Development of a food composition database to assess the dietary intake of plant bioactives in multiple populations

Diet is one of the most influential factors affecting morbidity and mortality risks. It is well-established that an increased consumption of plant-based foods, such as fruit, vegetables, legumes, and whole grains, can significantly contribute to decreasing the risk of cardiovascular diseases, cancer and all-cause mortality. These effects can be attributed to fiber, vitamins, minerals, and a vast array of bioactive molecules that may interact with each other and, finally, exert beneficial and protective effects on human body. However, food matrices are complex structures not fully characterized yet, whose composition greatly depends on several factors, such as the type of cultivar and growing conditions. Moreover, they are important repositories of bioactive molecules, mainly grouped into different families: (poly)phenols, terpenoids, N-containing compounds, and miscellaneous phytochemicals. Nonetheless, the detection and quantification in foods of these bioactives are usually challenging. This complexity generates major gaps in the scientific knowledge of human diet composition and, lastly, its health effects. These gaps in the intake of plant bioactives are visible in the literature: (poly)phenols are the most studied compounds and their intake has been deeply assessed in multiple populations. Additionally, the consumption of carotenoids and few other compounds have been investigated. Nevertheless, intake data of many other bioactives, such as glucosinolates, low-molecular weight terpenoids, and thiosulfinates, are incomplete or missing. The absence of a unique and comprehensive food composition database about the concentration of plant bioactives in foods contributes to this situation: indeed, the information available in the literature is usually fragmented and current phytochemical food composition databases are generally focused only on main compounds. Based on these considerations, this Doctoral Thesis aimed to develop a phytochemical food composition database, to assess the dietary intake of plant bioactives in multiple populations. A Phytochemical Food Database (PhytoFooD) was created by collecting and analysing plant bioactive concentrations in foods from national and international databases and from an extensive literature search. This tool currently reports qualitative and quantitative information on 1,067 bioactive compounds in 1,410 raw and processed plant-based foods. When available, information on the phytochemical concentration variability in foods was reported. Lastly, a robustness index of each obtained data was assigned. Afterwards, PhytoFooD was applied to different population settings. It was linked to dietary data of 26 European countries, gathered in the EFSA Comprehensive Food Consumption Database. To our knowledge, this is the most comprehensive assessment at population level of (poly)phenols, terpenoids, N-containing compounds, and miscellaneous phytochemicals. Terpenoids emerged as the most consumed bioactive compounds in the European adult population, followed by (poly)phenols, N-containing compounds and, lastly, miscellaneous phytochemicals. Particularly, monoterpenoids, phenolic acids, alkaloids and phytates were the predominant classes of their respective bioactive families. Main food sources and phytochemicals were also evaluated. These findings also revealed a pronounced variability in the dietary intake of plant bioactives within and among countries, probably representing different dietary habits across countries. Lastly, the dietary intake of plant bioactives was evaluated at individual level in a healthy Italian population, participating into the Oral (Poly)phenol Challenge Test study (OPCT). PhytoFooD was linked to food consumption data of 297 OPCT adult volunteers, to estimate the dietary intake of (poly)phenol, terpenoid, N-containing compound, and miscellaneous phytochemical families and classes. Terpenoids resulted the most consumed bioactive molecules, followed by N-containing compound, miscellaneous phytochemical families and, lastly, (poly)phenols. Further analyses were performed to investigate the role of demographic factors -such as age and sex- and main food sources to the intake of phytochemicals. As for the European population, an extensive variability characterized the dietary consumption of bioactive compounds in the OPCT cohort, both when considering different phytochemical families and classes, and diverse population groups. The findings of this Doctoral Thesis represent key steps in the dietary assessment of plant bioactive compounds and, ultimately, in the current knowledge of diet-related health effects. Additionally, they provide new evidence to the chemical composition of human diet and reinforce the current knowledge about food and diet complexity. Moreover, these results pose new questions about the health effects of less-studied phytochemicals, opening the field for innovative personalized nutrition strategies.