Chronic low-grade inflammation in vegetarians and vegans: Biomarker evidence and methodological considerations

The association between vegetarian and vegan dietary patterns and chronic low-grade inflammation represents a growing area within nutritional epidemiology, with potential implications for lifestyle-based prevention and management of non-communicable diseases. Although recent meta-analyses of cross-sectional studies conducted over the past 25 years suggest a trend toward lower levels of inflammatory biomarkers among vegetarians compared to non-vegetarians, the strength of this evidence remains limited. This chapter offers a state-of-the-art overview of this topic, providing a brief summary of key inflammatory biomarkers, assay technologies, and analytical considerations. It advocates for the use of high-sensitivity, high-throughput multiplex platforms to assess C-reactive protein as a clinically relevant marker, complemented by broader cytokine panels, to more precisely capture subtle differences across distinct dietary groups. Special emphasis is placed on the critical evaluation of findings from cross-sectional studies and related meta-analyses, with particular attention to their inherent methodological limitations.