The association of healthful diets and cognitive function: a review

Building research in diet and cognition (BRIDGE): Baseline characteristics of older obese African American adults in a randomized controlled trial to examine the effect of the Mediterranean diet with and without weight loss on cognitive functioning

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The MedDiet is correlated with slower cognitive decline in longitudinal studies.

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Self-reported MedDiet adherence positively associated with select cognitive domains.

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Women outperformed men across verbal tasks, including learning and memory.

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Younger participants outperformed older participants on cognitive assessments.

In the United States, >5.4 million people age 65 and older are affected by cognitive impairment and dementia, including Alzheimer’s disease. African Americans are more likely than non-Hispanic whites to suffer from these disorders. Obesity is linked to accelerated age-related cognitive decline, and weight loss through caloric restriction is a potential strategy to prevent this cognitive impairment. Adherence to a healthful dietary pattern, such as the Mediterranean Diet (MedDiet), has also shown positive effects on reducing risk for dementia. African Americans are disproportionately affected by obesity and have less healthful diets than non-Hispanic whites. We present baseline characteristics from a three-arm randomized controlled trial that randomized 185 obese (BMI ≥ 30 kg/m² and ≤ 50 kg/m²) healthy older adults (55–85 years of age) to: 1) Typical Diet Control (TDC); 2) MedDiet alone (MedDiet-A) intervention; or 3) MedDiet caloric restricted intervention to promote weight loss (MedDiet-WL). The majority of the sample was African American (91.4%) and female (85.9%). The two active interventions (MedDiet-A and MedDiet-WL) met once weekly for 8 months, and the TDC received weekly general health newsletters. Baseline data were collected between January 2017 and July 2019 in Chicago, IL. In our sample, closer adherence to a MedDiet pattern was associated with higher attention and information processing (AIP) and higher executive functioning (EF). Consistent with the literature, we saw that older participants performed more poorly on the cognitive assessments than younger participants, and women outperformed men across verbally mediated tasks, especially ones related to learning and memory.

Changes in Motor Skills, Sensory Profiles, and Cognition Drive Food Selection in Older Adults With Preclinical Dysphagia

Purpose Self-selection and self-avoidance of certain foods is one possible indicator of preclinical (prior to any clinical intervention) dysphagia in healthy older adults. Self-selection of food choices is influenced by changes in a combination of factors, including neuromuscular, sensory, and individual patient characteristics. Changes to these factors occur both centrally or peripherally and can be part of typical, healthy aging. Alterations in motor, sensory, or cognitive skills may lead to self-imposed modifications to food choices and, therefore, highlight potential risk for dysphagia. Conclusions For effective screening and assessments procedures in healthy aging adults, the diagnosis of preclinical dysphagia will likely require a multifaceted assessment. A combination of assessment methods using objective and subjective measurements of neuromuscular, sensory, and individual patient factors, as well as knowledge of food avoidance, may provide insight for identifying community-dwelling older adults at risk for dysphagia and allow for earlier monitoring and intervention.

Brain Ageing, Cognition and Diet: A Review of the Emerging Roles of Food-Based Nootropics in Mitigating Age-related Memory Decline

BACKGROUND

Age-related cognitive decline has been suggested to result from an increase in the brain neuron loss, which is attributable to continued derangement of the brain's oxidant/ antioxidant balance. Increased oxidative stress and a concomitant decrease in the brain's antioxidant defense system have been associated with functional senescence and organismal ageing. However, nature has configured certain foods to be rich sources of nootropic agents, with research showing that increased consumption of such foods or food ingredients may be protective against ageing-related memory decline. This knowledge is becoming increasingly valuable in an era when the boundary that separates food from medicine is becoming blurred. In this review, we examine extant literature dealing with the impact of ageing on brain structure and function, with an emphasis on the roles of oxidative stress. Secondly, we review the benefits of food-based antioxidants with nootropic effects and/or food-based nootropic agents in mitigating memory decline; with a view to improving our understanding of likely mechanisms. We also highlight some of the limitations to the use of food-based nootropics and suggest ways in which they can be better employed in the clinical management of age-related cognitive decline.

CONCLUSION

While it is known that the human brain endures diverse insults in the process of ageing, food-based nootropics are likely to go a long way in mitigating the impacts of these insults. Further research is needed before we reach a point where food-based nootropics are routinely prescribed.

Dietary Patterns Associated with Cognitive Function among the Older People in Underdeveloped Regions: Finding from the NCDFaC Study

Although dietary patterns are crucial to cognitive function, associations of dietary patterns with cognitive function have not yet been fully understood. This cross-sectional study explored dietary patterns associated with cognitive function among the older adults in underdeveloped regions, using 1504 community-dwelling older adults aged 60 and over. Diet was assessed using a food frequency questionnaire and 24-h dietary recall. Factor analysis was used to extract dietary patterns. Global cognitive function was assessed using the Mini-Mental State Examination (MMSE). Two dietary patterns, a “mushroom, vegetable, and fruits” (MVF) pattern and a “meat and soybean products” (MS) pattern, were identified. The MVF pattern, characterized by high consumption of mushrooms, vegetables, and fruits was significantly positively associated with cognitive function (p < 0.05), with an odds ratio of (95% CIs) 0.60 (0.38, 0.94) for cognitive impairment and β (95% CIs) 0.15 (0.02, 0.29) for –log (31-MMSE score). The MS pattern, characterized by high consumption of soybean products and meat, was also associated with better cognitive function, with an odds ratio of 0.47 (95% CIs 0.30, 0.74) for cognitive impairment and β (95% CIs) 0.34 (0.21, 0.47) for –log (31-MMSE score). Our results suggested that both the MVF and MS patterns were positively associated with better cognitive function among older adults in underdeveloped regions.

The Impact of the Mediterranean Diet on the Cognitive Functioning of Healthy Older Adults: A Systematic Review and Meta-Analysis

Evidence from epidemiologic studies suggests a relation between the Mediterranean diet (MeDi) and cognitive function, but results are inconsistent. Prior reviews have not provided pooled data from meta-analysis of longitudinal studies and randomized controlled trials (RCTs), or they included younger adult participants. This systematic review and meta-analysis examines the impact of the MeDi on the cognitive functioning of healthy older adults. Fifteen cohort studies with 41,492 participants and 2 RCTs with 309 and 162 participants in intervention and control groups, respectively, were included. The primary outcome of interest was cognitive function, divided into domains of memory and executive function. Meta-analysis of cohort studies revealed a significant association between MeDi and older adults' episodic memory (n = 25,369, r = 0.01, P = 0.03) and global cognition (n = 41,492, r = 0.05, P ≤ 0.001), but not working memory (n = 1487, r = 0.007, P = 0.93) or semantic memory (n = 1487, r = 0.08, P = 0.28). Meta-analysis of RCTs revealed that compared with controls, the MeDi improved delayed recall (n = 429, P = 0.01), working memory (n = 566, P = 0.03), and global cognition (n = 429, P = 0.047), but not episodic memory (n = 566, P = 0.15), immediate recall (n = 566, P = 0.17), paired associates (n = 429, P = 0.20), attention (n = 566, P = 0.69), processing speed (n = 566, P = 0.35), or verbal fluency (n = 566, P = 0.12). The strongest evidence suggests a beneficial effect of the MeDi on older adults' global cognition. This article discusses the influence of study design and components of the MeDi on cognitive function and considers possible mechanisms.

Factors affecting aging cognitive function among community-dwelling older adults

AIM

The study purpose was to determine factors affecting aging cognitive function of 3,645 community-dwelling older adults in Korea.

METHODS

The Hasegawa Dementia Scale assessed aging cognitive function, blood analyses and anthropometrics assessed cardio-metabolic risk factors, and the Geriatric Depression Scale Short Form Korean Version assessed depressive symptoms.

RESULTS

Participants with poor aging cognitive function were more likely to be in the late age group (≥75 y) and currently smoking and have a medical history of stroke, high body mass index, and high level of depressive symptoms; they were also less likely to engage in regular meals and physical activities.

CONCLUSION

Regular meals and physical activities may be primary factors for clinical assessment to identify older adults at risk for aging cognitive function. With aging, depressive symptoms and other unhealthy lifestyle behaviours should be managed to prevent cognitive function disorders.

Dietary Factors and Cognitive Function in Poor Urban Settings

A significant body of evidence suggests that poor dietary intake is associated with reduced cognitive function. However, few studies have examined this relation in poor urban settings. Our brief review suggests that (a) higher overall diet quality may play a particularly important role in cognitive function among the poorest; and (b) greater vitamin E intake is related to better cognitive performance, at least in part, via fewer depressive symptoms. The broader recent literature strongly suggests the beneficial role of diet for learning and memory, and potentially synergistic influences on other cognitive domains. However, adherence to healthful diet among urban poor may be limited by factors such as cost and access. Here, we propose several potential moderators and mediators of diet-cognition relations among urban poor. Future studies should focus on the complex interplay among factors that influence the role of diet in cognitive function among poor, urban-dwelling persons.

[Vitamins and nutritional supplements in older persons: How to diagnose and when to substitute?]

Despite an excellent food supply in Germany, a large percentage of older persons living at home or institutionalized older persons suffer from or are at risk for malnutrition. The purpose of this article is to highlight the association between nutrient deficiencies and age-related diseases and give rational recommendations for substitution. Both malnutrition and low levels of specific nutrients are associated with cognitive and functional impairment, dementia, and depression in older persons. Most prevalent are deficiencies in vitamin B1, vitamin B12, and vitamin D. Serum levels are often misleading and show false negative results in vitamin B1 and B12 deficiencies; therefore, determination of erythrocyte transketolase activity (ETKA) and the thiamine pyrophosphate (TPP) effect for vitamin B1 and of methylmalonic acid and holotranscobalamine for vitamin B12 is recommended. Prophylactic supplementation with vitamins is not supported by prospective trials; however, positive data from observational studies support a Mediterranean diet combined with intake of vitamins, antioxidants, and unsaturated fatty acids. Older persons should be regularly screened for malnutrition and the threshold for determination of vitamin B1, B12, and vitamin D should be low. Vitamin substitution should be reserved for proven deficits. There is now data regarding cognition from prospective trials on effects of a healthy diet combined with other life-style factors like physical and cognitive activity.

Senior Centers and Nutritional Outcomes: A Texas Example

Healthy diet and weight control are important for elders and senior centers (SCs). The authors consider effects of SCs on attendee nutrition and health and efforts to improve diets and weight. Data derive from surveys in 2006 (N = 798) and 2007 (N = 742) at 21 multipurpose SCs in Tarrant County, Texas, supplemented with data from 2012 (N = 1,402). Measures included attendee agreement that SC meals improved nutrition, improved health, attempts to improve diets, and success in controlling weight. Cumulative and binary logistic regression methods were employed. SC attendance and social engagement explained agreement that SC meals improved nutrition and health but were not shown to predict changes in diet or weight control. Findings suggest success of SC programs, as well as physician recommendations, in influencing attendee nutritional behavior and perceptions of nutrition and health effects. Practice recommendations include SC collaborations with local health providers to promote attendee nutritional health.

Diet quality and cognitive function in an urban sample: findings from the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study

OBJECTIVE

Poor diet quality contributes to morbidity, including poor brain health outcomes such as cognitive decline and dementia. African Americans and individuals living in poverty may be at greater risk for cognitive decrements from poor diet quality.

DESIGN

Cross-sectional.

SETTING

Baltimore, MD, USA.

SUBJECTS

Participants were 2090 African Americans and Whites (57 % female, mean age=47·9 years) who completed two 24 h dietary recalls. We examined cognitive performance and potential interactions of diet quality with race and poverty status using baseline data from the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study. Healthy Eating Index-2010 (HEI-2010) scores were calculated and interpreted using federal guidelines. A neurocognitive test battery was administered to evaluate cognitive function over several domains.

RESULTS

Linear regression analyses showed that lower HEI-2010 scores were associated with poorer verbal learning and memory (P<0·05) after adjustment for covariates. Diet quality within the sample was poor. Significant interactions of HEI-2010 and poverty status (all P<0·05) indicated that higher diet quality was associated with higher performance on tests of attention and cognitive flexibility, visuospatial ability and perceptual speed among those below the poverty line. No significant race interactions emerged. Higher diet quality was associated with better performance on two measures of verbal learning and memory, irrespective of race and poverty status.

CONCLUSIONS

Findings suggest that diet quality and cognitive function are likely related at the population level. Future research is needed to determine whether the association is clinically significant.