The goal of this intervention study is to determine whether consumption of different fractions of chicken eggs, including egg whites, egg yolks, and whole eggs, confer different changes in markers of HDL function and T cell profiles in younger vs. older men and women. The study will address the following objectives:

• Objective 1: Determine if daily consumption of egg fractions differentially alter HDL profiles across age groups.
• Objective 2: Determine if daily consumption of egg fractions differentially alter immune cell profiles across age groups.

Participants will be asked to consume egg whites, egg yolks, and whole eggs on a daily basis for 4-weeks each, and avoid eating eggs for a total of 8 weeks at different points in the study. Participants will additionally be provided guidance on following a generally healthy diet, and will be asked to complete surveys about dietary intake and physical activity, as well as provide blood samples throughout the course of the study.

Researchers will compare whether daily consumption of egg whites, egg yolks, and whole eggs differentially alter markers of HDL function and T cell profiles in younger vs. older adults.

Inclusion Criteria:

• 18-30 years old, or 50-75 years old (at time of screening)
• Body mass index (BMI) < 30 kg/m2
• Willing to consume whole eggs, egg whites, or egg yolks on a daily basis during study periods, and refrain from eating eggs during other study periods
• Do not fit any exclusion criteria

Exclusion Criteria:

• < 18 years old; 31-49 years old; > 75 years old
• BMI ≥ 30 kg/m2 or body weight < 110 pounds
• Weight changes > 10% over the last 4 weeks
• Self-reported history of diabetes, 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 or intolerance to eggs, egg components, or egg products
• Implanted medical device (e.g., pacemaker) or other health condition that would prevent measurement of body composition by bioelectrical impedance
• Highly elevated fasting lipid and glucose levels (triglyceride levels higher than 500 mg/dL, fasting glucose higher than 126 mg/dL), or total cholesterol < 120 mg/dL and HDL-cholesterol < 15 mg/dL
• Currently taking lipid-lowering medications (e.g. statins, fibrates), anti-inflammatory medications (e.g., NSAIDs, corticosteroids), or medications that primarily affect blood clotting (e.g., warfarin)