Ultra-Processed Food Consumption and Systemic Inflammatory Biomarkers: A Scoping Review

Background/Objectives: The consumption of ultra-processed foods (UPF) has increased worldwide and has been hypothesized to contribute to chronic diseases, including conditions characterized by inflammatory dysregulation. We conducted a scoping review to map the human evidence on the relationship between UPF consumption and systemic inflammatory biomarkers. Methods: We developed a search strategy combining terms for UPF with terms for circulating inflammatory biomarkers, including C-reactive protein (CRP/hs-CRP), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), plasminogen activator inhibitor-1 (PAI-1), and leptin. Findings were synthesized separately for children/adolescents and adults. Results: A total of 24 studies were included. CRP/hs-CRP was assessed in 21; IL-6 in 9; TNF-α in 8; IL-1β in 5; leptin in 5; MCP-1 in 5; PAI-1 in 5; and IL-8 in 2. In children/adolescents, CRP/hs-CRP tended to be higher with greater UPF intake in large cohorts and in preterm infants, whereas smaller or clinically selected samples did not show an association. For other biomarkers, IL-6 generally did not vary with UPF, TNF-α and IL-1β showed no association across studies, and the two IL-8 analyses yielded mixed results. In adults, 11/17 analyses reported higher CRP/hs-CRP levels with greater UPF intake, 5/17 reported no association, and 1/17 reported an association limited to women. IL-6 was predominantly higher with greater UPF intake; TNF-α likewise tended to be higher with UPF across several settings; IL-1β showed no association; MCP-1 and PAI-1 provided limited, inconsistent signals; leptin results were mixed. Conclusions: Higher UPF consumption is frequently associated with elevated systemic inflammatory biomarkers—most consistently CRP/hs-CRP—across adults and selected pediatric contexts. Signals for IL-6 and TNF-α appear in specific populations, whereas IL-1β, MCP-1, PAI-1, and leptin show inconsistent patterns.