Evaluating the sustainability of vegetarian, vegan, and New Nordic diets in Sweden : Combining environmental and nutritional aspects

Abstract: Changing the western dietary pattern toward a healthier diet with reduced intake of animal foods is a commonly recognized strategy in the ongoing effort for global sustainability. Since animal foods tend to have a high environmental impact, vegetarian diets are often suggested as an ecological alternative to the typical Western diet. The low sum of environmental impacts, however, does not on its own necessarily translate to a sustainable diet. Sustainability encompasses many other aspects, such as nutritional adequacy, affordability, and cultural acceptability. As regards the elimination of animal foods in particular, health-related aspects ought to be considered since some nutrients are supplied primarily via animal products which may lead to nutritional deficiencies and potential negative health effects in the long term. Furthermore, since the main function of diets is the supply of (adequate) nutrition, the environmental impacts of diets ought to be compared in light of their nutritional quality. In this project the environmental impact on climate change, land use, blue water footprint, and biodiversity damage potential of four diets is assessed, along with their nutritional adequacy and financial cost. The four assessed diets are: an average Swedish diet, New Nordic diet, vegetarian diet, and vegan diet. The environmental impacts are normalized with a nutritient-rich diet score (NRD) to compare the impacts of diets in relation to their nutritional quality. The vegan diet, followed by the vegetarian diet, resulted in the lowest overall impact with the exception of blue water footprint, however, the normalization with NRD score lessened the relative differences between the New Nordic, vegetarian, and vegan diet. Furthermore, the nutritional assessment showed a potentially unsustainable intake of vitamin D in vegetarians and vit. D and B12 in vegans, which is not properly reflected in the nutritional quality score. Nevertheless, the use of the nutritional score is fairly simple and provides opportunity for linking the health-related aspect of diets to their environmental impact. Joined with indicators on other sustainability aspects, such as the economic, this method can offer a more holistic picture of the sustainability of diets.