Mediterranean Diet

Townsend et al. (2023) found in a systematic review that studies showed the Mediterranean diet to be associated with better cognitive performance, reduced rate of cognitive decline, less global cognitive decline, reduced chances for mild cognitive impairment, lower risk of dementia, lower risk for Alzheimer’s disease, improved cognition, increased processing speed, and less likelihood for mild cognitive impairment to progress to Alzheimer’s disease.  14 out of the 21 studies looking at the Mediterranean diet used the characterization developed by Trichopoulou et al. (1995):  high ratio of monounsaturated to saturated fat, moderation of alcohol, high intake of legumes, grains, fruits and vegetables, and low intake of meat and dairy.  Valls-Pedret et al. (2015) did an RCT with 447 healthy Spaniards who were on average 67 years old and had either diabetes or several other risk factors for cardiovascular disease.  None of the participants had been diagnosed with cardiovascular disease, depression, or cognitive impairment.  They compared two groups on the Mediterranean diet to a control group who was educated on the benefits of a low-fat diet.  One of the Mediterranean diet groups was supplemented with an entire liter of extra virgin olive oil per week, while the other group received 30 grams of walnuts, hazelnuts and almonds per day.  They all took a cognition test at the beginning and at the end of their participation, which was on average four years later.  Both of the Mediterranean diet groups scored better than they had at baseline, while the control group scored worse.  The olive oil group generally scored the best, although the nut group scored slightly higher for memory. 

References:

Townsend, R. F., Logan, D., O’Neill, R. F., Prinelli, F., Woodside, J. V., & McEvoy, C. T. (2023). Whole Dietary Patterns, Cognitive Decline and Cognitive Disorders: A Systematic Review of Prospective and Intervention Studies. Nutrients, 15(2). 

Trichopoulou, A., Kouris-Blazos, A., Wahlqvist, M. L., Gnardellis, C., Lagiou, P., Polychronopoulos, E., Vassilakou, T., Lipworth, L., & Trichopoulos, D. (1995). Diet and overall survival in elderly people. BMJ (Clinical Research Ed.), 311(7018), 1457–1460. 

Valls-Pedret, C., Sala-Vila, A., Serra-Mir, M., Corella, D., de la Torre, R., Martínez-González, M. Á., Martínez-Lapiscina, E. H., Fitó, M., Pérez-Heras, A., Salas-Salvadó, J., Estruch, R., & Ros, E. (2015). Mediterranean Diet and Age-Related Cognitive Decline: A Randomized Clinical Trial. JAMA Internal Medicine, 175(7), 1094–1103.