Key take-aways
- A cohort study was conducted in Spain to compare the health and environmental benefits of the Planetary Health Diet (PHD) and the Mediterranean Diet.
- Compared to participants with low adherence, higher adherence to both diets was similarly associated with lower all-cause mortality and with comparable low environmental impact.
- This study highlights the advantages of the plant-based diets, with wider adoption of healthy and sustainable diets needed to prevent excess premature deaths worldwide.
Milan, Italy – 4 April 2025. Two plant-based diets were associated with similar survival benefits and low environmental impact, according to research presented today at ESC Preventive Cardiology 2025,1 a scientific congress of the European Society of Cardiology (ESC).
Diet contributes significantly to cardiovascular disease mortality, with estimates indicating that across the European region, one in every five premature deaths could be prevented by an optimised diet.2
"In 2019, the Planetary Health Diet (PHD) was developed to optimise global dietary quality while keeping the environmental impacts of food production within sustainable planetary boundaries,3" said study author Dr. Mercedes Sotos Prieto of the Autonomous University of Madrid, Spain. "However, there was a lack of evidence on how the PHD compares with the Mediterranean Diet, a plant-based diet with established health and environmental benefits, that is well rooted in Mediterranean countries. We evaluated the effects of both diets on all-cause mortality and environmental impact in a large representative Spanish population."
The PHD involves energy intake of around 2,500 kcal/day and focuses primarily on high consumption of fruits and vegetables, whole grains, legumes, nuts and unsaturated oils; moderate intake of dairy, starchy vegetables, poultry and fish; and low consumption of saturated fats, red meat and added sugars.
The Mediterranean Diet is characterised by a pattern rich in fruits and vegetables (seasonal), legumes, whole grains and nuts, with olive oil as the main dietary fat, greater consumption of white or lean meats than of red or processed meats, and with moderate consumption of dairy products, fish and eggs.
In the analysis, data on food intake were collected from 11,488 participants in the Study on Nutrition and Cardiovascular Risk in Spain (ENRICA), a prospective cohort study of individuals recruited between June 2008 and October 2010.4 The PHD Index (0–140 points) was calculated for each participant based on their consumption of 15 food groups: whole grains, starchy vegetables, vegetables, whole fruits, dairy foods, red/processed meat, chicken and other poultry, eggs, fish/shellfish, nuts, non-soy legumes, soybean/soy foods, added saturated and trans-fat, added unsaturated oils, and added sugar and fruit juice. Adherence to the Mediterranean Diet was assessed using the 14-item MEDAS score (0–14 points), which is based on components such as using olive oil for cooking and dressings, eating white meat and seafood over red meat, the consumption of fruits, vegetables, legumes and nuts, and low intake of high-fat dairy products, commercial baked goods and sugar-sweetened/carbonated beverages. The environmental impact of each diet was assessed using the SHARP-Indicators Database (SHARP-ID), which includes data on greenhouse gas emissions and land use. Mortality data were obtained from the National Death Index of Spain. Analyses were performed across tertiles of adherence to the diets, with adjustment for confounders.
Study participants had a mean age of 47.5 years (range, 18–96 years) and around a half (52.5%) were women. A total of 1,157 all-cause deaths occurred during a mean follow-up of 14.4 years.
Higher adherence to the PHD and Mediterranean Diet was similarly associated with lower all-cause mortality. Participants in the top third for adherence to the PHD had a 22% lower chance of dying than those in the lowest third (adjusted hazard ratio [HR] 0.78; 95% confidence interval [CI] 0.66–0.91). For the Mediterranean Diet, participants in the top third for adherence had a 21% lower chance of dying than those in the lowest third (adjusted HR 0.79; 95% CI 0.68–0.93). Adherence to some components of the PHD (fruits, dairy and unsaturated oils) and the Mediterranean Diet (nuts, low consumption of soda and pastries) was independently associated with lower mortality.
In terms of environmental impact, both diets had similarly low footprints. For the PHD, the average level of greenhouse gas emissions was 4.15 kg of CO₂ per day and average level of land use was 5.54 m2 per daily food intake. The average level of greenhouse gas emissions for the Mediterranean Diet including dairy was 4.36 kg of CO₂ per day and the average level of land use was 5.43 m2 per daily food intake. Dairy and meat products were the largest footprint contributors.
Dr. Sotos Prieto concluded: "Higher adherence to both diets was similarly associated with lower all-cause mortality and with comparable low environmental impact, highlighting the substantial health and planetary advantages of adopting one of these plant-based diets."
