Grape juice and red wine: Composition, processing, and health implications

Grapes are among the most widely cultivated and consumed fruits worldwide, generating strong interest in their derivatives, particularly juice and wine. Although both originate from the same food matrix, whole grape juice and red wine differ markedly in chemical composition, production methods, post-harvest handling, and health effects. In this context, this review compares these beverages in terms of nutritional composition, sensory properties, bioactive compound concentration, production techniques, regulations, environmental impact, health effects, gut microbiota interactions, and consumption trends. Drawing on recent scientific literature, clinical trials, and international guidelines, the review highlights key factors influencing consumption and consumer choice. Whole grape juice presents specific absorption and digestion mechanisms, modulating GLP-1 metabolism and enzyme activity. Red wine, in turn, is metabolized through hepatic oxidative pathways due to ethanol, involving ADH and ALDH, which may pose risks with chronic intake. Still, both beverages promote a healthy gut microbiota by improving the Bacteroidetes/Firmicutes ratio and increasing beneficial bacteria like Lactobacillus. Grape juice shows higher symbiotic potential, while wine provides greater phenolic content and bioactivity, supporting cardiovascular health. Consumer preference is multifactorial, influenced by sensory characteristics such as aroma and flavor. Both can be part of a balanced diet aligned with individual nutritional needs when consumed in moderation. Current evidence highlights the complexity of the metabolism of whole grape juice and red wine, and reinforces the need for further randomized clinical trials to clarify their long-term effects and underlying mechanisms.