DEFINITION AND CRITICAL EVALUATION OF NUTRITIONAL STRATEGIES TO ACHIEVE THE DEVELOPMENT OF OPTIMIZED HEALTHY AND SUSTAINABLE DIETARY PATTERNS: FROM THEORY TO PRACTICE

The concept of sustainable food systems is not new, but nowadays the definition of dietary patterns or recommendations able to improve both health and contribute to the transformation of food systems is strongly advocated. In the current scenario, the recognized intersection of climate change, population growth, and the increasing incidence of chronic diseases represents a global challenge involving also diets and food production. In the last years, scientific evidence accumulated on the definition of optimized diet that can be considered both healthy and sustainable. In 2019 the EAT–Lancet Commission on healthy diets from sustainable food systems addressed these issues and defined plausible range of intake for eight different food categories, as a useful starting point for the definition of locally adapted healthy and sustainable dietary patterns. For this reason, this authoritative proposal has also been defined as the “Planetary health diet”. However, given the complexity of the issues related to diet sustainability, this research field must be considered in its infancy, and several aspects still need to be elucidated. In this context, the present PhD thesis tried to contribute to such research topic thoroughly discussing the available results and providing new data. Specifically numerous tasks were addressed and described in four chapters. The first chapter included three sub-tasks devoted to: i) provide an overview of sustainability principles available in the Food-Based Dietary Guidelines (FBDGs); ii) define a methodology to adapt the Planetary health diet to the Italian/Mediterranean context (EAT-IT), evaluating its nutritional adequacy and main associated issues; iii) identify further strategies of diet adaptation for different energy targets addressing also specific nutritional needs. In the second chapter, the main goal was to evaluate the environmental impact associated with the developed EAT-IT dietary pattern to demonstrate its sustainability. By considering the need of human intervention studies to provide evidence on the role of sustainable diet in the real scenario, in the third chapter an explorative pilot study has been implemented to evaluate the feasibility of the EAT IT dietary pattern and its effect on nutritional and health related outcomes. Finally, since the optimization of healthy and sustainable diets in terms of nutrient composition can be extended also to the diverse bioactive compounds abundantly present in plant-based diets, the fourth chapter was focused on the opportunity to include specific bioactive-rich foods, through an evaluation of their potential health benefits, when consumed by a vulnerable group of population. Specifically, in this chapter, a systematic review of in vitro and in vivo study was carried out to assess and provide knowledge on the effect of plant-based foods (e.g. anthocyanin-rich blueberry) on vascular function in older subjects, and results obtained through an acute in vivo study with blueberry were reported and discussed. The main results from the first task indicated poor alignment of current FBDGs with sustainability principles. In addition, the Planetary health diet, when adapted to the Italian/Mediterranean food context, resulted as an overall balanced plant-based diet, characterized by low amount of meat and dairy and high amount of nuts and legumes. From a nutritional perspective, some critical nutrients, were identified (i.e. vitamin D, iron, and calcium). In the second part of the thesis, it has been demonstrated a low carbon footprint (CF), but not water footprint (WF) of the EAT-IT dietary pattern also underlying that the final levels of impact are strongly influenced by individual dietary choices within the same food category. As regards, the pilot dietary intervention developed in the third chapter, it was found an overall acceptability of the EAT-IT pattern in the young healthy volunteers enrolled. As regards nutritional intake, it was not drastically changed by the intervention, apart from a reduction in total energy intake and an increase of PUFA (in particular W-6) intake. Finally, the results of the fourth chapter evidenced the contribution of selected plant-based foods, and particularly anthocyanin-rich blueberry, in the modulation of health-related outcomes such as vascular function, with important implications for vulnerable targets (e.g. older subjects). Results from the randomized controlled trial (RCT) demonstrated that a selected anthocyanin-rich cultivar of blueberry could acutely improve arterial reactivity in older subjects and modulate plasma markers of vascular function, but not arterial stiffness and other metabolic and functional markers. Overall results support the importance of the identification of bioactive rich plant-based products, for their potential exploitation in healthy and sustainable diets. In conclusion, these data indicate that plant-based diets can be nutritionally adequate to satisfy requirements and are associated with lower carbon footprint. However, specific nutrients could result as critical and thus, on one hand, dietary plan should be finely tuned and critically evaluated depending on the target population; on the other hand, future strategies may also involve a discussion on the opportunity to include the formulation of new, fortified or enriched targeted foods. In this context, optimized diets should not only consider adequacy in terms of nutrient intake, but as far as possible, also the inclusion of specific bioactive-rich products able to provide additional health benefits. Finally, although the EAT-IT diet resulted apparently acceptable, further research is needed to assess the long-term impact of such type of plant-based diets on behavioral and related health outcomes.