Effect of dietary patterns on cognitive functions of older adults: A systematic review and meta-analysis of randomized controlled trials: Dietary Patterns on Cognition of Older Adults

Dietary patterns and transition from normal cognition to mild cognitive impairment and its reversion: A longitudinal study of older adults

BACKGROUND

The reversion from mild cognitive impairment (MCI) to normal cognition (NC) has received less attention than the progression to dementia. We aimed to estimate the MCI-to-NC reversion rate and examine dietary patterns associated with the cognitive transition among older adults.

METHODS

Longitudinal data from 11,211 adults aged 65 years and older were analyzed. Four dietary patterns including plant-based diet index (PDI), simplified healthy eating index (SHEI), dietary diversity score (DDS), and the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) were assessed with the food frequency questionnaire. Cognitive function was quantified with the Mini-Mental State Examination. The multi-state Markov models were applied to estimate associations between each dietary pattern and transition of cognitive status with four states: NC, MCI, dementia, and death.

RESULTS

Participants (mean [SD] age, 85.80 [11.13] years; 6211 women [55.40 %] and 5000 men [44.60 %]) were followed over a mean time of 4.76 (SD = 3.14) years. The rate of reversion from MCI to NC was 9.4 %. Hazard ratios (HRs, 95 % confidence interval [CI]) for the progression from NC to MCI were 0.87 (0.77-0.97), 0.81 (0.73-0.91), 0.95 (0.92-0.99), and 0.95 (0.92-0.99) for dietary patterns of healthful PDI (hPDI), SHEI, DDS, and MIND, respectively. Besides, a better adherence to hPDI (HR = 1.21, 95 % CI = 1.03 to 1.43) and SHEI (HR = 1.20, 95 % CI = 1.02 to 1.41) was associated with increased likelihoods to revert from MCI to NC.

CONCLUSIONS

Dietary patterns of hPDI, SHEI, DDS, and MIND were linked to decreased risks of NC-to-MCI progression, and hPDI and SHEI were associated with higher likelihoods of MCI-to-NC reversion in older adults. Interventional studies with dietary patterns were warranted to confirm our findings.

Predicting Cognitive Outcome Through Nutrition and Health Markers Using Supervised Machine Learning

BACKGROUND

Machine learning (ML) use in health research is growing, yet its application to predict cognitive outcomes using diverse health indicators is under-investigated.

OBJECTIVE

We utilized ML models to predict cognitive performance based on a set of health and behavioral factors, aiming to identify key contributors to cognitive function for insights into potential personalized interventions.

METHODS

Data from 374 adults aged 19-82 years (227 females) were used to develop ML models predicting cognitive performance (reaction time in milliseconds [ms]) on a modified Eriksen flanker task. Features included demographics, anthropometric measures, dietary indices (healthy eating index [HEI], Dietary Approaches to Stop Hypertension [DASH], Mediterranean, and Mediterranean-DASH Intervention for Neurodegenerative Delay [MIND]), self-reported physical activity, systolic (SBP) and diastolic blood pressure (DBP). The dataset was split (80:20) for training and testing. Predictive models (Decision Trees, Random Forest, AdaBoost, XGBoost, Gradient Boosting, Linear, Ridge, and Lasso Regression) were used with hyperparameter tuning and cross-validation. Feature importance was calculated using Permutation Importance, while Performance using Mean Absolute Error (MAE) and Mean Squared Error (MSE).

RESULTS

Random Forest Regressor exhibited the best performance, with the lowest MAE (ms) (training: 0.66, testing: 0.78) and MSE (ms2) (training: 0.70, testing:1.05). Age was the most significant feature (score: 0.208), followed by DBP (0.169), BMI (0.079), SBP (0.069), and HEI (0.048). Ethnicity (0.005) and sex (0.003) had minimal predictive effect.

CONCLUSION

Age, blood pressure, and BMI showed strong associations with cognitive performance, while diet quality had a subtler effect. These findings highlight the potential of ML models for developing personalized interventions and preventive strategies for cognitive decline.

Factors associated with a healthy diet and willingness to change dietary behavior in older adults at increased risk of dementia

BackgroundHealthy dietary patterns have been linked to reduced risks for cardiovascular diseases and dementia, making nutrition an essential part of a comprehensive approach for dementia prevention. Knowledge about factors associated with a healthy diet in people with increased dementia risk is scarce.ObjectiveTo analyze dietary habits and associated factors in older adults with increased dementia risk in Germany.MethodsWe used baseline-data of the AgeWell.de-trial (n = 1001, %female = 52.2, Mage = 69.0, SD = 4.9). Nutrition was assessed using a composite score, comprising 11 components covered by national recommendations for a healthy diet (range = 0-11 points). Linear regressions assessed associations of sociodemographic, social, health-related and psychological factors with consumption of a healthy diet. Further, we assessed stages of change based on the transtheoretical model of behavior change.ResultsConsumption of a healthy diet was moderate (Median = 4, IQR = 2). Female sex (b = 0.64, 95% CI: 0.41, 0.88), higher levels of motivation for healthy eating (b = 0.22, 95% CI: 0.10, 0.34) and higher self-efficacy (b = 0.33, 95% CI: 0.20, 0.46) were linked to a healthy diet. Regarding the stages of behavior change, the majority were in the maintenance stage (45.2%), followed by the contemplation (21.5%) and precontemplation (21.2%) stages.ConclusionsResults suggest room for improvement regarding a healthy diet in our sample. Lifestyle-based interventions in older adults should be tailored towards current levels of motivation and self-efficacy of participants. Including modules targeting motivation and self-efficacy might help maximize intervention effectiveness.

The risk associated with ultra-processed food intake on depressive symptoms and mental health in older adults: a target trial emulation

BACKGROUND

Longitudinal cohort studies across the lifespan suggest an association between ultra-processed food (UPF) and depression. However, the effect of UPF on depression and mental health in older adults has not been determined. Therefore, this study investigated the effect of UPF on depressive symptoms and mental health in community-dwelling older adults.

METHODS

A pragmatic target trial was designed and emulated using the ASPirin in Reducing Events in the Elderly longitudinal data. Participants were community-dwelling older adults (≥ 70 years) in Australia. We specified and emulated the protocol of a two-arm randomised pragmatic clinical trial using the level of UPF consumption as the intervention. Greater than or equal to 4 servings of UPF per day was considered the intervention, with less than 4 servings per day the control. Dietary consumption was assessed using a mail-based diet screening questionnaire, and the level of food processing was classified based on the NOVA classification. The study outcomes were depressive symptoms, defined as a score of ≥ 8 on the Center for Epidemiological Studies Depression 10-item scale, and general mental health, defined by the mental component summary score of the Short Form-12. We applied inverse probability treatment weighting to balance confounders. Marginal structural models were employed to estimate the population-level average effect of intervention using generalised estimated equations.

RESULTS

A total of 11,192 participants (3415 intervention and 7777 control) were eligible for the emulation. High UPF consumption at time zero was associated with an increased risk of depressive symptoms at follow-ups (RR: 1.10; CI: 1.04-1.18). The finding was consistent with sensitivity analyses; after excluding participants on antidepressants at time zero, the risk of depressive symptoms in the intervention group was increased by 11% compared to the control (RR: 1.11; 95% CI: (1.04-1.20)). Consumption of UPF adversely affected the mental component quality of life (β: - 0.40; CI: - 0.65 to - 0.15).

CONCLUSIONS

A higher level of UPF consumption was associated with a higher risk of depressive symptoms and adversely affected mental health among older adults.

Dietary Patterns and Geriatric Syndromes in Adults: Analysis of the 2018-19 National Health and Nutrition Survey

BACKGROUND

The study of dietary patterns in older adults (OA) and their association with geriatric syndromes (GS) is scarce in Latin America.

OBJECTIVE

To describe the association of dietary patterns with GS in the Mexican older adult population, using data from the 2018-19 National Health and Nutrition Survey.

METHODS

Dietary data were collected from 3,511 adults (≥60 years of age, both sexes) using a semi-quantitative food frequency questionnaire. Dietary patterns were derived by principal component analysis based on the consumption of 162 foods from 24 food groups. The GS studied were: frailty, depressive symptoms (DS), low appendicular skeletal muscle mass (ASMM); additionally, we studied inflammation (serum CRP>5 mg/L). Logistic regression models were used.

RESULTS

Four major dietary patterns were identified: a) "Western", b) "Prudent", c) "Soups", and d) "Traditional". The middle and higher tertiles of the "Prudent" pattern were associated with lower odds of DS (OR 0.71, p = 0.04; and OR 0.61, p = 0.008), respectively. The second tertile of the "Soups" pattern was associated with lower odds of low ASMM (OR 0.68, p = 0031) and inflammation (OR 0.58, p = 0.022). The highest tertile of the "Traditional" pattern was associated with low ASMM (OR 1.55, p = 0.008) and lower odds of inflammation (OR 0.69, p = 0.044). No association was found between the "Western" dietary pattern and GS.

CONCLUSIONS

Three of four major dietary patterns were associated with GS in older Mexican adults. Further studies are needed to address strategies to improve diet quality in this age group and its association with health and functional outcomes.

The Effect of Whole-Diet Interventions on Memory and Cognitive Function in Healthy Older Adults - A Systematic Review

An increasing number of cross-sectional studies suggests that diet may impact memory and cognition in healthy older adults. However, randomized controlled trials investigating the effects of whole-diet interventions on memory and cognition in healthy older adults are rather rare, and conflicting results are often reported. Therefore, a systematic review was conducted to compile the current evidence regarding the potential effects of whole-diet interventions on 1) memory and 2) other cognitive outcomes in older adults. Studies that reported on randomized controlled trials with dietary interventions in healthy older adults (≥60 y) were included. Studies utilizing supplements, single food items, or trials in specific patient groups (i.e., neurodegenerative diagnoses) were excluded. For the 23 included articles, the main outcomes examined fell into 1 or more of the following categories: cognitive task-based outcomes related to memory, other cognitive task-based outcomes, and additional outcomes related to cognitive function or disease risk. Three of the studies that investigated dietary interventions alone and 2 multidomain studies showed positive effects on memory function, whereas 5 multidomain interventions and 1 intervention that focused on diet alone showed positive effects on other cognitive outcomes. The effect of randomized, controlled whole-diet interventions on memory and cognitive function in healthy older adults is modest and inconclusive, highlighting the need for more well-designed, sufficiently powered studies. Furthermore, the potential mechanisms by which diet impacts cognition in healthy aging need to be elucidated. This systematic review is registered in PROSPERO as CRD42022329759.

Association between the Intake/Type of Cheese and Cognitive Function in Community-Dwelling Older Women in Japan: A Cross-Sectional Cohort Study

While many studies have described the association between cognitive decline and eating habits, little attention has been paid to its association with cheese intake. In this epidemiological study of 1035 community-dwelling women aged ≥ 65, we investigated the association between intake/type of cheese and cognitive function. The anthropometry, functional ability, and the frequency of food intake, including cheese, were assessed. The mini-mental state examination (MMSE) was used to assess cognitive function, and a score of 20-26 was operationally defined as mild cognitive decline. We found that the MMSE score was significantly different between the presence of cheese intake and not (cheese intake: 28.4 ± 1.9; non-cheese intake: 27.6 ± 2.4) and between those who consumed Camembert cheese and those who did not (Camembert cheese: 28.7 ± 1.4; others: 28.3 ± 2.0). After adjusting for confounders, multiple logistic regression identified four independent variables significantly associated with mild cognitive decline: Camembert cheese intake (odds ratio = 0.448, 95% confidence interval = 0.214-0.936), age, usual walking speed, and repetitive saliva swallowing test scores. Our results, while based on cross-sectional data from Japanese community-dwelling older women, identified the significant inverse association between Camembert cheese intake and mild cognitive decline.

Dietary (Poly)phenols and Cognitive Decline: A Systematic Review and Meta-Analysis of Observational Studies

SCOPE

This study aims to systematically review observational studies investigating the relation between dietary (poly)phenol consumption and various cognitive outcomes.

METHODS AND RESULTS

Embase and PubMed databases are searched from inception to April 2023 for observational studies investigating the relation between dietary (poly)phenol intake and cognitive outcomes. For quantitative analyses, random effects models, subgroup analyses, and dose-response analyses are performed. A total of 37 studies are included in the systematic review. Among (poly)phenols, a higher intake of flavonoids is associated with better cognitive function and lower odds of cognitive decline (although with some exceptions). A quantitative meta-analysis shows an overall inverse association with cognitive impairment and reduced association with the incidence of dementia or related disorders for total flavonoids (relative risk (RR) = 0.83, 95% confidence interval (CI): 0.76, 0.89), anthocyanins (RR = 0.73, 95% CI: 0.60, 0.89), flavones (RR = 0.77, 95% CI: 0.63, 0.94), flavan-3-ols (RR = 0.86, 95% CI: 0.82, 0.91), and flavonols (RR = 0.88, 95% CI: 0.80, 0.96). Data on other (poly)phenolic compounds (i.e., phenolic acids) are promising but too preliminary.

CONCLUSION

Habitual inclusion of flavonoids in the diet may play a preventive role against cognitive disorders.

Composition of healthy diets for older persons

PURPOSE OF REVIEW

This study aims to review recent evidence (2022-2023) on the role of diet in promoting healthy aging in older adults.

RECENT FINDINGS

Current evidence of diet and healthy aging is limited to epidemiological studies. A healthy diet is beneficial for individual domains of intrinsic capacity, that is, cognition, locomotion, vitality, psychological, and/or sensory functions, with sex-specific differences reported. Only a few studies used the multidimensional concept of intrinsic capacity as an outcome. This review supports that a healthy diet for older adults consists of plenty of plant-based foods, adequate protein-rich foods, and healthy fats. Next to quantity, improving the quality and variety within food groups play a role in optimizing health. Data on the associations between adherence to national food-based dietary guidelines and intrinsic capacity are scarce.

SUMMARY

A healthy diet, centered on plant-based foods, adequate protein-rich foods and healthy fats, potentially promotes healthy aging. Future studies may evaluate the association between adherence to healthy dietary patterns (particularly national food-based dietary guidelines) and the multidimensional concept of intrinsic capacity, with consideration of sex-specific differences. Clinical trials are warranted to inform the causal effects of diet and outcomes related to intrinsic capacity.