Feeding children with environmentally based dietary guidelines: The Nitrogen Footprint of school lunch menus adhering to the Spanish dietary guidelines

Abstract

It is at an early development stage the best opportunity for a society to learn the concepts of sustainable production and consumption. Schools can serve as effective and efficient ways for this purpose. This work quantifies the Nitrogen Footprint (NF) of twelve school menus developed following the Spanish dietary guidelines. The analysis considers six fall school menus and six spring school menus for 7 to 12 years old children. Fall menus present higher NF than spring menus, being on average 23 g N and 19 g N, respectively. This is mainly due to the presence of beef dishes in fall menus, which significantly increase the production NF. Menus including non-meat protein sources, such as legumes, exhibit the lowest N pollution. Menus with beef dishes remain the most intensive menus for fall and spring in terms of N pollution and energy intake, being 0.04 g N/kcal. The highest contributing stage to the total NF is the production (92.6 %), followed by consumption (5.8 %), while the distribution and cooking stages present lower contributions. In order to improve the overall NF, some reduction strategies are: (1) substitution of beef with other animal meat sources, (2) substitution of beef with non-meat sources, (3) improvement of wastewater treatment efficiency, and (4) recycling non-edible food. Substituting beef with non-meat sources achieves the highest reduction (76 %) compared to the total NF of the school menus. It is recommendable to include environmental aspects related to N emissions within the school guidelines in order to provide practical information to policymakers and guide-users.