Inclusion Criteria:  Caucasian Female 18-45 years of age For the high perceived stress group: a PSS score of 15 or higher and a STAI-S of 39 or higher For the low perceived stress group: a PSS score of 8 or lower and a STAI-S score of 24 or lower  Exclusion Criteria:  Any ongoing major medical, psychological, or psychiatric conditions and recent changes (3mo) in the use of psychoactive medications or other medications that interfere with the measured outcomes. Medical conditions such as current neurological, cardiovascular, hepatic, renal, autoimmune diseases, diabetes, or cancer. This includes having a current or past within 1 year diagnosis of GI disorders, including but not limited to IBS, IBD, Celiac, or other nutritional deficiency/disease, current eating disorder, or past weight loss surgery. Psychological conditions such as anxiety and depression (I.e., without history of Diagnostic and Statistical Manual (DSM-4) psychiatric diagnosis. Prior/Concomitant Therapy (e.g., Recent changes in the use of psychoactive medications or other medications that interfere with the measured outcomes, as determined by the PI). Subject involved in any other clinical study within the preceding month or in the exclusion period after another clinical study. Positive test for COVID-19 infection in the past month or if presenting symptoms of COVID-19 infection in the past 2 weeks.  Diet:  Participant who changes her dietary habits within the preceding 4 weeks. Participants on probiotics will be asked to wait 1 month before enrollment in the study. Participant with an eating disorder. Participant with special medicated diet (e.g., for obesity, anorexia, metabolic pathology). Participant under artificial nutrition in the last 1 month. Participant planning to modify her dietary habits during the course of the study.  Other Exclusions:  Pregnant women or women planning to become pregnant during the study; breast-feeding women based on the interview at screen (Visit 1) and the urine test on day of stress test (Visit 2). Smoker with a moderate to high level of dependence to nicotine (e.g., more than 1/2 a pack of cigarettes a day). Participant consuming regularly more than 3 units of alcohol per day (1 unit = 10mL or 8g). Participants not able to answer questionnaires by writing, whatever the reason. Participant with loos of liberty, by administrative or judicial decision. Participant who is major but with a legal guardian. Participant on antibiotics will be asked to wait 3 months before enrollment in the study.  Medications not Authorized:  Opiates/Narcotics Chronic/Daily use of analgesics Anti-seizure meds Antidepressants (5HT3's / Tricyclics etc.) are allowed as long as it's been a stable dose for 3 months Medications for ADD/ADHD (I.e., Adderall) Any medication for appetite suppression Chronic use of laxative/antidiarrheals/medications affecting GI motility Insulin Bile acid sequestrants Use of centrally acting medications that will interfere with CNS testing