Sustainability Dimensions of the Mediterranean Diet: A Systematic Review of the Indicators Used and Its Results

Abstract

The concern about sustainability is growing and the Mediterranean diet has been extensively identified as a promising model, with benefits for human and environmental health. This systematic review aims to identify and describe the indicators that have been used to evaluate the sustainability of the Mediterranean diet and the results from their application. A methodology using PRISMA guidelines was followed, and searches were performed in Web of Science, PubMed, Scopus, and GreenFile. A total of 32 studies assessing the sustainability of the Mediterranean diet were identified. Twenty-five of these studies quantified the environmental impact, 7 studies evaluated the nutritional quality, and 12 studies assessed the daily cost of this dietary pattern. A total of 33 distinct indicators were identified, of which 10 were used to assess the environmental dimension (mainly, carbon, water, and ecological footprint), 8 were used to assess the nutritional dimension (mainly Health score and Nutrient Rich Food Index), 1 was used to assess the economic dimension (dietary cost), and 8 used combined indicators. The remaining 6 indicators for the assessment of sociocultural dimension were only identified in 1 study but were not measured. The Mediterranean diet had a lower environmental impact than Western diets and showed a carbon footprint between 0.9 and 6.88 kg CO2/d per capita, a water footprint between 600 and 5280 m3/d per capita, and an ecological footprint between 2.8 and 53.42 m2/d per capita. With regard to the nutritional dimension, the Mediterranean diet had a high nutritional quality and obtained 122 points on the Health score and ranged between 12.95 and 90.6 points on the Nutrient Rich Food Index. The cost of the Mediterranean diet is similar to other diets and varied between 3.33 and 14.42€/d per capita. These findings show that no uniformity in assessing the MDiet's sustainability exists.

Keywords: Mediterranean diet; economic indicators; environmental indicators; nutritional indicators; sustainability.

Graphical Abstract

FIGURE 1

PRISMA flow diagram showing study selection. MDiet, Mediterranean diet; PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

FIGURE 2

Systematization of the results by indicator for the environmental sustainability of the MDiet. In orange are the results presented in the original paper. The converted results are in blue. In the carbon footprint graph, the letters A, B, C, and D correspond to the different system boundaries considered by the authors to calculate this footprint. Letter A corresponds to “Cradle to consumer”; letter B corresponds to “Cradle to farm gate”; letter C corresponds to “Cradle to market”; and letter D corresponds to “Not mentioned.” Rosi et al. (58) defined 2 MDiet scenarios, one for the spring and the other for the winter. Vanham et al. (70) defined 3 MDiet scenarios for 13 Mediterranean countries, one including meat, another seafood-vegetarian, and the last vegetarian. Vanham et al. (71) assessed the water footprint for the MDiet in 9 Mediterranean countries. Blas et al. (51) assessed the water footprint for the MDiet in 2 countries. Galli et al. (67) assessed the ecological footprint of food production and food consumption for 15 selected Mediterranean countries, and the data in this figure correspond to the ecological footprint of food consumption. Legend for carbon footprint/Mediterranean menu: Martinez et al. (56) defined 7 different MDiet-based menus for lunch, with M1 corresponding to the baseline menu with all of the typical food groups included, M2 to the menu without dairy and without legumes, M3 to the menu without meat, M4 to the menu without fish, M5 to the menu without eggs, M6 to the hypocaloric menu, and M7 to the astringent menu (designed to address intestinal illnesses). GHG, greenhouse gas; MDiet, Mediterranean diet.

FIGURE 3

Systematization of the results for the economical sustainability of the MDiet. In orange are the results presented in the original paper. The converted results are in blue. Lopez et al. (55) presents the MDiet cost in €/1000 kcal per adherence to MDiet quintile. To convert this result in €/d per capita, the average diet energy quintile values and the average of the respective cost were calculated. Pairotti et al. (57) presents the cost of an MDiet for an average Italian family. For the conversion in €/d per capita, we searched the average number of people per household in Italy for 2015 (n = 2.35 people) (110). Conversion from weeks to days was calculated considering 30 d/mo. MDiet, Mediterranean diet.

FIGURE 4

Results from the review showing the indicators used to assess the sustainability of the Mediterranean diet grouped according to the sustainability dimension considered. GHG, greenhouse gas; GHGE, greenhouse gas emissions; GWP, Global Warming Potential; LU, land use.