Dietary Inflammatory Index and Blood Inflammatory Markers in Young Men with Different Levels of Physical Activity: A Cross-Sectional Observational Study

Systemic inflammation is influenced by regular physical activity and diet. While moderate exercise can transiently alter inflammatory markers, high-intensity activity may increase muscle turnover without substantially elevating systemic inflammation. The combined effects of physical activity and dietary inflammatory potential in healthy young men remain poorly defined. In this cross-sectional observational study, 233 healthy men aged 18–30 years were categorized according to physical activity level: low (NA, n = 52), moderate (A, n = 93), and high (S, n = 88). Anthropometry and body composition were assessed using bioelectrical impedance. Dietary intake was recorded over 4 days and used to calculate the Dietary Inflammatory Index (DII). Blood samples were collected and analyzed for complete blood counts, high-sensitivity C-reactive protein (hs-CRP), serum amyloid A (SAA), and creatine kinase (CK). Differences between groups were evaluated using the Kruskal–Wallis test with Dunn’s post hoc correction, and principal component analysis (PCA) was performed to explore multivariate inflammatory patterns. The highest BMI, fat percentage, and DII were observed in low-activity men, whereas fat-free mass and CK activity were greatest in highly active men. Slightly higher systemic inflammatory markers (hs-CRP and SAA) were observed in moderately active men compared to other groups. PCA revealed two principal axes: PC1 representing systemic inflammation and PC2 representing leukocyte distribution. Weak associations were found between DII and these components, indicating a limited link between dietary inflammatory potential and circulating inflammatory biomarkers. Body composition is strongly influenced by physical activity, with high activity promoting lean mass and moderate activity associated with modest elevations in inflammatory markers. Dietary inflammatory potential was only weakly associated with systemic inflammation, suggesting that exercise-induced physiological stress may play a more prominent role in shaping inflammatory profiles in healthy young men.