In a recent study published in the journal Science of the Total Environment, The researchers investigated the environmental effects of a low-energy Mediterranean diet over one year in participants with metabolic syndrome.
Their results indicate that the intervention was associated with significant reductions in acidification, eutrophication and land use, with dietary adherence and calorie reduction playing a key role in mediating these environmental benefits.
Study: Effect of a dietary intervention based on a reduced-energy Mediterranean diet on environmental impacts. Image credit: leonori / Shutterstock
Record
Climate change poses serious threats to public health, including rising temperatures, changes in rainfall, increased drought, intensified heat waves, and increased transmission of diseases such as dengue and malaria.
It also affects agriculture and animal husbandry, reducing the quantity and quality of food. As the global population is expected to reach nearly 10 billion by 2050, the need for food will escalate, intensifying the environmental impacts of food systems, which are major contributors to greenhouse gas emissions, eutrophication, acidification, freshwater use and biodiversity loss.
The Food and Agriculture Organization of the United Nations defines sustainable diets as critical to mitigating these impacts by promoting nutrition and food security while minimizing environmental damage.
Previous research shows that diets lower in animal products and higher in plant foods are healthier and have a smaller environmental footprint. However, specific dietary interventions that can effectively reduce environmental impacts need to be explored.
About the study
This study addressed existing research gaps by examining the environmental benefits of a Mediterranean diet with reduced energy intake in older Spanish adults with metabolic syndrome. It focused on its potential to reduce greenhouse gas emissions, acidification, eutrophication and land use.
This study used data collected during the PREDIMED-Plus trial, a multicenter, randomized (non-blinded) eight-year study conducted in Spain. The trial included 6,874 participants, aged 55-75 for men and 60-75 for women, all with metabolic syndrome but without any cardiovascular disease in their medical history.
Participants had a body mass index (BMI) between 27 and 40 kg/m² and met three or more criteria for metabolic syndrome. They were randomly assigned to either an intervention group, which received a Mediterranean diet (MedDiet) with reduced energy and guidelines for physical activity and behavioral therapy, or a control group, which received MedDiet advice without promoting weight loss.
Dietary intake was assessed using a validated 143-item Food Frequency Questionnaire (FFQ) and dietary compliance was measured with the Panagiotakos Nutrition Score. Environmental impact indicators, including greenhouse gas emissions, energy use, land use, acidification and eutrophication, were calculated based on the EAT-Lancet Commission tables.
Data were analyzed using linear regression modeling adjusted for sex, age, education level, and baseline caloric intake. Mediation analysis was conducted to determine the extent to which changes in caloric intake and dietary adherence mediated the reduction in environmental impacts.
Foundings
The study found significant reductions in environmental influence factors between the intervention and control groups. Specifically, the intervention group showed greater reductions in acidification (−13.3 compared to −9.9 g of sulfur dioxide equivalent), eutrophication (−5.4 compared to −4.0 g of phosphate equivalent), and land use (−2.7 compared to −1.8 m.2).
In addition, IG showed significant reductions in caloric intake (−178.4 compared with −73.3 kcal) and higher dietary compliance for the intervention group (1.2 vs. 0.5 points).
Meat was the main contributor to environmental impacts in both groups, while fish and seafood contributed the most to GHG emissions.
Mediation analysis showed that calorie reduction partially mediated the observed relationship between the intervention and reductions in acidification, eutrophication, and land use, explaining 55%, 51%, and 38% of the total association, respectively.
Dietary adherence also partially mediated the relationship between these factors, with full mediation for GHG emissions (56%) and energy use (53%).
conclusions
This study highlights the positive effect of a one-year MedDiet intervention with reduced energy intake on environmental sustainability, particularly in reducing acidification, eutrophication and land use.
Innovatively explores the role of calorie reduction and MedDiet adherence in mediating this relationship, a new approach to the field. Despite limitations such as data variability and potential recall bias, the strengths of the study lie in the true assessment of environmental impacts and the large sample size.
The findings highlight the potential of MedDiet interventions to mitigate environmental damage, especially with regard to meat consumption. However, challenges remain in standardizing environmental impact databases and accounting for regional variations.
Future research could expand on these findings by exploring broader dietary patterns and their environmental impacts, fostering a deeper understanding of the diet-environment-health trilemma and promoting sustainable food choices.
Overall, this study highlights the potential of MedDiet interventions to enhance human health and environmental sustainability.
Journal Reference:
- Effect of a dietary intervention based on a reduced-energy Mediterranean diet on environmental impacts. Álvarez-Álvarez, L., Rubín-García, M., Vitelli-Storelli, F., García, S., Bouzas, C., Martínez-González, MA, Corella, D., Salas-Salvadó, J., Malcampo , M., Martínez, JA, Alonso-Gómez, AM, Wärnberg, J., Vioque, J., Romaguera. D, López-Miranda, J., Estruch, R., Tinahones, FJ, Lapetra, J., Serra-Majem, L., Bueno-Cavanillas, A., Martín-Sánchez, V. Science of the Total Environment (2024). DOI: 10.1016/j.scitotenv.2024.172610,
