Vitamin Supplementation and Dementia: A Systematic Review

Longitudinal change of energy expenditure, body composition and dietary habits in Progressive Supranuclear Palsy patients

INTRODUCTION

Alterations in metabolic status, body composition, and food intake are present in all neurodegenerative diseases. Aim of this study was to detect the progression of these changes in Progressive Supranuclear Palsy (PSP).

METHODS

We conducted a longitudinal study of 15 patients with PSP. The assessments were performed at baseline (T0) and after 7(IQR = 5) months of follow-up (T1). We collected anthropometric measures including body weight, height, body mass index and waist circumference, metabolic parameters through indirect calorimeters, body composition using bioimpedance analysis, and dietary habits with a validated questionnaire. PSP-rating scale (PSP-rs) was used to evaluate disease severity and dysphagia.

RESULTS

The majority of patients (66.66%) presented PSP-Richardson Syndrome and 33.33% the other variant syndromes of the disease. At T1 there was a decrease in intake of total daily calories (p < 0.001), proteins (p < 0.001), fibers (p = 0.001), calcium (p = 0.008), iron (p < 0.001), zinc (0.034), vitamin E (p = 0.006) and folates (p = 0.038) compared to T0. No other changes were found. As for T1 data, no significant differences were shown according to disease phenotypes or the presence of clinically significant dysphagia for solids.

CONCLUSIONS

Within a mid-term follow up, PSP patients presented reduced caloric and proteins intake regardless the presence of dysphagia. The PSP-rs is likely not adequate to assess dysphagia, which should be investigated by specific clinical scales or instrumental examinations. With the goal of maintaining adequate nutritional status, the administration of protein and vitamin supplements should be considered even in the absence of dysphagia evidenced by the rating scales.

Cognitive frailty in relation to vitamin B12 and 25-hydroxyvitamin D in an elderly population: a cross-sectional study from NHANES

Background

Nutritional support has been identified as a potential intervention for cognitive frailty; however, the association between 25-hydroxyvitamin D [25-(OH)D], vitamin B12, and cognitive frailty remains ambiguous.

Methods

This study utilized data from two cycles (2011-2012, 2013-2014) of the National Health and Nutrition Examination Survey (NHANES) to investigate this relationship. The researchers constructed a 41-item frailty index encompassing diverse aspects of physical functioning, psychological evaluation, and medical conditions, and evaluated each participant individually. The study utilized Spearman's rank correlation coefficient and univariate ordered logistic regression to assess the relationships between variables and cognitive frailty. Recursive feature elimination and cross-validation methods were employed to identify the most influential variables for building and optimizing multivariate ordered logistic regression models. Subgroup analyses and interaction tests were further conducted to validate the identified correlations.

Results

The findings of this study confirm a negative linear correlation between 25-(OH)D levels and cognitive frailty in older adults. Specifically, a one-unit increase in 25-(OH)D levels was associated with a 12% reduction in the risk of cognitive frailty. The result was further supported by subgroup analyses and interaction tests.

Conclusion

The existence of a negatively correlated linear association between 25-(OH)D levels and cognitive frailty in older adults is plausible, but further rigorously designed longitudinal studies are necessary to validate this relationship.

Effects of nutritional interventions on cognitive function in adult cancer survivors: A systematic review

AIM

To evaluate the effectiveness and safety of nutritional interventions (i.e. nutritional support, dietary patterns and dietary supplements) on cognitive function in cancer survivors.

DESIGN

Systematic review.

METHODS

A systematic and comprehensive search of PubMed, Web of Science, the Cochrane Library, Embase, and CINAHL was conducted from the inception until March 10, 2023. The last search was conducted on December 10, 2023.

REPORTING METHOD

PRISMA.

RESULTS

A total of 59 randomized controlled trials were included for analysis. Nutritional support, dietary patterns and dietary supplements improved cognitive function in cancer survivors with no apparent safety concerns. The anti-inflammatory diet, the fasting-mimicking diet and the web-based diet significantly improved cognitive function. Whereas the ketogenic diet or dietary advice to consume more soluble dietary fibres and less insoluble dietary fibres and lactose could not. There was evidence from dietary supplements to support the beneficial effects of polyunsaturated fatty acid supplements, traditional herbal medicines and other supplements.

CONCLUSIONS

Nutritional interventions have great promise for improving cognitive function in adult cancer survivors. Further validation of the nutritional interventions supported in this study in other survivors and exploration of more effective nutritional interventions are needed.

IMPLICATIONS FOR THE PROFESSION AND/OR PATIENT CARE

This work can support the construction of nutritional support interventions and dietary guidance programs to prevent cancer-related cognitive decline.

IMPACT

This work filled a gap in preventive strategies for cancer-related cognitive decline from a nutritional perspective. Nutritional support, dietary patterns, and dietary supplements can prevent cancer-related cognitive decline without serious safety concerns. This work highlighted nutritional interventions that have the potential to improve cognitive function in cancer survivors, benefiting the further construction of evidence-based nutritional intervention programs.

PROTOCOL REGISTRATION

PROSPERO.

PATIENT OR PUBLIC CONTRIBUTION

No patient or public contribution.

Association between dietary riboflavin intake and cognitive decline in older adults: a cross-sectional analysis

BACKGROUND

Research exploring the link between dietary riboflavin intake and cognitive decline in this demographic is limited. Our aim was to examine the association between riboflavin intake levels and cognitive decline.

METHODS

The National Health and Nutrition Examination Survey (NHANES) data from 2011 to 2014 were utilized in this cross-sectional analysis. The Consortium to Establish a Registry for Alzheimer's Disease test Word Learning delayed recall trial (DR), Digit Symbol Substitution Test (DSST), Animal Fluency Test(AFT) and Z test were used to evaluate cognitive performance. Multivariate logistic regression, restricted cubic spline and subgroup analysis were performed to evaluate the associations between riboflavin intake and cognitive decline.

RESULTS

The study included a total of 2255 patients, with 47.9% being male. The incidence of cognitive decline was 23.8%. After adjusting for all selected covariates, we found that high riboflavin intake was associated with a lower risk of cognitive impairment in adults in the United States. When riboflavin intake was used as a Categorical variable, compared to those with the lowest intake, the odds ratio (OR) of individuals with the highest riboflavin intake for DR test, AFT test, DSST test and Z test were 0.73 (95% CI: 0.53~1), 0.68(95% CI: 0.49-0.96),0.53(95% CI: 0.37-0.77) and 0.56(95% CI: 0.39-0.8). The study also found an L-shaped association between riboflavin intake and cognitive decline, with an inflection point at approximately 2.984 mg/d.

CONCLUSIONS

Our cross-sectional study in a nationwide sample of American old adults suggests that dietary riboflavin intake was negative associated with cognitive decline.

Dietary folate intake and serum klotho levels in adults aged 40-79 years: a cross-sectional study from the national health and nutrition examination survey 2007-2016

Objective

This study aims to explore the relationship between dietary folate intake and serum Klotho levels in adults from aged 40 to 79 years in the United States, seeking to elucidate the intricacies of their interaction.

Methods

Analyzing data from the National Health and Nutrition Examination Survey (NHANES) spanning 2007 to 2016. The survey research determined folate intake through a 24-h dietary recall and nutrient density modeling, and assessed Klotho levels using enzyme-linked immunosorbent assay (ELISA). The relationship between folate intake and Klotho levels was evaluated using weighted linear regression, and complemented by analysis via smoothed curve models for nuanced understanding.

Results

The study encompassed 10,278 participants, with an average age of 57.64 years, revealing a noteworthy positive correlation between dietary folate and serum Klotho levels. The regression coefficient stood at 0.11 (95% confidence interval, 0.05, 0.18) post-adjustment for various covariates. When dietary folate intake was categorized into quartiles, the second, third, and fourth quartiles exhibited statistically significant differences compared to the lowest quartile. This indicates that higher folate intake correlates with increased serum Klotho levels. These findings underscore the potential benefits of elevating folate intake to enhance serum Klotho levels. Stratified analysis indicated that this association was more pronounced among males aged 60 years or older and individuals with hypertension.

Conclusion

The findings suggest a significant correlation between increased dietary folate intake and elevated serum Klotho levels in adults aged 40-79 years. Hinting at the potential nutritional influences on the aging process and associated health conditions. This calls for further exploration into the mechanisms and broader implications of this association.

Vitamin B6, B12, and Folate's Influence on Neural Networks in the UK Biobank Cohort

BACKGROUND

One-carbon metabolism coenzymes may influence brain aging in cognitively unimpaired adults.

METHODS

Baseline data were used from the UK Biobank cohort. Estimated intake of vitamin B6, B12, and folate was regressed onto neural network functional connectivity in five resting-state neural networks. Linear mixed models tested coenzyme main effects and interactions with Alzheimer's disease (AD) risk factors.

RESULTS

Increased B6 and B12 estimated intake were linked with less functional connectivity in most networks, including the posterior portion of the Default Mode Network. Conversely, higher folate was related to more connectivity in similar networks. AD family history modulated these associations: Increased estimated intake was positively associated with stronger connectivity in the Primary Visual Network and Posterior Default Mode Network in participants with an AD family history. In contrast, increased vitamin B12 estimated intake was associated with less connectivity in the Primary Visual Network and the Cerebello-Thalamo-Cortical Network in those without an AD family history.

CONCLUSIONS

The differential patterns of association between B vitamins and resting-state brain activity may be important in understanding AD-related changes in the brain. Notably, AD family history appears to play a key role in modulating these relationships.

Exploring the association between number of teeth, food intake, and cognitive function: A 9-year longitudinal study

OBJECTIVES

This study aimed to investigate the association between the number of teeth, food intake, and cognitive function in Japanese community-dwelling older adults.

METHODS

This 9-year longitudinal study included a total of 293 analyzable participants who participated in baseline and follow-up surveys. Dental status (number of teeth and periodontal pocket depth), dietary assessment using the brief-type self-administered diet history questionnaire, cognitive function, and the following confounding factors were evaluated: educational level, financial satisfaction, living situation, smoking and drinking habits, history of chronic diseases, apolipoprotein E-ε4 carrier, body mass index, handgrip strength, instrumental activities of daily living, and depressive symptomatology. The Japanese version of the Montreal Cognitive Assessment was used to evaluate cognitive function. A multinomial logistic regression analysis for the intake level of each food categorized into three groups (low, moderate, high), and a generalized estimating equation (GEE) for cognitive function over nine years were performed.

RESULTS

After controlling for confounding factors, the number of teeth was shown to be associated with the intake of green-yellow vegetables and meat. Furthermore, the GEE indicated that the lowest quartile of intake of green-yellow vegetables significantly associated with lower cognitive function (unstandardized regression coefficient [B] = -0.96, 95 % confidence interval [CI]: -1.72 to -0.20), and the lowest quartile of intake of meat significantly associated with lower cognitive function (B = -1.42, 95 % CI: -2.27 to -0.58).

CONCLUSIONS

The intake of green and yellow vegetables and meat, which is influenced by the number of teeth, was associated with cognitive function in Japanese community-dwelling older adults.

CLINICAL SIGNIFICANCE

There are few studies that have examined the association between oral health, food intake, and cognitive function. This 9-year longitudinal study suggests that it is important to maintain natural teeth to enable the functional means to consume green-yellow vegetables and meat, and thereby help maintain cognitive function.

Enhancing medication management in hemodialysis patients: Exploring the impact of patient-centered pharmacist care and motivational interviewing

BACKGROUND

Patients on hemodialysis (HD) often uses several medications, making them highly susceptible to medication-related problems (MRP) thereby leading to medication nonadherence. Therefore, an innovative pharmaceutical care strategy incorporating drug therapy optimization (DTO) and motivational interviewing (MI) can mitigate medication-related problems and optimize patient care.

AIMS AND OBJECTIVE

The objective of this study is to assess the efficacy of pharmacist led interventions in utilizing DTO and MI techniques in managing medication related problems among patients undergoing hemodialysis.

METHOD AND DESIGN

A12-months, cross sectional prospective study was conducted among 63 End Stage Renal Disease (ESRD) patients on HD. DTO was conducted by the pharmacist to identify the MRP by reviewing complete medication list gathered from patient interview and medical records. All MRPs was classified using the PCNE classification version 9.00 and medication issues, that require patient involvement were categorized as patient-related, while those that necessitate physician intervention were classified as physician-related. The DTO was performed at the baseline, 6-month and at the final month of the study. Identified medication issues were communicated to the site nephrologist and was tracked during next follow up. Whereas MI was conducted physically at Month-3 and via telephone on month-6 and month-9 to address patient related medication issues.

RESULTS

Mean age of the study population was 48.5±14 years. While the mean number of prescribed medications was 8.1±2 with 57% of the patients taking more than 5 types of medication. After 12 months of pharmacist intervention using DTO and MI, a mean reduction in MRP was observed for both patient-related and physician-related MRPs across three time series. However, further analysis using repeated measure ANOVA revealed that the reduction in patient-related MRPs was statistically significant [F(1.491, 92.412) = 60.921, p < 0.05], while no statistically significant difference was detected in physician-related MRPs [F(2, 124) = 2.216, P = 0.113].

CONCLUSION

Pharmaceutical care service through DTO and MI can effectively reduce and prevent drug-related issues to optimize medication therapy among HD patients.

Association of physical activity and vitamin D deficiency with cognitive impairment in older adults: a population based cross-sectional analysis

Objectives

The global aging situation is becoming increasingly critical and cognitive impairment in the elderly has become a public health burden of concern. Physical activity (PA) and vitamin D may play a key role in improving cognitive impairment. However, little studies have examined the interaction between these two. The purpose of this study was to assess the association of PA and vitamin D with cognitive impairment in older adults, as well as the interactions of PA and vitamin D.

Materials and methods

This study was conducted by multi-stage random sampling of elderly people ≥60 years old, and a total sample of 2,492 (1,207 male and 1,285 female, mean age of 69.41 ± 6.75 years) with complete data was included in the analysis. PA was assessed by the Global Physical Activity Questionnaire, and < 600 MET-min/week was used as the division criteria. Serum vitamin D was measured by high-performance liquid chromatography tandem mass spectrometry, and 25-hydroxyvitamin D2/D3 concentration < 20 ng/mL was used as a vitamin D deficiency criterion. Cognitive function was assessed by three subtests: the Consortium to Establish a Registry for Alzheimer's disease word learning test (CERAD-WL) for immediate and delayed learning, the Animal Fluency Test (AFT) for verbal fluency; and the Digit Symbol Substitution Test (DSST) for information processing speed and switching attention. All three subtests were scored at less than the lowest quartile of the score as a criterion for cognitive impairment. Statistical analysis was performed using SPSS for chi-square test, rank sum test, interaction analysis, subgroup analysis, and regression analysis.

Results

Lower level of PA is associated with higher odds of cognitive impairment (CERAD W-L: OR = 1.596, 95% CI: 1.338-1.905, p < 0.001; AFT: OR = 1.833, 95% CI: 1.534-2.190, p < 0.001; DSST: OR = 1.936, 95% CI: 1.609-2.329, p < 0.001). Vitamin D deficiency has significant effects in AFT (OR = 1.322, 95% CI: 1.103-1.584, p = 0.003) and DSST (OR = 1.619, 95% CI: 1.345-1.948, p < 0.001). After adjusted for covariates, PA and vitamin D have multiplicative interaction on AFT (OR = 0.662, 95% CI: 0.448-0.977, p = 0.038) and DSST (OR = 0.775, 95% CI: 0.363-0.868, p = 0.009). The interaction between PA and vitamin D was not significant in the CERAD W-L (OR = 0.757, 95% CI: 0.508-1.128, p = 0.172).

Conclusion

The results showed that lower level of PA and vitamin D deficiency were associated with higher odds of cognitive impairment in the elderly population and that there was a multiplicative interaction between PA and vitamin D on cognitive function, with a significant effect of vitamin D on cognitive impairment in high PA conditions.

Influence of maternal folate depletion on Art3 DNA methylation in the murine adult brain; potential consequences for brain and neurocognitive health

The developmental origins of health and disease hypothesis suggest early-life environment impacts health outcomes throughout the life course. In particular, epigenetic marks, including DNA methylation, are thought to be key mechanisms through which environmental exposures programme later-life health. Adequate maternal folate status before and during pregnancy is essential in the protection against neural tube defects, but data are emerging that suggest early-life folate exposures may also influence neurocognitive outcomes in childhood and, potentially, thereafter. Since folate is key to the supply of methyl donors for DNA methylation, we hypothesize that DNA methylation may be a mediating mechanism through which maternal folate influences neurocognitive outcomes. Using bisulphite sequencing, we measured DNA methylation of five genes (Art3, Rsp16, Tspo, Wnt16, and Pcdhb6) in the brain tissue of adult offspring of dams who were depleted of folate (n = 5, 0.4 mg folic acid/kg diet) during pregnancy (~19-21 days) and lactation (mean 22 days) compared with controls (n = 6, 2 mg folic acid/kg diet). Genes were selected as methylation of their promoters had previously been found to be altered by maternal folate intake in mice and humans across the life course, and because they have potential associations with neurocognitive outcomes. Maternal folate depletion was significantly associated with Art3 gene hypomethylation in subcortical brain tissue of adult mice at 28 weeks of age (mean decrease 6.2%, P = .03). For the other genes, no statistically significant differences were found between folate depleted and control groups. Given its association with neurocognitive outcomes, we suggest Art3 warrants further study in the context of lifecourse brain health. We have uncovered a potential biomarker that, once validated in accessible biospecimens and human context, may be useful to track the impact of early-life folate exposure on later-life neurocognitive health, and potentially be used to develop and monitor the effects of interventions.

Supplements for cognitive ability in patients with mild cognitive impairment or Alzheimer's disease: a protocol for systematic review and network meta-analysis of randomised controlled trials

INTRODUCTION

Considering the increasing incidence of Alzheimer's disease (AD) and mild cognitive impairment (MCI) worldwide, there is an urgent need to identify efficacious, safe and convenient treatments. Numerous investigations have been conducted on the use of supplements in this domain, with oral supplementation emerging as a viable therapeutic approach for AD or MCI. Nevertheless, given the multitude of available supplements, it becomes imperative to identify the optimal treatment regimen.

METHODS AND ANALYSIS

Eight academic databases and three clinical trial registries will be searched from their inception to 1 June 2023. To identify randomised controlled trials investigating the effects of supplements on patients with AD or MCI, two independent reviewers (X-YZ and Y-QL) will extract relevant information from eligible articles, while the risk of bias in the included studies will be assessed using the Rob 2.0 tool developed by the Cochrane Collaboration. The primary outcome of interest is the overall cognitive function. Pair-wise meta-analysis will be conducted using RevMan V.5.3, while network meta-analysis will be carried out using Stata 17.0 and ADDIS 1.16.8. Heterogeneity test, data synthesis and subgroup analysis will be performed if necessary. The GRADE system will be employed to assess the quality of evidence. This study is scheduled to commence on 1 June 2023 and conclude on 1 October 2023.

ETHICS AND DISSEMINATION

Ethics approval is not required for systematic review and network meta-analysis. The results will be submitted to a peer-reviewed journal or at a conference.

TRIAL REGISTRATION NUMBER

PROSPERO (CRD42023414700).

The Interplay of Sports and Nutrition in Neurological Health and Recovery

This comprehensive review explores the dynamic relationship between sports, nutrition, and neurological health. Focusing on recent clinical advancements, it examines how physical activity and dietary practices influence the prevention, treatment, and rehabilitation of various neurological conditions. The review highlights the role of neuroimaging in understanding these interactions, discusses emerging technologies in neurotherapeutic interventions, and evaluates the efficacy of sports and nutritional strategies in enhancing neurological recovery. This synthesis of current knowledge aims to provide a deeper understanding of how lifestyle factors can be integrated into clinical practices to improve neurological outcomes.

Vascular dementia: From pathobiology to emerging perspectives

Vascular dementia (VaD) is the second most common type of dementia. VaD is synonymous with ageing, and its symptoms place a significant burden on the health and wellbeing of older people. Despite the identification of a substantial number of risk factors for VaD, the pathological mechanisms underpinning this disease remain to be fully elucidated. Consequently, a biogerontological imperative exists to highlight the modifiable lifestyle factors which can mitigate against the risk of developing VaD. This review will critically examine some of the factors which have been revealed to modulate VaD risk. The survey commences by providing an overview of the putative mechanisms which are associated with the pathobiology of VaD. Next, the factors which influence the risk of developing VaD are examined. Finally, emerging treatment avenues including epigenetics, the gut microbiome, and pro-longevity pharmaceuticals are discussed. By drawing this key evidence together, it is our hope that it can be used to inform future experimental investigations in this field.

The associations of serum vitamin D status and vitamin D supplements use with all-cause dementia, Alzheimer's disease, and vascular dementia: a UK Biobank based prospective cohort study

BACKGROUND

Prior studies on vitamin D and dementia outcomes yielded mixed results and had several important limitations.

OBJECTIVES

We aimed to assess the associations of both serum vitamin D status and supplementation with all-cause dementia, Alzheimer's disease (AD), and vascular dementia (VD) incidence.

METHODS

With a prospective cohort study design, we comprehensively assessed the associations of vitamin D and multivitamin supplementation, as well as vitamin D deficiency {25-hydroxyvitamin D [25(OH)D] <30 nmol/L}, and insufficiency [25(OH)D 30 to <50 nmol/L], with the 14-year incidence of all-cause dementia, AD, and VD in 269,229 participants, aged 55 to 69, from the UK Biobank.

RESULTS

Although 5.0% reported regular vitamin D use and 19.8% reported multivitamin use, the majority of participants exhibited either vitamin D deficiency (18.3%) or insufficiency (34.0%). However, vitamin D deficiency was less prevalent among users of vitamin D (6.9%) or multivitamin preparations (9.5%) than among nonusers (21.5%). Adjusted Cox regression models demonstrated 19% to 25% increased risk of all 3 dementia outcomes for those with vitamin D deficiency [hazard ratio (HR) 95% confidence interval (CI)]: 1.25 (1.16, 1.34) for all-cause dementia; 1.19 (1.07-1.31) for AD; 1.24 (1.08-1.43) for VD] and 10% to 15% increased risk of those with vitamin D insufficiency [HR (95% CI): 1.11 (1.05, 1.18) for all-cause dementia; 1.10 (1.02-1.19) for AD; 1.15 (1.03-1.29) for VD]. Regular users of vitamin D and multivitamins had 17% and 14% lower risk of AD [HR (95% CI): 0.83 (0.71, 0.98)] and VD [HR (95% CI): 0.86 (0.75, 0.98)] incidence, respectively.

CONCLUSIONS

Although our findings indicate the potential benefits of vitamin D supplementation for dementia prevention, randomized controlled trials are essential for definitive evidence.

The Association of Redox Regulatory Drug Target Genes with Psychiatric Disorders: A Mendelian Randomization Study

Redox regulatory drug (RRD) targets may be considered potential novel drug targets of psychosis due to the fact that the brain is highly susceptible to oxidative stress imbalance. The aim of the present study is to identify potential associations between RRD targets' perturbation and the risk of psychoses; to achieve this, Mendelian randomization analyses were conducted. The expression quantitative trait loci (eQTL) and protein QTL data were used to derive the genetic instrumental variables. We obtained the latest summary data of genome-wide association studies on seven psychoses as outcomes, including schizophrenia (SCZ), bipolar disorder (BD), major depressive disorder (MDD), attention-deficit/hyperactivity disorder, autism, obsessive-compulsive disorder and anorexia nervosa. In total, 95 unique targets were included in the eQTL panel, and 48 targets in the pQTL one. Genetic variations in the vitamin C target (OGFOD2, OR = 0.784, p = 2.14 × 10-7) and melatonin target (RORB, OR = 1.263, p = 8.80 × 10-9) were significantly related to the risk of SCZ. Genetic variation in the vitamin E (PRKCB, OR = 0.248, p = 1.24 × 10-5) target was related to an increased risk of BD. Genetic variation in the vitamin C target (P4HTM: cerebellum, OR = 1.071, p = 4.64 × 10-7; cerebellar hemisphere, OR = 1.092, p = 1.98 × 10-6) was related to an increased risk of MDD. Cognitive function mediated the effects on causal associations. In conclusion, this study provides supportive evidence for a causal association between RRD targets and risk of SCZ, BD or MDD, which were partially mediated by cognition.

Effects of folic acid supplementation on cognitive impairment: A meta-analysis of randomized controlled trials

OBJECTIVE

With the increasing number of patients with cognitive impairment, nonpharmacological ways to delay cognitive impairment have attracted people's attention, such as lifestyle changes and nutritional supplementation. Folic acid supplementation appears to be a promising treatment option. However, it remains controversial whether folic acid supplementation is effective in delaying adult's cognitive impairment. Therefore, we conducted a meta-analysis to analyze the effects of folic acid supplementation on different cognitive impairments.

METHODS

We systematically searched PubMed, Web of Science, EMbase, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure (CNKI), WanFang and VIP databases for randomized controlled trials on January 22, 2024. The included population comprised those diagnosed with cognitive impairment. We included trials that compared folic acid treatment with placebo, other dosing regimens, or other intervention controls. Conducting quality evaluation of included studies according to the Cochrane Risk of Bias tool. Statistical analyses were performed using Review Manager software.

RESULTS

Twenty-two trials, including 3604 participants, met inclusion criteria. Compared with controls, the cognitive function of Alzheimer's disease (AD) patients showed improvement with folic acid supplementation: supplementation with < 3 mg (standardized mean differences (SMD) = 0.15, 95% confidence interval (CI) -0.10 to 0.41), and supplementing with ≥ 3 mg folic acid could improve cognitive function in AD patients (SMD = 1.03, 95% CI 0.18 to 1.88). Additionally, it reduced homocysteine (HCY) levels (mean differences (MD) = -4.74, 95% CI -8.08 to -1.39). In mild cognitive impairment (MCI) patients, cognitive function improved with folic acid supplementation: supplementation with > 400 μg (SMD = 0.38, 95% CI 0.13 to 0.63), and supplementation with ≤ 400 μg (SMD = 1.10, 95% CI 0.88 to 1.31). It also reduced HCY levels at intervention ≤ 6 months (MD = -3.93, 95% CI -5.05 to -2.82) and intervention > 6 months (MD = -4.38, 95% CI -5.15 to -3.61). However, supplementing with folic acid did not improve cognitive function in vascular cognitive impairment (VCI) patients, with folic acid supplements < 3 mg (SMD = -0.07, 95% CI -0.23 to -0.08), folic acid supplements ≥ 3 mg (SMD = 0.46, 95% CI -0.57 to 1.49), however, it reduced HCY levels at intervention > 6 months (MD = -5.91, 95% CI -7.13 to -4.69) and intervention ≤ 6 months (MD = -11.15, 95% CI -12.35 to -9.95).

CONCLUSIONS

Supplement folic acid is beneficial to the cognitive profile of patients with MCI, supplementation with ≥ 3 mg folic acid can improve cognitive function in AD patients.

A Blended Vitamin Supplement Improves Spatial Cognitive and Short-Term Memory in Aged Mice

Although many types of antioxidant supplements are available, the effect is greater if multiple types are taken simultaneously rather than one type. However, it is difficult to know which type and how much to take, as it is possible to take too many of some vitamins. As it is difficult for general consumers to make this choice, it is important to provide information based on scientific evidence. This study investigated the various effects of continuous administration of a blended supplement to aging mice. In 18-month-old C57BL/6 mice given a blended supplement ad libitum for 1 month, spatial cognition and short-term memory in the Morris water maze and Y-maze improved compared with the normal aged mice (spontaneous alternative ratio, normal aged mice, 49.5%, supplement-treated mice, 68.67%, p < 0.01). No significant differences in brain levels of secreted neurotrophic factors, such as nerve growth factor and brain-derived neurotrophic factor, were observed between these two groups. In treadmill durability tests before and after administration, the rate of increase in running distance after administration was significantly higher than that of the untreated group (increase rate, normal aged mice, 91.17%, supplement-treated aged mice, 111.4%, p < 0.04). However, training had no reinforcing effect, and post-mortem serum tests showed a significant decrease in aspartate aminotransferase, alanine aminotransferase, and total cholesterol values. These results suggest continuous intake of a blended supplement may improve cognitive function and suppress age-related muscle decline.

Risk of Common Neurological Disorders in Adult Patients with Inflammatory Bowel Disease: A Systematic Review and Meta-analysis

BACKGROUND

Several studies investigated the risks of neurological conditions in patients with inflammatory bowel disease (IBD), with some variability in findings. We aimed to perform a systematic review and meta-analysis of available evidence to elucidate the association between IBD and the risks of common neurological disorders.

METHODS

We conducted a literature search through Embase, PubMed, Scopus, and ProQuest databases from inception to June 30, 2023, to identify cohort studies assessing the risk of developing stroke, all-cause dementia, Parkinson's disease (PD), multiple sclerosis (MS), seizure/epilepsy, and peripheral neuropathy in adult IBD patients compared with non-IBD population. We combined hazard ratios (HRs) with 95% confidence intervals (CIs) to compute pooled estimates using a random-effects model.

RESULTS

In total, 22 cohort studies were included, of which 9 studies reported 7074 stroke events in 202 460 IBD patients, 5 studies reported 3783 all-cause dementia diagnoses in 109 602 IBD patients, 7 studies reported 932 PD diagnoses in 354 792 IBD patients, and 1 study reported 6 MS events in 35 581 IBD patients. We observed increased risks of incident stroke (pooled HR = 1.19; 95% CI, 1.06-1.31), all-cause dementia (pooled HR = 1.22; 95% CI, 1.05-1.38), PD (pooled HR = 1.39; 95% CI, 1.20-1.58), and MS (HR = 2.89; 95% CI, 1.02-8.42). No eligible studies were found on peripheral neuropathy and seizure/epilepsy.

CONCLUSIONS

Inflammatory bowel disease may be modestly associated with increased risks of stroke, all-cause dementia, and PD. Further longitudinal studies are warranted to investigate potential links with MS, seizure/epilepsy, and peripheral neuropathy, as well as their clinical significance.

A metal-complex based chemosensor for the detection of riboflavin and folate

The vitamins of riboflavin and folate are necessary nutrients for maintaining the proper functioning of human body. Riboflavin and folate deficiency will cause nerve damage, leading to peripheral neuritis, depression, tongue inflammation and other diseases. The sensitive detection of riboflavin and folate keeps its significance for patients and food quality control. In this study, a quinoline-pyridine-combined chemosensor (HQ-TPE) modified by tetraphenylethene was developed. After chelating Cd2+, the chemosensor exhibited high selectivity and sensitivity for riboflavin and folate. Moreover, it can discriminate the two different vitamins through different fluorescent responses, which should arise from the different intermolecular π-π interactions between the sensor HQ-TPE and the analyte upon coordination of riboflavin or folate with Cd2+. More importantly, the chemosensor could be used in visual semi-quantitative determination of riboflavin and folate in real samples (milk and lettuce). Therefore, the sensor presented here will not only be a powerful tool for the detection of riboflavin and folate, but also provides a new template for the design of metal complex as fluorescent sensor.

Association of antioxidants use with the risk of dementia among community-dwelling adults in the United Kingdom biobank

Background

Data regarding the association between antioxidant supplementation and incident dementia are limited.

Methods

We included 494,632 adults (54.5% females) aged 40-71 years at baseline from the United Kingdom Biobank in the final analysis. Incident dementia was ascertained using hospital inpatient and death records up to January 2021.

Results

Over a median follow-up of 11.9 years, 7,128 new cases of all-cause dementia, 2,772 cases of Alzheimer's disease, and 1,397 cases of vascular dementia were recorded. The hazard ratio (95% CI) for incident dementia associated with zinc supplementation was 0.84 (0.74-0.96), and the association remained significant after adjusting for all confounders (0.84 (0.74-0.96)). In the full model, zinc supplementation was associated with a reduced risk of Alzheimer's disease [HR (95% CI): 0.71 (0.57-0.88)]. There was no significant association between zinc supplementation and the risk of vascular dementia. No significant associations with incident dementia were observed for other antioxidant supplementation. The association between zinc supplementation and incident dementia was significant among individuals with [HR (95% CI): 0.34 (0.15-0.77)] and without cataract [0.87 (0.77-0.99)] but it was stronger among those with cataract (p value for interaction = 0.0271).

Conclusion

Our findings suggest that zinc supplementation may help reduce the risk of all-cause dementia and Alzheimer's disease in middle-aged or older adults, especially among those with cataracts.

Vitamin D Reduces GABA-Positive Astrocytes in the 5xFAD Mouse Model of Alzheimer's Disease

Background

Vitamin D has neuroprotective and immunomodulating functions that may impact glial cell function in the brain. Previously, we reported molecular and behavioral changes caused by deficiency and supplementation of vitamin D in an Alzheimer's disease (AD) mouse model. Recent studies have highlighted reactive astrocytes as a new therapeutic target for AD treatment. However, the mechanisms underlying the therapeutic effects of vitamin D on the glial cells of AD remain unclear.

Objective

To investigate the potential association between vitamin D deficiency/supplementation and the pathological progression of AD, including amyloid-β (Aβ) pathology and reactive astrogliosis.

Methods

Transgenic hemizygous 5XFAD male mice were subjected to different dietary interventions and intraperitoneal vitamin D injections to examine the effects of vitamin D deficiency and supplementation on AD. Brain tissue was then analyzed using immunohistochemistry for Aβ plaques, microglia, and astrocytes, with quantifications performed via ImageJ software.

Results

Our results demonstrated that vitamin D deficiency exacerbated Aβ plaque formation and increased GABA-positive reactive astrocytes in AD model mice, while vitamin D supplementation ameliorated these effects, leading to a reduction in Aβ plaques and GABA-positive astrocytes.

Conclusions

Our findings highlight the significant impact of vitamin D status on Aβ pathology and reactive astrogliosis, underscoring its potential role in the prevention and treatment of AD. This study provides the first in vivo evidence of the association between vitamin D and reactive astrogliosis in AD model mice, indicating the potential for targeting vitamin D levels as a novel therapeutic approach for AD.

Current perspectives on prevention of vascular cognitive impairment and promotion of vascular brain health

INTRODUCTION

The true global burden of vascular cognitive impairment (VCI) is unknown. Reducing risk factors for stroke and cardiovascular disease would inevitably curtail VCI.

AREAS COVERED

The authors review current diagnosis, epidemiology, and risk factors for VCI. VCI increases in older age and by inheritance of known genetic traits. They emphasize modifiable risk factors identified by the 2020 Lancet Dementia Commission. The most profound risks for VCI also include lower education, cardiometabolic factors, and compromised cognitive reserve. Finally, they discuss pharmacological and non-pharmacological interventions.

EXPERT OPINION

By virtue of the high frequencies of stroke and cardiovascular disease the global prevalence of VCI is expectedly higher than prevalent neurodegenerative disorders causing dementia. Since ~ 90% of the global burden of stroke can be attributed to modifiable risk factors, a formidable opportunity arises to reduce the burden of not only stroke but VCI outcomes including progression from mild to the major in form of vascular dementia. Strict control of vascular risk factors and secondary prevention of cerebrovascular disease via pharmacological interventions will impact on burden of VCI. Non-pharmacological measures by adopting healthy diets and encouraging physical and cognitive activities and urging multidomain approaches are important for prevention of VCI and preservation of vascular brain health.

25-hydroxyvitamin D concentrations and risk of incident dementia, mild cognitive impairment, and delirium in 443,427 UK Biobank participants

This study aimed to investigate the association between serum 25-hydroxyvitamin D (25(OH)D) levels and dementia, mild cognitive impairment (MCI), and delirium. Participants from the United Kingdom (UK) Biobank with complete information on serum 25(OH)D concentrations were enrolled. Dementia, MCI and delirium were defined using the UK Biobank algorithm. 443,427 participants with a mean (standard deviation) age of 56.8 (8.0) years were included in this study. Based on Cox regression models, serum 25(OH)D concentrations were inversely associated with the risk of dementia, MCI, and delirium in a dose-dependent manner after adjusting for demographics (P-trend <0.001). In comparison with 25(OH)D levels less than 32.4 nmol/L, participants with the highest 25(OH)D levels (i.e., >64.4 nmol/L) had the lowest risk of dementia (hazards ratio [HR]: 0.58, 95% confidence interval [CI] 0.49-0.69, P<0.001), MCI (HR: 0.55, 95% CI 0.37-0.84, P=0.005), and delirium (HR: 0.63, 95% CI 0.51-0.79, P<0.001). These results were consistent with the sensitivity analysis, in which participants with events occurring within the first two years of follow-up were excluded. This study found that a lower serum 25(OH)D concentration was significantly associated with a higher risk of dementia (including Alzheimer's disease and vascular dementia), MCI, and delirium.

Can Nutrition Contribute to a Reduction in Sarcopenia, Frailty, and Comorbidities in a Super-Aged Society?

Many countries are facing the advent of super-aging societies, where sarcopenia and frailty will become pertinent problems. The prevalence of comorbidities is a major problem in countries with aged populations as elderly people suffer from various diseases, such as diabetes, heart failure, chronic kidney disease and dementia. All of these diseases are associated with sarcopenia and frailty, and they frequently cause falls, fractures, and a decline in activities of daily living. Fractures in the elderly people are associated with bone fragility, which is influenced by diabetes and chronic kidney disease. Nutritional support for chronic disease patients and sarcopenic individuals with adequate energy and protein intake, vitamin D supplementation, blood glucose level management for individuals with diabetes, obesity prevention, nutritional education for healthy individuals, and the enlightenment of society could be crucial to solve the health-related problems in super-aging societies.

Vitamins and Human Health: Systematic Reviews and Original Research

Vitamins are a group of organic compounds essential to physiological functions in the body [...].

Case report: Post-COVID new-onset neurocognitive decline with bilateral mesial-temporal hypometabolism in two previously healthy sisters

Background

Long coronavirus disease (COVID) is increasingly recognized in adults and children; however, it is still poorly characterized from a clinical and diagnostic perspective, particularly in the younger populations.

Case presentation

We described the story of two sisters-with high social and academic performance before their severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection-who reported severe neurocognitive problems, initially classified as psychologic pandemic distress and eventually found to have significant brain hypometabolism.

Conclusions

We provided a detailed clinical presentation of neurocognitive symptoms in two sisters with long COVID associated with brain hypometabolism documented in both sisters. We believe that the evidence of objective findings in these children further supports the hypothesis that organic events cause persisting symptoms in a cohort of children after SARS-CoV-2 infection. Such findings highlight the importance of discovering diagnostics and therapeutics.

Probiotics and Commensal Bacteria Metabolites Trigger Epigenetic Changes in the Gut and Influence Beneficial Mood Dispositions

The effect of the intestinal microbiome on the gut-brain axis has received considerable attention, strengthening the evidence that intestinal bacteria influence emotions and behavior. The colonic microbiome is important to health and the pattern of composition and concentration varies extensively in complexity from birth to adulthood. That is, host genetics and environmental factors are complicit in shaping the development of the intestinal microbiome to achieve immunological tolerance and metabolic homeostasis from birth. Given that the intestinal microbiome perseveres to maintain gut homeostasis throughout the life cycle, epigenetic actions may determine the effect on the gut-brain axis and the beneficial outcomes on mood. Probiotics are postulated to exhibit a range of positive health benefits including immunomodulating capabilities. Lactobacillus and Bifidobacterium are genera of bacteria found in the intestines and so far, the benefits afforded by ingesting bacteria such as these as probiotics to people with mood disorders have varied in efficacy. Most likely, the efficacy of probiotic bacteria at improving mood has a multifactorial dependency, relying namely on several factors that include the agents used, the dose, the pattern of dosing, the pharmacotherapy used, the characteristics of the host and the underlying luminal microbial environment (e.g., gut dysbiosis). Clarifying the pathways linking probiotics with improvements in mood may help identify the factors that efficacy is dependent upon. Adjunctive therapies with probiotics for mood disorders could, through DNA methylation molecular mechanisms, augment the intestinal microbial active cohort and endow its mammalian host with important and critical co-evolutionary redox signaling metabolic interactions, that are embedded in bacterial genomes, and that in turn can enhance beneficial mood dispositions.

Non-linear relationship between dietary vitamin E intake and cognitive performance in older adults

OBJECTIVES

This study aimed to explore the relationship between dietary vitamin E (VE) intake and cognitive function in older adults.

STUDY DESIGN

This was a cross-sectional study.

METHODS

We applied data from the National Health and Nutrition Examination Survey obtained during 2011-2014 that met our requirements. The cognitive ability assessments included the Consortium to Establish a Registry for Alzheimer's Disease Word Learning (CERAD-WL) and Delayed Recall (CERAD-DR) tests, the animal fluency test, the Digit Symbol Substitution Test, and a composite z-score calculated by summing z-scores of individual tests. We used binary logistic regression analysis to explore the relationship between VE intake and cognitive performance. The results are reported using odds ratios and 95% confidence intervals. Our study also included sex-stratified analyses and sensitivity analysis. A restricted cubic splines model was used to evaluate the dose-response relationship between dietary VE intake and cognitive function.

RESULTS

This study found that a higher intake of dietary VE was associated with a lower risk of cognitive impairment in patients. Sensitivity analysis shows stable results. The results of the gender stratification analysis showed that dietary VE intake was negatively related to the risk of cognitive disorder among females. An irregular L-shaped dose-response relationship was observed between dietary VE intake and cognitive impairment risk.

CONCLUSIONS

Dietary VE intake was negatively related to the risk of cognitive disorder in older adults, with a higher VE intake lowering the risk.

Molecular biomarkers and cognitive impairment in multiple sclerosis: State of the field, limitations, and future direction - A systematic review and meta-analysis

OBJECTIVE

Multiple sclerosis (MS) is associated with cognitive impairment (CI) such as slowed information processing speed (IPS). Currently, no immunocellular or molecular markers have been established in cerebrospinal fluid and serum analysis as surrogate biomarkers with diagnostic or predictive value for the development of CI. This systematic review and meta-analysis aims to sum up the evidence regarding currently discussed markers for CI in MS.

METHODS

A literature search was conducted on molecular biomarkers of CI in MS, such as neurofilament light chain, chitinases, and vitamin D.

RESULTS

5543 publications were screened, of which 77 entered the systematic review. 13 studies were included in the meta-analysis. Neurofilament light chain (CSF: r_p = -0.294, p = 0.003; serum: r_p = -0.137, p = 0.001) and serum levels of vitamin D (r_p = 0.190, p = 0.014) were associated with IPS outcomes.

CONCLUSIONS

Neurofilament light chain and vitamin D are promising biomarkers to track impairments in IPS in MS. Further longitudinal research is needed to establish the use of molecular biomarkers to monitor cognitive decline.

The role of nutrition and the Mediterranean diet on the trajectories of cognitive decline

The worldwide burden of dementia is immense, and set to increase to unprecedented levels in the coming decades, due to population aging. In the absence of disease-modifying treatment, there is therefore a strong rationale to support the assumption that acting on modifiable risk factors, especially in midlife, is a good strategy for reducing the burden of dementia. Among these risk factors, nutrition is key, as it is fundamental to healthy aging, and has interrelated benefits on a number of organ systems, metabolic processes and health states that can all contribute to modifying the risk of dementia. In this paper, we review the methodological challenges of comparing studies of dietary interventions. We then discuss the effect of genetics and the environment on brain health, and review in particular the literature data on the effect of nutrition on cognition. We summarize the body of data reporting the largely beneficial effects of the Mediterranean diet on brain health, and the possible mechanisms that mediate these effects. Finally, we discuss future perspectives for further research in the field, notably the "gut-brain axis", thought to be a key mediator of the effect of nutrition on brain health.

Study of Diet Habits and Cognitive Function in the Chinese Middle-Aged and Elderly Population: The Association between Folic Acid, B Vitamins, Vitamin D, Coenzyme Q10 Supplementation and Cognitive Ability

A growing body of evidence suggests that vitamin supplements play a role in the prevention of cognitive decline. The objective of the present cross-sectional study was to evaluate the relationship between cognitive ability and folic acid, B vitamins, vitamin D (VD) and Coenzyme Q10 (CoQ10) supplementation. The sample consisted of 892 adults aged above 50 who were assessed for their cognitive status in the Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine (China) from July 2019 to January 2022. According to the degree of cognitive impairment, the subjects were divided into a normal control (NC) group, subjective cognitive decline (SCD) group, mild cognitive impairment (MCI) group and Alzheimer's disease (AD) group. The results indicated a lower risk of AD in the daily VD-supplemented subjects with MCI compared to those who were not supplemented; a lower risk of cognitive impairment in those with normal cognitive who consumed VD, folic acid or CoQ10 on a daily basis compared those who did not; and a lower risk of cognitive impairment in subjects with normal cognitive performance who consumed B vitamin supplements, either daily or occasionally, compared to those who did not. The correlation was independent of other factors that potentially affect cognition, such as education level, age, etc. In conclusion, our findings confirmed a lower prevalence of cognitive impairment in those who took vitamins (folic acid, B vitamins, VD, CoQ10) daily. Therefore, we would recommend daily supplementation of vitamins (folic acid, B vitamins, VD, CoQ10), especially group B vitamins, as a potential preventive measure to slow cognitive decline and neurodegeneration in the elderly. However, for the elderly who have already suffered from cognitive impairment, VD supplementation may also be beneficial for their brains.

Is Citicoline Effective in Preventing and Slowing Down Dementia?-A Systematic Review and a Meta-Analysis

BACKGROUND

Cognitive impairment is a staggering personal and societal burden; accordingly, there is a strong interest in potential strategies for its prevention and treatment. Nutritional supplements have been extensively investigated, and citicoline seems to be a promising agent; its role in clinical practice, however, has not been established. We systematically reviewed studies on the effect of citicoline on cognitive performance.

METHODS

We searched the PubMed and Cochrane Library databases for articles published between 2010 and 2022. Relevant information was extracted and presented following the PRISMA recommendations. Data were pooled using the inverse-variance method with random effects models.

RESULTS

We selected seven studies including patients with mild cognitive impairment, Alzheimer's disease or post-stroke dementia. All the studies showed a positive effect of citicoline on cognitive functions. Six studies could be included in the meta-analysis. Overall, citicoline improved cognitive status, with pooled standardized mean differences ranging from 0.56 (95% CI: 0.37-0.75) to 1.57 (95% CI: 0.77-2.37) in different sensitivity analyses. The overall quality of the studies was poor.

DISCUSSION

Available data indicate that citicoline has positive effects on cognitive function. The general quality of the studies, however, is poor with significant risk of bias in favor of the intervention. Other: PubMed and the Cochrane Library.

Vitamin D in Neurological Diseases

Vitamin D may have multiple effects on the nervous system and its deficiency can represent a possible risk factor for the development of many neurological diseases. Recent studies are also trying to clarify the different effects of vitamin D supplementation over the course of progressive neurological diseases. In this narrative review, we summarise vitamin D chemistry, metabolism, mechanisms of action, and the recommended daily intake. The role of vitamin D on gene transcription and the immune response is also reviewed. Finally, we discuss the scientific evidence that links low 25-hydroxyvitamin D concentrations to the onset and progression of severe neurological diseases, such as multiple sclerosis, Parkinson's disease, Alzheimer's disease, migraine, diabetic neuropathy and amyotrophic lateral sclerosis. Completed and ongoing clinical trials on vitamin D supplementation in neurological diseases are listed.

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.

Folate Pathway Gene Single Nucleotide Polymorphisms and Neural Tube Defects: A Systematic Review and Meta-Analysis

Neural tube defects (NTDs) are congenital abnormalities in the central nervous system. The exact etiology of NTDs is still not determined, but several genetic and epigenetic factors have been studied. Folate supplementation during gestation is recommended to reduce the risk of NTDs. In this review we examine single nucleotide polymorphisms (SNPs) of the genes in the folate pathway associated with NTD. We reviewed the literature for all papers discussing both NTDs and SNPs in the folate pathway. Data were represented through five different genetic models. Quality assessment was performed using the Newcastle-Ottawa Scale (NOS) and Cohen's Kappa inter-rater coefficient assessed author agreement. Fifty-nine papers were included. SNPs in MTHFR, MTRR, RFC genes were found to be highly associated with NTD risk. NOS showed that high quality papers were selected, and Kappa Q-test was 0.86. Our combined results support the notion that SNPs significantly influence NTDs across the population, particularly in Asian ethnicity. Additional high-quality research from diverse ethnicities is needed and meta-regression analysis based on a range of criteria may provide a more complete understanding of the role of folate metabolism in NTDs.

Sex-Specific Associations of Dietary Iron Intake with Brain Iron Deposition on Imaging and Incident Dementia: A Prospective Cohort Study

OBJECTIVES

The study aimed to evaluate the association of dietary iron intake with incident dementia and brain iron deposition.

DESIGN/SETTING/PARTICIPANTS

We included dementia-free participants from the UK Biobank who completed at least one 24-hour dietary recall at study baseline (2009-2012) and were followed up to 2021. Incident dementia was determined through linkage to medical records and death registries. Brain MRI was conducted in a subgroup of participants since 2014, with T2* measurements being used as indicators of brain iron deposition.

MEASUREMENTS

Cox proportional hazard models were used to assess the associations of high (top quintile) and low (bottom quintile) versus medium (quintile 2 to 4) level of dietary iron intake with incident dementia, respectively. Linear regression was applied to assess the relations between dietary iron intake and brain T2* measurements.

RESULTS

During follow-up (mean = 9.5 years), a total of 1,454 participants (650 women and 804 men) developed dementia among 191,694 participants (55.0% female; mean age, 56.2 years). When adjusted for sociodemographic, lifestyle, and other dietary factors, participants with low dietary iron intake (< 10.05 mg/day) had a significantly higher dementia risk (hazard ratio [HR], 1.50, 95% confidence interval [CI], 1.19-1.89), while the relation for high intake (> 16.92 mg/day) was non-significant (HR, 1.16, 95% CI, 0.92-1.46). A significant gender difference (P-interaction < 0.001) was observed, with a U-shaped association in male participants (HR for low vs. medium, 1.56, 95% CI, 1.14-2.13; HR for high vs. medium, 1.39, 95% CI, 1.03 - 1.88; P-nonlinearity < 0.001) and no significant association in females, regardless of their menopause status. In general, dietary iron intake was not related to T2* measurements of iron deposition in most brain regions.

CONCLUSION

Our findings suggested a U-shape relationship between dietary iron intake and risk of dementia among males, but not females.

Impact of vitamin D on cognitive functions in healthy individuals: A systematic review in randomized controlled clinical trials

Various functions in the central nervous system, such as growth, development, and cognition can be influenced by vitamins and minerals, which are capable of helping to maintain brain health and function throughout life. Cognition is understood as the aspects related to knowledge, learning, and understanding, as well as the ability to develop these functions. A possible association between low levels of vit D and deficit in the performance of cognitive functions in healthy humans or with some pathological condition is discussed. Because of this, the present systematic review analyzed only randomized clinical trials carried out in healthy non-athlete adults about intellectual and/or mental processes involving cognitive functions to identify whether these individuals with different levels of vit D are capable of interfering with the performance of the cognitive function. To do so, we adopted the PRISMA method criteria and registered it in the PROSPERO database. The search was performed in PubMed (MEDLINE), PsycINFO, Science Direct, Scopus, and Web of Science databases, 2,167 records were identified. The 5 most frequent cognitive domains in the selected studies were: processing speed, attention, verbal learning/memory, executive function, and general cognitive functions. We found that there are positive changes in the following domains: verbal memory and verbal working memory, learning memory, attention, executive function, and also cognitive function in general. We highlight the following suggestions for improvements that vitamin D supplementation may promote in the cognitive domains of healthy adults: a) low doses between 400 and 600 IU/d seem to be more effective when compared to doses between 2,400 and 5,000 IU/d and b) food fortification and enrichment with vit D, need further studies, as they seem to be more or as effective as synthetic supplementation. We evident that there is a need for trials that evaluate the control of vit D levels for healthy adult individuals is important, as they have the potential to minimize health problems, especially those involved in the reduction of cognitive abilities. Thus, the development of more clinical trials to obtain satisfactory answers on this topic needs to be encouraged.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42021262413.