A cross sectional study to examine the association between dietary patterns and cognitive impairment in older Chinese people in Hong Kong

Dietary patterns are associated with cognitive function in the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort

Identifying factors that contribute to the preservation of cognitive function is imperative to maintaining quality of life in advanced years. Of modifiable risk factors, diet quality has emerged as a promising candidate to make an impact on cognition. The objective of this study was to evaluate associations between empirically derived dietary patterns and cognitive function. This study included 18 080 black and white participants aged 45 years and older from the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort. Principal component analysis on data from the Block98 FFQ yielded five dietary patterns: convenience, plant-based, sweets/fats, Southern, and alcohol/salads. Incident cognitive impairment was defined as shifting from intact cognitive status (score >4) at first assessment to impaired cognitive status (score ≤4) at latest assessment, measured by the Six-Item Screener. Learning, memory and executive function were evaluated with the Word List Learning, Word List Delayed Recall, and animal fluency assessments. In fully adjusted models, greater consumption of the alcohol/salads pattern was associated with lower odds of incident cognitive impairment (highest quintile (Q5) v. lowest quintile (Q1): OR 0·68; 95 % CI 0·56, 0·84; P for trend 0·0005). Greater consumption of the alcohol/salads pattern was associated with higher scores on all domain-specific assessments and greater consumption of the plant-based pattern was associated with higher scores in learning and memory. Greater consumption of the Southern pattern was associated with lower scores on each domain-specific assessment (all P < 0·05). In conclusion, dietary patterns including plant-based foods and alcohol intake were associated with higher cognitive scores, and a pattern including fried food and processed meat typical of a Southern diet was associated with lower scores.

Mediterranean Diet, Cognitive Function, and Dementia: A Systematic Review of the Evidence

A growing body of evidence suggests that adherence to the Mediterranean diet (MD) may protect against cognitive decline and dementia. Many epidemiologic studies and several randomized controlled trials (RCTs) have found positive effects of the MD on cognitive function, but findings remain inconsistent. The aim of this systematic review was to provide an update on the current knowledge of the effects of the MD on cognitive function, cognitive impairment, Alzheimer disease (AD), and all-type dementia. Five databases were searched-PubMed, Embase, CINAHL, CENTRAL, and PsycINFO (1806 to 25 May 2015)-with the use of prespecified criteria. Human studies that were published in English without any restriction on study type, population assessed, intervention period, follow-up time, or publication date, and that examined the association between adherence to the MD and cognitive function or dementia symptoms (as measured by cognitive function tests), were included. Only primary publication types were included. Thirty-two studies from 25 unique cohorts, including 5 RCTs and 27 observational studies, met the inclusion criteria. The majority of studies showed that the MD was associated with improved cognitive function, a decreased risk of cognitive impairment or decreased risk of dementia, or AD. Three studies found no correlation between the MD and AD, 3 further studies found no association between the MD and cognitive impairment, and 5 studies found no association between the MD and cognitive function. There was large heterogeneity, and studies differed with regard to quality. Based on the findings and the limitations in study design, we conclude that adherence to the MD is associated with better cognitive performance. However, it should be noted that the majority of findings come from epidemiologic studies that provide evidence for a correlation between the MD and cognition but not for a cause-and-effect relation. More controlled trials are required to establish a causational relation.

Association between the Mediterranean-style Dietary Pattern Score and Physical Performance: Results from TRELONG Study

OBJECTIVE

To determine the association between Mediterranean-Style Dietary Pattern Score and physical performance.

DESIGN

Data analysis of a longitudinal study of a representative, age stratified, population sample.

SETTING

The TREVISO LONGEVA (TRELONG) Study, in Treviso, Italy.

PARTICIPANTS

In 2010, 123 men and 181 women, age 77 years and over (mean age 86.3 ± 6.8 years).

MEASUREMENTS

Performing a logistic regression in a multivariate analysis, hand grip strength and Short Physical Performance Battery (SPPB) were tested in relation to Mediterranean-Style Dietary Pattern Score (MSDPS).

RESULTS

The hand grip mean value was 10.9 kg (± 9.5) and the SPPB score was 6.3 (± 3.8). The MSDPS mean value in this study sample was 38.1/100 (± 8.1). A significant association (p=0.036) between a high adherence to the Mediterranean diet (fourth quartile) and higher performance lower limbs (SPPB>7) was found. No correlation was reported for the hand grip strength.

CONCLUSION

We found an association statistically significant between a high adherence to the Mediterranean diet and higher physical performance.

Cognition and Indicators of Dietary Habits in Older Adults from Southern Brazil

OBJECTIVE

To assess the association between unhealthy dietary habits and cognition in older adults from Southern Brazil.

METHODS

This cross-sectional study analyzed data from the second wave of a population- and household-based epidemiological survey (2013-2014) conducted in the city of Florianópolis. A total of 1,197 older adults (778 women) over 60 years old participated in the study. Cognition, the dependent variable, was measured by the Mini-Mental State Examination (MMSE). The independent variables were the following indicators of unhealthy dietary habits: low intake of fruits and vegetables (≤ 4 servings/day); fish (< 1 serving/week); and habitual fatty meat intake (yes/no). Adjustments were made for age, education level, income, smoking status, alcohol intake, leisure-time physical activity, depression symptoms, chronic diseases, and body mass index. Simple and multiple linear regression analyses were performed, considering sampling weights and stratification by gender.

RESULTS

The mean MMSE scores for men and women were 25.15 ± 5.56 and 24.26 ± 5.68, respectively (p = 0.009). After adjustments, in women low fruit and vegetable intake (≤ 4 servings/day) was independently associated with the lowest MMSE scores. No associations were found in men. Additionally, women's mean MMSE scores increased as their daily frequency of fruit and vegetable intake increased (p = 0.001).

CONCLUSION

Women with low fruit and vegetable intake according to the World Health Organization (WHO) have lower cognition scores. Regular intake of fruits, vegetables, and fish in exchange of fatty meats may be a viable public policy strategy to preserve cognition in aging.

Dietary Patterns High in Red Meat, Potato, Gravy, and Butter Are Associated with Poor Cognitive Functioning but Not with Rate of Cognitive Decline in Very Old Adults

BACKGROUND

Healthy dietary patterns (DPs) have been linked to better cognition and reduced risk of dementia in older adults, but their role in cognitive functioning and decline in the very old (aged ≥85 y) is unknown.

OBJECTIVE

We investigated the association between previously established DPs from the Newcastle 85+ Study and global and attention-specific cognition over 5 y.

METHODS

We followed up with 302 men and 489 women (1921 birth cohort from Northeast United Kingdom) for change in global cognition [measured by the Standardized Mini-Mental State Examination (SMMSE)] over 5 y and attention (assessed by the cognitive drug research attention battery) over 3 y. We used 2-step clustering to derive DPs and mixed models to determine the relation between DPs and cognition in the presence of the dementia susceptibility gene.

RESULTS

Previously, we characterized 3 DPs that differed in intake of red meat, potato, gravy, and butter and varied with key health measures. When compared with participants in DP1 (high red meat) and DP3 (high butter), participants in DP2 (low meat) had higher SMMSE scores at baseline (P < 0.001) and follow-ups, and better initial attention (P < 0.05). Membership in DP1 and DP3 was associated with overall worse SMMSE scores (β = 0.09, P = 0.01 and β = 0.08, P = 0.02, respectively) than membership in DP2 after adjustment for sociodemographic factors, lifestyle, multimorbidity, and body mass index (BMI). Additional adjustment for apolipoprotein (apoE) ε4 genotype attenuated the association to nonsignificant in women but not in men in DP1 (β = 0.13, P = 0.02). Participants in DP1 and DP3 also had overall worse concentration (β = 0.04, P = 0.002 and β = 0.028, P = 0.03, respectively) and focused attention (β = 0.02, P = 0.01 and β = 0.02, P = 0.03, respectively), irrespective of apoE ε4 genotype, but similar rate of decline in all cognitive measures over time.

CONCLUSION

DPs high in red meat, potato, gravy (DP1), or butter (DP3) were associated with poor cognition but not with the rate of cognitive decline in very old adults.

Dietary patterns and successful ageing: a systematic review

PURPOSE

Nutrition is a key determinant of chronic disease in later life. A systematic review was conducted of studies examining dietary patterns and quality of life, physical function, cognitive function and mental health among older adults.

METHODS

Literature searches in MEDLINE complete, Academic Search Complete, CINAHL Complete, Ageline, Global health, PsycINFO, SCOPUS and EMBASE and hand searching from 1980 up to December 2014 yielded 1236 results. Inclusion criteria included dietary pattern assessment via dietary indices or statistical approaches, a sample of community-dwelling adults aged 45 years and over at baseline and a cross-sectional or longitudinal study design. Exclusion criteria included a single 24-h recall of diet, evaluation of single foods or nutrients, clinical or institutionalised samples and intervention studies. Risk of bias was assessed using the six-item Effective Public Health Practice Project's Quality Assessment Tool for Quantitative Studies.

RESULTS

There were 34 articles (11 cross-sectional and 23 longitudinal) included with 23 studies examining dietary indices and 13 studies using empirical analysis. Most studies examined mental health (n = 10) or cognitive function (n = 18), with fewer studies examining quality of life (n = 6) and physical function (n = 8). Although dietary pattern and outcome assessment methods varied, most studies reported positive associations between a healthier diet and better health outcomes.

CONCLUSION

Overall, the number of studies using dietary patterns to investigate diet and successful ageing is small, and further investigation in longitudinal studies is needed, particularly for quality-of-life outcomes. This review provides support for the importance of a healthy diet for the ageing population globally.

Dietary Patterns Derived by Cluster Analysis are Associated with Cognitive Function among Korean Older Adults

The objective of this study was to investigate major dietary patterns among older Korean adults through cluster analysis and to determine an association between dietary patterns and cognitive function. This is a cross-sectional study. The data from the Korean Multi-Rural Communities Cohort Study was used. Participants included 765 participants aged 60 years and over. A quantitative food frequency questionnaire with 106 items was used to investigate dietary intake. The Korean version of the MMSE-KC (Mini-Mental Status Examination-Korean version) was used to assess cognitive function. Two major dietary patterns were identified using K-means cluster analysis. The "MFDF" dietary pattern indicated high consumption of Multigrain rice, Fish, Dairy products, Fruits and fruit juices, while the "WNC" dietary pattern referred to higher intakes of White rice, Noodles, and Coffee. Means of the total MMSE-KC and orientation score of the participants in the MFDF dietary pattern were higher than those of the WNC dietary pattern. Compared with the WNC dietary pattern, the MFDF dietary pattern showed a lower risk of cognitive impairment after adjusting for covariates (OR 0.64, 95% CI 0.44-0.94). The MFDF dietary pattern, with high consumption of multigrain rice, fish, dairy products, and fruits may be related to better cognition among Korean older adults.

Role of dietary protein and thiamine intakes on cognitive function in healthy older people: a systematic review

The effectiveness of nutritional interventions to prevent and maintain cognitive functioning in older adults has been gaining interest due to global population ageing. A systematic literature review was conducted to obtain and appraise relevant studies on the effects of dietary protein or thiamine on cognitive function in healthy older adults. Studies that reported on the use of nutritional supplementations and/or populations with significant cognitive impairment were excluded. Seventeen eligible studies were included. Evidence supporting an association between higher protein and/or thiamine intakes and better cognitive function is weak. There was no evidence to support the role of specific protein food sources, such as types of meat, on cognitive function. Some cross-sectional and case-control studies reported better cognition in those with higher dietary thiamine intakes, but the data remains inconclusive. Adequate protein and thiamine intake is more likely associated with achieving a good overall nutritional status which affects cognitive function rather than single nutrients. A lack of experimental studies in this area prevents the translation of these dietary messages for optimal cognitive functioning and delaying the decline in cognition with advancing age.

Dietary patterns, cognitive decline, and dementia: a systematic review

Nutrition is an important modifiable risk factor that plays a role in the strategy to prevent or delay the onset of dementia. Research on nutritional effects has until now mainly focused on the role of individual nutrients and bioactive components. However, the evidence for combined effects, such as multinutrient approaches, or a healthy dietary pattern, such as the Mediterranean diet, is growing. These approaches incorporate the complexity of the diet and possible interaction and synergy between nutrients. Over the past few years, dietary patterns have increasingly been investigated to better understand the link between diet, cognitive decline, and dementia. In this systematic review we provide an overview of the literature on human studies up to May 2014 that examined the role of dietary patterns (derived both a priori as well as a posteriori) in relation to cognitive decline or dementia. The results suggest that better adherence to a Mediterranean diet is associated with less cognitive decline, dementia, or Alzheimer disease, as shown by 4 of 6 cross-sectional studies, 6 of 12 longitudinal studies, 1 trial, and 3 meta-analyses. Other healthy dietary patterns, derived both a priori (e.g., Healthy Diet Indicator, Healthy Eating Index, and Program National Nutrition Santé guideline score) and a posteriori (e.g., factor analysis, cluster analysis, and reduced rank regression), were shown to be associated with reduced cognitive decline and/or a reduced risk of dementia as shown by all 6 cross-sectional studies and 6 of 8 longitudinal studies. More conclusive evidence is needed to reach more targeted and detailed guidelines to prevent or postpone cognitive decline.

Role of dietary pattern analysis in determining cognitive status in elderly Australian adults

Principal Component Analysis (PCA) was used to determine the association between dietary patterns and cognitive function and to examine how classification systems based on food groups and food items affect levels of association between diet and cognitive function. The present study focuses on the older segment of the Australian Diabetes, Obesity and Lifestyle Study (AusDiab) sample (age 60+) that completed the food frequency questionnaire at Wave 1 (1999/2000) and the mini-mental state examination and tests of memory, verbal ability and processing speed at Wave 3 (2012). Three methods were used in order to classify these foods before applying PCA. In the first instance, the 101 individual food items asked about in the questionnaire were used (no categorisation). In the second and third instances, foods were combined and reduced to 32 and 20 food groups, respectively, based on nutrient content and culinary usage—a method employed in several other published studies for PCA. Logistic regression analysis and generalized linear modelling was used to analyse the relationship between PCA-derived dietary patterns and cognitive outcome. Broader food group classifications resulted in a greater proportion of food use variance in the sample being explained (use of 101 individual foods explained 23.22% of total food use, while use of 32 and 20 food groups explained 29.74% and 30.74% of total variance in food use in the sample, respectively). Three dietary patterns were found to be associated with decreased odds of cognitive impairment (CI). Dietary patterns derived from 101 individual food items showed that for every one unit increase in ((Fruit and Vegetable Pattern: p = 0.030, OR 1.061, confidence interval: 1.006–1.118); (Fish, Legumes and Vegetable Pattern: p = 0.040, OR 1.032, confidence interval: 1.001–1.064); (Dairy, Cereal and Eggs Pattern: p = 0.003, OR 1.020, confidence interval: 1.007–1.033)), the odds of cognitive impairment decreased. Different results were observed when the effect of dietary patterns on memory, processing speed and vocabulary were examined. Complex patterns of associations between dietary factors and cognition were evident, with the most consistent finding being the protective effects of high vegetable and plant-based food item consumption and negative effects of ‘Western’ patterns on cognition. Further long-term studies and investigation of the best methods for dietary measurement are needed to better understand diet-disease relationships in this age group.

Cognitive impairment, genomic instability and trace elements

Cognitive impairments are often related to aging and micronutrient deficiencies. Various essential micronutrients in the diet are involved in age-altered biological functions such as, zinc, copper, iron, and selenium that play pivotal roles either in maintaining and reinforcing the antioxidant performances or in affecting the complex network of genes (nutrigenomic approach) involved in encoding proteins for biological functions. Genomic stability is one of the leading causes of cognitive decline and deficiencies or excess in trace elements are two of the factors relating to it. In this review, we report and discuss the role of micronutrients in cognitive impairment in relation to genomic stability in an aging population. Telomere integrity will also be discussed in relation to aging and cognitive impairment, as well as, the micronutrients related to these events. This review will provide an understanding on how these three aspects can relate with each other and why it is important to keep a homeostasis of micronutrients in relation to healthy aging. Micronutrient deficiencies and aging process can lead to genomic instability.

Cognitive function in a middle aged cohort is related to higher quality dietary pattern 5 and 25 years earlier: the CARDIA study

BACKGROUND

Preserving cognitive function is an important public health issue. We investigated whether dietary pattern associates with cognitive function in middle-age.

METHODS

We studied 2435 participants in the community-based Coronary Artery Risk Development in Young Adults (CARDIA) study of black and white men and women aged 18-30 in 1985-86 (year 0, Y0). We hypothesized that a higher A Priori Diet Quality Score, measured at Y0 and Y20, is associated with better cognitive function measured at Y25. The diet score incorporated 46 food groups (each in servings/day) as the sum of quintile ranks of food groups rated beneficial, 0 for food groups rated neutral, and reversed quintile ranks for food groups rated adverse; higher score indicated better diet quality. Y25 cognitive testing included verbal memory (Rey Auditory-Verbal Learning Test (RAVLT)), psychomotor speed (Digit Symbol Substitution Test (DSST)) and executive function (Stroop).

RESULTS

Per 10-unit higher diet score at Y20, the RAVLT was 0.32 words recalled higher, the DSST was 1.76 digits higher, and the Stroop was 1.00 seconds+errors lower (better performance) after adjusting for race, sex, age, clinic, and energy intake. Further adjustment for physical activity, smoking, education, and body mass index attenuated the association slightly. Diet score at Y0 and increase in diet score over 20 years were also positively associated with each cognitive test.

CONCLUSIONS

A higher quality dietary pattern was associated with better cognitive function 5 years and even 25 years later in apparently healthy middle-aged adults.

Mediterranean diet and cognitive decline over time in an elderly Mediterranean population

PURPOSE

Evidence suggests that dietary patterns compatible with the traditional Mediterranean diet (MD) may protect against cognitive decline. We prospectively assessed whether adherence to MD in the Mediterranean country of Greece is inversely associated with cognitive decline in the elderly and whether any particular MD component may play a key role.

METHODS

Elderly men and women (N = 401) residing in the greater Athens area had dietary variables ascertained in 1994-1999. Adherence to MD was represented by the MD score [MDS, 0-3 (low), 4-5 (intermediate), 6-9 (high)]. The mini-mental state examination (MMSE) was administered by trained professionals to individuals aged 65 years or older in 2004-2006 (first assessment) and re-administered in 2011-2012 (second assessment). MMSE change (cMMSE) was categorized as: improved/unchanged (cMMSE ≥ 0), mildly lower (cMMSE -1 to -4) or substantially lower (cMMSE ≤ -5). Associations were evaluated through multinomial logistic regression.

RESULTS

Decline in MMSE performance was inversely associated with adherence to MD. For mild versus no decline, odds ratio (OR) comparing high to low MD adherence was 0.46 [95% confidence interval (CI) 0.25-0.87, p = 0.012]. For substantial versus no decline, OR comparing high to low MD adherence was 0.34 (95% CI 0.13-0.89, p = 0.025). Among the nine MDS components, only vegetable consumption exhibited a significant inverse association with cognitive decline.

CONCLUSIONS

Closer adherence to the traditional MD is highly likely to protect against cognitive decline in this elderly Mediterranean population. Higher vegetable consumption appears to play a key role, possibly in synergy with additional components of the diet.

Current evidence on dietary pattern and cognitive function

With global aging population, age-related cognitive decline becomes epidemic. Lifestyle-related factor is one of the key preventative measures. Dietary pattern analysis which considers dietary complexity has recently used to examine the linkage between nutrition and cognitive function. A priori approach defines dietary pattern based on existing knowledge. Results of several dietary pattern scores were summarized. The heterogeneity of assessment methods and outcome measurements lead to inconsistent results. Posteriori approach derives a dietary pattern independently of the existing nutrition-disease knowledge. It showed a dietary pattern abundant with plant-based food, oily fish, lower consumption of processed food, saturated fat, and simple sugar which appears to be beneficial to cognitive health. Despite inconclusive evidence from both approaches, diet and exercise, beneficial for other diseases, remains to be the two key modifiable factors for cognitive function. Large-scale prospective studies in multiethics population are required to provide stronger evidence in the future.