Effects of Grape Powder on Psychological Distress and Gut Microbiota in College Students

The goal of this trial is to investigate the effect of freeze-dried table grape powder (FTGP) on psychological distress and gut microbiota in college students. The main questions it aims to answer are: Does FTGP reduce anxiety, depression, and perceived stress? Does FTGP improve the gut microbiota? Researchers will compare FTGP to a placebo to see how FTGP affects psychological distress and gut microbiota. Participants will: Drink a daily supplement containing FTGP or a placebo for 4 weeks. Record consumption of grape powder or placebo in a compliance log. Complete surveys and provide stool samples. Three in-person visits.

Inclusion Criteria: * Aged 18-30 years old * Able to give written informed consent. * BMI 18.5-24.9 kg/m2 * Healthy (self-reported) * Can read and speak English Exclusion Criteria: * Currently taking medications that interfere with polyphenol * Currently using or have used antibiotics continuously for \>3 days within 3 months prior to enrollment * Have had surgery involving the intestinal lumen within the last 30 days * Have a documented diagnosis of celiac disease or/and inflammatory bowel diseases * Are pregnant or breastfeeding * Have prediabetes and diabetes * Have had bariatric surgery * Are immunocompromised ( e.g., cancer treatment, bone marrow/organ transplant, immune deficiency, or poorly controlled HIV/AIDS) * Are unable to provide consent * Are hospitalized, * Have a history of or current alcohol, drug, or medication abuse (self-reported), * Have contraindication to any substance in the investigational product or who are currently enrolled in other interventional trials