Dietary Fat Quality Is Associated With Distinct Lipoprotein Profiles but Comparable Post-Exercise Inflammatory Responses

Introduction: While dietary patterns modify immunometabolic phenotypes, whether habitual plant-based diets alter inflammatory responsiveness to strenuous exercise remains unclear. Objective: To evaluate post-exercise inflammatory cytokine responses and muscle recovery in omnivorous (OMN), lacto-ovo-vegetarian (LOV), and strict vegetarian (SV) trained men. Methods: Trained men (n = 36; OMN = 13, LOV = 10, SV = 13) completed an exhaustive eccentric knee-extension protocol on an isokinetic dynamometer. Blood was collected pre-, immediately post-, and 24h post-exercise for LPS-stimulated whole-blood cytokine assays and 1H-NMR plasma metabolomics. Isokinetic performance was also evaluated. Results: Habitual dietary analysis revealed no differences in total energy, carbohydrate, protein, total fat, or monounsaturated fat (g) intake. However, OMN consumed more saturated fat than LOV and SV, whereas SV consumed more polyunsaturated fat than OMN (g, p < 0.05). Concurrently, targeted metabolomics identified 21 metabolites differing by diet: OMN exhibited higher levels across all 7 LDL subfraction parameters (LDL-2, LDL-3, LDL-4), while SV and LOV presented higher HDL-2 and HDL-3 subfractions. In muscle performance, vegetarian diets were superior in 10 of 17 parameters (LOV in movement speed and angular torque; SV in relative strength and power; OMN in total work). Despite these distinct metabolomic signatures and functional advantages, post-exercise inflammatory responses remained equivalent across dietary patterns: IL-6 increased post-exercise (p < 0.05) without group differences; TNF-alpha, IL-10, and the TNF-alpha/IL-10 ratio showed no group or interaction effects. Conclusion: Disparities in dietary fat quality translate into distinct plasma lipid-related metabolomic phenotypes and specific muscle performance advantages. However, these variations do not alter acute post-exercise inflammatory responses or muscle recovery.