Linking Environmental Impacts and Nutritional Value in a Life Cycle Perspective for Different Dairy Products

The dairy sector faces increasing pressure to reduce environmental impacts while maintaining nutritional quality and product diversity. Cheese production is particularly complex, as it involves a wide range of processing technologies and energy demands, from fresh cheeses to long-ripened products. This study presents an evaluation based on Environmental Product Declarations and Life Cycle Assessment applied to fourteen dairy and plant-based products, including milk, fresh products, cheese, and plant-based alternatives. Environmental impacts are expressed as Global Warming Potential (GWP, kg CO₂eq/kg product) and disaggregated across upstream, core, and downstream phases. For studies with limited system boundaries, downstream proxy values, covering distribution, household refrigeration, and packaging end-of-life, were estimated using a harmonized set of assumptions to ensure cross-product comparability. To move beyond mass-based functional units, impacts are also expressed relative to a Nutrient Density Unit (NDU) encompassing energy, protein, fat, carbohydrates, and calcium, key nutrients in which dairy products excel. Further analyses examine the influence of post-farm processing efficiency through five decarbonization scenarios, including energy efficiency improvements and industrial heat pump electrification under varying electricity mixes, applied to four representative products and address the robustness of the nutritional metric through a simplified Nutrient Rich Food index in which fat is treated as a nutrient to limit. Results show that while mass-based GWP favours minimally processed and plant-based products (0.72–1.6 kg CO₂eq/kg) over longripened cheeses (9–20 kg CO₂eq/kg), nutritional normalization substantially narrows, and in some cases reverses, this gap: mean GWP/NDU values are 39 for milk, 34 for fresh dairy, 30 for cheese, and 12 for plant-based alternatives, reducing the category-level difference from approximately thirteen-fold to roughly two-and-a-half-fold. Processing decarbonization reduces GWP/NDU by 4–24 % depending on product type, with UHT milk showing the strongest response and long-ripened cheeses the most limited, given the dominance of upstream agricultural emissions. The NRF-based robustness check confirms that relative product rankings remain broadly stable under alternative nutritional metrics. This framework supports transparent sustainability communication, product benchmarking, and evidence-based decision-making in the food sector.