The association between adherence to a Mediterranean style diet and cognition in older people: The impact of medication

Cross-sectional and longitudinal associations between adherence to Mediterranean diet with physical performance and cognitive function in older adults: A systematic review and meta-analysis

OBJECTIVES

The present study investigated the association between adherence to Mediterranean diet (MeDi) and physical performance and cognitive function in older adults.

METHODS

We conducted a systematic review and meta-analysis of cross-sectional and longitudinal studies that investigated older adults aged 60+ years and assessed adherence to MeDi diet using validated composite scores. Observational studies, including cross-sectional, case-control, and longitudinal cohort studies, if crude baseline data was available, which investigated as a primary or secondary outcome the association of MeDi diet adherence with physical performance and/or cognitive function in non-demented older adults were included in the cross-sectional analysis. For the longitudinal analysis, case-control and longitudinal cohort studies that investigated the longitudinal associations between adherence to MeDi diet with the incidence of mild cognitive impairment (MCI), dementia, and/or Alzheimer's disease (AD), and/or changes in physical performance and cognition in non-demented older adults were included. Studies published in other languages than English were excluded. Studies were retrieved from MEDLINE, SCOPUS, CINAHL, and AgeLine databases until May 19, 2021. The risk of bias was evaluated using the Newcastle - Ottawa Quality Assessment Scale (NOS). A pooled effect size was calculated based on standard mean differences (SMD), log odds ratio (OR) and log risk ratio (RR). This study is registered on PROSPERO (CRD42021250254).

RESULTS

Nineteen cross-sectional studies that investigated 19.734 community-dwelling and institutionalized older adults free of disability and dementia were included. A high adherence to MeDi was cross-sectionally associated with better walking speed (SMD = 0.42; 95 % Confidence Interval (CI) = 0.12-0.72, P = 0.006; I² = 65 %, P = 0.06), knee muscle strength speed (SMD = 0.26; 95 % CI = 0.17-0.36, P < 0.00001; I² = 0 %, P = 0.69), global cognition (SMD = 0.24; 95 % CI = 0.15-0.33, P < 0.00001; I² = 85 %, P < 0.00001), and memory (SMD = 0.18; 95 % CI = 0.13-0.25, P < 0.00001; I² = 100 %, P < 0.00001). The association between MeDi adherence and global cognition remained significant after stratifying the analysis by the region where the study was conducted, MeDi diet adherence composite score, and Mini Mental State Examination (MMSE). Studies had a moderate to low risk of bias. In relation to longitudinal analysis, thirty-four prospective studies with an average follow-up period that varied from 3.0 to 12.6 years and investigated 98.315 community-dwellers were included. Results indicated that older adults with high MeDi scores had a lower decline in global cognition RR = 0.26; 95 % CI = 0.23-0.29, P < 0.00001; I² = 100 %, P < 0.00001). In contrast, no significant associations between MeDi and mobility, MCI, dementia were found. A low risk of bias was found in the longitudinal studies.

DISCUSSION

Findings of the present study indicated that high adherence to MeDi was cross-sectionally associated with physical performance and cognitive function. Results of the pooled analysis of longitudinal studies revealed that high adherence to MeDi reduced the risk of global cognitive decline in non-demented older adults. However, no significant associations between MeDi adherence and the incidence of mobility problems, MCI, and dementia were found. Although important, our findings should be carefully interpreted due to the presence of heterogeneity and publication bias.

Dietary patterns in middle age: effects on concurrent neurocognition and risk of age-related cognitive decline

Context

Diet plays a critical role in cognitive integrity and decline in older adults. However, little is known about the relationship between diet and cognitive integrity in middle age.

Objective

To investigate the relationship between dietary patterns in healthy middle-aged adults and neurocognition both in middle age and later in life.

Data Sources

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, the following electronic databases were searched: Web of Science, Scopus, PubMed, and PsychInfo.

Data Extraction

Data from eligible articles was extracted by 2 reviewers.

Data Analysis

Articles included in the systematic review were synthesized (based on the synthesis without meta-analysis reporting guidelines) and assessed for quality (using the Joanna Briggs Institute checklist for randomized controlled trials, cohort studies, and cross-sectional studies) by 2 reviewers.

Results

Of 1558 studies identified, 34 met the eligibility criteria for inclusion. These comprised 9 cross-sectional studies, 23 longitudinal or prospective cohort studies, and 2 randomized controlled trials. Findings were mixed, with some studies reporting a significant positive relationship between adherence to various “healthy” dietary patterns and neurocognition, but others reporting no such relationship.

Conclusion

This systematic review demonstrated that adherence to the Mediterranean diet and other healthy dietary patterns in middle age can protect neurocognition later in life.

Systematic Review Registration

PROSPERO registration no. CRD42020153179.

The role of nutrition in space exploration: Implications for sensorimotor, cognition, behavior and the cerebral changes due to the exposure to radiation, altered gravity, and isolation/confinement hazards of spaceflight

Multi-year crewed space exploration missions are now on the horizon; therefore, it is important that we understand and mitigate the physiological effects of spaceflight. The spaceflight hazards-radiation, isolation, confinement, and altered gravity-have the potential to contribute to neuroinflammation and produce long-term cognitive and behavioral effects-while the fifth hazard, distance from earth, limits capabilities to mitigate these risks. Accumulated evidence suggests that nutrition has an important role in optimizing cognition and reducing the risk of neurodegenerative diseases caused by neuroinflammation. Here we review the nutritional perspective of how these spaceflight hazards affect the astronaut's brain, behavior, performance, and sensorimotor function. We also assess potential nutrient/nutritional countermeasures that could prevent or mitigate spaceflight risks and ensure that crewmembers remain healthy and perform well during their missions. Just as history has taught us the importance of nutrition in terrestrial exploration, we must understand the role of nutrition in the development and mitigation of spaceflight risks before humans can successfully explore beyond low-Earth orbit.

Adherence to the Mediterranean Diet and Healthy Aging: A Narrative Review over the Last Decade

Objective: Even though modern medicine has significantly contributed to the extension of human lifespan, it has failed to delay the upsurge of chronic diseases. Health benefits of the Mediterranean diet are well established. Thus, adherence to this diet pattern may be the key to healthy aging. Ôhe aim of this review is to investigate the potential benefits of the Mediterranean diet on healthy aging. Methods: A literature search of three databases (ScienceDirect, MEDLINE and The Cochrane Library) was conducted in order to trace all relevant studies published between January 1st 2010 and June 6th 2020 that focused on the impact of adherence to the Mediterranean diet on the physical and mental well-being of individuals aged 60 or older. Results:Twenty-two studies fulfilled the selection criteria and were classified into six groups, according to the main outcome of each study: mental health (eight studies), frailty (6), cardiovascular risk factors (3), plasma levels of uric acid (1), length of hospital stay (1), and aging mechanisms (3). Based on these studies, the protective role of Mediterranean diet on depression, cardiovascular and frailty risk was established. Moreover, adherence to the Mediterranean diet resulted in reduced plasma uric acid levels as well as decreased length of hospital stay and mortality risk among patients who were urgently admitted for any cause in a tertiary hospital. In contrast, results on the effect of Mediterranean diet on cognition were controversial, as studies presented positive or neutral correlations. Conclusions: This review provides evidence on the association between adherence to the Mediterranean diet and healthy aging and highlights the importance of conducting more studies among seniors in order to provide further insight into this matter.

"Influence of diet on mood and social cognition: a pilot study"

Recently, a relationship has been observed between nutrition and social cognition. In this aspect, several dietary patterns, or even some probiotics, have been reported as social cognition modulators. However, to date, no studies have reported the effects of specific nutrients. Our aim was to evaluate the relationship between dietary macronutrients and the processing of social and affective information. Participants were undergraduates from the University of Extremadura (Badajoz, Spain) aged 21.3 ± 2.9 years., with a BMI of 22.8 ± 3.9 (kg m-2). The students' social cognition and diet were analysed through questionnaires and a dietary record. The diets were analysed with DIAL v.1.18® software (Alce Ingeniería®). The participants filled out the WHO-5 well-being index, Beck's anxiety inventory, Beck's depression inventory, ruminative response scale (RSS), Leiden index of depression sensitivity (LEIDS-r), empathy quotient (EQ), and interpersonal reactivity index (IRI). To analyse the data, nutrients were grouped through principal component analysis (PCA) into lipids, carbohydrates and proteins. Additionally, we assayed if these principal components were associated with psychological questionnaire scores using multiple linear regression analyses. The dietary pattern differed from the traditional Mediterranean diet due to high intake of proteins and saturated fatty acids. Regarding social cognition and macronutrients, we found a positive association between lipids, specifically cholesterol, and the Perspective-Taking Scale (an IRI component). Carbohydrates influenced the RSS, indicating that complex carbohydrates may be a risk factor for depression. Moreover, the brooding factor, a component of the RRS, was negatively affected by dietary carbohydrates and proteins, specifically by fiber and aspartate. Diet may influence several variables related to social cognition and mood. Particularly, a low-cholesterol diet rich in fiber, complex carbohydrates, and aspartate apparently provides benefits, improving the processing of social and affective information and psychic well-being.

Foods, nutrient intakes and Mediterranean dietary pattern in midlife are not associated with reaction times: a longitudinal analysis of the UK Women’s Cohort Study

Associations between dietary factors and general cognition in the elderly have been documented; however, little is known about reaction time ability in relation to midlife diet. The present study aimed to investigate associations between reaction time and midlife dietary factors, specifically foods, nutrients and Mediterranean diet (MeDi) pattern. The UK Women’s Cohort Study collected dietary information from middle-aged women (52 (sd 9·4) years old) using a validated 217-item FFQ in 1995–1998. In 2010–2011, a sub-group of 664 participants completed online reaction time ability tests including simple reaction time (SRT) and choice reaction time; 503 participants were eligible for analysis. Participants were grouped into fast and slow groups by their median reaction time. The intake of particular foods, nutrients, adherence to the MeDi and cooking methods (roasting/baking, frying and barbecuing/grilling) were explored in relation to reaction times. We did not find any significant associations between reaction times and investigated foods, nutrients or adherence to the MeDi in adjusted models. However, consumers of roasted/baked fish and fried vegetables were associated with slower SRT (adjusted OR 1·46, 95 % CI 1·00, 2·13, P = 0·049; and adjusted OR 1·64, 95 % CI 1·12, 2·39, P = 0·010, respectively) compared with non-consumers of that particularly cooked food. Overall, our findings show no significant associations between midlife diet and reaction time ability 10–15 years later.

Findings of a Pilot Study Investigating the Effects of Mediterranean Diet and Aerobic Exercise on Cognition in Cognitively Healthy Older People Living Independently within Aged-Care Facilities: The Lifestyle Intervention in Independent Living Aged Care (LIILAC) Study

BACKGROUND

Cognitive decline and Alzheimer disease are more prevalent in our aging population. Modifiable risk factors, such as diet and sedentary lifestyle, have been proposed as key to potentially ameliorating cognitive decline. Both exercise and Mediterranean diet (MedDiet) have been linked to reduced levels of cardiovascular disease and other comorbidities. Higher levels of exercise and MedDiet adherence may prove to be cognitively protective, both individually and synergistically.

OBJECTIVES

The aim was to investigate the effect of a 6-mo program of MedDiet, exercise, and a combination of both, on cognition, mood, and general health in older persons living independently in aged-care communities.

METHODS

The Lifestyle Intervention in Independent Living Aged Care (LIILAC) Study (ACTRN12614001133628) involved 102 participants, aged 60-90 y, who were randomly assigned to 1 of 4 intervention groups. Change in overall memory performance was assessed as the primary outcome. Additionally, changes in cognitive task performance, as well as mood, wellness, cardiovascular function, and blood biomarkers, were investigated.

RESULTS

While there was no significant change in overall memory performance, there was a significant improvement in spatial working memory performance in the combined exercise and diet group, relative to controls. This combined intervention group also showed an overall improvement in their emotional state, as assessed by the Depression Anxiety Stress Scale, as did the exercise-only group.

CONCLUSIONS

This research indicates that diet and exercise programs have the potential to improve aspects of cognition and mood in an aging population. However, given the lower than optimal sample size and lack of resources to reinforce the interventions during the trial, further larger randomized controlled trials are required to substantiate whether the introduction of diet and exercise programs into independent-living facilities is a viable method to preserve cognitive health in older people. This trial was registered at www.ANZCTR.org.au ACTRN 12614001133628 (LIILAC Study).