Study Evaluating the Effects of Red Grape Juice Consumption on Metabolism in Men With Coronary Artery Disease

Previous studies have suggested that both red wine and red grape juice exert beneficial effects on cardiovascular health, including reductions in inflammatory biomarkers and cardiovascular events. However, the influence of grape polyphenols on the plasma metabolome in men with chronic coronary artery disease (CAD) remains poorly understood. Human plasma contains a wide range of metabolites that reflect physiological and pathological processes, making metabolomic profiling a valuable approach for investigating the biological effects of dietary interventions. Recent advances in mass spectrometry-based technologies have greatly expanded the ability to characterize these metabolic changes.

This prospective, randomized, controlled crossover study aims to investigate the effects of red grape juice consumption on the plasma metabolome of patients with chronic CAD. Fifty men aged 46 to 69 years with a confirmed diagnosis of chronic CAD will be enrolled. Participants will undergo two 3-week intervention periods in random order: daily consumption of 400 mL of red grape juice and a control period involving complete abstinence from polyphenol-rich foods. Plasma metabolomic profiling will be performed using gas chromatography-mass spectrometry (GC-MS) by Prof. Carlos Labate at the Department of Genetics, Luiz de Queiroz College of Agriculture (ESALQ), University of São Paulo. Eligibility criteria were established to ensure a homogeneous study population and to minimize potential confounding factors. We hypothesize that red grape juice consumption will modulate metabolic pathways involved in lipid metabolism, carbohydrate metabolism, and energy production, providing further insight into the mechanisms by which grape polyphenols promote cardiovascular health without the risks associated with alcohol consumption.

Inclusion criteria

Individuals aged 46 to 69 years with established chronic coronary artery disease diagnosed more than 30 days after acute myocardial infarction, angiographic evidence of ≥50% stenosis in one or more epicardial coronary arteries, previous percutaneous coronary intervention, or previous coronary artery bypass graft surgery, with a body mass index (BMI) <30 kg/m² and without symptoms of angina or dyspnea.

Exclusion criteria

Exclusion criteria

include the use of antibiotics within the eight weeks preceding study enrollment; heart failure (New York Heart Association functional class ≥II); renal insufficiency (creatinine clearance <30 mL/min calculated using the Cockcroft-Gault equation); and hepatic insufficiency (defined by thrombocytopenia, reduced serum albumin, and prolonged prothrombin time). Individuals with cancer, inflammatory bowel disease, obstructive biliary disease, or a history of digestive surgery, including cholecystectomy, gastrectomy, or colectomy, will also be excluded. Patients with diabetes mellitus, those receiving antidiabetic medications, or those with hypertriglyceridemia will be excluded because of the high sugar content of red grape juice (400 mL contains approximately 280 kcal and 60 g of carbohydrates). The use of illicit drugs and habitual consumption of wine or other alcoholic beverages are also exclusion criteria. In addition, individuals with unstable angina, moderate valvular heart disease, Chagas disease, permanent pacemaker implantation, chronic obstructive pulmonary disease (COPD), aortic aneurysm, or aortic ectasia measuring less than 40 mm will be excluded.