Diet and Cardiometabolism in Rosario

This study will collect demographic, medical, dietary, and biochemical data to evaluate differences among vegan (VGN), ovo-lacto-vegetarian (OLV), and omnivorous (OMNI) participants. Demographic information will include age, sex, district of residence, marital status, number of children, occupation, health coverage (public, social security, or private), and highest educational level attained. Questions were adapted from the Argentine National Surveys of Households and Risk Factors.

Medical history will include current or past significant diseases, psychiatric conditions, reproductive status (premenopausal or menopausal), and habitual medication use. Participants taking drugs that may alter study outcomes (such as antihypertensives, lipid-lowering agents, or oral contraceptives) within the past 6 months will be excluded. Tobacco use will be classified as current, former, or never smoker. Information on supplement use and alcohol intake will also be collected. Alcohol consumption will be categorized as non-drinker, within recommended limits (up to one drink per day for women and two for men), or risk drinker (above these limits). Physical activity will be evaluated using the International Physical Activity Questionnaire (IPAQ) in it's short version, allowing classification into low, moderate, or high activity levels.

Self-perceived quality of life will be assessed with the EQ5D-3L questionnaire validated in Argentina, covering five health dimensions (mobility, self-care, daily activities, pain/discomfort, and anxiety/depression). Following national survey methodology, answers will be grouped into "no problem" or "some problem."

Dietary satisfaction will be evaluated using the DSat-28 questionnaire, which measures satisfaction in domains such as healthy lifestyle, eating out, cost, and food concerns. Higher scores indicate greater satisfaction.

Physical examination will include blood pressure measurement (validated automatic device), weight, height, and waist circumference according to WHO standards. Body composition will be assessed using bioelectrical impedance analysis (BIA), a validated method showing high correlation with DXA. Maximum voluntary isometric grip strength assessed with a calibrated hand dynamometer.

Participants will self-report their dietary pattern as vegan (VGN), ovo-lacto-vegetarian (OLV), or omnivorous (OMNI). They will also indicate the estimated month and year of diet adoption and their main motivation (ethics, environment, health, taste, religion, spirituality, habit, or other). Dietary intake will be recorded for three days (two weekdays and one weekend day), and nutrient composition will be analyzed using MAR24 software, validated for the Argentine population.

Fasting blood samples (12 hours) will be obtained to determine hematological, metabolic, and biochemical parameters. These include complete blood count, renal and liver function (urea, creatinine, AST, ALT, alkaline phosphatase, bilirubin, total proteins, albumin), lipid profile (total, HDL, and LDL cholesterol, triglycerides, apolipoprotein B), glucose and HbA1c, insulin (for HOMA-IR calculation), thyroid function (TSH), inflammation (high-sensitivity C-reactive protein), uric acid, vitamin B12, homocysteine, and iron status (serum iron, transferrin, percentage of transferrin saturation, and ferritin).

Inclusion criteria

• Adults aged 18 to 65 years.
• Residence in the city of Rosario or surrounding areas.
• Without major diseases.
• BMI >18.5 and <30.
• Adherence to a vegan, vegetarian, or omnivorous diet for at least 1 consecutive year at the time of recruitment.

Exclusion criteria

• Acute or chronic diseases (cancer, infections, heart disease, or others), gastrointestinal disorders affecting diet, diabetes mellitus, chronic kidney or liver disease, or any other condition that could affect study outcomes.
• Food allergies or intolerances that substantially affect the individual's usual diet.
• Pregnant or breastfeeding women.
• High-performance athletes (>15 hours per week of high-intensity physical activity).
• Use of medications that could affect study outcomes, including antihypertensives, lipid-lowering drugs, hypoglycemic agents, glucocorticoids, and anti-obesity drugs. Note: vitamin, mineral, or other dietary supplements are not exclusion criteria.
• Problematic use of alcohol or other drugs.
• Simultaneous participation in another clinical trial.
• Inability (physical or psychological) to perform the procedures required by this study.
• Blood transfusions within the last 3 months.