2. Materials and Methods
- Assess and discuss the recent randomized clinical trials (RCT) and cohort studies dealing with the impact of healthy diet on cognitive performance in both cognitively unimpaired and impaired seniors;
- Discuss the most recent findings regarding this research topic.
- The review period was limited to 1 January 2016 and 28 February 2021.
- The articles had to be published in peer-review English written journals.
- Only randomized controlled trials and cohort studies were included into the review.
- The primary results had to focus on the impact of MedDiet on cognitive functions among elderly people.
- The subjects had to be at the age 55+ years old.
- The exclusion criteria were as follows:
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
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|Author and Type of the Study||Aim of the Study||Characteristics of the Research Sample and MedDiet||Outcome Measures||Findings|
|de Amicis et al.  cohort study-cross-sectional|
|To examine the impact of MedDiet on cognitive performance of older Italian people.||279 subjects, aged 65+ years (80 men, 199 women), conducted between|
June 2015 and December 2016.
|14-item questionnaire, Mini-Mental State Examination (MMSE).||The MedDiet is associated with a lower risk of cognitive impairment (odds ratio (OR) = 0.39; 95% confidence interval (CI), 0.15–0.99; p = 0.045).|
|de la Rubia et al. |
|To identify modifications in the main cognitive functions of patients with AD after following a coconut oil enriched Mediterranean diet.||44 patients with AD, aged 65 to 85 years old, an experimental group (22 patients) followed a coconut oil enriched Mediterranean diet, and a control group (22 patients) followed a Mediterranean-style diet. It lasted 21 days.||7 min screen, which analyses temporal orientation, visuospatial and visuoconstructive abilities, and semantic and episodic memory.||The experimental group improved in episodic, temporal orientation, and semantic memory|
and it seems that the positive effect is more evident in women with mild-moderate state, although other improvements
in males and severe state were also shown.
|Karstens et al.  cohort study-cross-sectional|
|To explore cross-sectional associations|
between the MedDiet and cognitive and neuroimaging phenotypes
associated with AD and VaD (separately) among cognitively unimpaired seniors.
|82 healthy seniors at the age of 68.8 years, 50% males and 50% females; participants were divided into high and low (median split) adherence groups.||Block Food Frequency Questionnaire 2005, standardized cognitive assessment battery of tests (i.e., the California Verbal Learning Tests, trail making tests—Part A, Part B, and the Wechsler Test of Adult Reading), MRI, T1-weighted images, FreeSurfer 6.0 segmentation pipeline.||The high MedDiet group was better at learning and memory performance (β = 0.52, SE = 0.21, t (74) = 2.53, p = 0.01, d = 1.23).|
|Mantzorou et al. |
|To assess MedDiet adherence of older Greeks on their cognitive functions and mental state.||2092 males and females, both cognitively healthy and unhealthy, mean age 74.97 ± 8.41 years, from seven different Greek cities.||Mini-Mental State Examination (MMSE), Geriatric Depression Scale (GDS), and Mediterranean Diet Score (MedDietScore) questionnaires.||Higher MD adherence is strongly associated with better cognitive status and less depressive symptomatology.|
|Marseglia et al. |
China, France, Italy, Netherlands, Poland, Sweden, UK
|To explore the impact of NU-AGE’s dietary intervention on age-related cognitive decline.||1279 healthy seniors, age range: 65–79 years, from five European centers, a control group 638, was adhered to MedDiet and an intervention group 641, was adhered to habitual diet.||CERAD—neuropsychological battery, MMSE, Babcock Story Recall Test, pattern comparisons, digit cancellation, trail making tests, word list memory, 15-items Boston Naming Test, Constructional Praxis Test, category fluency. Assessed cognitive domains: global cognition, perceptual speed, executive function, episodic memory, verbal abilities, and constructional praxis.||Subjects with higher adherence to the NU-AGE diet experienced considerable improvements in global cognition (β 0.20 (95% CI 0.004, 0.39), p-value = 0.046) and episodic memory (β 0.15 (95% CI 0.02, 0.28), p-value = 0.025) after 1 year, compared to those adults with lower adherence to NU-AGE diet. Both groups of subjects improved in global cognition and in all cognitive domains after 1 year.|
|Mazza et al. |
|To examine whether the replacement of all vegetable oils with a lower amount of extra-virgin olive oil, in the contest of a Mediterranean Diet, would improve|
cognitive performances, among elderly Italian individuals.
|110 participants, mean age was 70 ± 4 years; an experimental group had MedDiet in which all vegetable oils|
(including olive oil, high-oleic sunflower oil, high-oleic
sunflower oil, canola oil and hydrogenated vegetable oils) were substituted by extra-virgin OO at dose of 20–30 g per day, and a control MedDiet alone. It lasted 1 year.
|Neuropsychological tests (MMSE and ADAS-cog), anthropometric measurements and cardiovascular risk factors assessment, dietary intake data were assessed by a 24-h recall and a 7-day food record and calculated using nutritional software MetaDieta, biochemical evaluation.||A higher reduction of ADAS-cog scores (improved test) after 1 year in the seniors of the MedDiet plus low dose of extra-virgin OO group than that observed with a MedDiet alone|
(−3.0 ± 0.4 Vs. −1.6 ± 0.4 respectively).
|Paknahad et al. |
|To examine the impact of the Mediterranean diet on cognitive functions in patients with PD.||80 patients, mean age-60 years, the experimental group followed MedDiet (n = 40) or control (n = 40) group. It lasted 10 weeks.||Montreal Cognitive Assessment (MoCA) test, BMI test, Nutritionist IV software.||The mean score of the|
dimensions of executive function, language, attention, concentration, and active memory and the total score of
cognitive assessment significantly increased in the intervention compared with the control group (p < 0.05, for all).
|Wade et al. |
|To explore the cognitive effects of MedDiet with additional red meat.||A 24-week parallel crossover design compared MedDiet with 2–3 weekly servings of fresh, lean pork (MedPork) and a low-fat (LF) control diet. 35 participants aged between 45 and 80 years and at risk of cardiovascular disease followed each|
intervention for 8 weeks, separated by an 8-week washout period.
|Cambridge Neuropsychological Test Automated Battery, SF-36 Health Survey, Profile of Mood States.||Compared to LF, the MedPork intervention led to higher processing speed|
performance (p = 0.01) and emotional role functioning (p = 0.03).
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