Diet quality represents one of the fundamental determinants of human health and significantly influences long-term health (1). A balanced diet may play a role in preventing the development of chronic diseases, such as type-2 diabetes, cancer, and cardiovascular disorders, supposedly by regulating the immune system and inflammatory processes (2, 3). In fact, diet is not only a source of energy and essential nutrients required for the sustenance and proper functioning of the body, but it also plays a crucial role as a direct modulator of systemic inflammatory processes (4). An activation of the immune responses as a chronic, subclinical phenomenon might lead to detrimental effects on overall health (5). This inflammatory process is characterized by consistently elevated levels of pro-inflammatory mediators and cytokines, which contribute over time to the progressive deterioration of biological systems (6). Chronic inflammation is implicated in several major health challenges including cardiovascular diseases, which represent the leading cause of mortality worldwide, metabolic disorders such as metabolic syndrome and obesity, and impairments in psychological and cognitive wellbeing, often linked to oxidative stress and neuroinflammation (7).

The qualitative and quantitative composition of meals may significantly influence the balance between pro- and anti-inflammatory mediators, with important long-term health consequences (8). Diets characterized by high consumption of simple sugars, refined carbohydrates and saturated fats may lead to increased production of pro-inflammatory mediators potentially contributing to the long-term deterioration of overall wellbeing (2). When sustained over time, this heightened inflammatory state promotes the development and progression of worsening health conditions (9). Furthermore, prolonged exposure to certain nutrients (i.e., trans fatty acids and simple sugars, among others) appears to negatively affect fundamental cellular and molecular processes, such as oxidative stress and the regulation of immune pathways, thereby amplifying the risk of developing complex pathological conditions and reducing the body’s overall resilience to physiological and environmental stressors (10). In contrast, dietary patterns characterized by a high intake of anti-inflammatory and antioxidant-rich foods, such as fruits, vegetables, legumes, whole grains and nuts, have been consistently associated with reduced levels of key inflammatory biomarkers, including C-reactive protein (CRP), various pro-inflammatory interleukins, and tumor necrosis factor-α (TNF-α) (11). These foods, being rich in plant-derived bioactive compounds, such as polyphenols, modulate inflammatory pathways and gut microbiota (12). Among the most extensively studied and globally recognized healthy dietary patterns is the Mediterranean diet (13), to which higher adherence not only ascertain better nutritional adequacy of the diet (14), but also represents a paradigmatic anti-inflammatory dietary model (15). Its primary components, including extra virgin olive oil, fruit and vegetables, legumes, nuts, and fatty fish, have been widely documented for their ability to reduce systemic inflammation and improve various markers of metabolic and cardiovascular health (16). A substantial body of scientific evidence has shown that high adherence to this dietary pattern is associated with a lower incidence of cardiovascular diseases (17), neurodegenerative disorders (18), and certain types of cancer (19), underlined by a low-grade subclinical chronic inflammation (20), partially mediated by gut microbiome dysbiosis (21).

Beyond their role in disease prevention, anti-inflammatory dietary patterns have been shown to positively affect not only physical health but also perceived wellbeing and overall QoL (22). Regular consumption of nutrient-dense foods contributes to improved physical and mental wellbeing, enhancing daily energy, cognitive function, and overall mood (23). These effects suggest that diet can act not only as a preventive factor against disease but also as a true modulator of perceived health, integrating clinical outcomes with psychological and psychosocial dimensions (24). Such benefits are particularly evident in older adults, for whom a balanced diet can help maintain autonomy, cognitive function, and overall QoL (25). Several indices have been developed to estimate the inflammatory potential of the diet based on the composition of pro- and anti-inflammatory elements (26–28). Among them, the Dietary Inflammatory Score (DIS) is an easy tool that could be considered both in a clinical setting or at population level to assess the inflammatory potential of the diet, but it has never been used to assess its association with QoL. Its easy calculation and the lack of previous studies on the topic provide the rationale for the choice of the DIS as a candidate tool to be applied at a broader level. The aim of this study was to investigate the relationship between the DIS and QoL in a representative sample of Italian adults in order to assess how adherence to pro- or anti-inflammatory diets may influence not only clinical and biological health parameters but also perceived wellbeing and individuals’ subjective perception of their own QoL.

The mean DIS score of the study sample was −0.058 (range −16.487 to 9.400), with mean scores in the tertiles of −2.151 ± 1.828, 0.1667 ± 0.404, and 1.931 ± 1.118. Participants were equally distributed across age groups, with 58.5% of participants being female and 61.7% non-smokers (Table 1). All participants were also equally distributed across categories of education and occupational level, with the majority reporting medium physical activity levels (Table 1). Obesity accounted for 17.6% of individuals, while hypertension resulted in much higher prevalence (Table 1). Regarding the background characteristics of the study sample across DIS tertiles, the most notable differences were observed for age groups, smoking and physical activity, with a higher proportion of younger, smoker, and medium physically active participants belonging to the group with higher DIS scores, reflecting a more pro-inflammatory diet (Table 1).

The general dietary intakes by tertiles of DIS is presented in Table 2. The sample consumed a fairly adequate amount of daily fruit and vegetables, high intake of cereals (although only a small proportion whole grains), high intake of nuts, and relatively low alcohol (Table 2). Red meat is also consumed within recommended ranges while processed meat intake was relatively high (Table 2). Total food consumption and nutrient intake reflected the rationale behind the calculation of the DIS. Participants with lower DIS scores tended to consume higher amounts of fruits (258.7 ± 208.0 g/d vs. 645.8 ± 446.9 g/d), vegetables (196.3 ± 115.8 g/d vs. 378.1 ± 244.1 g/d), whole grains (30.8 ± 58.6 g/d vs. 53.3 ± 65.5 g/d), legumes (34.3 ± 43.0 g/d vs. 48.9 ± 70.0 g/d), dairy products (179.2 ± 162.0 g/d vs. 227.0 ± 210.4 g/d), fish (61.7 ± 73.0 g/d vs. 87.7 ± 111.6 g/d), nuts (15.8 ± 20.5 g/d vs. 29.9 ± 68.2 g/d), and alcohol (6.2 ± 11.1 mL/d vs. 9.4 ± 12.8 mL/d) (Table 2). Conversely, participants with higher DIS scores showed a more frequent consumption of refined grains (241.4 ± 141.9 g/d vs. 144.1 ± 105.2 g/d), red meat (40.8 ± 28.3 g/d vs. 30.1 ± 25.7 g/d), processed meat (23.9 ± 27.8 g/d vs. 12.9 ± 17.9 g/d), sweets and desserts (70.1 ± 75.5 g/d vs. 55.7 ± 61.7 g/d), and sugar-sweetened beverages (80.8 ± 164.4 mL/d vs. 20.8 ± 51.6 mL/d) (Table 2).

Findings consistent with food group consumption were also found concerning the distribution of selected macro- and micronutrients across DIS tertiles (Table 3). Participants with higher DIS scores had a greater total energy intake (2,225 ± 905.1 kcal/d vs. 2226.5 ± 868.3 kcal/d), a higher consumption of total lipids (65.0 ± 33.3 g/d vs. 65.3 ± 29.1 g/d), particularly saturated fats (26.3 ± 13.2% vs. 24.7 ± 12.0%), and a lower intake of omega-3 fatty acids (total omega-3: 1.6 ± 0.8% vs. 2.0 ± 1.1%; seafood omega-3: 0.5 ± 0.5% vs. 0.7 ± 0.8%), fiber (29.1 ± 15.4 g/d vs. 42.3 ± 22.5 g/d), vitamins (vitamin A: 689.3 ± 325.9 μg/d vs. 1199.8 ± 566.2 μg/d; vitamin C: 115.4 ± 73.1 mg/d vs. 241.3 ± 148.6 mg/d; vitamin E: 8.4 ± 4.3 mg/d vs. 10.6 ± 4.6 mg/d), and minerals (calcium: 711.7 ± 282.3 mg/d vs. 930.3 ± 380.5 mg/d; potassium: 3317.0 ± 1657.9 mg/d vs. 4849.3 ± 2239.5 mg/d; magnesium: 363.9 ± 124.5 mg/d vs. 455.5 ± 154.3 mg/d) (Table 3).

The overall mean MANSA score was 62.6 ± 9.5 (range 31 to 84). The association between DIS and QoL and its individual components are shown in Table 4. Higher DIS values, reflecting a more pro-inflammatory diet, were associated with a higher likelihood of reporting low overall QoL (adjusted OR = 1.77; 95% CI: 1.27–2.46). In addition, several specific domains of QoL showed significant associations with DIS, including overall life satisfaction (adjusted OR = 1.36; 95% CI: 1.02–1.80), social relationships as reflected by the amount and quality of friendships (adjusted OR = 1.48; 95% CI: 1.13–1.95), personal safety (adjusted OR = 1.34; 95% CI: 1.01–1.76), satisfaction with cohabitation (adjusted OR = 1.45; 95% CI: 1.09–1.94), physical health (adjusted OR = 1.65; 95% CI: 1.25–2.18), and mental health (adjusted OR = 1.68; 95% CI: 1.25–2.24).

The findings of this study confirm a significant association between higher dietary inflammatory potential, as quantified by the DIS score, and worse QoL in Italian adults. Specifically, the impact extends across several QoL domains, including overall life satisfaction, physical and mental health, social relationships, and perceived personal safety. Notably, the association between diet and QoL was not mediated by metabolic conditions (such as obesity, hypertension, type-2 diabetes, and dyslipidemia) since there were no significant differences in distribution of such variables between individuals with different DIS tertiles. These observations can be interpreted in light of the pathophysiological mechanisms linking low-grade chronic inflammation to adverse psycho-physical health outcomes (20). Previous studies have demonstrated that diets characterized by a high intake of pro-inflammatory foods promote the production of pro-inflammatory cytokines (IL-6, TNF-α, CRP), oxidative stress, and the activation of neuroendocrine pathways involved in stress response (36). On the contrary, preclinical evidences highlight many components of a healthy diet with both prebiotic and biotic properties, including (poly) phenols (37) fermentable dietary fibers and probiotics (38), like Lactobacillus species, which may reduce chronic inflammation via modulation of gut microbiota (39), and as more recently suggested via oral microbiota (40). These processes have been associated with depressive symptoms, fatigue, reduced vitality, and cognitive impairment, all of which contribute to a negative perception of subjective wellbeing (41). Our results are supported by previous literature documenting the association between systemic inflammatory markers and reduced mental health, psychological wellbeing, and physical performance (42). A systematic review and meta-analysis investigating inflammatory markers in individuals with clinically significant depression, anxiety, or post-traumatic stress disorder (PTSD) found that each of these conditions is associated with an inflammatory response, even in the absence of comorbid mental or physical health problems typically linked to inflammation (43). Also, a systematic review reported consistency in a significant inverse relationship between DII scores and overall QoL and/or its subscales across various populations, including patients with asthma, osteoarthritis, hemodialysis, multiple sclerosis, obese women, and healthy individuals (44). These studies strengthen the hypothesis that the inflammatory potential of the diet represents a modifiable determinant of QoL, suggesting that nutritional strategies aimed at lowering dietary inflammatory load, such as implementation of Mediterranean diet (45), may serve as both preventive and therapeutic approaches not only for the reduction of chronic disease risk but also for the promotion of overall wellbeing and QoL (46).

Analyzing the dietary composition, it emerged that participants with lower DIS scores tended to consume greater amounts of fruits, vegetables, whole grains, legumes, dairy products, fish, nuts, and alcohol. Conversely, individuals with higher DIS scores consumed refined grains, red and processed meat, sweets, and sugar-sweetened beverages more frequently. This differentiation suggests that a diet rich in plant-based foods rich in fiber and phytochemical, such as (poly) phenols, as well as rich in sources of unsaturated fats is associated with a more favorable inflammatory profile, whereas the intake of foods high in simple sugars and saturated fats promotes a pro-inflammatory state (47), consistent with previous evidence (48). In parallel, the analysis of macro- and micronutrients showed that higher DIS values were associated with greater total energy intake and a higher intake of lipids, particularly saturated fats, alongside a reduced intake of omega-3 fatty acids, fiber, vitamins, and minerals (49). These findings further support the link between diet quality, inflammation, and potential effects on QoL, suggesting that nutritional balance plays a key role in modulating the inflammatory state and, consequently, subjective wellbeing (50). Moreover, chronic low-grade inflammation may worsen overall physical health by contributing to chronic pain conditions, reduced motor functionality, and increased vulnerability to metabolic and cardiovascular diseases (51). These effects, in addition to directly lowering physical QoL, may indirectly impair social and relational dimensions, limiting active participation in community life and negatively affecting interpersonal satisfaction and perceived personal security (52). It is important to emphasize that these physiological impairments extend their impact beyond objective physical health, exerting profound effects on health-related QoL (53). Functional limitations arising from chronic inflammatory states can hinder the performance of daily activities, compromise independence, and increase reliance on social support networks, as well as negatively affect social and relational domains by limiting active participation in community and occupational activities, reducing opportunities for interpersonal interaction, and diminishing the perception of social connectedness (54). Consequently, chronic inflammation may generate a cycle in which reduced physical functioning leads to lower social participation, which in turn can exacerbate psychological stress and perceived vulnerability, highlighting the bidirectional interplay between physiological and psychosocial determinants of wellbeing (55).

Finally, when considering background characteristics, participants with higher DIS values were more likely to be smokers and to engage in lower levels of physical activity. This association suggests that the effect of diet on inflammatory status and, consequently, on QoL, cannot be considered in isolation but should be interpreted within a broader behavioral context (56). It is well established that both cigarette smoking and physical inactivity promote the activation of inflammatory pathways and oxidative stress, thereby contributing to increased systemic levels of pro-inflammatory cytokines (57). In particular, tobacco smoke is known to be a significant source of reactive oxygen and nitrogen species (ROS and RNS), which can damage cellular and sub-cellular components such as lipids, proteins, and nucleic acids (58). A substantial body of evidence has highlighted that smoking-induced ROS and the resulting oxidative stress play a central role in the activation of inflammatory processes and in the mechanisms of carcinogenesis (59).

The co-occurrence of these unhealthy behaviors with a pro-inflammatory dietary pattern may therefore exert a synergistic effect, amplifying the risk of impaired physical and mental health and worsening perceived QoL (60). These findings underscore the importance of preventive approaches including interventions aimed at smoking cessation and the promotion of physical activity (61). Despite these encouraging findings, important gaps remain in the scientific literature, particularly regarding studies specifically focused on the relationship between the inflammatory potential of the diet and self-perceived quality of life in the general population, and even more so within cultural and dietary contexts such as Italy (62). Given the central role of food in the Italian lifestyle and the growing interest in promoting health through integrated nutritional and psychosocial approaches, exploring this link may provide valuable insights for public health strategies.

The study has several strengths. Key strengths include the use of validated instruments to assess both dietary intake and quality of life, enhancing the reliability and comparability of the findings despite reliance on self-reported data. The application of an evidence-based dietary inflammatory score allows a biologically plausible evaluation of the relationship between diet and quality of life. Analyses accounted for a wide range of sociodemographic, lifestyle, and health-related confounders, reducing the potential for residual confounding. Additionally, the focus on an Italian adult population provides novel context-specific evidence in a Mediterranean setting, and the assessment of multiple QoL domains offers a comprehensive perspective on wellbeing.

The findings of this study should be interpreted in light of some limitations. First, the cross-sectional design raises the possibility of reverse causality. Second, the use of self-reported dietary intake and QoL measures may introduce recall bias. However, the instruments used were all validated and represent the gold standard for such types of studies. Third, although we adjusted for several factors that could reasonably affect the associations, residual confounding for unmeasured variables may still occur. Finally, because the study was conducted on a representative sample of the Southern Italian population, the generalizability of the results to other populations may be limited.

In conclusion, the inflammatory properties of an individual’s diet could represent a key underlying mechanism explaining the observed relationships between dietary patterns and overall health outcomes. Diets with higher pro-inflammatory potential may contribute to an increased risk of chronic conditions, while dietary patterns rich in anti-inflammatory components could support the maintenance of physiological balance, enhance wellbeing, and improve long-term health. These findings suggest that promoting dietary patterns with lower inflammatory potential may represent a feasible strategy to support overall wellbeing in the general population, alongside established lifestyle recommendations. From a clinical and public health perspective, consideration of the inflammatory properties of the diet could complement existing nutritional guidance aimed at improving patient-centered outcomes such as quality of life. Future research should prioritize longitudinal studies to clarify temporal and causal relationships and intervention trials to determine whether reducing dietary inflammatory potential leads to meaningful improvements in quality of life. Additionally, studies integrating objective inflammatory biomarkers and exploring potential effect modification by age, sex, or clinical conditions are warranted to better elucidate underlying mechanisms and identify populations most likely to benefit. Overall, understanding the inflammatory impact of diet provides valuable insights for developing nutritional strategies aimed at promoting optimal health and preventing disease across diverse populations.