Vitamin K status and cognitive function in healthy older adults

Modification of Gas6 Protein in the Brain by a Functional Endogenous Tissue Vitamin K Cycle

The TAM receptor ligand Gas6 is known for regulating inflammatory and immune pathways in various organs including the brain. Gas6 becomes fully functional through the post-translational modification of multiple glutamic acid residues into γ-carboxyglutamic in a vitamin K-dependent manner. However, the significance of this mechanism in the brain is not known. We report here the endogenous expression of multiple components of the vitamin K cycle within the mouse brain at various ages as well as in distinct brain glial cells. The brain expression of all genes was increased in the postnatal ages, mirroring their profiles in the liver. In microglia, the proinflammatory agent lipopolysaccharide caused the downregulation of all key vitamin K cycle genes. A secreted Gas6 protein was detected in the medium of both mouse cerebellar slices and brain glial cell cultures. Furthermore, the endogenous Gas6 γ-carboxylation level was abolished through incubation with the vitamin K antagonist warfarin and could be restored through co-incubation with vitamin K1. Finally, the γ-carboxylation level of the Gas6 protein within the brains of warfarin-treated rats was found to be significantly reduced ex vivo compared to the control brains. In conclusion, we demonstrated for the first time the existence of a functional vitamin K cycle within rodent brains, which regulates the functional modification of endogenous brain Gas6. These results indicate that vitamin K is an important nutrient for the brain. Furthermore, the measurement of vitamin K-dependent Gas6 functionality could be an indicator of homeostatic or disease mechanisms in the brain, such as in neurological disorders where Gas6/TAM signalling is impaired.

The Role of Vitamin K in the Development of Neurodegenerative Diseases

Neurodegenerative diseases are a growing global health problem with enormous consequences for individuals and society. The most common neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases, can be caused by both genetic factors (mutations) and epigenetic changes caused by the environment, in particular, oxidative stress. One of the factors contributing to the development of oxidative stress that has an important effect on the nervous system is vitamin K, which is involved in redox processes. However, its role in cells is ambiguous: accumulation of high concentrations of vitamin K increases the content of reactive oxygen species increases, while small amounts of vitamin K have a protective effect and activate the antioxidant defense systems. The main function of vitamin K is its involvement in the gamma carboxylation of the so-called Gla proteins. Some Gla proteins are expressed in the nervous system and participate in its development. Vitamin K deficiency can lead to a decrease or loss of function of Gla proteins in the nervous system. It is assumed that the level of vitamin K in the body is associated with specific changes involved in the development of dementia and cognitive abilities. Vitamin K also influences the sphingolipid profile in the brain, which also affects cognitive function. The role of vitamin K in the regulation of biochemical processes at the cellular and whole-organism levels has been studied insufficiently. Further research can lead to the discovery of new targets for vitamin K and development of personalized diets and therapies.

Amyloidogenic and Neuroinflammatory Molecular Pathways Are Contrasted Using Menaquinone 4 (MK4) and Reduced Menaquinone 7 (MK7R) in Association with Increased DNA Methylation in SK-N-BE Neuroblastoma Cell Line

Besides its role in coagulation, vitamin K seems to be involved in various other mechanisms, including inflammation and age-related diseases, also at the level of gene expression. This work examined the roles of two vitamin K2 (menaquinones) vitamers, namely, menaquinone-4 (MK4) and reduced menaquinone-7 (MK7R), as gene modulator compounds, as well as their potential role in the epigenetic regulation of genes involved in amyloidogenesis and neuroinflammation. The SK-N-BE human neuroblastoma cells provided a "first-line" model for screening the neuroinflammatory and neurodegenerative molecular pathways. MK7R, being a new vitamin K form, was first tested in terms of solubilization, uptake and cell viability, together with MK4 as an endogenous control. We assessed the expression of key factors in amyloidogenesis and neuroinflammation, observing that the MK7R treatment was associated with the downregulation of neurodegeneration- (PSEN1 and BACE1) and neuroinflammation- (IL-1β and IL-6) associated genes, whereas genes retaining protective roles toward amiloidogenesis were upregulated (ADAM10 and ADAM17). By profiling the DNA methylation patterns of genes known to be epigenetically regulated, we observed a correlation between hypermethylation and the downregulation of PSEN1, IL-1β and IL-6. These results suggest a possible role of MK7R in the treatment of cognitive impairment, giving a possible base for further preclinical experiments in animal models of neurodegenerative disease.

Improving Cognitive Function with Nutritional Supplements in Aging: A Comprehensive Narrative Review of Clinical Studies Investigating the Effects of Vitamins, Minerals, Antioxidants, and Other Dietary Supplements

Cognitive impairment and dementia are burgeoning public health concerns, especially given the increasing longevity of the global population. These conditions not only affect the quality of life of individuals and their families, but also pose significant economic burdens on healthcare systems. In this context, our comprehensive narrative review critically examines the role of nutritional supplements in mitigating cognitive decline. Amidst growing interest in non-pharmacological interventions for cognitive enhancement, this review delves into the efficacy of vitamins, minerals, antioxidants, and other dietary supplements. Through a systematic evaluation of randomized controlled trials, observational studies, and meta-analysis, this review focuses on outcomes such as memory enhancement, attention improvement, executive function support, and neuroprotection. The findings suggest a complex interplay between nutritional supplementation and cognitive health, with some supplements showing promising results and others displaying limited or context-dependent effectiveness. The review highlights the importance of dosage, bioavailability, and individual differences in response to supplementation. Additionally, it addresses safety concerns and potential interactions with conventional treatments. By providing a clear overview of current scientific knowledge, this review aims to guide healthcare professionals and researchers in making informed decisions about the use of nutritional supplements for cognitive health.

Associations between circulating cardiovascular disease risk factors and cognitive performance in cognitively healthy older adults from the NuAge study

Introduction

Cardiovascular disease risk factors (CVRFs) contribute to the development of cognitive impairment and dementia.

Methods

This study examined the associations between circulating CVRF biomarkers and cognition in 386 cognitively healthy older adults (mean age = 78 ± 4 years, 53% females) selected from the Quebec Longitudinal Study on Nutrition and Successful Aging (NuAge). Memory, executive function, and processing speed were assessed at baseline and 2-year follow-up. CVRF biomarkers included total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglycerides, glucose, insulin, high sensitivity C-reactive protein (hs-CRP), homocysteine, protein carbonyls, and cortisol. Linear mixed models were used to determine associations between individual CVRF biomarkers and cognition at both time points.

Results

HDL-C was most consistently associated with cognition with higher values related to better performance across several domains. Overall, stronger and more consistent relationships between CVRF biomarkers and cognition were observed in females relative to males.

Discussion

Findings suggest that increases in the majority of circulating CVRFs are not associated with worse cognition in cognitively healthy older adults.

Molecular Docking and Dynamics Simulation Studies Predict Potential Anti-ADAR2 Inhibitors: Implications for the Treatment of Cancer, Neurological, Immunological and Infectious Diseases

Altered RNA editing has been linked to several neurodevelopmental disorders, including autism spectrum disorder (ASD) and intellectual disability, in addition to depression, schizophrenia, some cancers, viral infections and autoimmune disorders. The human ADAR2 is a potential therapeutic target for managing these various disorders due to its crucial role in adenosine to inosine editing. This study applied consensus scoring to rank potential ADAR2 inhibitors after performing molecular docking with AutoDock Vina and Glide (Maestro), using a library of 35,161 compounds obtained from traditional Chinese medicine. A total of 47 compounds were predicted to be good binders of the human ADAR2 and had insignificant toxicity concerns. Molecular dynamics (MD) simulations, including the molecular mechanics Poisson–Boltzmann surface area (MM/PBSA) procedure, also emphasized the binding of the shortlisted compounds. The potential compounds had plausible binding free energies ranging from −81.304 to −1068.26 kJ/mol from the MM/PBSA calculations. ZINC000085511995, a naphthoquinone had more negative binding free energy (−1068.26 kJ/mol) than inositol hexakisphosphate (IHP) [−873.873 kJ/mol], an agonist and a strong binder of ADAR2. The potential displacement of IHP by ZINC000085511995 in the IHP binding site of ADAR2 could be explored for possible deactivation of ADAR2. Bayesian-based biological activity prediction corroborates the neuropharmacological, antineoplastic and antiviral activity of the potential lead compounds. All the potential lead compounds, except ZINC000014612330 and ZINC000013462928, were predicted to be inhibitors of various deaminases. The potential lead compounds also had probability of activity (Pa) > 0.442 and probability of inactivity (Pi) < 0.116 values for treating acute neurologic disorders, except for ZINC000085996580 and ZINC000013462928. Pursuing these compounds for their anti-ADAR2 activities holds a promising future, especially against neurological disorders, some cancers and viral infections caused by RNA viruses. Molecular interaction, hydrogen bond and per-residue decomposition analyses predicted Arg400, Arg401, Lys519, Trp687, Glu689, and Lys690 as hot-spot residues in the ADAR2 IHP binding site. Most of the top compounds were observed to have naphthoquinone, indole, furanocoumarin or benzofuran moieties. Serotonin and tryptophan, which are beneficial in digestive regulation, improving sleep cycle and mood, are indole derivatives. These chemical series may have the potential to treat neurological disorders, prion diseases, some cancers, specific viral infections, metabolic disorders and eating disorders through the disruption of ADAR2 pathways. A total of nine potential lead compounds were shortlisted as plausible modulators of ADAR2.

Revisiting the Role of Vitamins and Minerals in Alzheimer's Disease

Alzheimer's disease (AD) is the most common type of dementia that affects millions of individuals worldwide. It is an irreversible neurodegenerative disorder that is characterized by memory loss, impaired learning and thinking, and difficulty in performing regular daily activities. Despite nearly two decades of collective efforts to develop novel medications that can prevent or halt the disease progression, we remain faced with only a few options with limited effectiveness. There has been a recent growth of interest in the role of nutrition in brain health as we begin to gain a better understanding of what and how nutrients affect hormonal and neural actions that not only can lead to typical cardiovascular or metabolic diseases but also an array of neurological and psychiatric disorders. Vitamins and minerals, also known as micronutrients, are elements that are indispensable for functions including nutrient metabolism, immune surveillance, cell development, neurotransmission, and antioxidant and anti-inflammatory properties. In this review, we provide an overview on some of the most common vitamins and minerals and discuss what current studies have revealed on the link between these essential micronutrients and cognitive performance or AD.

The emerging relationship between vitamin K and neurodegenerative diseases: a review of current evidence

Neurodegenerative disease refers to a group of disorders that predominantly damage the neurons in the brain. Despite significant progress in the knowledge of neurodegenerative diseases, there is currently no disease-modifying drug available. Vitamin K was first established for its involvement in blood clotting, but there is now compelling evidence indicating its role in the neurological system. In particular, the results of recent studies on the effects of vitamin K2 on preventing apoptosis, oxidative stress, and microglial activation in neuron cells through its role in electron transport are very promising against Alzheimer's disease. In addition to its protective effect on cognitive functions, its inhibitory effects on inflammation and α-synuclein fibrillization in Parkinson's disease, which has been revealed in recent years, are remarkable. Although there are many studies on the mechanism and possible treatment methods of neurodegenerative diseases, especially Parkinson's and Alzheimer's disease, studies on the relationship between vitamin K and neurodegenerative diseases are very limited, yet have promising findings. Vitamin K has also been proposed for therapeutic use in multiple sclerosis patients to lower the intensity or to slow down the progression of the disease. Accordingly, the aim of this study is to review the current evidence for the use of vitamin K supplementation in neurodegenerative diseases, in particular Alzheimer's disease, Parkinson's disease, and multiple sclerosis.

New Insights into Vitamin K-From Its Natural Sources through Biological Properties and Chemical Methods of Quantitative Determination

Vitamin K is one of the many health-promoting substances whose impact on the human body has been underestimated until recently. However, recently published research results have changed this situation, prompting some researchers to consider it a new panacea for diseases of old age. The result is a significant increase in interest in the accurate analysis of vitamin K in various types of samples, ranging from food, through dietary supplements, to biological matrices and clinical trials, both observational and interventional. This review summarizes the current state of knowledge about the proven and speculated biological activity of vitamin K and its importance for the world's aging societies, including the methods used for its isolation and analysis in various matrices types. Of all the analytical methods, the currently preferred methods of choice for the direct analysis of vitamin K are chromatographic methods, in particular liquid chromatography-tandem mass spectrometry. This technique, despite its sensitivity and selectivity, requires an appropriate stage of sample preparation. As there is still room for improvement in the efficiency of these methods, especially at the sample preparation stage, this review shows the directions that need to be taken to make these methods faster, more efficient and more environmentally friendly.

Vitamin K Status and Cognitive Function in Adults with Chronic Kidney Disease: The Chronic Renal Insufficiency Cohort

Vitamin K is linked to cognitive function, but studies in individuals with chronic kidney disease (CKD), who are at risk for vitamin K insufficiency and cognitive impairment, are lacking. The cross-sectional association of vitamin K status biomarkers with cognitive performance was evaluated in ≥55-y-old adults with CKD (N = 714, 49% female, 44% black). A composite score of a cognitive performance test battery, calculated by averaging the z scores of the individual tests, was the primary outcome. Vitamin K status was measured using plasma phylloquinone and dephospho-uncarboxylated matrix Gla protein [(dp)ucMGP]. Participants with low plasma (dp)ucMGP, reflecting higher vitamin K status, had better cognitive performance than those in the two higher (dp)ucMGP categories based on the composite outcome (P = 0.03), whereas it did not significantly differ according to plasma phylloquinone categories (P = 0.08). Neither biomarker was significantly associated with performance on individual tests (all P > 0.05). The importance of vitamin K to cognitive performance in adults with CKD remains to be clarified.

Vitamin B-12 Intake from Dairy but Not Meat Is Associated with Decreased Risk of Low Vitamin B-12 Status and Deficiency in Older Adults from Quebec, Canada

BACKGROUND

Vitamin B-12 deficiency can result in irreversible neurologic damages. It is most prevalent among older adults (∼5%-15%), mainly due to impaired absorption. Vitamin B-12 bioavailability varies between food sources, so their importance in preventing deficiency may also vary.

OBJECTIVES

Using the NuAge Database and Biobank, we examined the associations between vitamin B-12 intake (total and by specific food groups) and low vitamin B-12 status and deficiency in older adults.

METHODS

NuAge-the Quebec Longitudinal Study on Nutrition and Successful Aging-included 1753 adults aged 67-84 y who were followed 4 y. Analytic samples comprised 1230-1463 individuals. Dietary vitamin B-12 intake was assessed annually using three 24-h dietary recalls. Vitamin B-12 status was assessed annually as low serum vitamin B-12 (<221 pmol/L), elevated urinary methylmalonic acid (MMA)/creatinine ratio (>2 μmol/mmol), and a combination of both (deficiency). Vitamin B-12 supplement users were excluded. Multilevel logistic regressions, adjusted for relevant confounders, were used.

RESULTS

Across all study years, 21.8%-32.5% of participants had low serum vitamin B-12, 12.5%-17.0% had elevated urine MMA/creatinine, and 10.1%-12.7% had deficiency. Median (IQR) total vitamin B-12 intake was 3.19 μg/d (2.31-4.37). Main sources were "dairy" and "meat, poultry, and organ meats." The ORs (95% CIs) in the fifth quintile compared with the first of total vitamin B-12 intake were as follows: for low serum vitamin B-12, 0.52 (0.37, 0.75; P-trend < 0.0001); for elevated urine MMA/creatinine, 0.63 (0.37, 1.08; P-trend = 0.091); and for vitamin B-12 deficiency, 0.38 (0.18, 0.79; P-trend = 0.006). Similarly, ORs (95% CIs) in the fourth quartile compared with the first of dairy-derived vitamin B-12 intake were 0.46 (0.32, 0.66; P-trend < 0.0001), 0.51 (0.30, 0.87; P-trend = 0.006), and 0.35 (0.17, 0.73; P-trend = 0.003), respectively. No associations were observed with vitamin B-12 from "meat, poultry, and organ meats."

CONCLUSIONS

Higher dietary vitamin B-12 intake, especially from dairy, was associated with decreased risk of low vitamin B-12 status and deficiency in older adults. Food groups might contribute differently at reducing risk of deficiency in older populations.

Serum ω-3 Fatty Acids and Cognitive Domains in Community-Dwelling Older Adults from the NuAge Study: Exploring the Associations with Other Fatty Acids and Sex

BACKGROUND

Omega-3 (n-3) PUFAs are suggested to play a role in the prevention of cognitive decline. The evidence may be inconsistent due to methodologic issues, including interrelations with other long-chain (14 or more carbons) fatty acids (LCFAs) and use of sex as a confounding factor rather than an effect modifier.

OBJECTIVES

This study evaluated the association between serum n-3 PUFAs and performance across 4 cognitive domains, overall and by sex, while controlling for other LCFAs.

METHODS

In total, 386 healthy older adults (aged 77.4 ± 3.8 y; 53% females) from the Quebec Longitudinal Study on Nutrition and Successful Aging underwent a cognitive evaluation and blood sampling. Verbal and nonverbal episodic memory, executive functioning, and processing speed were evaluated. Serum LCFA concentrations were measured by gas chromatography. LCFAs were grouped according to standard fatty acid classes and factor analysis using principal component analysis (FA-PCA). Multivariate linear regression models were performed, including unadjusted and adjusted models for other LCFAs.

RESULTS

Higher n-3 PUFA concentrations were associated with better nonverbal memory and processing speed in fully adjusted models not including other LCFAs (βs of 0.21 and 0.19, respectively). The magnitude of these associations varied when other LCFAs were entered in the model (βs of 0.27 and 0.32, respectively) or when FA-PCA factors were considered (βs of 0.27 and 0.21, respectively). Associations with verbal episodic memory were limited to higher concentrations of EPA, whereas there was no association between n-3 PUFAs and executive functioning. Higher n-3 PUFAs were associated with better verbal and nonverbal episodic memory in females and with better executive functioning and processing speed in males.

CONCLUSIONS

These results suggest that other LCFAs should be considered when evaluating the association between n-3 PUFAs and cognitive performance in healthy older adults. Sex differences across cognitive domains warrant further investigation.

Vitamin K2 (Menaquinone-7) Reverses Age-Related Structural and Cognitive Deterioration in Naturally Aging Rats

Aging is a naturally occurring process inevitably affecting each living human. The brain is adversely affected by aging with increased risks of developing various neurological disorders. Thus, it is essential to investigate practical approaches that can counteract the impact of aging on the brain. Vitamin K2 (Vit. K2) is a naturally occurring vitamin with reported valuable therapeutic effects. The current study highlights the role of Vit. K2 administration in counteracting age-related changes in the brain using naturally aging rats. Three-month-old rats were assigned to two groups: an ageing control group receiving a drug vehicle and an ageing group orally gavaged with Vit. K2 (30 mg/kg, once daily 5 days per week). Treatment was continued for 17 months. Ten three-month-old rats were used as the adult control. Vit. K2 improved functional performance, reduced social anxiety, depressive-like behavior, and enhanced memory performance with concomitant preservation of hippocampal and cerebral cortex tyrosine hydroxylase expression. Biochemically, Vit. K2 administration restored oxidative-anti-oxidative homeostasis in the brain. Vit. K2 modulated inflammatory signaling, as evidenced by suppression in the brain of NLRP3, caspase-1, Il-1β, TNFα, IL-6, and CD68 expression. Concomitantly, histopathological examination revealed consistent hippocampal and cerebral cortex improvement. Thus, it can be inferred that Vit K2 can slow down age-related changes in the brain associated with modulation of NLRP3/caspase-1/Nrf-2 signaling.

Feasibility and preliminary efficacy of the LEAD trial: a cluster randomized controlled lifestyle intervention to improve hippocampal volume in older adults at-risk for dementia

BACKGROUND

Healthy diet and exercise are associated with reduced risk of dementia in older adults. The impact of diet and exercise interventions on brain health is less consistent, especially with dietary interventions which rely on varying approaches. Our objective was to evaluate the feasibility and preliminary efficacy of a 6-month intervention combining exercise with a novel dietary counseling approach to improve hippocampal volume among older adults at-risk for dementia.

METHODS

Participants with vascular risk factors and subjective cognitive decline or early mild cognitive impairment were cluster randomized in groups of 3-4 to the diet intervention (DIET) or control education (ED) group. All participants engaged in 1 h of supervised exercise per week and additional exercise at home. DIET involved 1 h per week of group-based dietary counseling comprising education, goal setting, and strategy training. ED involved 1 h per week of group-based brain health education classes. Our primary outcome was change in hippocampal volume from baseline to 6 months. Secondary outcomes included changes in cognitive function, blood biomarkers, diet, and fitness. Recruitment challenges and early discontinuation of the trial due to COVID-19 necessitated a revised focus on feasibility and preliminary efficacy.

RESULTS

Of 190 older adults contacted, 14 (7%) were eligible and enrolled, constituting 21% of our recruitment target. All participants completed the intervention and attended 90% of exercise and DIET/ED sessions on average. All 6-month assessments prior to COVID-19 were completed but disruptions to in-person testing resulted in incomplete data collection. No serious adverse events occurred and all participants expressed positive feedback about the study. Preliminary findings did not identify any significant changes in hippocampal volume; however, substantial improvements in diet and HbA1c were observed with DIET compared to ED (d = 1.75 and 1.07, respectively).

CONCLUSIONS

High adherence and retention rates were observed among participants and preliminary findings illustrate improvements in diet quality and HbA1c. These results indicate that a larger trial is feasible if difficulties surrounding recruitment can be mitigated.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03056508 .

Vitamin K dietary intake is associated with cognitive function in an older adult Mediterranean population

BACKGROUND

In the last years, evidence that dietary vitamin K could have a role in the cognitive domain has increased. However, data from large trials are limited. The objective of this study was to assess the association of 2 year changes in the dietary intake of vitamin K with cognitive function measured through neuropsychological performance tests.

METHODS

In 5,533 participants of the multicentre PREDIMED-Plus study (48.1% women, age 65.1 ± 4.9 years with overweight/obesity and metabolic syndrome), we assessed the adjusted odds ratios of cognitive function decline according to 2 year changes in vitamin K intake. Participants answered a battery of cognitive function tests and Food Frequency Questionnaires (FFQs) in order to estimate the vitamin K dietary intake.

RESULTS

After adjusting for potential cofounders, the highest tertile of change of dietary vitamin K intake (median [IQR]; 194.4 μg/d [120.9, 373.1]) was inversely associated with a Mini-Mental State Examination (MMSE) score ≤24 (OR [95% CI]; 0.53 [0.35, 0.79] P for trend = 0.002) compared with a decrease in the intake of vitamin K (median [IQR]; -97.8 μg/d [-292.8, -51.5]). A significant positive association between changes in dietary vitamin K intake and the semantic verbal fluency test scores (OR [95% CI]; 0.69 [0.51, 0.94] P for trend = 0.019) was found.

CONCLUSIONS

An increase of the intake of dietary vitamin K was associated with better cognitive function scores, independently of recognised risk factors for cognitive decline, in an older adult Mediterranean population with high cardiovascular risk.

Association of Vitamin K Insufficiency With Cognitive Dysfunction in Community-Dwelling Older Adults

Vitamin K is a fat-soluble vitamin shown to be associated with several age-related diseases. Although a small number of epidemiological studies described the relationship between vitamin K status and cognitive impairment, vitamin K status was estimated by relatively special methods in previous reports. Here, we demonstrated the association of the concentration of undercarboxylated osteocalcin (ucOC) in serum, which is a biomarker for vitamin K insufficiency, with cognitive function in a cross-sectional study. A total of 800 community-dwelling older adults (mean age = 75.9) were invited to geriatric health examination, including a Mini-Mental State Examination (MMSE) and a blood test. By using binary logistic regression analysis, the risk of cognitive impairment equivalent or below the mild cognitive impairment level for each tertile of ucOC was examined, with the lowest tertile as the reference. We found a significant association of impaired cognitive function and concentration of ucOC in the highest tertile of ucOC, with the odds ratio of 1.65 (95% CI, 1.06 to 2.59, P = 0.028). When the analysis was repeated with each domain of MMSE, the highest tertile of ucOC was associated with impaired orientation, calculation, and language. As far as we know, this is the first report on the significant association of single ucOC measurement and cognitive impairment. Our analysis also suggests that vitamin K insufficiency could be associated with selected categories of cognitive function. Since the single measurement of ucOC in serum is a simple and widely available method for vitamin K evaluation, it could be useful as a biomarker of neurodegenerative diseases affecting the cognitive functions.

Association of vitamin K with cognitive decline and neuropathology in community‐dwelling older persons

Higher vitamin K intakes have been associated with better cognitive function, suggestive of a vitamin K mechanistic effect or simply reflective of a healthy diet. To test the hypothesis that brain vitamin K is linked to cognitive decline and dementia, vitamin K concentrations were measured in four brain regions, and their associations with cognitive and neuropathological outcomes were estimated in 325 decedents of the Rush Memory and Aging Project. Menaquinone‐4 (MK4) was the main vitamin K form in the brain regions evaluated. Higher brain MK4 concentrations were associated with a 17% to 20% lower odds of dementia or mild cognitive impairment (MCI) (P‐value < .014), with a 14% to 16% lower odds of Braak stage ≥IV (P‐value < 0.045), with lower Alzheimer's disease global pathology scores and fewer neuronal neurofibrillary tangles (P‐value < 0.012). These findings provide new and compelling evidence implicating vitamin K in neuropathology underlying cognitive decline and dementia.

Effects of Dietary Food Components on Cognitive Functions in Older Adults

Population aging has recently been an important issue as the number of elderly people is growing worldwide every year, and the extension of social security costs is financially costly. The increase in the number of elderly people with cognitive decline is a serious problem related to the aging of populations. Therefore, it is necessary to consider not only physical care but also cognitive patterns in the future care of older adults. Since food contains a variety of bioactive substances, dietary patterns may help improve age-related cognitive decline. However, the relationship between cognitive function and individual food components remains ambiguous as no clear efficacy or mechanism has been confirmed. Against this background, this review summarizes previous reports on the biological process of cognitive decline in the elderly and the relationship between individual compounds in foods and cognitive function, as well as the role of individual components of food in cognitive function, in the following order: lipids, carotenoids, vitamins, phenolic compounds, amino acids, peptides, and proteins. Based on the research presented in this review, a proper diet that preserves cognitive function has the potential to improve age-related cognitive decline, Alzheimer's disease, and Parkinson's disease. Hopefully, this review will help to trigger the development of new foods and technologies that improve aging and cognitive functions and extend the healthy life span.

Vitamin K2 Holds Promise for Alzheimer's Prevention and Treatment

Recent studies have highlighted the importance of vitamin K2 (VK2) in human health. However, there have been no clinical studies investigating the role of VK2 in the prevention or treatment of Alzheimer's disease (AD), a debilitating disease for which currently there is no cure. In reviewing basic science research and clinical studies that have connected VK2 to factors involved in AD pathogenesis, we have found a growing body of evidence demonstrating that VK2 has the potential to slow the progression of AD and contribute to its prevention. In our review, we consider the antiapoptotic and antioxidant effects of VK2 and its impact on neuroinflammation, mitochondrial dysfunction, cognition, cardiovascular health, and comorbidities in AD. We also examine the link between dysbiosis and VK2 in the context of the microbiome's role in AD pathogenesis. Our review is the first to consider the physiological roles of VK2 in the context of AD, and, given the recent shift in AD research toward nonpharmacological interventions, our findings emphasize the timeliness and need for clinical studies involving VK2.

Exogenous Vitamins K Exert Anti-Inflammatory Effects Dissociated from Their Role as Substrates for Synthesis of Endogenous MK-4 in Murine Macrophages Cell Line

Vitamins K exert a range of activities that extend far beyond coagulation and include anti-inflammatory effects, but the mechanisms involved in anti-inflammatory action remain unclear. In the present study, we showed that various forms of exogenous vitamins-K1, K3, K2 (MK-4, MK-5, MK-6 and MK-7)-regulated a wide scope of inflammatory pathways in murine macrophages in vitro, including NOS-2, COX-2, cytokines and MMPs. Moreover, we demonstrated for the first time that macrophages are able to synthesise endogenous MK-4 on their own. Vitamins with shorter isoprenoid chains-K1, K3 and MK-5-exhibited stronger anti-inflammatory potential than vitamins with longer isoprenoid chains (MK-6 and MK-7) and simultaneously were preferably used as a substrate for MK-4 endogenous production. Most interesting, atorvastatin pretreatment inhibited endogenous MK-4 production but had no impact on the anti-inflammatory activity of vitamins K. In summary, our results demonstrate that macrophages are able to synthesise endogenous MK-4 using exogenous vitamins K, and statin inhibits this process. However, the anti-inflammatory effect of exogenous vitamins K was independent of endogenous MK-4 synthesis.

Milk, yogurt and cheese intake is positively associated with cognitive executive functions in older adults of the Canadian Longitudinal Study on Aging

BACKGROUND

Dairy products provide essential nutrients such as calcium, vitamins B12 and D, and include bioactive peptides and fermented products, which may be beneficial for cognition, especially in older adults. Yet, few studies of large contemporary cohorts have investigated this relationship using sensitive domain-specific cognitive tests.

METHODS

In community-dwelling older adults of the Canadian Longitudinal Study on Aging (2011-2015), we examined cross-sectional associations between total and specific dairy product intake and performance in three cognitive domains (executive functions, memory, psychomotor speed). Cheese, milk, yogurt, regular-fat, low-fat and fermented dairy product intake frequencies were estimated using a food frequency questionnaire; participants were classified into quartiles. MANCOVA models were applied to estimate differences.

RESULTS

In 7,945 participants (65-86 y, 49% women, 97% Caucasian), the mean dairy product intake was 1.9 (1.1) times/d. Total dairy product, cheese and low-fat dairy product intake were positively associated with the executive function domain and yogurt intake with the memory domain (all p<0.05), independently of important covariates including age, gender, education and diet quality. Intakes of total dairy product, cheese and low-fat dairy were associated with verbal fluency specifically (all p<0.05). Participants with a dairy product intake > 2.5 times/d had a higher score compared to those consuming less. No associations were found with psychomotor speed.

CONCLUSIONS

This large cohort study suggests a specific role for dairy components in executive function phonemic verbal fluency and memory. Dairy product intake, a modifiable factor, may be targeted in cognitive health-promoting interventions.

The Role of Vitamin K in Humans: Implication in Aging and Age-Associated Diseases

As human life expectancy is rising, the incidence of age-associated diseases will also increase. Scientific evidence has revealed that healthy diets, including good fats, vitamins, minerals, or polyphenolics, could have antioxidant and anti-inflammatory activities, with antiaging effects. Recent studies demonstrated that vitamin K is a vital cofactor in activating several proteins, which act against age-related syndromes. Thus, vitamin K can carboxylate osteocalcin (a protein capable of transporting and fixing calcium in bone), activate matrix Gla protein (an inhibitor of vascular calcification and cardiovascular events) and carboxylate Gas6 protein (involved in brain physiology and a cognitive decline and neurodegenerative disease inhibitor). By improving insulin sensitivity, vitamin K lowers diabetes risk. It also exerts antiproliferative, proapoptotic, autophagic effects and has been associated with a reduced risk of cancer. Recent research shows that protein S, another vitamin K-dependent protein, can prevent the cytokine storm observed in COVID-19 cases. The reduced activation of protein S due to the pneumonia-induced vitamin K depletion was correlated with higher thrombogenicity and possibly fatal outcomes in COVID-19 patients. Our review aimed to present the latest scientific evidence about vitamin K and its role in preventing age-associated diseases and/or improving the effectiveness of medical treatments in mature adults ˃50 years old.

The Association Between Dietary Pattern Adherence, Cognitive Stimulating Lifestyle, and Cognitive Function Among Older Adults From the Quebec Longitudinal Study on Nutrition and Successful Aging

OBJECTIVES

This study examined the effect of dietary patterns and engagement in cognitive stimulating lifestyle (CSL) behaviors on the trajectory of global cognition, executive function (EF), and verbal episodic memory (VEM).

METHODS

Western and prudent dietary patterns were empirically derived using food frequency questionnaire responses from 350 community-dwelling older adults (mean age: 73.7 years) participating in the Quebec Longitudinal Study on Nutrition and Successful Aging. CSL was represented by a binary composite indicator based on education, occupational complexity, and social engagement. Global cognition, EF, and VEM were assessed prospectively.

RESULTS

Primary effect models revealed an association between higher Western dietary pattern score and a greater rate of decline in global cognition and EF. Higher Western dietary pattern adherence was also associated with poorer baseline VEM. Primary effect models also revealed that CSL was independently associated with baseline global cognition and EF. Effect modification models suggested an interactive effect between Western dietary pattern and CLS on global cognition only. No associations were found for prudent dietary pattern score.

DISCUSSION

Contributing to existing research supporting the negative impact of consuming an unhealthy diet on cognitive function, the current study suggests increased vulnerability among older adults who do not engage in a CSL. These findings can inform the development of lifestyle intervention programs that target brain health in later adulthood.

Effects of Matcha Green Tea Powder on Cognitive Functions of Community-Dwelling Elderly Individuals

Matcha Green Tea Powder contains a variety of active ingredients beneficial to health, such as tea catechins, lutein and vitamin K. It is also known that these ingredients confer benefits upon cognitive functions of elderly people. Therefore, we aimed to investigate the relationship between a daily supplementation of Matcha and the change in cognitive functions of community-dwelling elderly people. A randomized, double-blind, placebo-controlled 12-week trial was performed. Sixty-one participants were recruited and randomly assigned to receive test drink containing 3 g powder from fresh Matcha or placebo powder per day. Changes in cognitive function were assessed utilizing a psychometric test battery. Daily food intake was assessed by a Brief-type Self-administered Diet History Questionnaire (BDHQ). In the gender-specific analysis, a significant cognitive enhancement was observed in the Montreal Cognitive Assessment (MoCA) score in the active group of women. In dietary analysis, we found a significant inverse correlation between consumption of vitamin K in daily diet, excluding test drinks, and change in MoCA. The present study suggests that daily supplementation of Matcha Green Tea Powder has protective effects against cognitive decline in community-dwelling elderly women.

Vitamins: a nutritional intervention to modulate the Alzheimer's disease progression

Background: Alzheimer's disease is known as one of the fastest growing lethal diseases worldwide where we have limited and undesired ways for regulating its pathological progress. Now-a-days, nutritional compounds have been using to treat several brain disorders and one of them; vitamins were strongly reported to combat cognition and memory deterioration in neurodegenerative diseases including Alzheimer's disease. Objective: Here, the author tried to find the precise physiological roles, status, and worth of vitamins in the brain and how exactly these nutrients modulate progression of Alzheimer's disease. Results & Discussion: After a comprehensive and systematic literature review, the author reports that vitamins have various targets in Alzheimer's disease pathogenesis by which they act to avert the neuronal dysfunction in the disease. Several Alzheimer's disease-associated neurological deficits have reported regulating by vitamin intake but the beneficial effects identified mostly in combinatorial and long-term studies. Conclusion: In this way, the author suggests that it might be better to test vitamins with other components over single vitamin approach for a compatible and synergistic effect as well as using a combination of vitamin with other compounds can target multiple pathways. This strategy may help in deteriorating memory dysfunction and cognition impairment in Alzheimer's disease pathophysiology.Abbreviations: APOE: apolipoprotein E; APP: amyloid precursor protein; ATP: adenosine triphosphate; Aβ- β-amyloid; cGMP: cyclic guanine monophosphate; CNS: central nervous system; DNA: deoxyribonucleic acid; IU: international units; RA: retinoic acid; RAR: retinoic acid receptor; RNA: ribonucleic acid; ROS: reactive oxygen species; tHcy: total homocysteine; α: alpha; β: beta; γ: gama; ε: epsilon; g: gram; µ: micron; mg: milligram; ⬆: increased,⬇: decreased.

A Review of Nutritional Requirements of Adults Aged ≥65 Years in the UK

Appropriate dietary choices in later life may reduce the risk of chronic diseases and rate of functional decline, however, there is little well-evidenced age-specific nutritional guidance in the UK for older adults, making it challenging to provide nutritional advice. Therefore, the aim of this critical review was to propose evidence-based nutritional recommendations for older adults (aged ≥65 y). Nutrients with important physiological functions in older adults were selected for inclusion in the recommendations. For these nutrients: 1) recommendations from the UK Scientific Advisory Committee for Nutrition (SACN) reports were reviewed and guidance retained if recent and age-specific, and 2) a literature search conducted where SACN guidance was not sufficient to set or confirm recommendations for older adults, searching Web of Science up to March 2020. Data extracted from a total of 190 selected publications provided evidence to support age-specific UK recommendations for protein (1.2 g·kg-1·d-1), calcium (1000 mg·d-1), folate (400 μg·d-1), vitamin B-12 (2.4 μg·d-1), and fluid (1.6 L·d-1 women, 2.0 L·d-1 men) for those ≥65 y. UK recommendations for carbohydrates, free sugars, dietary fiber, dietary fat and fatty acids, sodium, and alcohol for the general population are likely appropriate for older adults. Insufficient evidence was identified to confirm or change recommendations for all other selected nutrients. In general, significant gaps in current nutritional research among older adults existed, which should be addressed to support delivery of tailored nutritional guidance to this age group to promote healthy aging.

Vitamin K Concentration and Cognitive Status in Elderly Patients on Anticoagulant Therapy: A Pilot Study

Objectives

Recent studies have suggested that vitamin K may exert significant effects on the central nervous system. The present study investigates the relationship between vitamin K plasmatic levels and cognitive functions in elderly patients on oral anticoagulant therapy (OAT).

Design

At the Thrombosis Centre of Haematology, “Sapienza” University of Rome, 85 patients on OAT, aged between 75 and 92, were randomly enrolled in the study. Patients were on OAT with vitamin K antagonists (VKAs). Vitamin K1 concentrations were determined using standardized High-Performance Liquid Chromatography (HPLC). Cognitive functions were assessed using the Milan Overall Dementia Assessment (MODA).

Results

MODA scores are positively correlated to vitamin K1 concentration. Patients with vitamin K1 below 0.100 μg/L and between 0.100 and 0.400 μg/L and between 0.100 and 0.400 μg/L and between 0.100 and 0.400 p < 0.001). Even long-term OAT (>10 years) does not affect MODA scores. Education seems to exert a greater role on the cognitive status in comparison with aging.

Conclusions

The study shows a positive association between vitamin K1 concentration and cognitive status in elderly patients (≥75 years) on OAT. The relationship between vitamin K1 concentration and MODA scores is described by a linear model. Cognitive status is not influenced by the duration of OAT but by the years of education.

Vitamin K as a Diet Supplement with Impact in Human Health: Current Evidence in Age-Related Diseases

Vitamin K health benefits have been recently widely shown to extend beyond blood homeostasis and implicated in chronic low-grade inflammatory diseases such as cardiovascular disease, osteoarthritis, dementia, cognitive impairment, mobility disability, and frailty. Novel and more efficient nutritional and therapeutic options are urgently needed to lower the burden and the associated health care costs of these age-related diseases. Naturally occurring vitamin K comprise the phylloquinone (vitamin K1), and a series of menaquinones broadly designated as vitamin K2 that differ in source, absorption rates, tissue distribution, bioavailability, and target activity. Although vitamin K1 and K2 sources are mainly dietary, consumer preference for diet supplements is growing, especially when derived from marine resources. The aim of this review is to update the reader regarding the specific contribution and effect of each K1 and K2 vitamers in human health, identify potential methods for its sustainable and cost-efficient production, and novel natural sources of vitamin K and formulations to improve absorption and bioavailability. This new information will contribute to foster the use of vitamin K as a health-promoting supplement, which meets the increasing consumer demand. Simultaneously, relevant information on the clinical context and direct health consequences of vitamin K deficiency focusing in aging and age-related diseases will be discussed.

Concentrations of Circulating Phylloquinone, but Not Cerebral Menaquinone-4, Are Positively Correlated with a Wide Range of Cognitive Measures: Exploratory Findings in Centenarians

BACKGROUND

Vitamin K (VK) exists in the form of phylloquinone (PK) and menaquinones (MKs). Roles of VK on cognitive health in the elderly are emerging, but there is limited evidence on VK uptake and metabolism in human brain.

OBJECTIVES

The primary objective of this study was to characterize VK distribution in brains of an elderly population with varied cognitive function. In addition, associations among circulating (a biomarker of VK intake) and cerebral VK concentrations and cognition were investigated.

METHODS

Serum or plasma (n = 27) and brain samples from the frontal cortex (FC; n = 46) and the temporal cortex (TC; n = 33) were acquired from 48 decedents (aged 98-107 y; 25 demented and 23 nondemented) enrolled in the Georgia Centenarian Study. Both circulating and brain VK concentrations were measured using HPLC with fluorescence detection. Cognitive assessment was performed within 1 y prior to mortality. Partial correlations between serum/plasma or cerebral VK concentrations and cognitive function were performed, adjusting for covariates and separating by dementia and antithrombotic use.

RESULTS

MK-4 was the predominant vitamer in both FC (mean ± SD = 4.92 ± 2.31 pmol/g, ≥89.15% ± 5.09% of total VK) and TC (4.60 ± 2.11 pmol/g, ≥89.71% ± 4.43% of total VK) regardless of cognitive status. Antithrombotic users had 34.0% and 53.9% lower MK-4 concentrations in FC (P < 0.05) and TC (P < 0.001), respectively. Circulating PK was not correlated with cerebral MK-4 or total VK concentrations. Circulating PK concentrations were significantly associated with a wide range of cognitive measures in nondemented centenarians (P < 0.05). In contrast, cerebral MK-4 concentrations were not associated with cognitive performance, either before or after exclusion of antithrombotic users.

CONCLUSIONS

Circulating VK concentrations are not related to cerebral MK-4 concentrations in centenarians. Cerebral MK-4 concentrations are tightly regulated over a range of VK intakes and cognitive function. Circulating PK may reflect intake of VK-rich foods containing other dietary components beneficial to cognitive health. Further investigation of VK uptake and metabolism in the brain is warranted.

Future Therapeutic Perspectives into the Alzheimer's Disease Targeting the Oxidative Stress Hypothesis

Alzheimer's disease (AD) is a neurodegenerative disease that is usually accompanied by aging, increasingly being the most common cause of dementia in the elderly. This disorder is characterized by the accumulation of beta amyloid plaques (Aβ) resulting from impaired amyloid precursor protein (APP) metabolism, together with the formation of neurofibrillary tangles and tau protein hyperphosphorylation. The exacerbated production of reactive oxygen species (ROS) triggers the process called oxidative stress, which increases neuronal cell abnormalities, most often followed by apoptosis, leading to cognitive dysfunction and dementia. In this context, the development of new therapies for the AD treatment is necessary. Antioxidants, for instance, are promising species for prevention and treatment because they are capable of disrupting the radical chain reaction, reducing the production of ROS. These species have also proven to be adjunctive to conventional treatments making them more effective. In this sense, several recently published works have focused their attention on oxidative stress and antioxidant species. Therefore, this review seeks to show the most relevant findings of these studies.

Exploratory analysis of covariation of microbiota-derived vitamin K and cognition in older adults

BACKGROUND

Vitamin K has multiple important physiological roles, including blood coagulation and beneficial effects on myelin integrity in the brain. Some intestinal microbes possess the genes to produce vitamin K in the form of menaquinone (MK). MK appears in higher concentration in tissues, such as the brain, particularly MK4, than the dietary form of phylloquinone (PK). Lower PK concentrations have been reported in patients with Alzheimer disease while higher serum PK concentrations have been positively associated with verbal episodic memory. Despite knowledge of the importance of vitamin K for various health parameters, few studies have measured MK concentration and biosynthesis by gut commensals.

OBJECTIVE

The aim of the current study was to investigate the relation between genes involved in gut-microbiota derived MK, concentrations of MK isoforms, and cognitive function.

METHODS

Shotgun metagenomic sequencing of the gut microbiome of 74 elderly individuals with different cognitive ability levels was performed. From this, gene counts for microbial MK biosynthesis were determined. Associations between clusters of individuals, grouped based on a similar presence and prevalence of MK biosynthesis genes, and cognitive ability were investigated. Fecal MK concentrations were quantified by HPLC to investigate correlations with subject clusters.

RESULTS

Separation of subject groups defined by banded quantification of the genetic potential of their microbiome to biosynthesize MK was associated with significant differences in cognitive ability [assessed using the Mini-Mental State Examination (MMSE)]. Three MK isoforms were found to be positively associated with MMSE, along with the identification of key components of the MK pathway that drive this association. Although the causality and direction of these associations remain unknown, these findings justify further studies.

CONCLUSIONS

This study provides evidence that although total concentrations of MK did not covary with cognition, certain MK isoforms synthesized by the gut microbiome, particularly the longer chains, are positively associated with cognition.

Association between fat-soluble nutrient status and auditory and visual related potentials in newly diagnosed non-screened infants with cystic fibrosis: A case-control study

Nutritional deficiencies often precede the diagnosis of cystic fibrosis (CF) in infants, and occur at a stage where the rapidly developing brain is more vulnerable to insult. We aim to compare fat-soluble nutrient status of newly diagnosed non-screened infants with CF to that of healthy infants, and explore the association with neurodevelopment evaluated by electroencephalography (EEG). Our results show that CF infants had lower levels of all fat-soluble vitamins and docosahexaenoic acid (DHA) compared to controls. The auditory evoked potential responses were higher in CF compared to controls whereas the visual components did not differ between groups. DHA levels were correlated with auditory evoked potential responses. Although resting state frequency power was similar between groups, we observed a negative correlation between DHA levels and low frequencies. This study emphasizes the need for long-term neurodevelopmental follow-up of CF infants and pursuing intervention strategies in the future.

The Relationships Between Vitamin K and Cognition: A Review of Current Evidence

Vitamin K is a fat-soluble nutrient discovered in 1935 and its role in blood coagulation has been thoroughly explored. In recent years, studies conducted in vitro and on animals highlighted vitamin K involvement in brain cells development and survival. In particular, vitamin K seems to have an antiapoptotic and anti-inflammatory effect mediated by the activation of Growth Arrest Specific Gene 6 and Protein S. Moreover, this vitamin is involved in sphingolipids metabolism, a class of lipids that participate in the proliferation, differentiation, and survival of brain cells. An altered expression in sphingolipids profile has been related to neuroinflammation and neurodegeneration. This review stems from a growing interest in the role of vitamin K in brain functions, especially in cognition, also in view of an expected increase of prevalence of Alzheimer's disease and other forms of dementia. It collects recent researches that show interesting, even though not definitive, evidence of a direct correlation between vitamin K levels and cognitive performance. Moreover, vitamin K antagonists, used worldwide as oral anticoagulants, according to recent studies may have a negative influence on cognitive domains such as visual memory, verbal fluency and brain volume. The aim of this review is to analyze the evidence of clinical studies carried out up to date on the relationship between vitamin K intake and cognitive performances. The involvement of vitamin K antagonists (VKAs) in declining cognitive performances is also addressed separately.

The poly-omics of ageing through individual-based metabolic modelling

BACKGROUND

Ageing can be classified in two different ways, chronological ageing and biological ageing. While chronological age is a measure of the time that has passed since birth, biological (also known as transcriptomic) ageing is defined by how time and the environment affect an individual in comparison to other individuals of the same chronological age. Recent research studies have shown that transcriptomic age is associated with certain genes, and that each of those genes has an effect size. Using these effect sizes we can calculate the transcriptomic age of an individual from their age-associated gene expression levels. The limitation of this approach is that it does not consider how these changes in gene expression affect the metabolism of individuals and hence their observable cellular phenotype.

RESULTS

We propose a method based on poly-omic constraint-based models and machine learning in order to further the understanding of transcriptomic ageing. We use normalised CD4 T-cell gene expression data from peripheral blood mononuclear cells in 499 healthy individuals to create individual metabolic models. These models are then combined with a transcriptomic age predictor and chronological age to provide new insights into the differences between transcriptomic and chronological ageing. As a result, we propose a novel metabolic age predictor.

CONCLUSIONS

We show that our poly-omic predictors provide a more detailed analysis of transcriptomic ageing compared to gene-based approaches, and represent a basis for furthering our knowledge of the ageing mechanisms in human cells.

Vitamin K status and inflammation are associated with cognition in older Irish adults

Studies have shown associations between reduced vitamin K status and poor cognitive function. However, despite this apparent link, direct studies measuring cognitive function, vitamin K status and inflammation are lacking. In the current study, The ELDERMET cohort was investigated to identify associations between cognition, vitamin K status and inflammation. The primary aim of the ELDERMET study was to investigate the relationship between gut bacteria, diet, lifestyle and health in 500 older Irish adults. Significant differences in serum phylloquinone, dietary phylloquinone and inflammatory markers were found across varying levels of cognitive function, after controlling for sex, age, body mass index (BMI), triglycerides and blood pressure. In addition, significantly higher levels of dietary phylloquinone were found in those with better cognition compared to those with the poorest function. Higher levels of inflammatory were also associated with poor cognition. Furthermore, both dietary and serum phylloquinone were significant independent predictors of good cognitive function, after controlling for confounders. This study highlights the importance of dietary vitamin K as a potentially protective cognitive factor; it also provides evidence for the correlation between cognition and inflammation. Strategies should be devised by which elderly populations can access rich dietary sources of phylloquinone to maintain cognition.

Use of Vitamin K Antagonists and Brain Morphological Changes in Older Adults: An Exposed/Unexposed Voxel-Based Morphometric Study

BACKGROUND

Vitamin K antagonists (VKAs) are commonly used for their role in haemostasis by interfering with the vitamin K cycle. Since vitamin K also participates in brain physiology, this voxel-based morphometric study aimed to determine whether the duration of exposure to VKAs correlated with focal brain volume reduction in older adults.

METHODS

In this exposed/unexposed (1: 2) study nested within the GAIT (Gait and Alzheimer Interactions Tracking) cohort, 18 participants exposed to VKA (mean age 75 ± 5 years; 33.3% female; mean exposure 2,122 ± 1,799 days) and 36 matched participants using no VKA (mean age 75 ± 5 years; 33.3% female) underwent MRI scanning of the brain. Cortical grey and white matter volumes were automatically segmented using statistical parametric mapping. Age, gender, educational level, history of atrial fibrillation, type of MRI, and total intracranial volume were included as covariables.

RESULTS

The duration of exposure to VKA correlated inversely across the whole brain with the subvolumes of two clusters in the grey matter (right frontal inferior operculum and right precuneus) and one cluster in the white matter (left middle frontal gyrus). In contrast, the grade of white matter hyperintensities did not differ according to the use of VKA.

CONCLUSION

We found focal atrophies in older adults exposed to VKA. These findings provide new insights elucidating the effects of VKAs on brain health and function in older adults.

Vitamin K Deficiency Induced by Warfarin Is Associated With Cognitive and Behavioral Perturbations, and Alterations in Brain Sphingolipids in Rats

Initially discovered for its role in blood coagulation, there is now convincing evidence that vitamin K (VK) has important actions in the nervous system. In brain, VK is present in the form of menaquinone-4 (MK-4), a byproduct of the main dietary source, phylloquinone. It contributes to the biological activation of various proteins (i.e., Gas6), and participates in the synthesis of sphingolipids, a class of lipids widely present in brain cell membranes with important cell signaling functions. In a previous study, we reported that lifetime consumption of a low VK diet resulted in mild cognitive impairment in aged rats, a finding associated with an alteration of the sphingolipid profile. To confirm the role of VK as it relates to sphingolipids, cognition, and behavior outside the context of aging, we conducted a study of acute VK deficiency using a pharmacological model of VK deficiency in brain. In this procedure, rats (8 weeks) are maintained on a ratio of warfarin (a VK antagonist) to VK whereby coagulation is maintained while inducing VK deficiency in extrahepatic tissues. After 10 weeks of treatment, rats who were subjected to the warfarin plus phylloquinone protocol (WVK) exhibited longer latencies in the Morris water maze test as well as lower locomotor activity and exploratory behavior in the open field test, when compared to control rats. The WVK treatment resulted in a dramatic decrease in MK-4 level in all brain regions despite the presence of high local concentrations of phylloquinone, which suggests an inhibition of the biosynthetic MK-4 pathway in the presence of warfarin. Additionally, WVK treatment affected sphingolipid concentrations in key brain regions, notably those of the ganglioside family. Finally, brain MK-4 was correlated with performances in the open field test. This study confirms the modulatory role of VK in cognition and behavior and the implication of sphingolipids, notably those of the ganglioside family.

A potential biotechnological process for the sustainable production of vitamin K1

The primary objective of this review is to propose an approach for the biosynthesis of phylloquinone (vitamin K₁) based upon its known sources, its role in photosynthesis and its biosynthetic pathway. The chemistry, health benefits, market, and industrial production of vitamin K are also summarized. Vitamin K compounds (K vitamers) are required for the normal function of at least 15 proteins involved in diverse physiological processes such as coagulation, tissue mineralization, inflammation, and neuroprotection. Vitamin K is essential for the prevention of Vitamin K Deficiency Bleeding (VKDB), especially in neonates. Increased vitamin K intake may also reduce the severity and/or risk of bone fracture, arterial calcification, inflammatory diseases, and cognitive decline. Consumers are increasingly favoring natural food and therapeutic products. However, the bulk of vitamin K products employed for both human and animal use are chemically synthesized. Biosynthesis of the menaquinones (vitamin K₂) has been extensively researched. However, published research on the biotechnological production of phylloquinone is restricted to a handful of available articles and patents. We have found that microalgae are more suitable than plant cell cultures for the biosynthesis of phylloquinone. Many algae are richer in vitamin K₁ than terrestrial plants, and algal cells are easier to manipulate. Vitamin K₁ can be efficiently recovered from the biomass using supercritical carbon dioxide extraction.

Effects of nutrient and bioactive food components on Alzheimer's disease and epigenetic

Alzheimer's disease (AD) is the most common form of dementia in the elderly and is a chronic neurodegenerative disease that is becoming widespread. For this reason, in recent years factors affecting the development, progression and cognitive function of the AD have been emphasized. Nutrients and other bioactive nutrients are among the factors that are effective in AD. In particular, vitamins A, C and E, vitamins B₁, B₆ and B₁₂, folate, magnesium, choline, inositol, anthocyanins, isoflavones etc. nutrients and bioactive nutrients are known to be effective in the development of AD. Nutrients and nutrient components may also have an epigenetic effect on AD. At the same time, nutrients and bioactive food components slow down the progression of the disease. For this reason, the effect of nutrients and food components on AD was examined in this review.

Vitamins K1 and K2: The Emerging Group of Vitamins Required for Human Health

Objective

To review the evidence for the use of vitamin K supplementation in clinical conditions such as osteoporosis, vascular calcification, arthritis, cancer, renal calculi, diabetes, and warfarin therapy.

Quality of Evidence

PubMed was searched for articles on vitamin K (K1 and K2) along with books and conference proceedings and health conditions listed above. Level I and II evidence supports the use of vitamins K1 and K2 in osteoporosis and Level II evidence supports vitamin K2 in prevention of coronary calcification and cardiovascular disease. Evidence is insufficient for use in diabetes, arthritis, renal calculi, and cancer.

Main Message

Vitamin K2 may be a useful adjunct for the treatment of osteoporosis, along with vitamin D and calcium, rivaling bisphosphonate therapy without toxicity. It may also significantly reduce morbidity and mortality in cardiovascular health by reducing vascular calcification. Vitamin K2 appears promising in the areas of diabetes, cancer, and osteoarthritis. Vitamin K use in warfarin therapy is safe and may improve INR control, although a dosage adjustment is required.

Conclusion

Vitamin K supplementation may be useful for a number of chronic conditions that are afflicting North Americans as the population ages. Supplementation may be required for bone and cardiovascular health.

Association between osteocalcin gamma-carboxylation and insulin resistance in overweight and obese postmenopausal women

AIM

In mice, osteocalcin (OCN) acts as a bone-derived hormone promoting insulin sensitivity and glucose tolerance. In that species, OCN endocrine action is inhibited when its first glutamic acid residue (Glu13) is γ-carboxylated (Gla). The importance of this posttranslational modification for OCN function in human is still unclear. Our objectives were to identify an assay to assess γ-carboxylation of human OCN on its first Glu residue (Glu17) and to test its association with insulin resistance and inflammation profile in overweight women.

METHODS

Several ELISAs were tested to determine their specificity toward various forms of human OCN. Associations between OCN γ-carboxylation and determinants of glucose tolerance, insulin sensitivity, liver function and subclinical inflammation were then investigated in 129 non-diabetic overweight and obese postmenopausal women.

RESULTS

We identified assays allowing the measurement of total OCN (tOCN) and the ratio of Gla17/tOCN. Circulating Gla17/tOCN levels correlated negatively with insulin sensitivity assessed by hyperinsulinemic-euglyceamic clamp (P=0.02) or insulin sensitivity index derived from oral glucose tolerance test (P=0.00003), and positively with insulin resistance assessed by HOMA-IR (P=0.0005) and with markers of subclinical inflammation and liver enzymes, including C-reactive protein (CRP; P=0.007) and aspartate aminotransferase (AST; P=0.009).

CONCLUSIONS

γ-carboxylation of OCN on Glu17 residue correlates with insulin resistance and subclinical inflammation, suggesting that γ-carboxylation of OCN negatively regulates its endocrine action in humans.

Association of Dietary Patterns With Global and Domain-Specific Cognitive Decline in Chinese Elderly

BACKGROUND

Significant differences exist between eastern and western diets, and the way in which Chinese dietary intake relates to specific cognitive domains remains unclear. We aimed to assess the association between dietary patterns (DPs) and cognitive decline in Chinese elderly.

SETTING

Participants were recruited from the elderly health checkup program of a teaching hospital in Taipei, Taiwan.

PARTICIPANTS

A total of 475 elders (age ≥65) were included in this prospective cohort study.

MEASUREMENTS

The outcome comprised the decline of global and domain-specific cognition between baseline (2011-2013) and follow-up (2013-2015). Dietary data from the previous year were collected via a food frequency questionnaire at baseline, and a factor analysis was performed to identify DPs. Multivariable linear regression and logistic regression models were used to assess associations between Chinese DPs and cognitive decline over 2 years adjusting for selected covariates.

RESULTS

Three DPs (vegetable, meat, and traditional) were identified. Moderate- or high-score "vegetable" DP significantly protected against decline of logical memory (recall I: β = 0.16-0.18, odds ratio (OR) = 0.42-0.48; recall II: β = 0.17-0.21); while high-score DP increased executive function decline (β = -0.22). A high-score "meat" DP was related to decline of verbal fluency-total score (β = -0.19); while moderate- or high-score "meat" DP protected against attention decline (β = 0.20-0.22). High-score "traditional" DP protected against decline of logical memory-recall I (β = 0.18). No significant association was observed for global cognition.

CONCLUSION

These findings suggest that three DPs identified in Chinese elderly were associated with different cognitive domains. Further research is needed to explore the efficacy of dietary interventions in reducing cognitive decline in older adults.

Vitamin Supplementation as an Adjuvant Treatment for Alzheimer's Disease

Alzheimer's Disease (AD) is a slowly progressing neurodegenerative disorder representing a major health concern worldwide. This disorder is characterised by progressive dementia and cognitive decline. The pathological hallmarks of AD include the presence of Aβ plaques and tau neurofibrils. Research has shown that oxidative stress represents a major risk factor associated with AD pathology. Accumulation of Aβ plaques and relative lack of antioxidant defence mechanisms, including cellular antioxidant enzymes and dietary antioxidants like vitamins, assist in the exacerbation of oxidative stress. Reactive Oxygen Species (ROS) produced as the result of oxidative stress, that increase structural and functional abnormalities in brain neurons, which then manifests as dementia and decline in cognition. Data from numerous epidemiological studies suggests that nutrition is one of the most important yet modifiable risk factors for AD. Since oxidative stress contributes a great deal in the development and progression of AD, anything that could attenuate oxidative stress would help in decreasing the prevalence and incidence of AD. There is increasing evidence that supports the use of different antioxidant as an adjuvant treatment for AD. Vitamins are one such antioxidant that can be used as an adjuvant in AD treatment. This paper will focus on the evidence, based on current literature, linking the use of vitamin supplementations as an adjuvant treatment for AD.

Increased dietary vitamin K intake is associated with less severe subjective memory complaint among older adults

OBJECTIVES

Increased dietary intake of vitamin K, a fat-soluble nutrient involved in brain health and function, has been associated with better cognitive performance in older adults. Our objective was to determine whether the dietary vitamin K intake was associated with the presence and severity of subjective memory complaint among older adults.

STUDY DESIGN

Observational, cross-sectional cohort study.

MAIN OUTCOME MEASURES

One hundred sixty older adults taking no vitamin K antagonist were included. The daily dietary vitamin K intake was assessed using a 50-item food frequency questionnaire. The subjective memory complaint was assessed at the same time using the Memory Complaint Questionnaire (MAC-Q; score 0-30, best). Serious subjective memory complaint was defined as MAC-Q score ≤15. Age, gender, body mass index, education level, number of comorbidities, history of stroke, objective cognitive disorders, functional autonomy, mood, serum concentrations of vitamin B12, TSH, albumin, and estimated glomerular filtration rate were used as potential confounders.

RESULTS

Compared to participants without serious subjective memory complaint, those with serious subjective memory complaint (n=110) had a lower mean dietary vitamin K intake (298.0±191.8μg/day versus 393.8±215.2μg/day, P=0.005). Increased log dietary vitamin K intake was positively associated with the MAC-Q score used as a quantitative variable (fully adjusted β=0.79, P=0.031), and inversely with serious subjective memory complaint (fully adjusted OR=0.34, P=0.017).

CONCLUSIONS

Increased dietary vitamin K intake was associated with fewer and less severe subjective memory complaint in older adults taking no vitamin K antagonists. These findings provide epidemiological data supporting future vitamin K replacement trials.

Vitamin K Antagonists and Cognitive Function in Older Adults: The Three-City Cohort Study

BACKGROUND

A growing body of evidence supports a beneficial role for vitamin K in brain and cognition, notably in studies where animals are rendered vitamin K deficient by warfarin, a potent vitamin K antagonist (VKA). Given VKAs are commonly used oral anticoagulants in older persons, we investigated the relationship between VKA therapy and cognitive performances over 10 years in participants of the Three-City study.

METHODS

The Three-City cohort included 7,133 nondemented community dwellers, aged 65 years or older at baseline. Exposures to VKAs and platelet aggregation inhibitors, another antithrombotic agent, were determined at baseline. Participants underwent cognitive assessment at baseline and every 2 years over 10 years. Associations were analyzed with mixed linear models adjusting for many covariates including VKA and platelet aggregation inhibitor indications.

RESULTS

About 239 (3.4%) and 1,192 (16.7%) of the participants were treated with VKAs and platelet aggregation inhibitors at baseline, respectively. VKA treatment was significantly associated with worse performances on Benton Visual Retention Test assessing visual memory (adjusted mean difference -0.29; p = .02 in multivariate models) and Isaacs Set Test assessing verbal fluency (adjusted mean difference -1.37; p = .0009) at baseline. Treatment with VKAs was not associated with global cognitive functioning on the Mini Mental State Examination, neither with rate of subsequent decline in scores on all three cognitive tests. No associations were found between platelet aggregation inhibitors and cognitive performances or rate of decline.

CONCLUSION

These findings do not indicate a long-term detrimental effect of VKAs on cognition, but the risk-benefit balance of VKA treatment still deserves further research.

Vitamin K Status Is not Associated with Cognitive Decline in Middle Aged Adults

OBJECTIVES

The aim of this study was to examine the association between dephospho-uncarboxylated matrix Gla protein (dp-ucMGP), an indicator of vitamin K status, and cognitive decline, and the modifying role of 25(OH)D.

DESIGN

Longitudinal study with six years follow-up.

SETTING

Community based.

PARTICIPANTS

599 participants of the Longitudinal Aging Study Amsterdam (aged 55-65 years).

MEASUREMENTS

Information processing speed and a composite Z-score by combining three domains of cognition reflecting general cognitive functioning.

RESULTS

Generalized estimating equations (GEE) showed no significant associations between dp-ucMGP and decline in general cognitive functioning. Vitamin D modified the association between dp-ucMGP and speed of information processing (p<0.05). In the group with a 25(OH)D concentration > 50 nmol/l, the highest tertile of dp-ucMGP (>406 pmol/l), which corresponds to lower vitamin K levels, was associated with 1.5 higher score on information processing speed (p=0.023) as compared to the lowest tertile of dp-ucMGP.

CONCLUSION

In contrast to our hypothesis, a suboptimal vitamin K was not associated with cognitive decline in middle-aged adults.

Dietary Vitamin K Intake Is Associated with Cognition and Behaviour among Geriatric Patients: The CLIP Study

Our objective was to determine whether dietary vitamin K intake was associated with cognition and behavior among older adults. 192 consecutive participants ≥65 years, recruited in the cross-sectional CLIP (Cognition and LIPophilic vitamins) study, were separated into two groups according to the tertiles of dietary phylloquinone intake (i.e., lowest third below 207 µg/day versus the other two thirds combined). Daily dietary phylloquinone intake was estimated from 50-item interviewer-administered food frequency questionnaire. Cognition was assessed with Mini-Mental State Examination (MMSE); behaviour with Frontotemporal Behavioral Rating Scale (FBRS). Age, gender, social problems, education, body mass index (BMI), comorbidities, history of stroke, use vitamin K antagonists, inadequate fatty fish intake, serum thyroid-stimulating hormone (TSH), vitamin B12, albumin, and estimated glomerular filtration rate were used as confounders. Compared to participants in the lowest third of dietary phylloquinone intake (n = 64), those with higher intake had higher (i.e., better) mean MMSE score (22.0 ± 5.7 versus 19.9 ± 6.2, p = 0.024) and lower (i.e., better) FBRS score (1.5 ± 1.2 versus 1.9 ± 1.3, p = 0.042). In multivariate linear regressions, log dietary phylloquinone intake was positively associated with MMSE score (adjusted β = 1.66, p = 0.013) and inversely associated with FBRS score (adjusted β = −0.33, p = 0.037). Specifically, log dietary phylloquinone intake correlated negatively with FBRS subscore of physical neglect (r = −0.24, p = 0.001). Higher dietary phylloquinone intake was associated with better cognition and behavior among older adults.