Mediterranean diet and cognitive function: a French study.

BACKGROUND Evidence on the association between Mediterranean diet (MedDiet) adherence and cognition is presently inconsistent. OBJECTIVES The aims of this study were to investigate the association between midlife MedDiet adherence and cognitive performance assessed 13 y later among participants in the SU.VI.MAX (Supplementation with Vitamins and Mineral Antioxidants) study and to test the hypothesis of effect modification by occupation and education as cognitive reserve markers. DESIGN A Mediterranean Diet Score (MDS) and a Mediterranean-Style Dietary Pattern Score (MSDPS) were estimated by using repeated 24-h dietary records (1994-1996) from 3083 middle-aged subjects. Cognitive performance was assessed in 2007-2009 by using 6 neuropsychological tests, and a composite score was built. Subgroup analyses were performed according to occupational and educational status. Mean differences and 95% CIs were estimated through covariance analyses. RESULTS After potential confounders were accounted for, no association between MDS or MSDPS and cognitive scores was detected except for a lower phonemic fluency score with decreasing MSDPS (P = 0.048) and a lower backward digit span score with decreasing MDS (P = 0.03). In turn, a low MDS was related to a lower composite cognitive score in the small subsample of manual workers (n = 178, P-interaction = 0.04) who could be hypothesized to have low cognitive reserve. MedDiet adherence did not interact with educational level in relation to cognitive function. CONCLUSION This study did not find support for a beneficial effect of MedDiet adherence on cognitive function, irrespective of educational level, which is the strongest indicator of cognitive reserve.