Effects of Freeze-dried Grape Powder on Immune Profiles in Healthy Aging Adults

Inclusion Criteria: * 50-75 years old (at time of screening) * Body mass index (BMI) 18.5 to \< 30 kg/m2 * Willing to consume grape and control powder during study periods, and refrain from eating grapes and certain other polyphenol-rich foods and beverages during the study * Do not fit any exclusion criteria Exclusion Criteria: * \<50 years old and \>75 years old * BMI \<18.5 and ≥ 30 kg/m2 or body weight \< 110 pounds * Experienced \>10% weight change in the past 4 weeks * Elevated fasting glucose levels (fasting glucose higher than 126 mg/dL) and triglycerides greater than 500 mg/dL * Self-reported and/or physician-diagnosed history of diabetes mellitus, coronary heart disease, stroke, renal or liver disease, cancer, eating disorders, certain severe and/or relapsing/remitting autoimmune, inflammatory, or metabolic diseases, chronic infections, scleroderma, blood clotting disorders, intravenous drug use, or current pregnancy or lactation * Allergy to grapes or any ingredients in the grape or control powders * Implanted medical device (e.g., pacemaker) or other health condition that would prevent measurement of body composition by bioelectrical impedance * Currently taking lipid-lowering medications (e.g., statins, fibrates), glucose-regulating medications, anti-inflammatory medications (e.g., non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids), or medications that primarily affect blood clotting (e.g., warfarin), long-term antibiotics in the last 3 months, active use of probiotics during the intervention * Active smoker