Effects of Urolithin A Supplementation on Glucose Metabolism in Healthy Adults 55 >= Years Old: A Randomized Triple-Masked Controlled Clinical Trial

Eligibility Criteria

• * Provision of signed and dated informed consent form.
• * Stated willingness to comply with all study procedures and availably for the duration of the study.
• * Male or female, age \>= 55 years.
• * Able to speak and read English. (We do not have ready access to interpreters of different languages at the NIA Clinical Unit).
• * BMI \>= 27.
• * Ability to take oral medication and be willing to adhere to the daily regimen.
• * Ability to perform walking and treadmill tests without physical limitations.
• * In good general health, as evidenced by medical history/physical exam/laboratory results.
• * History of diabetes requiring treatment with any glucose lowering drug(s).
• * Fasting glucose \>= 126 on screening visit.
• * Is on treatment with an investigational drug or other intervention within 8 weeks of enrollment.
• * Hospitalization within 12 months for myocardial infarction, coronary revascularization or bypass surgery or stroke.
• * History of autoimmune disease, e.g., Hashimoto s thyroiditis, Myasthenia Gravis or Rheumatoid Arthritis.
• * Uncontrolled thyroid disease.
• * Chronic liver disease indicated by medical history or one of the liver enzymes greater than 2 times the normal range.
• * History of chronic kidney disease or GFR \<60 mL/min/1.73 m\^2.
• * Anemia (defined as hemoglobin level \<12 g/dl for men or \< 11 g/dl for women).
• * Poor venous access.
• * Uncontrolled hypertension as judged by the Investigator.
• * History of significant GI disease, e.g., IBS, Crohn s disease.
• * Active cancer or has had treatment for cancer in the last 1 year.
• * Medical condition requiring absolute and continuous need for long-term treatment with antibiotics, corticosteroids, immunosuppressors.
• * Currently pregnant or a nursing mother due to possible changes in hormones and metabolism.
• * History of, or laboratory evidence of HIV virus infection at Screening Visit.
• * History of, or laboratory evidence of Hepatitis B or C at Screening Visit.
• * Positive urine drug screen at Screening Visit (unless taking prescribed medication and at the discretion of the PI).
• * Reports claustrophobia and/or is not eligible to have an MRI as per the MRI eligibility form.
• * Weight \>= 300 lbs (MRI scanner weight limit).
• * Hip or knee replacement or other medical condition that prevents MRI research scans from being performed.
• * Diagnosed with cognitive impairment that clearly prevents the participant from providing informed consent.
• * Current smoker or tobacco use in the past year.
• * History of substance abuse, including marijuana use in the past year.
• * On average, consumes more than 1 alcoholic drink per day.
• * Any other condition which in the investigator s opinion may adversely affect the subject s ability to complete the study or its measures or which may pose significant risk to the subject.