A healthier daily diet is associated with greater immune fitness

Introduction: The aim of this cross-sectional study was to investigate the association between a healthier diet, perceived immune fitness, and biomarkers of the immune system. Methods: N = 108 participants (31 men and 77 women), 18–30 years old, completed a questionnaire, comprising the Healthy Diet Scale (HDS) and a 1-item scale assessing perceived immune fitness. In addition, saliva samples were collected and C-reactive protein (CRP) and cytokine concentrations of interleukin (IL)− 1β and IL-8 were determined. Results: Overall, a significant correlation was found between the HDS score and perceived immune fitness (r = 0.221, p = 0.021), suggesting that a healthier diet was associated with a better immune fitness. The HSD score correlated significantly and negatively with saliva CRP concentrations (r = −0.240, p = 0.013). No significant correlations were found with other biomarkers. In women, the HDS correlated significantly with perceived immune fitness (r = 0.247, p = 0.030) and CRP levels ( r = −0.281, p = 0.014). In men, correlations with perceived immune fitness ( r = −0.219, p = 0.237) and the biomarkers were not significant. Discussion: Significant associations between attaining a healthy diet, perceived immune fitness and CRP were found. More research is needed to investigate the observed sex differences and underlying mechanisms.