Does higher food biodiversity in the Dutch diet lead to lower environmental impact?

PURPOSE: Global diets exert substantial pressure on both public and planetary health. At the same time, diets are becoming more monotonous, with growing reliance on a limited number of staple species. Food biodiversity, the variety of biological species in the diet, and dietary environmental impact represent complementary, but distinct, dimensions of sustainable diets. However, because these dimensions capture different aspects of sustainability, it remains unclear whether diets with higher food biodiversity are also associated with lower environmental impacts. METHODS: We examined associations between food biodiversity, measured as Dietary Species Richness (DSR), and six environmental impact indicators using data from the Dutch National Food Consumption Survey (DNFCS) 2012-2016. DSR scores (DSR Total, DSR Plant, DSR Animal) were calculated as the total unique species consumed over two 24-hour dietary recalls, regardless of quantities consumed. Environmental impacts associated with food consumption over the same recall period were derived from the Dutch life cycle assessment (LCA) food database (RIVM, v2019). Linear regression analyses were conducted, adjusting for age, sex, educational level, seasonality, mean daily energy intake, and weight of total food intake. RESULTS: Higher DSR scores were generally associated with higher environmental impacts, including greenhouse gas emissions (β = 0.107, 95% CI 0.076 to 0.138), freshwater eutrophication (β = 1.28e-5, 95% CI 1.04e-5 to 1.51e-5), land use (β = 0.049, 95% CI 0.032 to 0.067), and blue water consumption (β = 0.014, 95% CI 0.012 to 0.015). Exploratory analyses adjusting for energy intake and total food intake attenuated most associations, while several associations remained statistically significant. CONCLUSION: Increasing DSR alone is unlikely to improve LCA-based environmental sustainability. Promoting diets that are both biodiverse and environmentally sustainable therefore requires consideration of both food biodiversity and the environmental characteristics of food production.