Re: DISCORDANT EFFECTS ON ANXIETY AND DEPRESSION OF MEDITERRANEAN DIET AND OF PHYSICAL ACTIVITY ENHANCEMENT
We appreciate the comments by Trovato FM et al in their Letter to the Editor regarding our recently published trial on Mediterranean Diet (MedDiet) and cognition (The PREDIMED-NAVARRA trial) . The PREDIMED- NAVARRA trial found a favorable effect of MedDiet on cognitive function . This protection was independent of other confounders including mood disorders and physical activity. In a previous report, Trovato et al stressed the complex relationships between cognition, mood disorders and lifestyle factors, such as MedDiet and physical activity . We concur with them that mood disorders, MedDiet, physical activity and other lifestyle factors jointly influence cognitive performance. Adjusting for all these factors is the accepted strategy in observational studies to deal with confounding. However, the PREDIMED-NAVARRA trial followed a randomised design and the randomisation allowed us to reduce the possibilities for residual confounding. Furthermore, when we adjusted for some factors, including incident depression, our results did not change. We decided to adjust for depression as a potential confounder because the available evidence points to a protective effect of MedDiet on depression. Recently, a meta-analysis has reported a protective effect of MedDiet on depression (pooled RR=0.68, 95%CI: 0.54-0.86) . This meta-analysis was almost completely based on cross-sectional findings (regarding depression), since few longitudinal studies have focused on this topic. Among longitudinal studies, it is worthwhile to underline that Sanchez- Villegas A et al showed that a better adherence to the MedDiet pattern was associated with lower incidence of depression after 4.4-year of median follow-up in the Seguimiento Universidad de Navarra (SUN) cohort study. Interestingly, an inverse dose-response trend was found . In any case, we agree with Trovato et al that an extensive clinical research is needed to further understand the complex mechanisms by which lifestyle-based preventive strategies can influence the risk of cognitive impairment, depression and other chronic diseases.
1. Martinez-Lapiscina EH, Clavero P, Toledo E, et al. Mediterranean diet improves cognition: the PREDIMED-NAVARRA randomised trial. J Neurol Neurosurg Psychiatry 2013;84:824-6. 2. Trovato GM, Catalano D, Martines GF, et al. Mediterranean diet: Relationship with anxiety and depression. Ann Neurol 2013. Aug 8. [Epub ahead of print] 3. Psaltopoulou T, Sergentanis TN, Panagiotakos DB, et al. Mediterranean diet and stroke, cognitive impairment, depression: A meta-analysis. Ann Neurol 2013. May 30 [Epub ahead of print] 4. Sanchez-Villegas A, Delgado-Rodriguez M, Alonso A, et al. Association of the Mediterranean dietary pattern with the incidence of depression: the Seguimiento Universidad de Navarra/University of Navarra follow-up (SUN) cohort. Arch Gen Psychiatry 2009;66:1090-8.
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