Mediterranean Diet Linked to Lower Risk of Cognitive Decline

by | Jan 17, 2024 | 2023, Brain Health, Cognitive Health, Mediterranean Diet

Written by Taylor Woosley, Staff Writer. Results of a nested case-control study show that after adjusting for potential confounding factors, participants with a higher MedDiet metabolomic score were less likely to experience cognitive decline (p = 0.048). 

Mediterranean DietBy 2030, an estimated one in five Americans will be 65 years of age or older and, consequently, the prevention of chronic age-related diseases is of growing public health significance1. Dementia is the seventh leading cause of death worldwide, affecting approximately 55 million people, with numbers expected to rise in the next decade2. Despite the social and economic burden of cognitive disorders, few treatment options exist, and no cures are currently available3.

The Mediterranean diet (MedDiet) is one of the most studied and well-known dietary patterns worldwide and has been associated with a wide range of benefits for health4. The MedDiet is characterized by daily consumption of fruits, vegetables, nuts, olive oil, and moderate consumption of fish, poultry, red meat, and red wine5. Previous research has shown that greater adherence to the MedDiet demonstrated a reduction in dementia risk, prevention of mild cognitive impairment, and better performance on cognitive function tests6.

Tor-Roca et al. developed a MedDiet-based metabolomic score and conducted a nested case-control study to analyze its association with cognitive decline in two sample sets from The Three-City Cohort (3C Study). The 3C Study was a population-based cohort on dementia that included people ≥65 years from three French cities. Information regarding sociodemographic and lifestyle characteristics, medical information, neuropsychological testing, anthropometric measurements, blood pressure, and fasting blood samples were obtained at baseline. Follow-up visits with repeated health and neuropsychological assessments were completed every 2-3 years. Data used in the nested case-control study was from subjects not diagnosed with dementia at baseline, who had available serum samples, and partook in at least one repeated cognitive evaluation over the 12 years of the study.

A composite score of global cognition was created based on the average Z-scores of five neuropsychological tests (Mini-Mental State Examination (MMSE), Benton Visual Retention Test, Isaac’s Set Test, Trail-Making Test part A, and Trail-Making Test part B). Linear mixed models were utilized to estimate individual slopes of cognitive change. Cases were defined as participants with the worst cognitive decline slopes. They were then matched with a control (a subject with a better cognitive decline slope) with similar data regarding age, sex, and education level. 211 cases were matched to 211 controls, resulting in a validation sample of 422 participants.

A targeted metabolomics analysis of serum samples was conducted and the MedDiet metabolomic score (MDMS) was created using a 14-point linear scale that featured two dietary metabolomic biomarkers of seven key categories of the MedDiet (vegetables, fruits, legumes, cereals, dairy, fats, and fish). Dietary information of participants was provided through completion of a comprehensive food frequency questionnaire (FFQ) and a 24-hour dietary recall (24-HDR). Correlation analyses were conducted to assess the relation between the MedDiet score and MDMS and between food groups and dietary biomarkers of key food groups of the MedDiet. Significant findings of the study are as follows:

  • MedDiet score was positively correlated with MDMS (p = 0.012) in the Bordeaux cohort.
  • After adjusting for CD risk factors, number of medications used, and for ApoE-ε4 genotype, participants with a higher MDMS were less likely to experience cognitive decline (p = 0.048).
  • Stratified analysis findings assessing the associations between MDMS and cognitive decline risk in various subgroups found a close to significant interaction between MDMS and hypertension in the Bordeaux cohort (p for interaction = 0.006).

Results of the nested case-control study show that participants with a higher adherence to the MedDiet were prospectively associated with a lower cognitive decline risk in older participants who did not have dementia at baseline. Further research on the health benefits of following the Mediterranean Diet are necessary to better comprehend the potential neuroprotective benefits. Study limitations include only analyzing serum samples at baseline and the potential for residual confounding factors.

Source: Tor‐Roca, Alba, Alex Sánchez‐Pla, Aniko Korosi, Mercè Pallàs, Paul J. Lucassen, Pol Castellano‐Escuder, Ludwig Aigner et al. “A Mediterranean Diet‐Based Metabolomic Score and Cognitive Decline in Older Adults: A Case–Control Analysis Nested within the Three‐City Cohort Study.” Molecular Nutrition & Food Research (2023): 2300271.

© 2023 The Authors. Molecular Nutrition & Food Research published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution
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Posted January 17, 2024.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

References:

  1. Gonzales MM, Garbarino VR, Pollet E, et al. Biological aging processes underlying cognitive decline and neurodegenerative disease. J Clin Invest. May 16 2022;132(10)doi:10.1172/jci158453
  2. Devranis P, Vassilopoulou Ε, Tsironis V, et al. Mediterranean Diet, Ketogenic Diet or MIND Diet for Aging Populations with Cognitive Decline: A Systematic Review. Life (Basel). Jan 6 2023;13(1)doi:10.3390/life13010173
  3. Farnsworth von Cederwald B, Josefsson M, Wåhlin A, Nyberg L, Karalija N. Association of Cardiovascular Risk Trajectory With Cognitive Decline and Incident Dementia. Neurology. May 17 2022;98(20):e2013-e2022. doi:10.1212/wnl.0000000000200255
  4. Guasch-Ferré M, Willett WC. The Mediterranean diet and health: a comprehensive overview. J Intern Med. Sep 2021;290(3):549-566. doi:10.1111/joim.13333
  5. Finicelli M, Di Salle A, Galderisi U, Peluso G. The Mediterranean Diet: An Update of the Clinical Trials. Nutrients. Jul 19 2022;14(14)doi:10.3390/nu14142956
  6. Liu X, Morris MC, Dhana K, et al. Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) study: Rationale, design and baseline characteristics of a randomized control trial of the MIND diet on cognitive decline. Contemp Clin Trials. Mar 2021;102:106270. doi:10.1016/j.cct.2021.106270