Discrimination messes with an important part of your bodily function, raising risk of health complications, study suggests

Experiencing discrimination can change the way the gut and brain communicate, which can lead to cravings for unhealthy foods and an increased risk of obesity.

Researchers in California asked more than 100 participants of different races and ages, mostly women, to complete questionnaires about the level of discrimination they experience in their daily lives.

Participants then underwent MRI scans while the research team showed them pictures of junk food such as cake, ice cream and pizza, as well as images of healthier foods such as fruit and salad. The participants also provided stool samples so that researchers could measure their gut health.

The team found that showing pictures of unhealthy foods to people who experienced more discrimination triggered a greater response in the reward region of their brains, causing them to reach for sugary and high-fat foods.

The researchers believe this could increase the risk of obesity, which health officials say is reaching epidemic proportions in the US.

Dr. Arpana Gupta, senior study author and co-director of the Goodman-Luskin Microbiome Center at the University of California Los Angeles (UCLA), said: ‘We examined complex relationships between self-reported exposure to discrimination and poor food choices, and we can see that these processes lead to increased cravings for unhealthy foods, especially sweet foods, but also manifest as changes in bidirectional communication between the brain and the gut microbiome.”

The study, published Monday in the journal Nature mental health, included 107 Hispanic, Black, Asian, and White participants. The majority of participants, 87, were female, while 20 were male.

Fifty-five reported eating a standard American diet, which includes excess calories, saturated fat, added sugars and sodium. Meanwhile, 50 said they followed a non-standard American diet of healthier foods with fewer calories. Data were missing for the remaining two participants.

The participants were asked to complete questionnaires about the level of unfair treatment they regularly receive.

Based on their scores, researchers divided them into two groups: “high exposure to discrimination” and “lower exposure to discrimination.” Participants also provided stool samples to measure their gut bacteria.

While undergoing MRI scans, researchers noticed that people with higher levels of discrimination reported discrimination had greater responses from the brain’s reward center, known as the frontal-striatal region, when they saw unhealthy food, leading to more cravings.

Additionally, the study found that people who experienced more discrimination had higher levels of gut compounds called glutamate metabolites, which are associated with inflammation and oxidative stress, which is an imbalance between antioxidants and harmful substances known as free radicals.

These processes can damage cells and DNA, play a key role in aging and lead to increased body fat levels.

Based on their findings, the researchers believe that discrimination can lead to changes in communication between the gut and the brain, leading to cravings for comfort foods and unhealthy eating.

The gut-brain connection is a bidirectional pathway that connects the central nervous system and the enteric or intestinal nervous system, creating a relationship between the brain and the gastrointestinal tract.

The central nervous system, consisting of the brain and spinal cord, acts as a processing center and coordinates activities throughout the body.

The enteric nervous system, which controls gastrointestinal behavior, consists of two thin layers of between 200 million and 600 million neurons that line the gastrointestinal tract from the esophagus to the rectum.

The gut-brain connection affects hunger, fullness, food cravings, digestion, metabolism and stress levels. Therefore, stress, like facing discrimination, can lead to a craving for unhealthy foods.

Dr. Gupta said: ‘Our results show that the cross-talk between a person’s brain and gut can change in response to persistent experiences of discrimination – affecting food choice, cravings and brain function and contributing to changes in the gut chemistry involved are associated with stress and inflammation.

‘It appears that in response to stressful experiences of discrimination, we seek comfort in food, which manifests in increased cravings and desires for highly palatable foods, such as high-calorie foods and especially sweet foods.

“These changes may ultimately make people exposed to discrimination more vulnerable to obesity and obesity-related conditions.”

The study builds on Dr. Gupta’s previous research showing that the brain and gut respond differently to discrimination depending on the individual’s race or ethnicity.

In a 2022 study published in the journal Biological PsychiatryShe and her colleagues found that discrimination among black and Hispanic individuals was linked to anxiety. Furthermore, Asian participants who were victims of discrimination were more likely to experience behavioral changes.

The study authors said more research is needed, but it could lead to treatments for discrimination-related stress that target the brain or the gut.