Status of vitamins B-12 and B-6 but not of folate, homocysteine, and the methylenetetrahydrofolate reductase C677T polymorphism are associated with impaired cognition and depression in adults

Say hello to my little friend… micronutraceuticals in neuroenergetics, neuronal health, and neurodegenerative diseases

Vitamins and minerals (micronutraceuticals) maintain good health. However, the specific effects of these micronutraceuticals on brain health are often overlooked, or not even known. In this review, an overview of the direct and indirect effects of micronutraceuticals on brain energy metabolism (neuroenergetics) and neuronal health is provided. Thereafter, a holistic summary of the existing studies that have shown the impact of micronutraceuticals on neurodegenerative diseases. Lastly, this review concludes by identifying several research gaps that remain and provides suggestions for future research on these hot topics.

Transthyretin Orchestrates Vitamin B12-Induced Stress Resilience

BACKGROUND

Chronic stress significantly contributes to mood and anxiety disorders. Previous data suggest a correlative connection between vitamin B12 supplementation, depression, and stress resilience. However, the underlying mechanisms are still poorly understood.

METHODS

Using the chronic variable stress mouse model coupled with RNA sequencing, we identified vitamin B12-induced transcriptional changes related to stress resilience. Using viral-mediated gene transfer and in vivo epigenome editing, we revealed a functional pathway linking vitamin B12, DNA methylation (DNAme), and depression-like symptoms.

RESULTS

We identified Ttr (transthyretin) as a key sex-specific target of vitamin B12 in chronic stress. Accordingly, TTR expression was increased postmortem in the prefrontal cortex of male but not female patients with depression. Virally altered Ttr in the prefrontal cortex functionally contributed to stress- and depression-related behaviors, changes in dendritic spine morphology, and gene expression. In stressed mice, vitamin B12 reduced DNAme in the Ttr promoter region. Importantly, using in vivo epigenome editing to alter DNAme in the brains of living mice for the first time, we established a direct causal link between DNAme and Ttr and stress-associated behaviors.

CONCLUSIONS

Using state-of-the-art techniques, this study uncovered a mechanistic link between vitamin B12 supplementation, Ttr, and markers of chronic stress and depression, encouraging further studies into dietary interventions for mood disorders.

The Importance of Nutrition in Menopause and Perimenopause-A Review

Menopause is associated with an increased prevalence of obesity, metabolic syndrome, cardiovascular diseases, and osteoporosis. These diseases and unfavorable laboratory values, which are characteristic of this period in women, can be significantly improved by eliminating and reducing dietary risk factors. Changing dietary habits during perimenopause is most effectively achieved through nutrition counseling and intervention. To reduce the risk factors of all these diseases, and in the case of an already existing disease, dietary therapy led by a dietitian should be an integral part of the treatment. The following review summarizes the recommendations for a balanced diet and fluid intake, the dietary prevention of cardiovascular diseases, the role of sleep, and the key preventive nutrients in menopause, such as vitamin D, calcium, vitamin C, B vitamins, and protein intake. In summary, during the period of perimenopause and menopause, many lifestyle factors can reduce the risk of developing all the diseases (cardiovascular disease, insulin resistance, type 2 diabetes mellitus, osteoporosis, and tumors) and symptoms characteristic of this period.

Nutrient deficiency profiles and depression: A latent class analysis study of American population

BACKGROUND

Research into the effects of nutrition on depression is often performed by examining the effects of singular nutrients and dietary styles (e.g.: vegan, Mediterranean). The present study is the first one to establish the effects of patterns of nutritional deficiency within the American population and examines their effects on depression.

METHODS

Data was drawn from National Health and Nutrition Examination Survey (NHANES). Latent class analysis was performed to identify homogeneous groups of nutrient deficiency. A 3-step analysis was performed to establish class-dependant differences in depression severity. BCH analysis revealed unique predictors of depression dependant on most probable class.

RESULTS

Analysis revealed 4 classes of nutrient deficiency. Magnesium and dietary fibre were the least endorsed. 'Nutrient deprived' individuals showed the highest depression severity (Mean = 4.137, SD = 0.337). Profiles were predicted by different socioeconomic and anthropogenic predictors with meeting minimum calories showing the strongest odds of not being nutrient deprived (OR between 5.44 and 11.11). Overall, age (β = -0.115, p ≤ 0.01) and income (β = -0.147, p ≤ 0.01) were the strongest protecting factors while being female (β = 0.128, p ≤ 0.01) and arthritis (β = 0.130, p ≤ 0.01) were the strongest risk factors.

LIMITATIONS

The study involved binary variables based on minimum daily intakes and did not account for positive effects of exceeding minimum recommended doses.

CONCLUSIONS

The study supports the notion of a negative relationship between good nutrition and depression. Finding unique risk factors for depression symptoms supports the utility of nutrient deficiency profiling.

Homocysteine, Cognitive Functions, and Degenerative Dementias: State of the Art

There is strong evidence that homocysteine is a risk factor not only for cerebrovascular diseases but also for degenerative dementias. A recent consensus statement renewed the importance and the role of high levels of homocysteine in cognitive decline in several forms of degenerative dementia, such as Alzheimer's disease. Although the molecular mechanisms by which homocysteine causes cell dysfunction are known, both the impact of homocysteine on specific cognitive functions and the relationship between homocysteine level and non-Alzheimer dementias have been poorly investigated. Most of the studies addressing the impact of hyperhomocysteinemia on dementias have not examined the profile of performance across different cognitive domains, and have only relied on screening tests, which provide a very general and coarse-grained picture of the cognitive status of the patients. Yet, trying to understand whether hyperhomocysteinemia is associated with the impairment of specific cognitive functions would be crucial, as it would be, in parallel, learning whether some brain circuits are particularly susceptible to the damage caused by hyperhomocysteinemia. These steps would allow one to (i) understand the actual role of homocysteine in the pathogenesis of cognitive decline and (ii) improve the diagnostic accuracy, differential diagnosis and prognostic implications. This review is aimed at exploring and revising the state of the art of these two strictly related domains. Suggestions for future research are provided.

Vitamin B-6 and riboflavin, their metabolic interaction, and relationship with MTHFR genotype in adults aged 18-102 years

BACKGROUND

The generation of the active form of vitamin B-6, pyridoxal 5'-phosphate (PLP), in tissues is dependent upon riboflavin as flavin mononucleotide, but whether this interaction is important for maintaining vitamin B-6 status is unclear.

OBJECTIVE

To investigate vitamin B-6 and riboflavin status, their metabolic interaction, and relationship with methylenetetrahydrofolate reductase (MTHFR) genotype in adulthood.

METHODS

Data from 5612 adults aged 18-102 y were drawn from the Irish National Adult Nutrition Survey (NANS; population-based sample) and the Trinity-Ulster Department of Agriculture (TUDA) and Genovit cohorts (volunteer samples). Plasma PLP and erythrocyte glutathione reductase activation coefficient (EGRac), as a functional indicator of riboflavin, were determined.

RESULTS

Older (≥65 y) compared with younger (<65 y) adults had significantly lower PLP concentrations (P < 0.001). A stepwise decrease in plasma PLP was observed across riboflavin categories, from optimal (EGRac ≤1.26), to suboptimal (EGRac: 1.27-1.39), to deficient (EGRac ≥1.40) status, an effect most pronounced in older adults (mean ± SEM: 76.4 ± 0.9 vs 65.0 ± 1.1 vs 55.4 ± 1.2 nmol/L; P < 0.001). In individuals with the variant MTHFR 677TT genotype combined with riboflavin deficiency, compared with non-TT (CC/CT) genotype participants with sufficient riboflavin, we observed PLP concentrations of 52.1 ± 2.9 compared with 76.8 ±0.7 nmol/L (P < 0.001). In participants with available dietary data (i.e., NANS cohort, n = 936), PLP was associated with vitamin B-6 intake (nonstandardized regression coefficient β: 2.49; 95% CI 1.75, 3.24; P < 0.001), supplement use (β: 81.72; 95% CI: 66.01, 97.43; P < 0.001), fortified food (β: 12.49; 95% CI: 2.08, 22.91; P = 0.019), and EGRac (β: -65.81; 95% CI: -99.08, -32.54; P < 0.001), along with BMI (β: -1.81; 95% CI: -3.31, -0.30; P = 0.019).

CONCLUSIONS

These results are consistent with the known metabolic dependency of PLP on flavin mononucleotide (FMN) and suggest that riboflavin may be the limiting nutrient for maintaining vitamin B-6 status, particularly in individuals with the MTHFR 677TT genotype. Randomized trials are necessary to investigate the PLP response to riboflavin intervention within the dietary range. The TUDA study and the NANS are registered at www.ClinicalTrials.gov as NCT02664584 (27 January 2016) and NCT03374748 (15 December 2017), respectively.Clinical Trial Registry details: Trinity-Ulster-Department of Agriculture (TUDA) study, ClinicalTrials.gov no. NCT02664584 (January 27th 2016); National Adult Nutrition Survey (NANS), ClinicalTrials.gov no. NCT03374748 (December 15th 2017).

Altered mannose metabolism in chronic stress and depression is rapidly reversed by vitamin B12

GDP-Mannose Pyrophosphorylase B (GMPPB) is a key enzyme for glycosylation. Previous studies suggested a dysregulation of GMPBB and mannose in depression. Evidence, however, was sporadic and interventions to reverse these changes are unknown. Here, we show that GMPPB protein, but not RNA abundance is increased in the postmortem prefrontal cortex (PFC) of depressed patients and the chronic variable stress (CVS) mouse-model. This is accompanied by higher plasma mannose levels. Importantly, a single dose of intraperitoneally administered vitamin B12, which has previously been shown to rapidly reverse behavioral symptoms and molecular signatures of chronic stress in mice, normalized GMPPB plasma mannose levels and elevated GDP-mannose abundance. In summary, these data underline metabolic dysregulation in chronic stress and depression and provide further support for rapid effects of vitamin B12 on chronic stress.

Association of Methylenetetrahydrofolate Reductase C677T Gene Polymorphisms with Mild Cognitive Impairment Susceptibility: A Systematic Review and Meta-Analysis

Background

Methylenetetrahydrofolate reductase (MTHFR) C677T (rs1801133) gene polymorphisms are related to a growing risk of Alzheimer's disease; however, whether this association applies to mild cognitive impairment (MCI) remains unclear.

Objective

We conducted this meta-analysis to evaluate the contribution of MTHFR C677T (rs1801133) gene variants to the risk of MCI.

Methods

PubMed, Embase, Web of Science, and China National Knowledge Infrastructure databases were searched from their inception to March 21, 2021, with language restricted to English or Chinese. We used fixed or random effects to examine the association between MTHFR C677T (rs1801133) gene variants and MCI susceptibility. Forest plots of pooled odds ratios (ORs) and 95% confidence intervals (CIs) were generated.

Results

Eight articles with 2,175 participants were included in the present meta-analysis. There was no significant association between MTHFR C677T (rs1801133) gene variants and MCI susceptibility under the allelic (OR, 1.318; 95% CI, 0.964–1.801; p = 0.084), dominant (OR, 1.296; 95% CI, 0.925–1.817; p = 0.132), recessive (OR, 1.397; 95% CI, 0.845–2.312; p = 0.193), heterozygous (OR, 1.031; 95% CI, 0.855–1.243; p = 0.749), or homozygous (OR, 1.506; 95% CI, 0.850–2.667; p = 0.160) models.

Conclusion

The results suggest that MTHFR C677T (rs1801133) gene polymorphisms are not associated with MCI susceptibility. However, large-scale studies covering various factors are required.

Plasma homocysteine concentrations and depression: A twin study

Background

Homocysteine is an amino acid formed during metabolism of the essential amino acid methionine that plays an important role in energy metabolism and neurotransmitter synthesis. High levels of homocysteine have been linked to both depression and cardiovascular disease, however studies of depression have not always been consistent, possibly related to differences in methodology among studies. The study of twins in clinical research can be useful in controlling for confounding factors. The purpose of this study was to assess the relationship between depression and plasma homocysteine in a study of twins.

Methods

Homocysteine concentration was assessed in twins (N = 202) from the Vietnam Era Twin Registry, including twin pairs discordant for the diagnosis of Major Depressive Disorder (MDD) and twin pairs without MDD. Self reported depressive symptom levels were also measured as a continous variable using the Beck Depression Inventory (BDI).

Results

The average homocysteine concentration was 7.9 μmol/L (2.1 μmol/L SD, range of 2.0-17.1 μmol/L). There were no within twin pair differences in homocysteine concentration within twin pairs discordant for MDD and within twin pairs that differed for BDI score. There was a significant pair-level relationship between depressive symptoms as measured by mean BDI score and homocysteine concentration, such that the higher the mean BDI score of the twin pair, the higher the mean homocystein of the pair (p < .001). Every 10 point increase in BDI score was associated with an 0.8 μmol/L increase in homocysteine concentration at the pair level.

Conclusions

These findings are not consistent with a causal role for elevated homocysteine in the development of depression, but rather point to familial confounding or other factors that are shared by twin brothers and that contribute to both depression and homocysteine levels.

Depression and Vegetarians: Association between Dietary Vitamin B6, B12 and Folate Intake and Global and Subcortical Brain Volumes

Deficiency of vitamin B6 and vitamin B12, mostly in vegetarians, is found to be associated with depression and adverse neurological function. We investigated whether vitamin B6, B12, and folate have an effect on brain structure, especially among depressed people who follow a specific diet. The study sample comprised 9426 participants from the UK Biobank cohort with a mean age of 62.4 years. A generalized linear model controlling for age, sex, body mass index, ethnicity, town send deprivation index, educational qualification, smoking, and alcohol intake was used to test the association between study groups and structural brain volumes. Depression was more prevalent, and intake of vitamin B6 and B12 was lower among vegetarians, while non-vegetarians had a lower intake of folate. Overall, no significant association was observed between vitamin B6, B12, and folate intakes and both global and subcortical brain volumes among participants with depression. However, vitamin B12 intake was positively associated with right pallidum among non-depressed participants, and a significant interaction between vitamin B12 intake and depression status on the right pallidum was observed. Also, a significant interaction between folate intake and depression status on grey matter (GM) volume and left thalamus was observed. Upon diet stratification, folate intake is associated with total brain volume and GM volume among vegetarians with depression. Furthermore, no significant associations were observed for subcortical regions. Our findings suggest that dietary intake of vitamin B6 and B12 might have an effect on brain structure. Vegetarians, particularly those who suffer from depression may benefit from supplementing their diets with vitamins B6, B12, and folate to ensure brain health. Further studies, especially with a larger sample size and longitudinal design, are needed to confirm these findings.

The association between serum homocysteine and depression: A systematic review and meta-analysis of observational studies

BACKGROUND

Hyperhomocysteinaemia is known to interfere with neurological functions; however, there is a controversy regarding the relationship between homocysteine and depression.

MATERIALS AND METHODS

Science Direct, MEDLINE and ISI Web of Science were searched to find relevant articles, published up to August 2020. Studies were included if they compared homocysteine levels in healthy subjects with subjects with depression. Also, articles that reported the association between hyperhomocysteinaemia and risk of depression were included. Odds ratios of depression and means of homocysteine were used to ascertain the overall effect size.

RESULTS

Homocysteine level was higher in subjects with depression in comparison with healthy controls (weight mean difference = 2.53 µmol/L, 95% confidence interval: 1.77, 3.30), and the depression diagnostic tool was a source of heterogeneity. Homocysteine level was significantly higher in subjects with depression in studies that used Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV), Geriatric Depression Scale (GDS), Zung Self-Rating Depression Scale (ZDRS) and Beck Depression Index II (BDI-II) as depression diagnostic tools. Also, participants with hyperhomocysteinaemia had a higher chance of depression (Pooled risk = 1.34, 95% confidence interval: 1.19, 1.52), where the depression diagnostic tool was a source of heterogeneity. In contrast to ZDRS and Patient Health Questionnaire (PHQ) subgroups, hyperhomocysteinaemia yielded a significantly higher risk of depression in DSM-IV, GDS and 'other' subgroups.

CONCLUSION

Homocysteinemia level is higher in individuals with depression. However, the depression diagnostic tool used is instrumental in influencing their association, and thus, future studies should focus on the tools for depression assessment.

Pharmacodynamic Gene Testing in Prader-Willi Syndrome

Prader-Willi syndrome (PWS) is a rare genetic disorder with a complex neurobehavioral phenotype associated with considerable psychiatric co-morbidity. This clinical case series, for the first time, describes the distribution and frequency of polymorphisms of pharmacodynamic genes (serotonin transporter, serotonin 2A and 2C receptors, catechol-o-methyltransferase, adrenergic receptor 2A, methylene tetrahydrofolate reductase, and human leucocytic antigens) across the two major molecular classes of PWS in a cohort of 33 referred patients who met medical criteria for testing. When results were pooled across PWS genetic subtypes, genotypic and allelic frequencies did not differ from normative population data. However, when the genetic subtype of PWS was examined, there were differences observed across all genes tested that may affect response to psychotropic medication. Due to small sample size, no statistical significance was found, but results suggest that pharmacodynamic gene testing should be considered before initiating pharmacotherapy in PWS. Larger scale studies are warranted.

Vitamin B12 Supplementation: Preventing Onset and Improving Prognosis of Depression

Depression is a common mental health condition occurring across all ages, genders, and populations and is almost always multifaceted. It can manifest as a form of metabolic disorder, endocrine disorder, cardiovascular diseases, inflammatory disorders, deficiencies, or neurodegenerative disorders. Although there have been various treatment options available for the treatment of depression, it is still a sizable global health concern requiring more attention. This review article was produced by researching data and studies to prove a relationship between Vitamin B12 and depression. Numerous studies were reviewed, and based on these studies, it was concluded that supplementation of Vitamin B12 early enough can delay the onset of depression and improve the effect of anti-depressants when used in conjunction with Vitamin B12. Although other vitamins like Vitamin B6 and folate are known to have an impact on depression, we have primarily focused on Vitamin B12 in an attempt to offer the providers a foundation to address this concern with their patients prone to depression or have had a major depressive episode in their life.

Riboflavin Is an Important Determinant of Vitamin B-6 Status in Healthy Adults

BACKGROUND

Riboflavin is required to generate the active form of vitamin B-6 (pyridoxal 5'-phosphate; PLP) in tissues, but the relevance of this metabolic interaction for nutritional status of vitamin B-6 is unclear because riboflavin biomarkers are rarely measured in human studies.

OBJECTIVES

The purpose of this study was to identify the determinants of biomarkers of vitamin B-6 and riboflavin status and to examine the relationship between these nutrients in healthy adults.

METHODS

Multiple linear regression was performed on observational data in 407 healthy adults aged 18-92 y who did not use B-vitamin supplements. Vitamin B-6 status was assessed by plasma PLP concentrations and erythrocyte glutathione reductase activation coefficient (EGRac) was used as a functional indicator of riboflavin status.

RESULTS

Dietary intakes of vitamin B-6 and riboflavin were below the average requirements in 10% and 29% of participants, respectively. Suboptimal status of vitamin B-6 (PLP ≤30.0 nmol/L) was more prevalent in adults aged ≥60 y than in younger participants (i.e., 14% compared with 5%), whereas a high proportion (i.e., overall 37%) of both age groups had deficient riboflavin status (EGRac ≥1.40). In multiple regression analysis, EGRac (P = 0.019) was a significant determinant of plasma PLP, along with dietary vitamin B-6 intake (P = 0.003), age (P < 0.001), BMI (kg/m2) (P = 0.031), and methylenetetrahydrofolate reductase gene (MTHFR) genotype (P < 0.001). Significant determinants of EGRac were dietary riboflavin intake (P < 0.001), age (P < 0.001) and MTHFR genotype (P = 0.020). Plasma PLP showed a stepwise decrease across riboflavin status categories from optimal (EGRac ≤1.26) to low (EGRac 1.27-1.39) to deficient status (P = 0.001), independent of dietary vitamin B-6 intake.

CONCLUSIONS

The findings are consistent with the known metabolic dependency of vitamin B-6 on riboflavin status and indicate that riboflavin may be the limiting nutrient, particularly in older people, for maintaining adequate vitamin B-6 status.

Racial Differences in Dietary Relations to Cognitive Decline and Alzheimer's Disease Risk: Do We Know Enough?

The elderly population in the US is increasing and projected to be 44% minority by 2060. African Americans and Hispanics are at increased risk of cognitive impairment and Alzheimer’s disease compared to non-Hispanic whites. These conditions are associated with many other adverse health outcomes, lower quality of life, and substantial economic burden. In the past few decades, diet has been identified as an important modifiable risk factor for cognitive decline and Alzheimer’s disease. Some studies report poor diet quality among African American and Hispanic older adult populations compared to their white counterparts. We have a limited understanding of how diet affects brain health in different racial-ethnic groups. One primary reason for our lack of knowledge is that most cohort studies are of majority non-Hispanic white participants. Moreover, those that do include minority participants do not publish their findings stratified by racial-ethnic groups, and likely have a less accurate measurement of dietary intake among minority groups. In this review, we summarize the current, albeit limited, literature on racial/ethnic differences in dietary relations to dementia outcomes. We will also discuss methodological issues in conducting nutrition studies in diverse cultures, and suggestions for future research directions. Overcoming the gaps will make it possible to make dietary recommendations for Alzheimer’s prevention that are more relevant for different racial/ethnic groups and set us on a faster track to reduce health disparities.

Diet, Stress and Mental Health

Introduction: There has long been an interest in the effects of diet on mental health, and the interaction of the two with stress; however, the nature of these relationships is not well understood. Although associations between diet, obesity and the related metabolic syndrome (MetS), stress, and mental disorders exist, causal pathways have not been established. Methods: We reviewed the literature on the relationship between diet, stress, obesity and psychiatric disorders related to stress. Results: Diet and obesity can affect mood through direct effects, or stress-related mental disorders could lead to changes in diet habits that affect weight. Alternatively, common factors such as stress or predisposition could lead to both obesity and stress-related mental disorders, such as depression and posttraumatic stress disorder (PTSD). Specific aspects of diet can lead to acute changes in mood as well as stimulate inflammation, which has led to efforts to assess polyunsaturated fats (PUFA) as a treatment for depression. Bidirectional relationships between these different factors are also likely. Finally, there has been increased attention recently on the relationship between the gut and the brain, with the realization that the gut microbiome has an influence on brain function and probably also mood and behavior, introducing another way diet can influence mental health and disorders. Brain areas and neurotransmitters and neuropeptides that are involved in both mood and appetite likely play a role in mediating this relationship. Conclusions: Understanding the relationship between diet, stress and mood and behavior could have important implications for the treatment of both stress-related mental disorders and obesity.

Acute vitamin B12 supplementation evokes antidepressant response and alters Ntrk-2

Depression is the leading cause of disability worldwide. Although most research into risk factors focuses on stress, dietary factors also have a strong link with depression. For instance, chronic vitamin B12-supplementation may reduce depression risk and helps to reverse the prodepressive effects of early life stress in animal models. However, it is still unclear whether a single acute dose of vitamin B12 is sufficient to induce antidepressant effects on molecular or behavioral levels. Based on pharmacological work and CRISPR-dCas9 epigenome editing in Neuro2A-cells we provide in vitro evidence for a link between vitamin B12, gene expression and DNA methylation of the antidepressant-associated gene Ntrk-2, which codes for the BDNF-receptor TRKB. Using stress-induction protocols in C57Bl/6 J mice combined with behavioral testing and subsequent molecular tissue analysis, we establish in vivo evidence for antidepressant effects of vitamin B12. Acute supplementation with vitamin B12, but not folic acid, selectively altered DNA methylation and gene expression of Ntrk-2 in vitro, albeit DNA methylation and Ntrk-2 gene expression do not correlate in vivo. Importantly, one acute vitamin B12 injection improved multiple behavioral measures in tests for antidepressant action and at the same time reversed the effects of chronic and acute stress on Ntrk-2 levels in vivo, however causality has not been proven at this stage. Taken together, acute vitamin B12 supplementation can reverse stress effects on Ntrk-2 gene expression and improve behaviors that are associated with depression-like behavior in mice. Our findings encourage further investigation of vitamin B12-supplementation as a novel model for antidepressant action.

A systematic review of existing peripheral biomarkers of cognitive aging: Is there enough evidence for biomarker proxies in behavioral modification interventions?: An initiative in association with the nutrition, exercise and lifestyle team of the Canadian Consortium on Neurodegeneration in Aging

Peripheral biomarkers have shown significant value in predicting brain health and may serve as a useful proxy measurement in the assessment of evidence-based lifestyle behavior modification programs, including physical activity and nutrition programs, that aim to maintain cognitive function in late life. The aim of this systematic review was to elucidate which peripheral biomarkers are robustly associated with cognitive function among relatively healthy non-demented older adults. Following the standards for systematic reviews (PICO, PRIMSA), and employing MEDLINE and Scopus search engines, 222 articles were included in the review. Based on the review of biomarker proxies of cognitive health, it is recommended that a comprehensive biomarker panel, or biomarker signature, be developed as a clinical end point for behavior modification trials aimed at enhancing cognitive function in late life. The biomarker signature should take a multisystemic approach, including lipid, immune/inflammatory, and metabolic biomarkers in the biological signature index of cognitive health.

One-carbon metabolism gene polymorphisms are associated with cognitive trajectory among African-American adults

The sex-specific link between longitudinal annual rate of cognitive change (LARCC) and polymorphisms in one-carbon metabolism enzymatic genes remains unclear, particularly among African-American adults. We tested associations of 14 single nucleotide polymorphisms (SNPs) from MTHFR, MTRR, MTR, and SHMT genes and select MTHFR haplotypes and latent classes (SNPHAP/SNPLC) with LARCC. Up to 797 African-American participants in the Healthy Aging in Neighborhoods of Diversity across the Life Span study (age: 30-64 y, 52% women) had 1.6-1.7 (i.e., 1 or 2) repeated measures (follow-up time, mean = 4.69 y) on 9 cognitive test scores, reflecting verbal and visual memory, verbal fluency, psychomotor speed, attention, and executive function: California Verbal Learning Test-immediate recall (CVLT-List A), CVLT-DFR (delayed free recall), Benton Visual Retention Test (BVRT), Animal Fluency (AF), Digits Span Forward and Backward tests, and Trail Making Test parts A and B (Trails A and B). Multiple linear mixed-effects and multiple linear regression models were conducted. Overall, MTHFR SNPs rs4846051(A1317G, G>A) and rs1801131(A1298C, G>T) were associated with slower and faster declines on AF, respectively, whereas rs2066462(C1056T, A>G) was related to slower decline on Trails B (executive function). Among men, rs4846051(A1317G, G>A) was linked to faster decline on BVRT (visual memory), whereas rs2066462(C1056T, A>G) and rs9651118(C>T) were associated with slower decline on CVLT-List A and rs9651118(C>T) with faster decline on CVLT-DFR. Among women, a slower decline on the domain "verbal memory/fluency" was observed with rs1801133(C677T, A>G). MTHFR₂SNPHAP [rs1801133(C677T, A>G)/rs1801131(A1298C, G>T): GG] was associated with slower decline on AF among women, whereas MTHFR₃SNPHAP(AT) was linked with slower decline on CVLT-List A among men but faster decline on "verbal memory/fluency" among women. Similar patterns were observed for MTHFR SNPLCs. In sum, MTHFR gene variations can differentially impact longitudinal changes in multiple cognitive domains among African-American adults.

The Alkaline Phosphatase (ALPL) Locus Is Associated with B6 Vitamer Levels in CSF and Plasma

The active form of vitamin B6, pyridoxal phosphate (PLP), is essential for human metabolism. The brain is dependent on vitamin B6 for its neurotransmitter balance. To obtain insight into the genetic determinants of vitamin B6 homeostasis, we conducted a genome-wide association study (GWAS) of the B6 vitamers pyridoxal (PL), PLP and the degradation product of vitamin B6, pyridoxic acid (PA). We collected a unique sample set of cerebrospinal fluid (CSF) and plasma from the same healthy human subjects of Dutch ancestry (n = 493) and included concentrations and ratios in and between these body fluids in our analysis. Based on a multivariate joint analysis of all B6 vitamers and their ratios, we identified a genome-wide significant association at a locus on chromosome 1 containing the ALPL (alkaline phosphatase) gene (minimal p = 7.89 × 10⁻¹⁰, rs1106357, minor allele frequency (MAF) = 0.46), previously associated with vitamin B6 levels in blood. Subjects homozygous for the minor allele showed a 1.4-times-higher ratio between PLP and PL in plasma, and even a 1.6-times-higher ratio between PLP and PL in CSF than subjects homozygous for the major allele. In addition, we observed a suggestive association with the CSF:plasma ratio of PLP on chromosome 15 (minimal p = 7.93 × 10⁻⁷, and MAF = 0.06 for rs28789220). Even though this finding is not reaching genome-wide significance, it highlights the potential of our experimental setup for studying transport and metabolism across the blood–CSF barrier. This GWAS of B6 vitamers identifies alkaline phosphatase as a key regulator in human vitamin B6 metabolism in CSF as well as plasma. Furthermore, our results demonstrate the potential of genetic studies of metabolites in plasma and CSF to elucidate biological aspects underlying metabolite generation, transport and degradation.

Biomarkers of Nutrition for Development (BOND): Vitamin B-12 Review

This report on vitamin B-12 (B12) is part of the Biomarkers of Nutrition for Development (BOND) Project, which provides state-of-the art information and advice on the selection, use, and interpretation of biomarkers of nutrient exposure, status, and function. As with the other 5 reports in this series, which focused on iodine, folate, zinc, iron, and vitamin A, this B12 report was developed with the assistance of an expert panel (BOND B12 EP) and other experts who provided information during a consultation. The experts reviewed the existing literature in depth in order to consolidate existing relevant information on the biology of B12, including known and possible effects of insufficiency, and available and potential biomarkers of status. Unlike the situation for the other 5 nutrients reviewed during the BOND project, there has been relatively little previous attention paid to B12 status and its biomarkers, so this report is a landmark in terms of the consolidation and interpretation of the available information on B12 nutrition. Historically, most focus has been on diagnosis and treatment of clinical symptoms of B12 deficiency, which result primarily from pernicious anemia or strict vegetarianism. More recently, we have become aware of the high prevalence of B12 insufficiency in populations consuming low amounts of animal-source foods, which can be detected with ≥1 serum biomarker but presents the new challenge of identifying functional consequences that may require public health interventions.

Methylenetetrahydrofolate reductase and psychiatric diseases

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme for the critical process of one-carbon metabolism involving folate and homocysteine metabolisms. It is known that some polymorphism of MTHFR would result in reduction of MTHFR enzyme activity as well as DNA methylation process, later shown to have significant impacts in various psychiatric diseases. However, it is unclear whether the polymorphism of MTHFR could be an independent or an add-on risk factor for specific psychiatric symptoms, such as anxiety, depression, positive, or negative symptoms of schizophrenia, or acts as risk factor for specific psychiatric disorders, such as schizophrenia, major depression, autisms, and bipolar disorders. It is also understudied on whether folate supplements could be an effective treatment for psychiatric patients with defect MTHFR activity. In this review, we not only gathered the most recent discoveries on MTHFR polymorphism and related DNA methylation in various psychiatric disorders, but also highlighted the potential relationships between MTHFR activity and implication of folate-related function in specific mental diseases.

B-Vitamin Therapy for Kidney Transplant Recipients Lowers Homocysteine and Improves Selective Cognitive Outcomes in the Randomized FAVORIT Ancillary Cognitive Trial

BACKGROUND

Objectives: Elevated plasma total homocysteine (tHcy) is associated with increased risk of cardiovascular disease, stroke and dementia. Results of clinical trials using B-vitamins to reduce the cognitive risks attributed to tHcy have been inconsistent. The high prevalence of both hyperhomocysteinemia and cognitive impairment among kidney transplant recipients makes them an important population in which to evaluate the effect of lowering homocysteine on cognitive function. We therefore evaluated whether B-vitamin therapy to lower tHcy would prevent cognitive-decline in a cohort of stable kidney transplant recipients.

DESIGN

The study was a longitudinal ancillary of the FAVORIT trial, a randomized, placebo-controlled multi-site trial of high-dose B vitamins to reduce cardiovascular and cerebrovascular events in clinically stable kidney transplant recipients with elevated tHcy.

PARTICIPANTS

584 participants from 18 sites across North America.

INTERVENTION

The intervention consisted of a daily multivitamin containing high-doses of folate (5.0 mg), vitamin B12 (1.0 mg) and vitamin B6 (50 mg). The placebo consisted of a daily multi-vitamin containing no folate and recommended daily allowances of vitamins B12 and B6 (0 mg folate; 2.0 µg vitamin B12; 1.4 mg vitamin B6).

MEASUREMENTS

Annual neuropsychological assessment for up to 5 years (mean 3.3 years) using a standardized test battery. Efficacy was analyzed on an intention-to-treat basis using end-of-trial data. Subgroup analyses included stratification for baseline plasma B-vitamin and tHcy concentrations.

RESULTS

At baseline, cognitive impairment was common with 61% of participants falling more than one standard deviation below published norms for at least one cognitive test. Fewer than 1% of participants had insufficient plasma folate < 5 ng/ml or vitamin B12 < 148 pmol/L. However, 44.6% had plasma B6 concentrations < 30 nmol/L. At follow-up, processing speed and memory scores were modestly but significantly better in the B-vitamin supplement group than in controls (p≤0.05). There was no interaction between baseline tHcy, B-vitamin status and treatment on the cognitive outcomes.

CONCLUSIONS

High-dose B-vitamin supplementation provided modest cognitive benefit for kidney transplant recipients with elevated baseline tHcy. Since nearly all participants were folate and vitamin B12 sufficient at baseline, the potential cognitive benefits of folate and B12 supplementation in individuals with poor B-vitamin status remains to be determined.

Neuro-nutrients as anti-alzheimer's disease agents: A critical review

Alzheimer's disease (AD) is characterized by a massive neuronal death causing memory loss, cognitive impairment and behavioral alteration that ultimately lead to dementia and death. AD is a multi-factorial pathology controlled by molecular events such as oxidative stress, protein aggregation, mitochondrial dysfunction and neuro inflammation. Nowadays, there is no efficient disease-modifying treatment for AD and epidemiological studies have suggested that diet and nutrition have a significant impact on the development of this disorder. Indeed, some nutrients can protect all kind of cells, including neurons. As prevention is better than cure, life style improvement, with a special emphasis on diet, should seriously be considered as an anti-AD track and intake of nutrients promoting neuronal health is the need of the hour. Diets rich in unsaturated fatty acids, polyphenols and vitamins have been shown to protect against AD, whereas saturated fatty acids-containing diets deprived of polyphenols promote the development of the disease. Thus, Mediterranean diets, mainly composed of fruits, vegetables and omega-3 fatty acids, stand as valuable, mild and preventive anti-AD agents. This review focuses on our current knowledge in the field and how one can fight this devastating neurodegenerative disorder through the simple proper modification of our life style.

Homocysteine and Real-Space Navigation Performance among Non-Demented Older Adults

BACKGROUND

High plasma homocysteine (Hcy) level is related to higher risk of Alzheimer's disease (AD) and lower cognitive performance in older adults.

OBJECTIVE

To assess the association between plasma Hcy level and real-space navigation performance and the role of vascular risk and protective factors, APOE status, and white matter lesions (WML) on this association.

METHODS

Ninety-two non-demented older adults (29 with amnestic mild cognitive impairment, 46 with subjective cognitive decline, and 17 cognitively normal older adults) underwent spatial navigation testing of egocentric, allocentric, and mixed navigation in a real-space analogue of the Morris water maze, neuropsychological examination, blood collection, and MRI brain scan with evaluation of WML.

RESULTS

In the regression analyses controlling for age, gender, education, and depressive symptoms, higher plasma Hcy level was related to worse mixed and egocentric (β= 0.31; p = 0.003 and β= 0.23; p = 0.017) but not allocentric (p > 0.05) navigation performance. Additional controlling for vascular risk and protective factors, WML, and APOE status did not modify the results. High total cholesterol and low vitamin B12 and folate levels increased the adverse effect of Hcy on egocentric and mixed navigation. WML did not explain the association between plasma Hcy level and navigation performance.

CONCLUSION

Elevated plasma Hcy level may affect real-space navigation performance above and beyond vascular brain changes. This association may be magnified in the presence of high total cholesterol and low folate or vitamin B12 levels. Attention to the level of plasma Hcy may be a viable intervention strategy to prevent decline in spatial navigation in non-demented older adults.

Diet, nutrition and the ageing brain: current evidence and new directions

Globally populations are ageing. By 2050, it is estimated that there will be two billion people aged 60 years or over, of which 131 million are projected to be affected by dementia, while depression is predicted to be the second leading cause of disability worldwide by 2020. Preventing or delaying the onset of these disorders should therefore be a public health priority. There is some evidence linking certain dietary patterns, particularly the Mediterranean diet, with a reduced risk of dementia and depression. Specific dietary components have also been investigated in relation to brain health, with emerging evidence supporting protective roles forn-3 PUFA, polyphenols, vitamin D and B-vitamins. At this time, the totality of evidence is strongest in support of a role for folate and the metabolically related B-vitamins (vitamin B12, vitamin B6and riboflavin) in slowing the progression of cognitive decline and possibly reducing the risk of depression in ageing. Future studies incorporating new technologies, such as MRI and magnetoencephalography, offer much promise in identifying effective nutrition interventions that could reduce the risk of cognitive and mental disorders. This review will explore the ageing brain and the emerging evidence linking diet and specific nutrients with cognitive function and depression in ageing, with the potential to develop strategies that could improve quality of life in our ageing population.

B-Vitamin Intake and Biomarker Status in Relation to Cognitive Decline in Healthy Older Adults in a 4-Year Follow-Up Study

Advancing age can be associated with an increase in cognitive dysfunction, a spectrum of disability that ranges in severity from mild cognitive impairment to dementia. Folate and the other B-vitamins involved in one-carbon metabolism are associated with cognition in ageing but the evidence is not entirely clear. The hypothesis addressed in this study was that lower dietary intake or biomarker status of folate and/or the metabolically related B-vitamins would be associated with a greater than expected rate of cognitive decline over a 4-year follow-up period in healthy older adults. Participants (aged 60-88 years; n = 155) who had been previously screened for cognitive function were reassessed four years after initial investigation using the Mini-Mental State Examination (MMSE). At the 4-year follow-up assessment when participants were aged 73.4 ± 7.1 years, mean cognitive MMSE scores had declined from 29.1 ± 1.3 at baseline to 27.5 ± 2.4 (p < 0.001), but some 27% of participants showed a greater than expected rate of cognitive decline (i.e., decrease in MMSE > 0.56 points per year). Lower vitamin B6 status, as measured using pyridoxal-5-phosphate (PLP; <43 nmol/L) was associated with a 3.5 times higher risk of accelerated cognitive decline, after adjustment for age and baseline MMSE score (OR, 3.48; 95% CI, 1.58 to 7.63; p < 0.05). Correspondingly, lower dietary intake (0.9-1.4 mg/day) of vitamin B6 was also associated with a greater rate of cognitive decline (OR, 4.22; 95% CI, 1.28-13.90; p < 0.05). No significant relationships of dietary intake or biomarker status with cognitive decline were observed for the other B-vitamins. In conclusion, lower dietary and biomarker status of vitamin B6 at baseline predicted a greater than expected rate of cognitive decline over a 4-year period in healthy older adults. Vitamin B6 may be an important protective factor in helping maintain cognitive health in ageing.

Dietary B Vitamins and a 10-Year Risk of Dementia in Older Persons

B vitamins may lower the risk of dementia, yet epidemiological findings, mostly from countries with folic acid fortification, have remained inconsistent. We evaluated in a large French cohort of older persons the associations between dietary B vitamins and long-term incident dementia. We included 1321 participants from the Three-City Study who completed a 24 h dietary recall, were free of dementia at the time of diet assessment, and were followed for an average of 7.4 years. In Cox proportional hazards models adjusted for multiple potential confounders, including overall diet quality, higher intake of folate was inversely associated with the risk of dementia (p for trend = 0.02), with an approximately 50% lower risk for individuals in the highest compared to the lowest quintile of folate (HR = 0.47; 95% CI 0.28; 0.81). No association was found for vitamins B6 and B12. In conclusion, in a large French cohort with a relatively low baseline folate status (average intake = 278 µg/day), higher folate intakes were associated with a decreased risk of dementia.

Causes, Consequences and Public Health Implications of Low B-Vitamin Status in Ageing

The potential protective roles of folate and the metabolically related B-vitamins (vitamins B12, B6 and riboflavin) in diseases of ageing are of increasing research interest. The most common cause of folate and riboflavin deficiencies in older people is low dietary intake, whereas low B12 status is primarily associated with food-bound malabsorption, while sub-optimal vitamin B6 status is attributed to increased requirements in ageing. Observational evidence links low status of folate and the related B-vitamins (and/or elevated concentrations of homocysteine) with a higher risk of degenerative diseases including cardiovascular disease (CVD), cognitive dysfunction and osteoporosis. Deficient or low status of these B-vitamins alone or in combination with genetic polymorphisms, including the common MTHFR 677 C → T polymorphism, could contribute to greater disease risk in ageing by causing perturbations in one carbon metabolism. Moreover, interventions with the relevant B-vitamins to optimise status may have beneficial effects in preventing degenerative diseases. The precise mechanisms are unknown but many have been proposed involving the role of folate and the related B-vitamins as co-factors for one-carbon transfer reactions, which are fundamental for DNA and RNA biosynthesis and the maintenance of methylation reactions. This review will examine the evidence linking folate and related B-vitamins with health and disease in ageing, associated mechanisms and public health implications.

The Effects of Homocysteine Level in the Critically Ill Patient. A Review

Increased levels of homocysteine (HCYS) represent a risk factor for a series of physiopathological conditions: mental retardation, cardiovascular and neurodegenerative diseases, Parkinson's and Alzheimer's disease, depression, osteoporosis, endothelial dysfunction and inhibition of cell proliferation. This paper aims to present the pathophysiological implications of HCYS and the correlation of hyperhomocysteinemia (H-HCYS) with critical condition in the intensive care unit (ICU). Hypovitaminosis B and folate deficiency is directly involved in the inhibition of HCYS metabolism and the accumulation of HCYS in the plasma and tissues. Critically ill patients are more prone to H-HCYS due to hypermetabolism and accelerated synthesis produced by reactive oxygen species (ROS). In conclusion it can be affirmed that the determination and monitoring of HCYS plasma levels may be of interest in optimizing the therapy for critically ill patients. Moreover, by controlling HCYS levels, and implicitly the essential cofactors that intervene in the specific biochemical pathways, such as vitamin B6, vitamin B12 and folic acid can provide a diversified and personalized treatment for each patient.

Homocysteine and cognition: A systematic review of 111 studies

BACKGROUND

Elevated plasma homocysteine ​​(Hcy) levels have been associated with cognitive dysfunction in a wide range of conditions. The aim of this review is to establish which cognitive domains and populations are the most affected.

METHODS

We systematically review the literature and consider all articles that showed any relationship between plasma Hcy levels and scores achieved on cognitive performance tests in both, the general population and patients suffering from central nervous system disorders and other diseases. When effect sizes were available and combinable, several meta-analyses were performed.

RESULTS

We found 111 pertinent articles. There were 24 cohort studies, 18 randomized trials, 21 case-control studies, and 48 cross-sectional studies. This review reveals a positive trend between cognitive decline and increased plasma Hcy concentrations in general population and in patients with cognitive impairments. Results from the meta-analyses also confirm this trend. Treatment with vitamin supplementation fails to show a reduction in cognitive decline.

DISCUSSION

Further investigations are warranted to clarify this relationship. Earlier detection of the elevated Hcy levels may be an effective intervention to prevent cognitive impairment and dementia.

B Vitamins and the Brain: Mechanisms, Dose and Efficacy--A Review

The B-vitamins comprise a group of eight water soluble vitamins that perform essential, closely inter-related roles in cellular functioning, acting as co-enzymes in a vast array of catabolic and anabolic enzymatic reactions. Their collective effects are particularly prevalent to numerous aspects of brain function, including energy production, DNA/RNA synthesis/repair, genomic and non-genomic methylation, and the synthesis of numerous neurochemicals and signaling molecules. However, human epidemiological and controlled trial investigations, and the resultant scientific commentary, have focused almost exclusively on the small sub-set of vitamins (B9/B12/B6) that are the most prominent (but not the exclusive) B-vitamins involved in homocysteine metabolism. Scant regard has been paid to the other B vitamins. This review describes the closely inter-related functions of the eight B-vitamins and marshals evidence suggesting that adequate levels of all members of this group of micronutrients are essential for optimal physiological and neurological functioning. Furthermore, evidence from human research clearly shows both that a significant proportion of the populations of developed countries suffer from deficiencies or insufficiencies in one or more of this group of vitamins, and that, in the absence of an optimal diet, administration of the entire B-vitamin group, rather than a small sub-set, at doses greatly in excess of the current governmental recommendations, would be a rational approach for preserving brain health.

Dihydrofolate reductase 19-bp deletion polymorphism modifies the association of folate status with memory in a cross-sectional multi-ethnic study of adults

BACKGROUND

Folate status has been positively associated with cognitive function in many studies; however, some studies have observed associations of poor cognitive outcomes with high folate. In search of an explanation, we hypothesized that the association of folate with cognition would be modified by the interaction of high-folate status with a common 19-bp deletion polymorphism in the dihydrofolate reductase (DHFR) gene. To our knowledge, the cognitive effects of this gene have not been studied previously.

OBJECTIVE

We examined the association between cognitive outcomes with the 19-bp deletion DHFR polymorphism, folate status, and their interaction with high or normal plasma folate.

DESIGN

This was a pooled cross-sectional study of the following 2 Boston-based cohorts of community living adults: the Boston Puerto Rican Health Study and the Nutrition, Aging, and Memory in Elders study. Individuals were genotyped for the DHFR 19-bp deletion genotype, and plasma folate status was determined. Cognitive outcomes included the Mini-Mental State Examination, Center for Epidemiologic Studies Depression Scale, and factor scores for the domains of memory, executive function, and attention from a set of cognitive tests.

RESULTS

The prevalence of the homozygous deletion (del/del) genotype was 23%. In a multivariable analysis, high folate status (>17.8 ng/mL) was associated with better memory scores than was normal-folate status (fourth-fifth quintiles compared with first-third quintiles: β ± SE = -0.22 ± 0.06, P < 0.01). Carriers of the DHFR del/del genotype had worse memory scores (β ± SE = -0.24 ± 0.10, P < 0.05) and worse executive scores (β = -0.19, P < 0.05) than did those with the del/ins and ins/ins genotypes. Finally, we observed an interaction such that carriers of the del/del genotype with high folate had significantly worse memory scores than those of both noncarriers with high-folate and del/del carriers with normal-folate (β-interaction = 0.26 ± 0.13, P < 0.05).

CONCLUSIONS

This study identifies a putative gene-nutrient interaction that, if confirmed, would predict that a sizable minority carrying the del/del genotype might not benefit from high-folate status and could see a worsening of memory. An understanding of how genetic variation affects responses to high-folate exposure will help weigh risks and benefits of folate supplementation for individuals and public health.

Subjective well-being in older adults: folate and vitamin B12 independently predict positive affect

Vitamin B12, folate and homocysteine have long been implicated in mental illness, and growing evidence suggests that they may play a role in positive mental health. Elucidation of these relationships is confounded due to the dependence of homocysteine on available levels of vitamin B12 and folate. Cross-sectional and longitudinal relationships between vitamin B12, folate, homocysteine and subjective well-being were assessed in a sample of 391 older, community-living adults without clinically diagnosed depression. Levels of vitamin B12, but not folate, influenced homocysteine levels 18 months later. Vitamin B12, folate and their interaction significantly predicted levels of positive affect (PA) 18 months later, but had no impact on the levels of negative affect or life satisfaction. Cross-sectional relationships between homocysteine and PA were completely attenuated in the longitudinal analyses, suggesting that the cross-sectional relationship is driven by the dependence of homocysteine on vitamin B12 and folate. This is the first study to offer some evidence of a causal link between levels of folate and vitamin B12 on PA in a large, non-clinical population.

MTHFR: Genetic variants, expression analysis and COMT interaction in major depressive disorder

BACKGROUND

Methylenetetrahydrofolate reductase (MTHFR) genetic variations have been widely studied in major depressive disorder (MDD) and antidepressants outcome. An interaction with catechol-O-methyltransferase (COMT) has also been proved affecting depression. The aim of this study was to clarify the role of the most commonly studied single nucleotide polymorphisms (SNPs) of MTHFR gene in MDD and in treatment response mechanisms, along with the impact of the interaction with COMT.

METHODS

A total of 613 MDD patients, of whom 389 were classified as having treatment resistant depression (TRD), and 463 controls were enrolled. The A1298C, C677T and COMT Val158Met were genotyped. Genetic data were integrated with a transcriptional level analysis in peripheral blood cells (PBCs) and fibroblasts.

RESULTS

The A1298C CC homozygotes were more frequent in MDD patients compared to controls in women, increasing twice the genetic risk to develop depression. Moreover this genotype resulted in epistasis with COMT Met carriers in association with MDD. No significant effects were obtained concerning response to treatment. Transcriptional analyses highlighted a strong correlation between the mRNA levels of MTHFR in fibroblasts and COMT genotypes whereas no significant association with MDD was found. PBCs results revealed relevant influences of environmental factors.

LIMITATION

We did not measure folate and homocisteine levels.

CONCLUSION

This study showed the involvement of A1298C, Val158Met and their interaction in MDD. The transcriptional analyses supported the participation of COMT in the folate pathway, which partakes in the complex network of gene×gene and gene×environment interactions of MDD etiopathogenesis.

Evaluation of Nutritional Status of Patients with Depression

Aims and Objectives. Our goal was to determine nutritional status, body composition, and biochemical parameters of patients diagnosed with depression based on DSM-IV-TR criteria. Methods. A total of 59 individuals, aged 18–60 years admitted to Mental Health Centre of Kayseri Education and Research Hospital, were included in the study. The participants were randomly assigned to two groups; depression group (n = 29) and control group (n = 30). Anthropometric measurements, some biochemical parameters, demographic data, and 24-hour dietary recall were evaluated. Results. 65.5% of depression and 60.0% of control group were female. Intake of vitamins A, thiamine, riboflavin, B6, folate, C, Na, K, Mg, Ca, P, Fe, Zn, and fibre (p < 0.05) were lower in depression group. Median levels of body weight, waist circumference, hip circumference, waist-to-hip ratio (p < 0.05) were significantly higher in depression group. Fasting blood glucose levels, serum vitamins B12, and folic acid (p < 0.05) in depression group were lower than controls. Serum insulin and HOMA levels of two groups were similar. Conclusion. Some vitamin B consumption and serum vitamin B12 and folic acid levels were low while signs of abdominal obesity were high among patients with depression. Future research exploring nutritional status of individuals with depression is warranted.

Nutritional supplementation for Alzheimer's disease?

PURPOSE OF REVIEW

Evidence for the benefit of nutrition in Alzheimer's disease continues to accumulate. Many studies with individual vitamins or supplements show marginal, if any, benefit. However, new findings with combinatorial formulations demonstrate improvement in cognitive performance and behavioral difficulties that accompany Alzheimer's disease. Herein, we review some of the most recent clinical advances and summarize supportive preclinical studies.

RECENT FINDINGS

We present novel positive effects on Alzheimer's disease derived from diet, trace elements, vitamins and supplements. We discuss the inherent difficulty in conducting nutritional studies because of the variance in participants' nutritional history, versus pharmacological interventions in which participants are naive to the intervention. We examine the evidence that epigenetics play a role in Alzheimer's disease and how nutritional intervention can modify the key epigenetic events to maintain or improve cognitive performance.

SUMMARY

Overall consideration of the most recent collective evidence suggests that the optimal approach for Alzheimer's disease would seem to combine early, multicomponent nutritional approaches (a Mediterranean-style diet, multivitamins and key combinatorial supplements), along with lifestyle modifications such as social activity and mental and physical exercise, with ultimate addition of pharmacological agents when warranted.

Folate, vitamin B-6, and vitamin B-12 intake and mild cognitive impairment and probable dementia in the Women's Health Initiative Memory Study

BACKGROUND

Whether higher B vitamin intake (ie, B-6, B-12, and folate) is protective against cognitive decline in later life remains uncertain. Several prospective, observational studies find higher B vitamin intake to be associated with lower risk of dementia; other studies, including most trials of B vitamin supplementation, have observed no effect on cognition. We examined this question in a large population of older women carefully monitored for development of mild cognitive impairment (MCI) and probable dementia.

OBJECTIVE

To determine whether baseline folate, vitamin B-6, and/or vitamin B-12 intake, alone or in combination, are associated with incident MCI/probable dementia among older women.

DESIGN

Prospective, longitudinal cohort study. Participants were enrolled between 1993 and 1998, and B vitamin intake was self-reported using a food frequency questionnaire administered at baseline.

PARTICIPANTS/SETTING

Postmenopausal women (N=7,030) free of MCI/probable dementia at baseline in the Women's Health Initiative Memory Study.

MAIN OUTCOME MEASURES

Over a mean follow-up of 5.0 years, 238 cases of incident MCI and 69 cases of probable dementia were identified through rigorous screening and expert adjudication.

STATISTICAL ANALYSES

Cox proportional hazard models adjusting for sociodemographic and lifestyle factors examined the association of B vitamin intake above and below the Recommended Daily Allowance and incident MCI/probable dementia.

RESULTS

Folate intake below the Recommended Daily Allowance at study baseline was associated with increased risk of incident MCI/probable dementia (hazard ratio 2.0, 95% CI 1.3 to 2.9), after controlling for multiple confounders. There were no significant associations between vitamins B-6 or B-12 and MCI/probable dementia, nor any evidence of an interaction between these vitamins and folate intake.

CONCLUSIONS

Folate intake below the Recommended Daily Allowance may increase risk for MCI/probable dementia in later life. Future research should include long-term trials of folic acid supplementation to examine whether folate may impart a protective effect on cognition in later life.

Correlation of homocysteine metabolic enzymes gene polymorphism and mild cognitive impairment in the Xinjiang Uygur population

Background

The aim of this study was to investigate the genetic polymorphisms in the homocysteine (HCY) metabolic enzymes in the Xinjiang Uygur population who have mild cognitive impairment (MCI).

Material/Methods

Based on the epidemiological investigation, 129 cases of diagnosed Uygur MCI patients and a matched control group with 131 cases were enrolled for analyzing the association between the polymorphisms in the HCY metabolism related genes (C677T, A1298C, and G1968A polymorphisms in MTHFR, as well as the A2756G polymorphism in MS) and MCI by using the SNaPshot method. We then determined the homocysteine level in patients.

Results

In Xinjiang Uygur subjects, the A1298C polymorphisms in MTHFR and the A2756G polymorphisms in the MS gene in the MCI group were different from those in the control group. However, the C677T and G1968A polymorphisms in the MTHFR gene in MCI patients were not different from those in the control group. Multivariate logistic regression showed that, in addition to the well-known risk factors, such as low education level, high cholesterol level, high level of low-density lipoprotein, and high homocysteine levels, the A>G mutation in the MS gene at the rs1805087 locus was another independent risk factor for MCI in the Uyghur MCI population. The risk of MCI in G allele carriers was 2.265 times higher than that in matched control individuals (95% CI: 1.205~4.256, P<0.05).

Conclusions

The genetic polymorphism of HCY metabolizing enzymes is correlated to the occurrence of MCI in the Xinjiang Uygur population. The A2756G polymorphism in the MS gene could be an independent risk factor for MCI in the Xinjiang Uygur population.

Emerging roles for folate and related B-vitamins in brain health across the lifecycle

Nutrition plays a fundamental role in supporting the structural and functional development of the human brain from conception, throughout early infancy and extending into later life. A growing body of evidence suggests that folate and the metabolically related B-vitamins are essential for brain health across all age groups, owing to their specific roles in C1 metabolism and particularly in the production of S-adenosylmethionine, a universal methyl donor essential for the production of neurotransmitters. Emerging, though not entirely consistent, evidence suggests that maternal folate status throughout pregnancy may influence neurodevelopment and behaviour of the offspring. Furthermore optimal B-vitamin status is associated with better cognitive health in ageing. Of note, a recent clinical trial provided evidence that supplementation with folic acid and related B-vitamins over a 2-year-period reduced global and regional brain atrophy, as measured by MRI scan in older adults. In terms of potential mechanisms, the effects of these B-vitamins on cognitive health may be independent or may be mediated by nutrient-nutrient and/or relevant gene-nutrient interactions. Furthermore, a new area of research suggests that the in utero environment influences health in later life. Folate, an important cofactor in C1 metabolism, is indirectly involved in DNA methylation, which in turn is considered to be one of the epigenetic mechanisms that may underlie fetal programming and brain development. The present review will explore the evidence that supports a role for folate and the related B-vitamins in brain health across the lifecycle, and potential mechanisms to explain such effects.

Vitamin B-6 vitamers in human plasma and cerebrospinal fluid

BACKGROUND

Vitamin B-6 comprises a group of 6 interrelated vitamers and is essential for numerous physiologic processes, including brain functioning. Genetic disorders disrupting vitamin B-6 metabolism have severe clinical consequences.

OBJECTIVE

To adequately diagnose known and novel disorders in vitamin B-6 metabolism, a reference set is required containing information on all vitamin B-6 vitamers in plasma and cerebrospinal fluid (CSF).

DESIGN

Concentrations of vitamin B-6 vitamers in the plasma and CSF of 533 adult subjects were measured by ultra high-performance liquid chromatography-tandem mass spectrometry.

RESULTS

The relative vitamin B-6 vitamer composition of plasma [pyridoxal phosphate (PLP) > pyridoxic acid (PA) > pyridoxal] differed from that of CSF (pyridoxal > PLP > PA > pyridoxamine). Sex influenced vitamin B-6 vitamer concentrations in plasma and CSF and should therefore be taken into account when interpreting vitamin B-6 vitamer concentrations. The strict ratios and strong correlations between vitamin B-6 vitamers point to a tight regulation of vitamin B-6 vitamer concentrations in blood and CSF. Given the unique design of this study, with simultaneously withdrawn blood and CSF from a large number of subjects, reliable CSF:plasma ratios and correlations of vitamin B-6 vitamers could be established.

CONCLUSIONS

We provide an extensive reference set of vitamin B-6 vitamer concentrations in plasma and CSF. In addition to providing insight on the regulation of individual vitamers and their intercompartmental distribution, we anticipate that these data will prove to be a valuable reference set for the diagnosis and treatment of conditions associated with altered vitamin B-6 metabolism.

Concurrent occurrence of multiple positive lifestyle behaviors and depression among adults in the United States

BACKGROUND

To our knowledge, no studies have examined the dose-response association between concurrent occurrence of multiple positive health behaviors and depression. As a result, the purpose of this study was to examine the dose-response association between concurrent occurrence of lifestyle behaviors (i.e., diet, physical activity, and smoking) on depression symptoms among a national sample of U.S. adults (20-85 yr).

METHODS

Using data from the 2005-2006 NHANES (n=2574), diet was assessed from the healthy eating index variable; physical activity was assessed via accelerometry; smoking was assessed from cotinine levels; and depression was assessed from the Patient Health Questionnaire 9 (PHQ-9).

RESULTS

Each lifestyle behavior was independently associated with depression in the expected direction, and there was also evidence of a dose-response relationship. Compared to those having 0 positive lifestyle factors, those with 1, 2, and 3 positive lifestyle factors, respectively, were 15% (p=0.38), 67% (p=0.001), and 82% (p=0.01) less likely to be classifed as having moderate or greater depression symptoms (PHQ-9 ≥10).

LIMITATIONS

The main limitation of this study was the cross-sectional design.

CONCLUSION

there is a dose-response relationship between concurrent occurrence of positive lifestyle behaviors and depression symptoms.

Nutraceuticals in cognitive impairment and Alzheimer's disease

Several chemical substances belonging to classes of natural dietary origin display protective properties against some age-related diseases including neurodegenerative ones, particularly Alzheimer's disease (AD). These compounds, known as nutraceuticals, differ structurally, act therefore at different biochemical and metabolic levels and have shown different types of neuroprotective properties. The aim of this review is to summarize data from observational studies, clinical trials, and randomized clinical trials (RCTs) in humans on the effects of selected nutraceuticals against age-related cognitive impairment and dementia. We report results from studies on flavonoids, some vitamins and other natural substances that have been studied in AD and that might be beneficial for the maintenance of a good cognitive performance. Due to the substantial lack of high-level evidence studies there is no possibility for recommendation of nutraceuticals in dementia-related therapeutic guidelines. Nevertheless, the strong potential for their neuroprotective action warrants further studies in the field.