The GLUCID Study: Effect of Alcohol Reduction and Probiotic Interventions on Cognition and Brain Glucose Metabolism in Normal Aging Adults Who Are High-Risk Alcohol Drinkers

Inclusion Criteria: * Between 65 and 84 years of age * English speaking * Able to provide valid informed consent, understand requirement and risk/benefits of the study and comply with study protocol * Heavy drinker defined as \>14 alcoholic drinks/week for men and \>7 drinks/week for women * Interested in reducing their alcohol consumption Exclusion Criteria: * BMI ≥ 35 * Fasting Glucose \> 125 mg/dL * Current or previously diagnosed with Type 1 or 2 Diabetes * Requires the use of insulin and/or other glucose lowering agents * Unable to fast for 12 hours * Past serious alcohol withdrawal symptoms * MRI Contraindications (e.g., certain devices and implants, claustrophobic) * Diagnosed with a neurodegenerative disease (e.g., Alzheimer's Disease) * Diagnosed with a psychotic disorder * Current substance dependence diagnosis (except for mild or moderate alcohol) * Consumption of over 300 drinks in the past 30 days * Current probiotic use or recent probiotic use within the past 30 days * Current antibiotic use or recent antibiotic use within the past 30 days * In active cancer treatment and/or have advanced cancer * Taking daily steroids and/or immunosuppressants * Lifetime organ or bone marrow transplant; primary immunodeficiency (e.g., DiGeorge syndrome or Wiskott-Aldrich syndrome) or transplant recipient or prescribed immunosuppressant medications * PI's discretion