Food System

Nutritional LCA: the next step in measuring food sustainability

October 10, 2025

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The ecological transition of the food supply chain towards sustainability requires measurement tools to effectively integrate both environmental and nutritional dimensions. In this direction, the nutritional Life Cycle Assessment (nLCA) has developed as an evolution of the traditional Life Cycle Assessment (LCA), which, in the case of food, goes beyond the limitation of impact analysis based on mass units (such as kilograms of product) by addressing the primary function of food: nutrition.

As highlighted by the European Dairy Association (EDA, 2025), nLCA assesses the environmental impact required to provide a specific nutritional function, offering a more comprehensive measure of the sustainability of food systems. This approach is crucial for food security, consumer transparency, and the evolution of the Functional Unit in comparative studies, fostering a more balanced approach to nutritional and environmental sustainability.

Table of Contents

Life Cycle Assessment (LCA) and measurement of environmental impact

Nowadays, Life Cycle Assessment (LCA), defined by ISO 14040 and 14044 standards, remains one of the most effective and widely used tools for assessing the environmental impacts of a product or service throughout its life cycle — from raw materials extraction to their use, and disposal or recycling (Green Forum, 2025).

It is an extremely flexible methodology, adaptable to a wide range of products and services, thanks to the availability of extensive databases or the use of directly collected primary data, providing objective and potentially comparable results.

This tool — although extraordinarily useful for identifying pollution hotspots along supply chains and effectively reducing the environmental impacts of production, packaging, and transport of food products (Heller et al., 2013) — presents a discretional degree in the choice of the reference measurement unit for the impacts (the so-called Functional Unit, FU), which may hinder comparisons even among similar product categories.

The Functional Unit represents the minimum unit of product or service to which all environmental impacts are referred, and is chosen during the early stages of the LCA according to the analysis’s purpose and its relevance to typical use (Baldo et al., 2008).

If a comparative LCA study is to be conducted between different transport modes, for example, the Functional Unit is not the vehicle itself (such as a car, aeroplane, or train), since it does not directly represent the function of the service. Instead, the Functional Unit “1 passenger transported per kilometre” (passenger/km) is typically used as the reference unit: this way, environmental impacts are normalised by both distance travelled and the number of passengers transported, making comparisons between modes more fair and representative of their real functional efficiency.

In the food sector, the chosen Functional Unit is often 1 kg of product or a standard package (e.g., a can of beans or a pack of pasta). While practical and useful for comparing similar products within the same industrial category, this choice can be misleading when comparing foods with very different nutritional values. In such cases, the environmental impact per kilogram of product may be deceptive, since the quantities required to provide the same energy, nutrient, or micronutrient intake can vary considerably between foods.

The nutritional Life Cycle Assessment (nLCA) approach was developed specifically to overcome this limitation by integrating traditional environmental impact indicators with nutritional parameters. In this way, the Functional Unit no longer considers only the physical quantity of food but also its nutritional function (i.e. its contribution of energy, proteins, or micronutrients), allowing for more realistic comparisons between foods.

Nutritional LCA (nLCA)

The nutritional LCA (nLCA) is a life cycle analysis methodology that has evolved to account for the primary function of food: supporting and promoting human health through the provision of nutrients and other compounds (McLaren et al., 2021). The nLCA plays a key role in addressing the ‘triple challenge’ of obesity, malnutrition, and climate change, guiding the transition toward healthy and sustainable diets (Cardinaals et al., 2024). Integrating nutritional aspects is therefore crucial to avoid undesirable trade-offs in the food transition, as diets poor in essential nutrients cannot be considered healthy or sustainable in the long term (Cardinaals et al., 2024; EDA, 2025).

Since the early 2000s, researchers have begun incorporating nutritional principles into LCA studies of agri-food products (McAuliffe et al., 2023a). With growing interest in assessing the environmental performance of different foods and dietary patterns, numerous researchers have proposed alternative approaches to evaluate both environmental impact and nutritional value in a unified way (McLaren et al., 2021).

As early as 2015, Rothamsted Research (RRes) — a UK agricultural research institute active for over 170 years — launched a six-year program (“Soil-to-Nutrition”) aimed at identifying sustainable food systems that ensure food security while advancing the state of the art in LCA through extensive primary data collection across diverse types of farms (McAuliffe et al., 2023a).

Within this research framework, nutritional LCA was developed to determine the environmental impact required to achieve a specific nutritional function. The most common nutritional Functional Units (nFU) used for this purpose include mass or volume (100 g, 1 kg, 1 litre), typical or recommended serving size, the content of specific macro- or micronutrients (e.g., 100 g of protein, 100 mg of calcium), or energy potential (e.g., environmental impact per 100 kcal).

However, food is nutrition, not merely mass. People do not consume “kilograms” or “proteins” in the abstract but rather foods — complex matrices of essential macro- and micronutrients. Measuring environmental impact per kilogram of product or per gram of protein completely ignores the nutritional density and diversity a food provides. One kilogram of lentils and one kilogram of yoghurt, for example, perform very different nutritional functions in the human body (EDA, 2025).

The Food and Agriculture Organisation (FAO) has also acknowledged these limitations. In its 2021 report (McLaren et al., 2021), the FAO concluded that evaluating foods solely based on environmental impact per kilogram or per protein can’t be the only criterion guiding dietary choices.

Nutritional assessment should therefore consider not only the quantity of individual nutrients but also their overall nutritional value, for example, through the use of nutrient indexes. It is also necessary to distinguish between nutrients to encourage (e.g., calcium) and nutrients to limit (e.g., sodium), while also accounting for non-nutrient components that contribute to diet quality, such as dietary fibre.

Challenges in defining the Nutritional Functional Unit (nFU)

The introduction of nLCA has brought a significant shift in perspective, from assessing the impact of 1 kg of a given food to measuring the impact required to deliver a specific nutritional function. However, despite FAO guidelines, no single nutritional Functional Unit (nFU) has been systematically adopted across all studies (McLaren et al., 2021).

While nutrients are the chemical substances present in foods (e.g., proteins, iron, vitamins), nutrition is the biological process through which the human body uses these nutrients to sustain life and health. This process depends on complex factors such as digestibility and bioavailability; thus, the difficulty of defining nutritional functional units arises precisely from this complexity (McLaren et al., 2021).

The FAO report (McLaren et al., 2021) highlights several challenges in quantifying the true nutritional value of a food, beyond the data provided on its nutrition label:

Processing effects – Industrial processes (e.g., pasteurisation, extrusion) and domestic cooking (e.g., boiling, frying) can profoundly alter nutrient content and quality. Some processes destroy heat-sensitive vitamins, while others enhance the bioavailability of specific compounds.
Food matrix effects – The nutritional value of a food is not simply the sum of its individual nutrients. Interactions among components within the food matrix (e.g., fibers, fats, anti-nutrients) can affect nutrient absorption and utilization.
Meal effects – Foods are rarely consumed in isolation. Combining different foods within a meal can have synergistic or antagonistic effects. For instance, vitamin C in vegetables can enhance iron absorption from plant sources, while glucosinolates and tannins can limit the absorption of certain nutrients, including proteins (McAuliffe et al., 2023a).

In addition to these factors, nutrient quality is essential. In nLCA studies, protein quantity is often used as a reference unit. However, not all proteins are equal: their quality depends on the content and balance of essential amino acids — those that the body cannot synthesise on its own. To account for this, McAuliffe et al. (2023b) used a protein quality assessment system, the DIAAS (Digestible Indispensable Amino Acid Score), to create a protein-quality-adjusted Functional Unit.

When applied to measure the carbon footprint and land use of four animal-based foods (dairy beef, cheese, eggs, pork), this adjusted unit yielded higher scores compared to plant-based proteins (nuts, peas, tofu, wheat), due to the greater proportion of essential amino acids and better digestibility (McAuliffe et al., 2023a; McAuliffe et al., 2023b). However, the same authors advise that a balanced intake of amino acids can also be achieved through a varied diet combining different food groups, including plant proteins (Kyttä et al., 2025).

These complex concepts must be formalised within a rigorous nLCA methodology, primarily through careful definition of the Functional Unit. As suggested in the FAO report, assessing the nutritional adequacy of foods can also be supported by reference to nutritional requirement tables established by health authorities (e.g., Recommended Dietary Allowances, RDA). These values provide essential benchmarks to contextualise the nutrient and micronutrient content of products relative to the needs of a reference population (McLaren et al., 2021; Green et al., 2021).

Impact assessment in nLCA

The Life Cycle Impact Assessment (LCIA) phase translates raw inventory data (such as emitted pollutants or cubic meters of water used) into potential negative impacts on the environment and human health. McLaren et al. (2021) emphasise the importance of several key impact categories for food products, including:

Climate change. It is essential to consider not only CO₂ but also methane (CH₄), typical of livestock systems, and nitrous oxide (N₂O), linked to fertiliser use. The chosen LCA method (e.g., GWP100 vs. GTP100) can affect the relative weighting of these gases, so transparency in method selection and communication is critical.
Water use. The analysis should distinguish between “blue” water (withdrawn from rivers, lakes, and aquifers), “green” water (rainwater stored in soil), and “grey” water (volume needed to dilute pollutants). Since water use impacts depend on local scarcity, geographic and seasonal factors must be considered.
Biodiversity impacts. Agriculture is a major driver of global biodiversity loss (McLaren et al., 2021). The main impacts arise from land use (conversion of natural habitats), eutrophication (excess nutrients that damage aquatic ecosystems), and ecotoxicity (effects of pesticides on non-target organisms).
Human health impacts. Traditional LCA considers health impacts from exposure to fine particulate matter (PM2.5) and the toxicity of pesticides and contaminants. nLCA adds direct diet-related health effects, expressed in DALYs (Disability-Adjusted Life Years). This approach links consumption of specific foods to health risks, as illustrated in the FAO report by a simplified DALY calculation associated with chicken wing consumption in the United States (McLaren et al., 2021).
Antimicrobial resistance. This emerging category represents a growing global public health concern. Excessive antibiotic use in livestock can contribute to the development of antibiotic resistance. Although LCIA methods for this category are still under development, proposals already exist to characterise it both as an environmental burden (enrichment of resistance genes in the environment) and as a direct health threat (in DALYs) (McLaren et al., 2021).

The analysis of these complex interactions underscores the need for a shared, standardised methodology to ensure reliable nLCA studies.

nLCA: potential applications

nLCA is emerging as an essential tool to tackle the complex challenge of nourishing the global population healthily while protecting the planet. By integrating environmental and nutritional functions of food, nLCA provides crucial insights beyond traditional metrics, enabling more informed and strategic choices for future food systems. This approach could prove decisive for several growing areas of interest:

Assessment of superfoods. The development of specific tools such as the sNRF9.2 model by Fernández-Ríos et al. (2025) helps identify the most nutrient-dense products that can address population-level nutritional gaps. This represents a first step toward advancing objective environmental analysis of superfoods, providing new tools for consumer and policy decision-making (Fernández-Ríos et al., 2025).
Comparison of novel foods. nLCA methods (such as the Nutritional Footprint or Nutritionally Invested Environmental Impact) are fundamental for improving consumer understanding and comparison by aggregating environmental impact and nutritional quality into a single, consolidated index (Mazac et al., 2023). These methods also enable the comparative evaluation of animal-based food substitution with novel foods, which can reduce environmental impacts while maintaining nutritional quality.
Support for green public procurement policies (GPP). Combining environmental impact indicators with nutritional assessment is essential to support the development of sustainable food procurement policies (Casonato et al., 2024), both for setting minimum environmental criteria in tenders and for guiding the design, implementation, and monitoring of such policies in public institutions.

Provisional conclusions

Agri-food systems face complex challenges: providing healthy, nutritious diets for a growing population while respecting finite resources. The nutritional Life Cycle Assessment (nLCA) can help address this challenge by simultaneously evaluating both environmental impacts and nutritional properties of foods.

However, this research field still requires methodological clarity. Defining a standardised nutritional Functional Unit (nFU) remains an open challenge, and multidisciplinary collaboration between LCA experts and nutritionists is essential, since a diet cannot be considered “sustainable” if it is not also nutritionally adequate.

Our FARE (Food and Agriculture Requirements) unit is available to support operators and research consortia interested in developing nutritional Life Cycle Assessment (nLCA) to bridge the nutritional and environmental dimensions in the assessment of food systems.

Desirée Muscas

References

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