Does the Mediterranean Diet Protect against Stress-Induced Inflammatory Activation in European Adolescents? The HELENA Study
Since it is not known whether the Mediterranean diet can reverse the increased inflammation induced by stress, this 2018 study examined the two associations - between cortisol with inflammation, and cortisol with the adolescent Mediterranean diet score (aMDS) - before testing whether aMDS associates with cortisol levels and inflammation, and whether inflammation can be reduced by aMDS. The aMDS of the 242 adolescent participants (12.5-17.5 years old) was derived from their salivary cortisol levels, blood results and 2-day 24-h dietary recall. Several relationships involving cortisol were determined, including its inverse correlation with adherence to the Mediterranean Diet (B = -1.023, p = 0.002), and association with elevated tumor necrosis factor (TNF-α B = 11.887, p = 0.001) when adjusted for age, gender, parental education and body mass index (although this became insignificant when aMDS was included in the model). Moreover, when comparing lower and higher aMDS groups, the cortisol-TNF-α interaction was only seen in the lower aMDS group. The concentrations of TNF-α and interleukins (IL) IL-1, IL-2, IL-6 were also found to be lower in individuals highly adherent to the aMDS, compared with those who did not adhere to the diet score. These findings suggest that adherence to the Mediterranean diet may counteract the stress-induced alterations in inflammatory markers, which could ultimately lower prevalence rates of mental disorders.