**3. Phenolic compounds as modulators of immune reactions to food**

Over the past several years, non-communicable diseases (NCDs) such as cancer, cardiometabolic, neurodegenerative and autoimmune disorders have become of important health concerns for consumers and a growing public health issue everywhere in the world [26]. They typically result from an imbalance between people and their environment and lifestyle patterns, including physical inactivity, tobacco usage, alcohol abuse and related metabolic risks [27]. Essential for life, diet provides a vast source of molecules that are largely harmless for the majority of the world population. Nonetheless, compelling observational and interventional evidence is now available on the implication of modern unbalanced dietary habits/ diet - with its high saturated fat and sugar intake - on the incidence of low-grade, chronic, and systemic inflammation [28]. Furthermore, for some individuals, the intake of staple food like milk, eggs, nuts or bread can trigger a set of immune mechanisms that can lead to a severe allergic condition termed food allergy [29]. Besides food allergy there is a high number of immune reactions to food, some of them autoimmune disorders such as Celiac Disease. The rise of immunologic reactions to food are substantial and evolving public health issues, increasing over the last decade as epidemic [30]. Nevertheless, therapeutic options remain limited. One of the mechanisms leading to this subclinical, yet persistent adverse response to nonlife-threating situations, occurs through, for instance, food-induced structural and behavioral changes in gut microbiota [31]. The bacterial ecosystem living up in the gut play crucial roles in the induction of protective responses to pathogens, maintenance of body's homeostasis and tolerance to innocuous food antigens [32]. As a consequence, any environmental factor disturbing the richness and diversity of bacteria making up the gut microbiome could potentially affect host metabolism, impact intestinal barrier integrity and immune system functions [33]. A better understanding of the key nutritional mechanisms involved in such immune responses will likely be vital for disease prevention and development of new therapies. Indeed, consumption of antioxidants, mainly dietary phenolic compounds found in fruits and vegetables, has been related with low prevalence of immune reactions to food [34]. Used as nutraceuticals, PC are thought to dampen the onset of immune-related inflammation [35, 36]. Moreover, recent studies proved the ability of PC to bind food antigens [37, 38], which could modulate the disorders, but concerns still remain about their real function by the organism that assumes

PC through diet, because of their bioavailability, metabolism and pharmacokinetics. Scientific knowledge has to be improved to establish the basis for nutritional recommendations that help to prevent or minimize the prevalence and symptoms of immune reactions. A broad approach is herein explained to fully understand the immunomodulatory process of PC in food allergies and celiac disease from ingestion to immune systemic effects manifestation.
