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Nutrients Mar 2020Vitamin K acts as a cofactor and is required for post-translational γ-carboxylation of vitamin K-dependent proteins (VKDP). The current recommended daily intake (RDI)... (Review)
Review
Vitamin K acts as a cofactor and is required for post-translational γ-carboxylation of vitamin K-dependent proteins (VKDP). The current recommended daily intake (RDI) of vitamin K in most countries has been established based on normal coagulation requirements. Vitamin K1 and menaquinone (MK)-4 has been shown to decrease osteocalcin (OC) γ-carboxylation at RDI levels. Among the several vitamin K homologs, only MK-7 (vitamin K2) can promote γ-carboxylation of extrahepatic VKDPs, OC, and the matrix Gla protein at a nutritional dose around RDI. MK-7 has higher efficacy due to its higher bioavailability and longer half-life than other vitamin K homologs. As vitamin K1, MK-4, and MK-7 have distinct bioactivities, their RDIs should be established based on their relative activities. MK-7 increases bone mineral density and promotes bone quality and strength. Collagen production, and thus, bone quality may be affected by MK-7 or MK-4 converted from MK-7. In this review, we comprehensively discuss the various properties of MK-7.
Topics: Biological Availability; Bone Density; Bone and Bones; Collagen; Dietary Supplements; Humans; Osteocalcin; Recommended Dietary Allowances; Vitamin K 1; Vitamin K 2
PubMed: 32244313
DOI: 10.3390/nu12040965 -
Nutrients Jun 2020Vitamin K and its essential role in coagulation (vitamin K [Koagulation]) have been well established and accepted the world over. Many countries have a Recommended Daily... (Review)
Review
Vitamin K and its essential role in coagulation (vitamin K [Koagulation]) have been well established and accepted the world over. Many countries have a Recommended Daily Intake (RDI) for vitamin K based on early research, and its necessary role in the activation of vitamin K-dependent coagulation proteins is known. In the past few decades, the role of vitamin K-dependent proteins in processes beyond coagulation has been discovered. Various isoforms of vitamin K have been identified, and vitamin K2 specifically has been highlighted for its long half-life and extrahepatic activity, whereas the dietary form vitamin K1 has a shorter half-life. In this review, we highlight the specific activity of vitamin K2 based upon proposed frameworks necessary for a bioactive substance to be recommended for an RDI. Vitamin K2 meets all these criteria and should be considered for a specific dietary recommendation intake.
Topics: Diet; Dietary Supplements; Humans; Recommended Dietary Allowances; Vitamin K 1; Vitamin K 2; Vitamin K Deficiency
PubMed: 32575901
DOI: 10.3390/nu12061852 -
Journal of the American College of... Jan 2023The efficacy and safety of direct oral anticoagulants (DOACs) for patients with thrombotic antiphospholipid syndrome remain controversial. (Meta-Analysis)
Meta-Analysis
BACKGROUND
The efficacy and safety of direct oral anticoagulants (DOACs) for patients with thrombotic antiphospholipid syndrome remain controversial.
OBJECTIVES
The authors performed a systematic review and meta-analysis of randomized controlled trials that compared DOACs with vitamin K antagonists (VKAs).
METHODS
We searched PubMed, EMBASE, and Cochrane Central Register of Controlled Trials through April 9, 2022. The 2 main efficacy outcomes were a composite of arterial thrombotic events and venous thromboembolic events (VTEs). The main safety outcome was major bleeding. Random effects models with inverse variance were used.
RESULTS
Our search retrieved 253 studies. Four open-label randomized controlled trials involving 472 patients were included (mean control-arm time-in-therapeutic-range 60%). All had proper random sequence generation and adequate allocation concealment. Overall, the use of DOACs compared with VKAs was associated with increased odds of subsequent arterial thrombotic events (OR: 5.43; 95% CI: 1.87-15.75; P < 0.001, I = 0%), especially stroke, and the composite of arterial thrombotic events or VTE (OR: 4.46; 95% CI: 1.12-17.84; P = 0.03, I = 0%). The odds of subsequent VTE (OR: 1.20; 95% CI: 0.31-4.55; P = 0.79, I = 0%), or major bleeding (OR: 1.02; 95% CI: 0.42-2.47; P = 0.97; I = 0%) were not significantly different between the 2 groups. Most findings were consistent within subgroups.
CONCLUSIONS
Patients with thrombotic antiphospholipid syndrome randomized to DOACs compared with VKAs appear to have increased risk for arterial thrombosis. No significant differences were observed between patients randomized to DOACs vs VKAs in the risk of subsequent VTE or major bleeding.
Topics: Humans; Administration, Oral; Anticoagulants; Antiphospholipid Syndrome; Fibrinolytic Agents; Hemorrhage; Randomized Controlled Trials as Topic; Thrombosis; Venous Thromboembolism; Vitamin K
PubMed: 36328154
DOI: 10.1016/j.jacc.2022.10.008 -
Cell Reports May 2023Vitamin K is a micronutrient necessary for γ-carboxylation of glutamic acids. This post-translational modification occurs in the endoplasmic reticulum (ER) and affects...
Vitamin K is a micronutrient necessary for γ-carboxylation of glutamic acids. This post-translational modification occurs in the endoplasmic reticulum (ER) and affects secreted proteins. Recent clinical studies implicate vitamin K in the pathophysiology of diabetes, but the underlying molecular mechanism remains unknown. Here, we show that mouse β cells lacking γ-carboxylation fail to adapt their insulin secretion in the context of age-related insulin resistance or diet-induced β cell stress. In human islets, γ-carboxylase expression positively correlates with improved insulin secretion in response to glucose. We identify endoplasmic reticulum Gla protein (ERGP) as a γ-carboxylated ER-resident Ca-binding protein expressed in β cells. Mechanistically, γ-carboxylation of ERGP protects cells against Ca overfilling by diminishing STIM1 and Orai1 interaction and restraining store-operated Ca entry. These results reveal a critical role of vitamin K-dependent carboxylation in regulation of Ca flux in β cells and in their capacity to adapt to metabolic stress.
Topics: Mice; Animals; Humans; Vitamin K; Osteocalcin; Protein Processing, Post-Translational; Insulin; Stress, Physiological; Calcium
PubMed: 37171959
DOI: 10.1016/j.celrep.2023.112500 -
Digestive Diseases and Sciences Nov 2021Patients receiving anticoagulant therapies, such as vitamin K antagonists (VKAs) or direct oral anticoagulants (DOACs), commonly experience gastrointestinal (GI)... (Review)
Review
BACKGROUND
Patients receiving anticoagulant therapies, such as vitamin K antagonists (VKAs) or direct oral anticoagulants (DOACs), commonly experience gastrointestinal (GI) bleeding as a complication and may require anticoagulant reversal prior to endoscopic treatment. Anticoagulant reversal agents include prothrombin complex concentrates (PCCs; including 3 or 4 coagulation factors), plasma, vitamin K, and target-specific DOAC reversal agents (e.g., idarucizumab and andexanet alfa).
AIM
To review current US, as well as international, guidelines for anticoagulant reversal agents in patients on VKAs or DOACs presenting with GI bleeding prior to endoscopy, guideline-based management of coagulation defects, timing of endoscopy, and recommendations for resumption of anticoagulant therapy following hemostasis. Supporting clinical data were also reviewed.
METHODS
This is a narrative review, based on PubMed and Internet searches reporting GI guidelines and supporting clinical data.
RESULTS
GI-specific guidelines state that use of reversal agents should be considered in patients with life-threatening GI bleeding. For VKA patients presenting with an international normalized ratio > 2.5, guidelines recommend PCCs (specifically 4F-PCC), as they may exhibit greater efficacy/safety compared with fresh frozen plasma in reversal of VKA-associated GI bleeding. For DOAC patients, most guidelines recommend targeted specific reversal agents in the setting of GI bleeding; however, PCCs (primarily 4F-PCC) are often listed as another option. Resumption of anticoagulant therapy following cessation of GI bleeding is also recommended to reduce risks of future thromboembolic complications.
CONCLUSIONS
The utility of anticoagulant reversal agents in GI bleeding is recognized in guidelines; however, such agents should be reserved for use in truly life-threatening scenarios.
Topics: Anticoagulants; Blood Coagulation Factors; Gastrointestinal Hemorrhage; Humans; Practice Guidelines as Topic; Vitamin K
PubMed: 33403486
DOI: 10.1007/s10620-020-06728-y -
Nutrients Jan 2020Vitamin K health benefits have been recently widely shown to extend beyond blood homeostasis and implicated in chronic low-grade inflammatory diseases such as... (Review)
Review
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.
Topics: Adult; Aged; Aged, 80 and over; Aging; Biological Availability; Dietary Supplements; Female; Humans; Male; Middle Aged; Vitamin K; Vitamin K 1; Vitamin K 2; Vitamins
PubMed: 31947821
DOI: 10.3390/nu12010138 -
Advances in Nutrition (Bethesda, Md.) Feb 2022
Topics: Humans; Vitamin K
PubMed: 34971361
DOI: 10.1093/advances/nmab133 -
Frontiers in Public Health 2022Vitamin K (VK) as a nutrient, is a cofactor in the carboxylation of osteocalcin (OC), which can bind with hydroxyapatite to promote bone mineralization and increase bone... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Vitamin K (VK) as a nutrient, is a cofactor in the carboxylation of osteocalcin (OC), which can bind with hydroxyapatite to promote bone mineralization and increase bone strength. However, some studies have been inconsistent on whether vitamin K2 (VK2) can maintain or improve bone mineral density (BMD) and reduce the incidence of fractures in postmenopausal women. Therefore, the main objective of this meta-analysis was to determine the effect of VK2 as a nutritional supplement on BMD and fracture incidence in postmenopausal women.
METHODS
We searched PubMed, EMBASE, and Cochrane Library databases (published before March 17, 2022) and then extracted and pooled data from all randomized controlled trials (RCTs) that met the inclusion criteria.
RESULTS
Sixteen RCTs with a total of 6,425 subjects were included in this meta-analysis. The overall effect test of 10 studies showed a significant improvement in lumbar spine BMD (BMD LS) ( = 0.006) with VK2. The subgroup analysis of VK2 combination therapy showed that BMD LS was significantly maintained and improved with the administration of VK2 ( = 0.03). The overall effect test of the six RCTs showed no significant difference in fracture incidence between the two groups (RR=0.96, P=0.65). However, after excluding one heterogeneous study, the overall effect test showed a significant reduction in fracture incidence with VK2 (RR = 0.43, = 0.01). In addition, this meta-analysis showed that VK2 reduced serum undercarboxylated osteocalcin (uc-OC) levels and the ratio of uc-OC to cOC in both subgroups of VK2 combined intervention and alone. However, for carboxylated osteocalcin (cOC), both subgroup analysis and overall effect test showed no significant effect of VK2 on it. And the pooled analysis of adverse reactions showed no significant difference between the VK2 and control groups (RR = 1.03, 95%CI 0.87 to 1.21, = 0.76).
CONCLUSIONS
The results of this meta-analysis seem to indicate that VK2 supplementation has a positive effect on the maintenance and improvement of BMD LS in postmenopausal women, and it can also reduce the fracture incidence, serum uc-OC levels and the ratio of uc-OC to cOC. In conclusion, VK2 can indirectly promote bone mineralization and increase bone strength.
Topics: Bone Density Conservation Agents; Female; Humans; Osteocalcin; Osteoporosis, Postmenopausal; Randomized Controlled Trials as Topic; Vitamin K 2
PubMed: 36033779
DOI: 10.3389/fpubh.2022.979649 -
Nutrients Apr 2023Fatigue, characterised by lack of energy, mental exhaustion and poor muscle endurance which do not recover following a period of rest, is a common characteristic symptom... (Review)
Review
Fatigue, characterised by lack of energy, mental exhaustion and poor muscle endurance which do not recover following a period of rest, is a common characteristic symptom of several conditions and negatively impacts the quality of life of those affected. Fatigue is often a symptom of concern for people suffering from conditions such as fibromyalgia, chronic fatigue syndrome, cancer, and multiple sclerosis. Vitamins and minerals, playing essential roles in a variety of basic metabolic pathways that support fundamental cellular functions, may be important in mitigating physical and mental fatigue. Several studies have examined the potential benefits of nutrients on fatigue in various populations. The current review aimed to gather the existing literature exploring different nutrients' effects on fatigue. From the searches of the literature conducted in PubMed, Ovid, Web of Science, and Google scholar, 60 articles met the inclusion criteria and were included in the review. Among the included studies, 50 showed significant beneficial effects ( < 0.05) of vitamin and mineral supplementation on fatigue. Altogether, the included studies investigated oral or parenteral administration of nutrients including Coenzyme Q10, L-carnitine, zinc, methionine, nicotinamide adenine dinucleotide (NAD), and vitamins C, D and B. In conclusion, the results of the literature review suggest that these nutrients have potentially significant benefits in reducing fatigue in healthy individuals as well as those with chronic illness, both when taken orally and parenterally. Further studies should explore these novel therapies, both as adjunctive treatments and as sole interventions.
Topics: Humans; Quality of Life; Nutrients; Vitamins; Vitamin A; Vitamin K; Mental Fatigue
PubMed: 37432282
DOI: 10.3390/nu15092154 -
International Journal of Molecular... Aug 2021Cardiovascular diseases are the most common cause of death in the world. For almost 60 years, vitamin K antagonists (VKAs) were the mainstay of anticoagulation therapy,... (Review)
Review
Cardiovascular diseases are the most common cause of death in the world. For almost 60 years, vitamin K antagonists (VKAs) were the mainstay of anticoagulation therapy, but in recent years direct oral anticoagulants (DOACs) have become the anticoagulant treatment of choice. DOACs were initially considered drugs with no significant food interactions; however, clinical observations from daily practice have proved otherwise as interactions with food ingredients have been reported. Food, dietary supplements or herbs may contain substances that, when administered concomitantly with DOACs, can potentially affect the plasma concentration of the drugs. The aim of this paper was to evaluate the clinical significance of drug-food interactions of DOACs, such as dabigatran, rivaroxaban, apixaban, edoxaban and betrixaban. Patients treated with anticoagulants should avoid products containing and take special care with other food ingredients. As the interest in dietary supplements is on the rise, healthcare providers can contribute to the development of well-designed clinical trials on interactions between DOACs and food, and distribute sufficient knowledge about the proper use of these supplements among patients.
Topics: Administration, Oral; Anticoagulants; Dietary Supplements; Food-Drug Interactions; Humans; Vitamin K
PubMed: 34445237
DOI: 10.3390/ijms22168531