Gut Mini-Pill Study

Inclusion Criteria

• Men and postmenopausal women
• Age >50 to \<75 years
• BMI >20 to \<35 kg/m2
• Normotensive with or without medication
• Normal gastrointestinal function with regular bowel movements at least once every other day
• Normal kidney and liver function
• Willingness to swallow the mini-pills
• Willingness to collect and return multiple stool samples
• Adequate refrigerator and freezer space to store study entrées
• Intent to remain in the greater Boston area during the intervention periods

Exclusion Criteria

• Individuals self-reporting adhering to any type of vegetarian diet
• Lack of willingness to restrict fish intake to less than once per week during the dietary intervention phases
• Allergy/intolerance/religious reasons to avoid study foods or food ingredients, including known hypersensitivity to Blue 1 food coloring and wheat gluten.
• Regular use of prebiotics or probiotics within the past 3 months
• Regular use of laxatives or fiber supplements
• Chronic constipation
• Chronic use of antibiotics (except topical)
• Regular use of stomach acid lowering and weight loss medications such as GLP-1 agonists
• Use of dental prophylaxis
• Planned colonoscopy 2 months prior to or during the study period
• Gastroparesis
• Swallowing disorder, or inability or difficulty taking pills
• Malabsorptive and inflammatory bowel disease, diverticulosis, and history of diverticulitis, gastric/ esophageal/intestinal surgery, including lap banding or bariatric surgery.
• History of bowel obstruction, pancreas and liver disorders.
• Any form of active substance abuse or dependence (including drug or alcohol abuse). This information will be stored in REDCAP in a subsection that has no identifiers.
• Established major chronic diseases such as cardiovascular disease, diabetes, active cancer within the last 5 years, or any significant medical condition at the study MD's discretion
• A clinical condition that, in the judgment of the study MD or principal investigator, could potentially pose a health risk to the subject while involved in the study.
• Unwillingness to adhere to study protocol
• Intent to increase or decrease body weight during the study period
• No Social Security number (for payment and IRS forms).
• Individuals who directly report to any member of the research team.