Balancing Environmental Sustainability and Nutrition: Dietary Climate Impact in Relation to Micronutrient Intake and Status in a Swedish Cohort

Background: Dietary shift is necessary for improving public health, mitigating climate change, and achieving the Sustainable Development Goals. Adaption of climate-friendly diets might prevent chronic diseases and reduce mortality; however, consuming diets with a low climate impact have been suggested to increase risk of some micronutrient deficiencies. 

Objectives: This study aimed to examine whether self-reported dietary intake varying in climate impact is associated with nutritional risks and benefits based on both dietary intakes and blood concentrations of micronutrients. 

Methods: In the cross-sectional Malmö Diet and Cancer cohort (MDC, n = 25,970), dietary data were collected using a modified diet history method (food frequency questionnaire, diary, and interview). Blood samples were drawn and analyzed for micronutrients in different subgroups. Life cycle assessment data were used to estimate dietary greenhouse gas emissions (GHGE), from farm to fork. Quintiles of dietary climate impact were examined in relation to nutrient intake and status using linear and logistic regression. 

Results: The mean estimated dietary GHGE were 5.9 kg of carbon dioxide equivalents per day (females: 5.4, males: 6.6). Participants consuming a more climate-friendly diet had lower proportion of animal-sourced foods, energy intake, and intake of all micronutrients assessed (n = 17). Prevalence of anemia was higher in females consuming more climate-friendly diets, but the rates were low across all climate-diet groups (4.6% in Q1 compared with 3.3% in Q5; P-trend: 0.02), but not in males (P-trend: 0.131). No significant trends were observed in nutrient status of vitamin D, selenium, zinc, and folate across dietary GHGE quintiles. 

Conclusions: Despite a lower intake of micronutrients, more climate-friendly diets did not substantially increase risk of deficiencies. The study highlights the importance of measuring both nutrient intake and status when discussing nutritional consequences of sustainable eating.