Comparative life cycle assessment of conventional dairy products and plant-based analog and hybrid alternatives: current status and future perspectives

Conventional dairy products are associated with relatively high environmental burdens, largely driven by farm-level processes such as enteric methane emissions, feed production, and land use. These concerns have intensified interest in plant-based analog and hybrid dairy products as potential alternatives. However, environmental comparisons among these product categories remain inconsistent due to differences in functional units, methodological choices, and nutritional characteristics. This review synthesizes ISO 14040/14044 compliant Life Cycle Assessment studies to compare the environmental performance of conventional dairy products, plant-based analogs, and hybrid alternatives, focusing on key methodological drivers such as system boundaries, allocation methods, functional unit selection including nutrient-based units (nFU) and geographical data variability. Across the literature, plant-based analogs generally exhibit lower environmental impacts when assessed using mass- or volume-based functional units. However, this advantage diminishes markedly when nutritional value, protein quality, and bioavailability are considered, with some analog products approaching or even exceeding the impacts of conventional dairy. Hybrid products typically display intermediate environmental profiles, with impacts increasing in proportion to animal-derived fractions. Overall, heterogeneity in methodology and data availability limits comparability across studies. Future research should integrate nutritional dimensions, consumption and waste stages, and representative data to support robust, policy-relevant sustainability assessments within sustainable diet frameworks.