Before you read:
A recent study has found how racial discrimination is able to cause physical disorders in victims via the brain-gut microbiome (BGM) system.
While previous studies have established that structural racism contributes to psychosocial and biological disorders, questions on how exactly relevant experiences affect the body remain unanswered.
The new research, which appeared in the peer-reviewed scientific journal Biological Psychiatry, looked into the role of the BGM system in health issues caused by racism.
Building upon recent findings that stressful experiences pose a great impact on the BGM, researchers at the University of California, Los Angeles, looked into the changes influenced by discrimination in the bidirectional signaling between the brain and the gut microbiome.
The research team, led by Tien S. Dong, MD, Ph.D., and Gilbert C. Gee, Ph.D., included 154 adults from multiple racial and ethnic groups in Los Angeles.
The participants, who self-reported their race/ethnicity as Asian American, Black, Hispanic or White, reported experiences of different types of discrimination, including race, sex and age.
To measure discrimination, the researchers used the Everyday Discrimination Scale (EDS), which marks subjective experiences of daily discrimination across nine elements that assess a person’s life. Among the participants, 80 reported high discrimination while 74 reported low discrimination.
The scientists then reviewed the participants’ functional magnetic resonance imaging results to check the effects of discrimination on brain connectivity.
Blood samples were collected from the participants to measure inflammatory markers as well as fecal samples to assess their microbial population.
Combining all the data, the researchers were able to determine discrimination-related BGM alterations and psychological variables while controlling for sex, age, body mass index and diet.
Based on the new findings, exposure to discrimination has diverse effects on certain biological pathways.
Asian people with high discrimination exposure exhibited 11 higher fecal metabolites than those with low exposure to racism.
Black people showed differences in nine types of bacteria, while white participants exhibited changes in seven bacterial species.
The Hispanic participants had a higher level of Bacteroides stercosis, which is associated with a higher risk of colon cancer.
“Our research suggests that for Black and Hispanic individuals, discrimination leads to changes that include increased systemic inflammation,” Dr. Dong further explained.
For Asian individuals, the patterns suggest [that] possible responses to discrimination include somatization or the production of multiple medical symptoms with no discernible known cause. Among White individuals, discrimination was related to anxiety but not inflammation. But just as importantly, for all races, discrimination also had an increase in the emotional arousal and limbic regions of the brain, which is associated with the stress response of fight or flight. We also saw elevations in pro-inflammatory microbes such as Prevotella copri.
According to Biological Psychiatry editor John Krystal, MD, the research brings new insight into the impact of racism on people’s “emotions, brain activity, inflammatory markers in the blood, and the composition of the gut microbiome.”
We would not be surprised to learn that exposure to racism affects how we feel and how we cope with this exposure and other life stresses. However, this study goes further to highlight brain patterns of response to racism and other factors that affect physical health, including the types of bacteria growing in the gut and the levels of inflammation in the body. These are factors that influence many disease processes in the body.