The preventive efficacy of vitamin B supplements on the cognitive decline of elderly adults: a systematic review and meta-analysis

Effects of folic acid supplementation on cognitive function and inflammation in elderly patients with mild cognitive impairment: A systematic review and meta-analysis of randomized controlled trials

OBJECT

The aim was to assess the effect of folic acid supplementation on cognitive function and inflammatory cytokines in elderly patients with mild cognitive impairment.

METHODS

From its inception until February 2024, four databases including Web of Science were searched. Two researchers independently screened the literature, assessed the quality, extracted data, and conducted a meta-analysis using RevMan.

RESULTS

The systematic review included seven studies (with a total of 1102 participants, mean age 65-80 years), seven of which were appropriate for meta-analysis. Although a small number of studies found relatively large heterogeneity, the majority of studies showed significant benefit from folic acid supplementation, including the FSIQ (823 individuals, standardized mean difference [SMD] = 8.36, 95 % confidence interval [CI] = 0.79 - 1.08), Arithmetic (823 individuals, SMD = 0.17, 95 % CI = -0.03-0.31), Information, SMD = 1.73, 95 % CI 0.41-3.05), Digit Span (823 individuals, SMD = 0.17, 95 % CI = -0.03 - 0.31), Block Design (823 individuals, SMD = 0.26, 95 % CI 0.03-0.49), Picture Completion (823 individuals, SMD = 0.27, 95 % CI = -0.15 - 0.69) and Picture Arrangement (823 individuals, SMD = -0.12, 95 % CI = -0.26 - 0.01). Finally, folic acid supplementation had a significant effect on the reduction of most inflammatory cytokines, blood biomarkers of Alzheimer's disease, and Hcy.

CONCLUSIONS

Folic acid supplementation seems to have a positive impact on cognitive function in older adults with mild cognitive impairment, but further evidence of its effectiveness in improving inflammatory cytokines is needed from high-quality studies.

Effects of vitamins and polyunsaturated fatty acids on cognitive function in older adults with mild cognitive impairment: a meta-analysis of randomized controlled trials

PURPOSE

Vitamins and polyunsaturated fatty acids (PUFAs) have been studied extensively as safe and manageable nutrient interventions for mild cognitive impairment (MCI). The purpose of the current meta-analysis was to examine the effects of vitamins and PUFAs on cognition and to compare the effects of single and multiple nutrient subgroups in patients with MCI.

METHODS

Randomized controlled trials (RCTs) written in English and Chinese were retrieved from eight databases, namely, PubMed, CENTRAL, Embase, CINAHL, Web of Science, SinoMed, CNKI, and Wanfang Data, from their respective dates of inception until 16 July 2023. The quality of the included studies was assessed using the Cochrane Risk of Bias Tool 2.0. Meta-analyses were performed to determine the standardized mean differences (SMDs) in global cognitive function, memory function, attention, visuospatial skills, executive function, and processing speed between the supplement and control groups using 95% confidence intervals (CI) and I2. Prospero registration number: CRD42021292360.

RESULTS

Sixteen RCTs that studied different types of vitamins and PUFAs were included. The meta-analysis revealed that vitamins affected global cognitive function (SMD = 0.58, 95% CI = [0.20, 0.96], P = 0.003), memory function (SMD = 2.55, 95% CI = [1.01, 4.09], P = 0.001), and attention (SMD = 3.14, 95% CI = [1.00, 5.28], P = 0.004) in patients with MCI, and PUFAs showed effects on memory function (SMD = 0.65, 95% CI = [0.32, 0.99], P < 0.001) and attention (SMD = 2.98, 95% CI = [2.11, 3.84], P < 0.001). Single vitamin B (folic acid [FA]: SMD = 1.21, 95% CI = [0.87, 1.55]) supplementation may be more effective than multiple nutrients (FA and vitamin B12: SMD = 0.71, 95% CI = [0.41, 1.01]; and FA combined with docosahexaenoic acid [DHA]: SMD = 0.58, 95% CI = [0.34, 0.83]) in global cognitive function.

CONCLUSIONS

FA, vitamin B6, vitamin B12, and vitamin D may improve global cognitive function, memory function, and attention in patients with MCI. Eicosapentaenoic acid (EPA) and DHA may improve memory function and attention. We also noted that FA may exert a greater effect than a vitamin B combination (FA and vitamin B12) or the combination of FA and DHA. However, because of the low evidence-based intensity, further trials are necessary to confirm these findings.

Prevention, Assessment, and Management of Malnutrition in Older Adults with Early Stages of Cognitive Disorders

Malnutrition is common in older adults, and its risk is greater in those living with dementia. Relative to cognitively healthy peers, the prevalence of malnutrition is also increased in individuals with early stages of cognitive disorders owing to pathophysiological, cognitive, and psychosocial changes related to cognitive impairment. Malnutrition is associated with adverse health outcomes, including faster cognitive and functional decline. Here, we provide an overview of the prevention, assessment, and management of malnutrition in older adults, with a special focus on the aspects that are important to consider in individuals with early stages of cognitive disorders. Strategies to prevent malnutrition include systematic screening for malnourishment using validated tools to detect those at risk. If the screening reveals an increased risk of malnutrition, a detailed assessment including the individual's nutritional, medical, and functional status as well as dietary intake should be performed. The management of malnutrition in the early stages of cognitive disorders should be based on the findings of a comprehensive assessment and be personalized according to the individual's specific characteristics. In the article, we also provide an overview of the evidence on vitamin supplements and specific dietary patterns to prevent cognitive decline or attenuate its progression.

The role of nutrition in the prevention of cognitive decline

PURPOSE OF REVIEW

Dementia is a growing concern and underscores the urgent need for effective preventive measures targeting modifiable risk factors. Nutrition is a key player in the onset and progression of inflammation and cognitive decline. This review provides a comprehensive overview of the effects of different dietary patterns, vitamins and nutrients for preventing cognitive decline, mainly among healthy individuals and those with mild cognitive impairment.

RECENT FINDINGS

The Mediterranean diet, omega-3 long-chain polyunsaturated fatty acids and B vitamins are the most investigated, with evidence supporting protection against cognitive decline among older adults varying across studies. More recent interventions examined in this review, such as MIND Diet, are promising with positive results, but further research is needed to conclusively establish their efficacy. It is also crucial to consider complete lifestyle as physical activity for preventing cognitive decline.

SUMMARY

Definitive conclusions are difficult to draw. Future studies should adopt a comprehensive approach and focus on multinutrient strategies and whole diets.

Dietary pattern, food, and nutritional supplement effects on cognitive outcomes in mild cognitive impairment: a systematic review of previous reviews

CONTEXT

Nutritional interventions may benefit cognition in people with mild cognitive impairment (MCI). However, evidence is yet to be synthesized in a way that can inform recommendations for clinical and public health settings.

OBJECTIVE

To systematically review evidence on the effect of dietary patterns, foods, and nutritional supplements on cognitive decline in individuals with MCI.

DATA SOURCES

Guided by the Preferred Reporting items for Systematic Review and Meta-Analysis Protocols 2015 statement, the Medline, EMBASE, and CINAHL databases, the JBI Database of Systematic Reviews and Implementation Reports, Cochrane Database of Systematic Reviews, and Database of Abstracts of Reviews of Effects were searched (publication years 2005 to 2020). Included studies were English-language systematic reviews and meta-analyses of randomized controlled trials and cohort studies reporting on the effectiveness of nutritional interventions on cognition of individuals with MCI.

DATA EXTRACTION

Two reviewers independently selected studies and extracted data on cognitive outcomes and adverse events. Review quality was assessed using AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews-2). Primary study overlap was managed following Cochrane Handbook guidelines.

DATA ANALYSIS

Of the 6677 records retrieved, 20 reviews were included, which, in turn, reported on 43 randomized controlled trials and 1 cohort study that, together, addressed 18 nutritional interventions. Most reviews were limited by quality and the small number of primary studies with small sample sizes. Reviews were mostly positive for B vitamins, omega-3 fatty acids, and probiotics (including 12, 11 and 4 primary studies, respectively). Souvenaid and the Mediterranean diet reduced cognitive decline or Alzheimer's disease progression in single trials with <500 participants. Findings from studies with a small number of participants suggest vitamin D, a low-carbohydrate diet, medium-chain triglycerides, blueberries, grape juice, cocoa flavanols, and Brazil nuts may improve individual cognitive subdomains, but more studies are needed.

CONCLUSIONS

Few nutritional interventions were found to convincingly improve cognition of individuals with MCI. More high-quality research in MCI populations is required to determine if nutritional treatments improve cognition and/or reduce progression to dementia.

SYSTEMATIC REVIEW REGISTRATION

Open Science Framework protocol identifier DOI:10.17605/OSF.IO/BEP2S.

Maintaining brain health across the lifespan

Across the lifespan, the human body and brain endure the impact of a plethora of exogenous and endogenous factors that determine the health outcome in old age. The overwhelming inter-individual variance spans between progressive frailty with loss of autonomy to largely preserved physical, cognitive, and social functions. Understanding the mechanisms underlying the diverse aging trajectories can inform future strategies to maintain a healthy body and brain. Here we provide a comprehensive overview of the current literature on lifetime factors governing brain health. We present the growing body of evidence that unhealthy alimentary regime, sedentary behaviour, sleep pathologies, cardio-vascular risk factors, and chronic inflammation exert their harmful effects in a cumulative and gradual manner, and that timely and efficient intervention could promote healthy and successful aging. We discuss the main effects and interactions between these risk factors and the resulting brain health outcomes to follow with a description of current strategies aiming to eliminate, treat, or counteract the risk factors. We conclude that the detailed insights about modifiable risk factors could inform personalized multi-domain strategies for brain health maintenance on the background of increased longevity.

Roles of Oxidative Stress in Synaptic Dysfunction and Neuronal Cell Death in Alzheimer's Disease

Alzheimer's disease (AD) is a brain disorder that progressively undermines memory and thinking skills by affecting the hippocampus and entorhinal cortex. The main histopathological hallmarks of AD are the presence of abnormal protein aggregates (Aβ and tau), synaptic dysfunction, aberrant proteostasis, cytoskeletal abnormalities, altered energy homeostasis, DNA and RNA defects, inflammation, and neuronal cell death. However, oxidative stress or oxidative damage is also evident and commonly overlooked or considered a consequence of the advancement of dementia symptoms. The control or onset of oxidative stress is linked to the activity of the amyloid-β peptide, which may serve as both antioxidant and pro-oxidant molecules. Furthermore, oxidative stress is correlated with oxidative damage to proteins, nucleic acids, and lipids in vulnerable cell populations, which ultimately lead to neuronal death through different molecular mechanisms. By recognizing oxidative stress as an integral feature of AD, alternative therapeutic or preventive interventions are developed and tested as potential or complementary therapies for this devastating neurodegenerative disease.

Biomimetic Remodeling of Microglial Riboflavin Metabolism Ameliorates Cognitive Impairment by Modulating Neuroinflammation

Neuroinflammation, for which microglia are the predominant contributors, is a significant risk factor for cognitive dysfunction. Riboflavin (also known as vitamin B2) ameliorates cognitive impairment via anti-oxidative stress and anti-inflammation properties; however, the underlying mechanisms linking riboflavin metabolism and microglial function in cognitive impairment remain unclear. Here, it is demonstrated that riboflavin kinase (RFK), a critical enzyme in riboflavin metabolism, is specifically expressed in microglia. An intermediate product of riboflavin, flavin mononucleotide (FMN), inhibited RFK expression via regulation of lysine-specific methyltransferase 2B (KMT2B). FMN supplementation attenuated the pro-inflammatory TNFR1/NF-κB signaling pathway, and this effect is abolished by KMT2B overexpression. To improve the limited anti-inflammatory efficiency of free FMN, a biomimetic microglial nanoparticle strategy (designated as MNPs@FMN) is established, which penetrated the blood brain barrier with enhanced microglial-targeted delivery efficiency. Notably, MNPs@FMN ameliorated cognitive impairment and dysfunctional synaptic plasticity in a lipopolysaccharide-induced inflammatory mouse model and in a 5xFAD mouse model of Alzheimer's disease. Taken together, biomimetic microglial delivery of FMN may serve as a potential therapeutic approach for inflammation-dependent cognitive decline.

The role of diet in managing menopausal symptoms: A narrative review

Menopause is a natural stage that occurs when women stop menstruating, during which many women experience physical and psychological symptoms that can affect their quality of life and ability to work. Dietary modifications and food supplements may be explored by some women as alternatives to hormone replacement therapy, although existing reviews and expert position statements have given this limited consideration. This narrative review summarises the current evidence for dietary patterns, and botanical and food supplements, in the management of common menopausal symptoms, including vasomotor symptoms (VMS; hot flushes; night sweats), changes in bodyweight and composition, psychological symptoms (depression; anxiety; cognitive changes), sleep disturbances, joint pain, skin changes and urogenital symptoms. Soy isoflavones may reduce the frequency and/or severity of VMS, although results are inconsistent, and it is unclear whether dietary and supplemental sources have comparable effects. Adopting a healthier dietary pattern may support a healthy bodyweight and benefit VMS. However, evidence suggesting dietary patterns may benefit depression, anxiety, and cognition remains largely observational. While some botanicals, such as black cohosh and St John's Wort, have been reported in some studies to alleviate symptoms (such as VMS and depression), these are not currently recommended due to uncertainty about the appropriate dose and preparation, and potential safety concerns. Evidence for other symptoms is currently too limited to draw conclusions. While further trials at different menopausal stages are needed, adopting a healthier dietary pattern in accordance with dietary guidelines is likely to help support women's health before, during and after the menopausal transition.

Nutritional and lifestyle management of the aging journey: A narrative review

With age, the physiological responses to occasional or regular stressors from a broad range of functions tend to change and adjust at a different pace and restoring these functions in the normal healthy range becomes increasingly challenging. Even if this natural decline is somehow unavoidable, opportunities exist to slow down and attenuate the impact of advancing age on major physiological processes which, when weakened, constitute the hallmarks of aging. This narrative review revisits the current knowledge related to the aging process and its impact on key metabolic functions including immune, digestive, nervous, musculoskeletal, and cardiovascular functions; and revisits insights into the important biological targets that could inspire effective strategies to promote healthy aging.

Non-Enzymatic Antioxidants against Alzheimer's Disease: Prevention, Diagnosis and Therapy

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive memory loss and cognitive decline. Although substantial research has been conducted to elucidate the complex pathophysiology of AD, the therapeutic approach still has limited efficacy in clinical practice. Oxidative stress (OS) has been established as an early driver of several age-related diseases, including neurodegeneration. In AD, increased levels of reactive oxygen species mediate neuronal lipid, protein, and nucleic acid peroxidation, mitochondrial dysfunction, synaptic damage, and inflammation. Thus, the identification of novel antioxidant molecules capable of detecting, preventing, and counteracting AD onset and progression is of the utmost importance. However, although several studies have been published, comprehensive and up-to-date overviews of the principal anti-AD agents harboring antioxidant properties remain scarce. In this narrative review, we summarize the role of vitamins, minerals, flavonoids, non-flavonoids, mitochondria-targeting molecules, organosulfur compounds, and carotenoids as non-enzymatic antioxidants with AD diagnostic, preventative, and therapeutic potential, thereby offering insights into the relationship between OS and neurodegeneration.

Complementary and Alternative Medicine Approaches in Alzheimer Disease and Other Neurocognitive Disorders

As our population ages, there is interest in delaying or intervening in cognitive decline. While newer agents are under development, agents in mainstream use do not impact the course of diseases that cause cognitive decline. This increases interest in alternative strategies. Even as we welcome possible new disease-modifying agents, they are likely to remain costly. Herein, we review the evidence behind other complementary and alternative strategies for cognitive enhancement and prevention of cognitive decline.

Neurovascular Correlates of Cobalamin, Folate, and Homocysteine in Dementia

BACKGROUND

Cobalamin (Cbl) and folate are common supplements clinicians prescribe as an adjuvant therapy for dementia patients, on the presumption of their neurotrophic and/or homocysteine (Hcy) lowering effect. However, the treatment efficacy has been found mixed and the effects of Cbl/folate/Hcy on the human brain remain to be elucidated.

OBJECTIVE

To explore the neurovascular correlates of Cbl/folate/Hcy in Alzheimer's disease (AD) and subcortical ischemic vascular dementia (SIVD).

METHODS

Sixty-seven AD patients and 57 SIVD patients were prospectively and consecutively recruited from an outpatient clinic. Multimodal 3-Tesla magnetic resonance imaging was performed to quantitatively evaluate cerebral blood flow (CBF) and white matter integrity. The relationship between neuroimaging metrics and the serum levels of Cbl/folate/Hcy was examined by using the Kruskal-Wallis test, partial correlation analysis, and moderation analysis, at a significance level of 0.05.

RESULTS

As a whole, CBF mainly associated with Cbl/folate while white matter hyperintensities exclusively associated with Hcy. As compared with AD, SIVD exhibited more noticeable CBF correlates (spatially widespread with Cbl and focal with folate). In SIVD, a bilateral Cbl-moderated CBF coupling was found between medial prefrontal cortex and ipsilateral basal ganglia, while in the fronto-subcortical white matter tracts, elevated Hcy was associated with imaging metrics indicative of increased injury in both axon and myelin sheath.

CONCLUSIONS

We identified the neurovascular correlates of previously reported neurotrophic effect of Cbl/folate and neurotoxic effect of Hcy in dementia. The correlates exhibited distinct patterns in AD and SIVD. The findings may help improving the formulation of supplemental Cbl/folate treatment for dementia.

Interdisciplinary Approaches to Deal with Alzheimer's Disease-From Bench to Bedside: What Feasible Options Do Already Exist Today?

Alzheimer's disease is one of the most common neurodegenerative diseases in the western population. The incidence of this disease increases with age. Rising life expectancy and the resulting increase in the ratio of elderly in the population are likely to exacerbate socioeconomic problems. Alzheimer's disease is a multifactorial disease. In addition to amyloidogenic processing leading to plaques, and tau pathology, but also other molecular causes such as oxidative stress or inflammation play a crucial role. We summarize the molecular mechanisms leading to Alzheimer's disease and which potential interventions are known to interfere with these mechanisms, focusing on nutritional approaches and physical activity but also the beneficial effects of cognition-oriented treatments with a focus on language and communication. Interestingly, recent findings also suggest a causal link between oral conditions, such as periodontitis or edentulism, and Alzheimer's disease, raising the question of whether dental intervention in Alzheimer's patients can be beneficial as well. Unfortunately, all previous single-domain interventions have been shown to have limited benefit to patients. However, the latest studies indicate that combining these efforts into multidomain approaches may have increased preventive or therapeutic potential. Therefore, as another emphasis in this review, we provide an overview of current literature dealing with studies combining the above-mentioned approaches and discuss potential advantages compared to monotherapies. Considering current literature and intervention options, we also propose a multidomain interdisciplinary approach for the treatment of Alzheimer's disease patients that synergistically links the individual approaches. In conclusion, this review highlights the need to combine different approaches in an interdisciplinary manner, to address the future challenges of Alzheimer's disease.

Nutrients and amyloid β status in the brain: A narrative review

Amyloid beta (Aβ) is a peptide and a hallmark of Alzheimer's disease (AD). Emerging evidence suggests that Aβ levels could be influenced by diet. However, the evidence is sparse and for some nutrients, controversial. The aim of this narrative review is to gather the findings of observational and clinical trials involving human participants on the relationships between nutrients and brain Aβ status. Some dietary patterns are associated to reduced levels of Aβ in the brain, such as the Mediterranean diet, ketogenic diet as well as low intake of saturated fat, high-glycemic-index food, sodium, and junk/fast food. Low Aβ status in the brain was also associated with higher density lipoproteins (HDL) cholesterol and polyunsaturated fatty acids consumption. Data on alcohol intake is not conclusive. On the contrary, high Aβ levels in the brain were related to a higher intake of total cholesterol, triglycerides, low-density lipoproteins (LDL) cholesterol, saturated fat, sucrose, and fructose. Folic acid, cobalamin, vitamin E, and vitamin D were not associated to Aβ status, while high blood concentrations of Calcium, Aluminum, Zinc, Copper, and Manganese were associated with decreased Aβ blood levels but were not associated with Aβ cerebral spinal fluid (CSF) concentrations. In conclusion, certain dietary patterns and nutrients are associated to brain Aβ status. Further research on the association between nutrients and brain Aβ status is needed in order to pave the way to use nutritional interventions as efficacious strategies to prevent Aβ disturbance and potentially AD.

The association between altitude and serum folate levels in Tibetan adults on the Tibetan plateau

This study investigated the relationship between residence altitude and serum folate levels in healthy Tibetans living on the Tibetan Plateau. Participants were selected from those who underwent physical examinations at our health center between November 2019 and February 2020. Demographic characteristics and medical histories were collected, and fasting blood was tested for serum folate and other hematological indicators. The relationship between altitude and serum folate levels was analyzed using a multivariable linear regression model. Serum folate levels were associated with altitude (β = - 0.44; 95% confidence interval [CI] - 0.71; - 0.16), hemoglobin (β = - 0.01; 95% CI - 0.03; - 0.00), red blood cells (β = - 0.72; 95% CI - 1.18; - 0.27), hematocrit (β = - 0.07; 95% CI - 0.12; - 0.02), high-density lipoprotein cholesterol (β = 2.67; 95% CI 1.35; 3.98), and sex (β = 0.68; 95% CI 0.12; 1.23). Multivariate linear regression analysis revealed that altitude was negatively associated with serum folate levels. After adjusting for confounding factors, serum folate levels decreased by 0.33 ng/mL per each 500-m increase in altitude (β = - 0.33; 95% CI - 0.6; - 0.05; P = 0.022). Altitude was negatively associated with serum folate levels in Tibetan adults. The relationship between altitude and folate levels should be further explored in populations of different races and disease states. Further large-scale prospective studies should illustrate the causality of this relationship.

Oxidative stress and antioxidant defenses in mild cognitive impairment: A systematic review and meta-analysis

This study aims to systematically review and meta-analyze the nitro-oxidative stress (O&NS)/antioxidant (ANTIOX) ratio in the peripheral blood of people with mild cognitive impairment (MCI). We searched PubMed, Scopus, Google Scholar, and Web of Science for articles published from inception until July 31, 2021. Forty-six studies on 3.798 MCI individuals and 6.063 healthy controls were included. The O&NS/ANTIOX ratio was significantly higher in MCI than in controls with a Standardized Mean Difference (SMD)= 0.378 (95% CI: 0.250; 0.506). MCI individuals showed increased lipid peroxidation (SMD=0.774, 95%CI: 4.416; 1.132) and O&NS-associated toxicity (SMD=0.621, CI: 0.377; 0.865) and reduced glutathione (GSH) defenses (SMD=0.725, 95%CI: 0.269; 1.182) as compared with controls. MCI was also accompanied by significantly increased homocysteine (SMD=0.320, CI: 0.059; 0.581), but not protein oxidation, and lowered non-vitamin (SMD=0.347, CI: 0.168; 0.527) and vitamin (SMD=0.564, CI: 0.129; 0.999) antioxidant defenses. The results show that MCI is at least in part due to increased neuro-oxidative toxicity and suggest that treatments targeting lipid peroxidation and the GSH system may be used to treat or prevent MCI.

Vitamin Supplementation and Dementia: A Systematic Review

BACKGROUND

Dementia is a syndrome characterized by progressive cognitive impairment that interferes with independent function in daily activities. Symptoms of dementia depend on its cause and vary greatly between individuals. There is extensive evidence supporting a relationship between diet and cognitive functions. This systematic review studies the efficacy of using vitamin supplements in the diet as a solution to nutritional deficiencies and the prevention of dementia and mild cognitive impairment.

METHODS

An intensive search of different databases (PubMed, Web of Science, and Cochrane CENTRAL) was performed. Articles that were published between 2011 and November 2021 were retrieved using the mentioned search strategy. This systematic review has been conducted according to the PRISMA statement.

RESULTS

Folic acid supplementation proved to have better outcomes on cognitive tests than their respective control groups. The combined supplementation of folic acid and vitamin B12 showed some discrepancies between studies. Thiamine as supplementation did not only prove to have a positive impact on cognitive performance when given alone but also when given in combination with folic acid. Regarding vitamin D supplementation, the results observed were not so encouraging. A concomitant supplementation of low-dose vitamin E and vitamin C was also not associated with an improvement of cognitive function.

CONCLUSIONS

The findings of this systematic review suggest that supplementation of B Complex vitamins, especially folic acid, may have a positive effect on delaying and preventing the risk of cognitive decline. Ascorbic acid and a high dose of vitamin E, when given separately, also showed positive effects on cognitive performance, but there is not sufficient evidence to support their use. The results of vitamin D supplementation trials are not conclusive in assessing the potential benefits that vitamin D might have on cognition.

Dietary factors and brain health

PURPOSE OF REVIEW

Nutrition is a complex exposure (i.e., the food exposome) that influences brain function and health through multiple pathways. We review recent epidemiological studies that have improved the characterization of the food exposome and brain health in humans and have revealed promising nutrition-based strategies to prevent cognitive aging.

RECENT FINDINGS

A selection of epidemiological research from the past 18 months of both observational and clinical studies is presented, with a focus on novel findings, including novel nutrient and diet patterns, diet-related approaches to rescue brain energetics defects in aging, and biomarker-based studies to decipher specific neurobiological pathways of nutrition and brain health.

SUMMARY

Although healthy diets such as the Mediterranean diet promote brain health throughout life, specific diets, such as the Mediterranean-Dietary Approaches to Stop Hypertension Intervention for Neurodegenerative Delay diet, or specific nutrients (LC n-3 polyunsaturated fatty acids, carotenoids, vitamin D, B vitamins, polyphenols) alone or in combination, may prevent cognitive aging. Diet management approaches to rescue brain energetics defects such as the Modified Mediterranean-ketogenic diet may be promising to prevent neurodegenerative diseases. Expanding research also suggests that promotion of a healthy gut microbiome through prebiotic foods may preserve the diet-gut-brain axis with aging. Future studies should explore more individualized preventive approaches through a 'precision nutrition' framework.

Mechanistic Link between Vitamin B12 and Alzheimer’s Disease

Alzheimer’s disease (AD) is the most common form of dementia in the elderly population, affecting over 55 million people worldwide. Histopathological hallmarks of this multifactorial disease are an increased plaque burden and tangles in the brains of affected individuals. Several lines of evidence indicate that B12 hypovitaminosis is linked to AD. In this review, the biochemical pathways involved in AD that are affected by vitamin B12, focusing on APP processing, Aβ fibrillization, Aβ-induced oxidative damage as well as tau hyperphosphorylation and tau aggregation, are summarized. Besides the mechanistic link, an overview of clinical studies utilizing vitamin B supplementation are given, and a potential link between diseases and medication resulting in a reduced vitamin B12 level and AD are discussed. Besides the disease-mediated B12 hypovitaminosis, the reduction in vitamin B12 levels caused by an increasing change in dietary preferences has been gaining in relevance. In particular, vegetarian and vegan diets are associated with vitamin B12 deficiency, and therefore might have potential implications for AD. In conclusion, our review emphasizes the important role of vitamin B12 in AD, which is particularly important, as even in industrialized countries a large proportion of the population might not be sufficiently supplied with vitamin B12.

Emerging Nutrition Approaches to Support the Mind and Muscle for Healthy Aging

This narrative review highlights recent advances and ongoing trials using nutrition approaches for healthy aging. Focus will be placed on nutrition therapies that target cognition ("the mind") and mobility ("the muscle"), both critical components to maintaining a high quality of life for older adults. For "the mind," two seemingly incongruent therapies are being investigated to improve cognition-the MIND diet (high in carbohydrates and anti-oxidant fruits and vegetables) and the ketogenic diet (low in carbohydrates, high in fats). For "the muscle," a focus on protein and energy intake has dominated the literature, yet a recent clinical trial supports the use of whole-grains as a tool to improve whole-body protein turnover-a primary regulator of lean body mass and muscle. Finally, emerging data and clinical trials on caloric restriction have solidified this strategy as the only nutritional approach to slow intrinsic factors of whole-body aging, which may positively impact both "the mind" and "the muscle."

Effect of food insecurity on the cognitive problems among elderly in India

BACKGROUND

Food Insecurity (FI) is a crucial social determinant of health, independent of other socioeconomic factors, as inadequate food resources create a threat to physical and mental health especially among older person. The present study explores the associations between FI and cognitive ability among the aged population in India.

METHODS

To measure the cognitive functioning we have used two proxies, word recall and computational problem. Descriptive analysis and multivariable logistic regression was used to understand the prevalence of word recall and computational problem by food security and some selected sociodemographic parameters. All the results were reported at 95% confidence interval.

RESULTS

We have used the data from the first wave of longitudinal ageing study of India (LASI), with a sample of 31,464 older persons 60 years and above. The study identified that 17 and 5% of the older population in India experiencing computational and word recall problem, respectively. It was found that respondents from food secure households were 14% less likely to have word recall problems [AOR:0.86, 95% CI:0.31-0.98], and 55% likely to have computational problems [AOR:0.45, 95% CI:0.29-0.70]. We also found poor cognitive functioning among those experiencing disability, severe ADL, and IADL. Further, factors such as age, education, marital status, working status, health related factors were the major contributors to the cognitive functioning in older adults.

CONCLUSION

This study suggest that food insecurity is associated with a lower level of cognition among the elderly in India, which highlight the need of food policy and interventional strategies to address food insecurity, especially among the individuals belonging to lower wealth quintiles. Furthermore, increasing the coverage of food distribution may also help to decrease the burden of disease for the at most risk population. Also, there is a need for specific programs and policies that improve the availability of nutritious food among elderly.

Association between homocysteine levels and cognitive profile in Alzheimer's Disease

BACKGROUND

Growing evidence suggests that hyperhomocysteinemia (HHcy) constitutes a risk factor for Alzheimer's Disease (AD). The impact of HHcy on cognitive functions has mainly been investigated using screening neuropsychological tests that provide general, unspecific measures of cognitive level. Since an association between HHcy and temporo-mesial atrophy has been documented, we predicted that a fine-grained analysis of neuropsychological performance should show stronger Hcy effects on memory scores than on other cognitive scores.

OBJECTIVE

To determine the influence of Hcy level on cognitive profile evaluated with specific, sensitive neuropsychological tests in a wide AD cohort.

METHODS

323 patients with AD were enrolled in a cross-sectional study and underwent a neuropsychological examination exploring several cognitive domains (memory, language, visuoperception, visuospatial abilities, executive function, constructional praxis, ideomotor praxis). The effects of Hcy levels and other risk factors (including cholesterol, smoking habits, triglycerides, apoEε4 allele) were analysed.

RESULTS

Generalized Linear Model detected a significant drop in performance with increasing Hcy in 6/19 measures of cognitive functions, namely, in memory performance tasks as well as in Luria's motor planning test, with effect sizes ranging 1.4%-2.8% (Eta-squared), partialling out effects of other predictors.

CONCLUSIONS

HHcy was associated with poor performance in short and long-term spatial and verbal memory more than with other cognitive dysfunctions. These results support the hypothesis that medial temporal networks might be vulnerable to HHcy, consistently with data from neuroimaging studies suggesting a link in AD between temporal atrophy and HHcy; the effect on Luria's motor planning task suggests further involvement of frontal structures.