Jamie Stein

Background: Marathon running triggers a robust systemic inflammatory response. Whether habitual dietary fat composition modulates pre-race cytokine concentrations or the magnitude and recovery of the exercise-induced inflammatory response remains unknown. Methods: Thirty-one recreational marathon runners (58.1% female; mean age 38.4 ± 10.2 years) completed the Diet History Questionnaire III to assess habitual dietary fat intake—including chain-length-specific SFA, MFA, PFA, trans fatty acids, and CLA—over the preceding three months. Circulating IFN-γ, IL-1β, IL-4, IL-6, IL-10, and TNF-α were measured pre-race, immediately post-race, and 48 h post-race. Repeated measures ANOVA examined cytokine changes; multivariable regression models estimated fat–cytokine associations adjusted for 11 pre-specified covariates, with Benjamini–Hochberg FDR correction applied across all models. Results: IL-6 rose markedly post-race (p < 0.001, generalized η² = 0.615) before returning to pre-race levels by 48 h. IL-10 followed a similar trajectory (p < 0.001, generalized η² = 0.346). TNF-α showed a borderline non-significant trend (p = 0.056); IFN-γ, IL-1β, and IL-4 did not change significantly. MFA 20:1 was positively associated with IFN-γ concentrations at 48 h post-race (β = 13.66; 95% CI: 8.94, 18.38, p < 0.01, q = 0.04) and TNF-α (β = 9.14; 95% CI: 6.43, 11.86, p < 0.01, q = 0.02). Conclusions: Habitual intake of the long-chain monounsaturated fatty acid 20:1 was positively associated with IFN-γ and TNF-α at 48 h post-race. This pattern, emerging specifically at the 48 h post-race phase, suggests that the post-race period, once acute exercise-induced signaling has subsided, may be a window in which habitual dietary fat quality is most detectable in relation to circulating cytokines. Habitual fat quality may warrant consideration in future endurance recovery nutrition research. This exploratory finding calls for replication in larger cohorts.

Background: Marathon running triggers a robust systemic inflammatory response. Whether habitual dietary fat composition modulates pre-race cytokine concentrations or the magnitude and recovery of the exercise-induced inflammatory response remains unknown. Methods: Thirty-one recreational marathon runners (58.1% female; mean age 38.4 ± 10.2 years) completed the Diet History Questionnaire III to assess habitual dietary fat intake— including chain-length-specific SFA, MFA, PFA, trans fatty acids, and CLA — over the preceding three months. Circulating IFN-γ, IL-1β, IL-4, IL-6, IL-10, and TNF-α were measured pre-race, immediately post-race, and 48 hours post-race. Repeated-measures ANOVA examined cytokine changes; multivariable regression models estimated fat–cytokine associations adjusted for 11 pre-specified covariates, with Benjamini-Hochberg FDR correction applied across all models. Results: IL-6 rose markedly post-race (p < 0.001, generalized η² = 0.615) before returning to pre-race levels by 48 hours. IL-10 followed a similar trajectory (p < 0.001, generalized η² = 0.346). TNF-α showed a borderline non-significant trend (p = 0.056); IFN-γ, IL-1β, and IL-4 did not change significantly. MFA 20:1 was positively associated with IFN-γ concentrations at 48-hour post-race (β = 13.66; 95% CI: 8.94, 18.38, p<0.01, q=0.04) and TNF- α (β = 9.14; 95% CI: 6.43, 11.86, p<0.01, q=0.02). Conclusion: Habitual intake of the long-chain monounsaturated fatty acid 20:1 appear to be positively associated with IFN-γ and TNF-α at 48-hour post-race, suggesting it may slow resolution of exercise-induced inflammation. This pattern, emerging specifically during the recovery phase, suggests habitual fat quality may warrant consideration in future endurance-recovery nutrition research. This exploratory finding calls for replication in larger cohorts.

Background/Objectives: Carotenoids are pigmented phytochemicals known for their antioxidant properties, known to protect against oxidative damage, especially in the context of intense exercise. The purpose of this paper was to observe and analyze the short-term effects of running a full marathon on skin and plasma carotenoid levels in endurance runners. Methods: This study recruited 24 healthy endurance runners (12 male, 12 female; mean age 37 years) registered for a 26.2-mile marathon. Skin carotenoid (SC) measures were taken via reflection spectroscopy, and plasma carotenoid concentrations (lycopene and β-carotene) were assessed via HPLC at three time points: pre-race, immediately post-race, and 48 h post-race. Changes across time were analyzed using repeated-measures ANOVA. Results: Skin carotenoid levels significantly changed over time, dropping from pre-race to post-race (p < 0.001), reflecting rapid utilization. At 48 h post-race, SC levels rebounded significantly, exceeding baseline measurements (p = 0.019). Plasma lycopene concentrations increased significantly from pre-race to post-race (p = 0.018) and remained elevated at 48 h. Plasma β-carotene concentrations showed no statistically significant change. Conclusions: The significant acute depletion of SC levels immediately following the marathon reflects the rapid utilization of these dermal antioxidants in response to the high oxidative stress generated by intense exercise. The elevation in plasma lycopene may reflect hemoconcentration resulting from intense activity and possible mobilization from tissue stores. The rapid rebound and overshoot in SC levels 48 h after the race are consistent with a recovery pattern of dermal carotenoid levels following acute depletion.