Discrimination and the Brain-Gut-Microbiome (BGM) Axis

Obesity is a major public health problem related to a variety of illnesses such as heart disease and diabetes. Prior research indicates that social stressors contribute to risk for obesity, possibly through alterations in diet and physical activity. However, it is not fully clear how these alterations contribute to obesity. The purpose of this study is to examine how the stressors of social isolation and discrimination relate to eating behaviors and dietary patterns, and further, how these behaviors affect the brain-gut-microbiome (BGM) connections. This study will focus on Mexican and Filipina women because research shows that they encounter a high burden of obesity and exposure to social stressors. Approximately 300 Mexican and Filipina women will be screened and enrolled. They will then provide information about social stressors via food diaries, physical body measures (e.g. waist circumference), questionnaire data regarding diet and eating behaviors, and measures of physical activity. Stool and serum will be collected to analyze microbes and metabolomics, and MRI to assess brain changes in the reward network. Analytic techniques will be used to integrate data from these multiple data sources. This analysis will determine the unique differences associated with ethnicity and social stressors in moderating eating behaviors and dietary patterns. The results of this study will provide new information about a possible pathway whereby social stressors affect behavioral, neurological and microbiome mechanisms related to obesity risk and provide new information in BGM patterns in two understudied ethnic groups. In the long term, this research may suggest possible approaches for intervention that may help reduce inequalities in obesity and related health problems.


Eligibility Criteria:
Inclusion Criteria:

* Premenopausal females
* Ages 18-50
* Mexican or Filipino ancestry
* BMI 19-40
* Fluent in English
* Right-handed

Exclusion Criteria:

Co-Morbidities including but not limited to:

* Type I diabetes (insulin dependent)
* Vascular disease
* Drastic weight loss (more than 10lbs over the preceding 2months)
* Frequent Strenuous exercise (i.e. marathon runners/heavy weight lifting)
* Abdominal surgeries including weight loss surgery, or partial/complete resection of the stomach or bowel
* Untreated thyroid disease
* Neurological disease
* Major medical condition that may put the subject at risk or interfere with data collection as determined by the PI/MD
* Chronic pain
* Diagnosed DSM IV active psychiatric illness including eating disorders. Must not be active or present for at least 2 years.
* Use of medications known to affect hunger, satiety, and/or appetite.
* Unable to safely participate in the MRI (claustrophobia, presence of devices affected by MRI such as pacemakers, neurostimulators, or any metallic foreign body, etc.)
* Pregnant, lactating, postpartum less than 6mo
* Women of childbearing age who are not practicing birth control or are planning to get pregnant during the study.
* Body weight at enrollment greater than 400lbs due to weight restrictions on the MRI table
* Use of oral/IV antibiotics within the last 3 months
* Use of probiotics in the last month
* Heavy use of tobacco, alcohol, and/or drug use/abuse
* Significant change in usual diet and/or weight loss of more than 10lbs in the last 2months
* Refugees or recent immigration of less than 2 years in the USA.
* Temporary workers/visitors/students
* Recent international travel if more than 3 weeks within the last 3 months.

Use of the following medications is exclusionary:

* Opiates/narcotics
* Chronic daily use of high dose OTC analgesics
* Anti-seizure medications
* Medications for appetite suppression
* Chronic use of laxatives/antidiarrheals, medications affecting GI motility
* Insulin
* Bile Acid Sequestrants
* Centrally acting medications that will interfere with the neuroimaging testing
* Thyroid replacement medications (OK if stable for at least 3mo)
* Heavy use of tobacco/cannabis
* Heavy use of alcohol ( \>7/week for women)
* Antidepressants (5HT3's/Tricyclics) (OK if stable for at least 3mo)