both adults and children.
For example, a small
A larger study in the United Kingdom, which compared identical twins with divergent socioeconomic status to account for genetic and family influences, also found that people with lower socioeconomic status had less diverse gut microbiota.
The authors of the new opinion article conclude:
“[T]he existing literature demonstrates that the same social gradients that predict disparities in major classes of disease also predict variation in the [gut microbiome]. These relationships underscore the likely role of the [gut microbiome] in mediating socially driven health disparities.”
However, they emphasize that, to date, few studies have assessed how structural inequities affect the gut microbiome and health or how to redress the balance.
“Biomedical” approaches to improve the gut microbiota of minoritized populations might include prebiotics, probiotics, and fecal transplants.
But the authors also recommend “ecological” approaches to create stable and resilient gut microbiota communities.
For example, Prof. Amato told Medical News Today that there is some evidence of greater antibiotic prescribing to the children of minoritized populations, though the picture is complex.
Lack of access to healthcare can result in reduced preventive care, more severe illness, and increased need for antibiotics due to worse infections or health-related procedures, such as surgery, she said.
On the other hand, other studies suggest that populations with good access to healthcare may receive more prescriptions for antibiotics for minor illnesses.
“So, greater antibiotic prescribing for infants and children of minoritized families could explain some of the observed differences in microbiomes between populations, but it will depend on the specific patterns of healthcare utilization observed in communities,” she said.
“We need more data to understand these dynamics better,” she added.
Prof. Amato also advocated carefully tailored policies that promote the exposure of infants and children to the microbes that will help them establish a strong and healthy gut microbiome.
“Kids that are exposed to soil and plants during their outdoor time at school have been shown to have more diverse microbiomes and better markers of immune function — so it might not just be a matter of building a playground in a neighborhood but building it out of the right materials,” she said.
In the United States, she observed, many employers have enlightened policies to provide space for mothers to pump breastmilk at work. But it may have unintended consequences for the gut microbiome of infants.
“While this allows mothers to fulfill infants’ nutritional needs, it ignores the fact that breastfeeding promotes skin-to-skin contact that facilitates microbial transmission from mother to infant,” she said.
“Breastmilk itself is also an important source of microbes and ‘microbe food,’ or oligosaccharides for infants, and we don’t know how storing breastmilk affects its microbial properties.”
She and her co-authors believe that future research should aim to deliver environmental interventions and develop therapies to restore and improve the microbiome of minoritized populations.
Of course, trying to ease the effect of discrimination by understanding these links is crucial. However, it does not, and should not, undermine efforts to tackle the underlying structural discrimination that impacts not only the gut microbiome but the person as a whole, their wider community, and society at large.