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Vitamin K (VK) plays many important functions in the body. The most important of them include the contribution in calcium homeostasis and anticoagulation. Vascular calcification (VC) is one of the most important mechanisms of renal pathology. The most potent inhibitor of this process-matrix Gla protein (MGP) is VK-dependent. Chronic kidney disease (CKD) patients, both non-dialysed and hemodialysed, often have VK deficiency. Elevated uncarboxylated matrix Gla protein (ucMGP) levels indirectly reflected VK deficiency and are associated with a higher risk of cardiovascular events in these patients. It has been suggested that VK intake may reduce the VC and related cardiovascular risk. Vitamin K intake has been suggested to reduce VC and the associated cardiovascular risk. The role and possibility of VK supplementation as well as the impact of anticoagulation therapy on VK deficiency in CKD patients is discussed.

Reported associations between vitamin K 1 and both all-cause and cause-specific mortality are conflicting. The 56,048 participants from the Danish Diet, Cancer, and Health prospective cohort study, with a median [IQR] age of 56 [52-60] years at entry and of whom 47.6% male, were followed for 23 years, with 14,083 reported deaths. Of these, 5015 deaths were CVD-related, and 6342 deaths were cancer-related. Intake of vitamin K 1 (phylloquinone) was estimated from a food-frequency questionnaire (FFQ), and its relationship with mortality outcomes was investigated using Cox proportional hazards models. A moderate to high (87-192 µg/d) intake of vitamin K 1 was associated with a lower risk of all-cause [HR (95%CI) for quintile 5 vs quintile 1: 0.76 (0.72, 0.79)], cardiovascular disease (CVD)-related [quintile 5 vs quintile 1: 0.72 (0.66, 0.79)], and cancer-related mortality [quintile 5 vs quintile 1: 0.80 (0.75, 0.86)], after adjusting for demographic and lifestyle confounders. The association between vitamin K 1 intake and cardiovascular disease-related mortality was present in all subpopulations (categorised according to sex, smoking status, diabetes status, and hypertension status), while the association with cancer-related mortality was only present in current/former smokers (p for interaction = 0.002). These findings suggest that promoting adequate intakes of foods rich in vitamin K 1 may help to reduce all-cause, CVD-related, and cancer-related mortality at the population level., (© 2021. The Author(s).)

Background & Aims: Vitamin K has been associated with various health outcomes, including non-fatal cardiovascular diseases (CVD) and cancer. However, little is known about the association between vitamin K intake and all-cause and cause specific mortality. This study aims to investigate the association between vitamin K intake and all-cause and cause-specific mortality., Methods: This prospective cohort study included 33,289 participants from the EPIC-NL cohort, aged 20-70 years at baseline and recruited between 1993 and 1997. Dietary intake was assessed at baseline with a validated food frequency questionnaire and intakes of phylloquinone, and total, short chain and long chain menaquinones were calculated. Information on vital status and causes of death was obtained through linkage to several registries. The association between the different forms of vitamin K intake and mortality was assessed with Cox proportional hazards, adjusted for risk factors for chronic diseases and nutrient intake., Results: During a mean follow-up of 16.8 years, 2863 deaths occurred, including 625 from CVD (256 from coronary heart disease (CHD)), 1346 from cancer and 892 from other causes. After multivariable adjustment, phylloquinone and menaquinones were not associated with all-cause mortality with hazard ratios for the upper vs. the lowest quartile of intake of 1.04 (0.92;1.17) and 0.94 (0.82;1.07) respectively. Neither phylloquinone intake nor menaquinone intake was associated with risk of CVD mortality. Higher intake of long chain menaquinones was borderline significantly associated (p trend  = 0.06) with lower CHD mortality with a HR 10μg of 0.86 (0.74;1.00). None of the forms of vitamin K intake were associated with cancer mortality or mortality from other causes., Conclusions: Vitamin K intake was not associated with all-cause mortality, cancer mortality and mortality from other causes., (Copyright © 2016. Published by Elsevier Ltd.)

Vitamin K plays important biological roles in maintaining normal blood coagulation, bone mineralization, soft tissue physiology, and neurological development. Menaquinone-7 is a form of vitamin K2 that occurs naturally in some animal-derived and fermented foods. It is also available as an ingredient of dietary supplements. Menaquinone-7 has greater bioavailability than other forms of vitamin K, which has led to increasing sales and use of menaquinone-7 supplements. This special article reviews the chemistry, nomenclature, dietary sources, intake levels, and pharmacokinetics of menaquinones, along with the nonclinical toxicity data available and the data on clinical outcomes related to safety (adverse events). In conclusion, the data reviewed indicate that menaquinone-7, when ingested as a dietary supplement, is not associated with any serious risk to health or with other public health concerns. On the basis of this conclusion, US Pharmacopeia monographs have been developed to establish quality standards for menaquinone-7 as a dietary ingredient and as a dietary supplement in various dosage forms., (© The Author(s) 2017. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Purpose: To develop a stable micellar formulation of vitamin K for oral delivery, because the commercial and clinically used formulation of vitamin K (Konakion® MM) destabilizes at gastric pH resulting in low bioavailability of this vitamin in neonates with cholestasis., Methods: Mixed micelles composed of EPC, DSPE-PEG 2000 and glycocholic acid, with and without vitamin K, were prepared by a film hydration method. The influence of pH on the stability of the micelles was analyzed by dynamic light scattering (DLS). The critical micelle concentration (CMC) was determined by fluorescence spectroscopy using pyrene and the morphology was evaluated by transmission electron microscopy . Caco-2 cells were used to study the cytocompatibilty., Results: Mixed micelles with mean diameters from 7.1 to 11.0 nm and a narrow size distribution (PDI < 0.2) were obtained after 3 membrane extrusion cycles. Konakion® MM formed aggregated particles at gastric pH, which was avoided through steric stabilization by introducing PEG. TEM showed that mixed micelles had a spherical size (diameter of around 10 nm) with a narrow size distribution in agreement with the DLS results. The loading capacities for vitamin K of mixed micelles with varying molar fractions of DSPE-PEG and EPC (from 0/100 to 50/50 (mol/mol)) were 10.8-5.0 w%, respectively. The mixed micelles showed good cytocompatibility at concentrations of glycocholic acid between 0.12 and 1.20 mM., Conclusions: Mixed micelles with superior stability to Konakion® MM at low pH were obtained by introducing DSPE-PEG 2000. These are therefore attractive oral formulations for vitamin K.

Background: There has been limited characterization of biological variables that impact vitamin K metabolism. This gap in knowledge can limit the translation of data obtained from preclinical animal studies to future human studies., Objective: The purpose of this study was to determine the effects of diet, sex, and housing on serum, tissue, and fecal vitamin K concentrations and gene expression in C57BL6 mice during dietary vitamin K manipulation., Methods: C57BL6 4-mo-old male and female mice were randomly assigned to conventional or suspended-wire cages and fed control [1400 ± 80 μg phylloquinone (PK)/kg] or deficient (31 ± 0.45 μg PK/kg) diets for 28 d in a factorial design. PK and menaquinone (MK) 4 plasma and tissue concentrations were measured by HPLC. Long-chain MKs were measured in all matrices by LC-atmospheric pressure chemical ionization-mass spectrometry. Gene expression was quantified by reverse transcriptase-polymerase chain reaction in the liver, brain, kidney, pancreas, and adipose tissue., Results: Male and female mice responded differently to dietary manipulation in a tissue-dependent manner. In mice fed the control diet, females had ∼3-fold more MK4 in the brain and mesenteric adipose tissue than did males and 100% greater PK concentrations in the liver, kidney, and mesenteric adipose tissue than did males. In mice fed the deficient diet, kidney MK4 concentrations were ∼4-fold greater in females than in males, and there were no differences in other tissues. Males and females differed in the expression of vitamin K expoxide reductase complex 1 (Vkorc1) in mesenteric adipose tissue and the pancreas and ubiA domain-containing protein 1 (Ubiad1) in the kidney and brain. There was no effect of housing on serum, tissue, or fecal concentrations of any vitamin K form., Conclusions: Vitamin K concentrations and expression of key metabolic enzymes differ between male and female mice and in response to the dietary PK concentration. Identifying factors that may impact study design and outcomes of interest is critical to optimize study parameters examining vitamin K metabolism in animal models., (© 2016 American Society for Nutrition.)

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.

Context: The Metabolic Syndrome (MetS) is a cluster of metabolic abnormalities and is associated with increased risk of diabetes and cardiovascular diseases. Phylloquinone, menaquinones, and vitamin K status are associated with several components of MetS, but the association with MetS has hardly been studied to date., Objective: This study aimed to examine whether the intake and/or status of vitamin K is associated with MetS and its components., Design: This study comprised two cohorts, one of 402 women and one of 400 men (age 40-80 y). At followup 625 participants were still alive and willing to participate. Data were analyzed both cross sectionally and longitudinally with Poisson and linear regression adjusted for multiple confounders. Baseline phylloquinone/menaquinone intakes were measured with a validated food frequency questionnaire and vitamin K status with serum desphospho-uncarborxylated matrix-Gla protein level., Results: At baseline 270 (34.5%) participants had MetS and 171 (35.7%) at followup. Cross sectionally, high menaquinones intakes were associated (P(trend) = .08) with a lower prevalence of MetS with a prevalence ratio (PR) of 0.74 (95% confidence interval [CI], 0.54-1.03) for the highest vs the lowest tertile. At followup, the highest tertiles of menaquinones intake (PR = 0.62; 95% CI, 0.40-0.95) and vitamin K status (PR = 0.57; 95% CI, 0.38-0.87) were associated (P(trend) = .01) with a lower occurrence of MetS. These associations were mainly driven by relations with lower triacylglycerol concentrations for menaquinones and lower waist circumference for vitamin K status. Phylloquinone intake was not associated with MetS prevalence., Conclusions: This study shows that a high intake of menaquinones and high vitamin K status are associated with a lower occurrence of MetS.

Although epidemiological findings support a role for vitamin K status in the improvement of bone indices in adult patients with Crohn's disease (CD), this needs to be confirmed in double-blind, randomised controlled trials (RCT) with phylloquinone (vitamin K1). By conducting two RCT, the present study aimed to first establish whether supplementation with 1000 μg of phylloquinone daily near-maximally suppresses the percentage of undercarboxylated osteocalcin in serum (%ucOC; marker of vitamin K status) in adult patients with CD currently in remission as it does in healthy adults and second determine the effect of supplementation with phylloquinone at this dose for 12 months on the indices of bone turnover and bone mass. The initial dose-ranging RCT was conducted in adult patients with CD (n 10 per group) using 0 (placebo), 1000 or 2000 μg of phylloquinone daily for 2 weeks. In the main RCT, the effect of placebo v. 1000 μg vitamin K/d (both co-administered with Ca (500 mg/d) and vitamin D3 (10 μg/d)) for 12 months (n 43 per group) on the biochemical indices of bone turnover (determined by enzyme immunoassay) and bone mass (determined by dual-energy X-ray absorptiometry) were investigated. At baseline, the mean %ucOC was 47 %, and this was suppressed upon supplementation with 1000 μg of phylloquinone daily ( - 81 %; P< 0·01) and not suppressed further by 2000 μg of phylloquinone daily. Compared with the placebo, supplementation with 1000 μg of phylloquinone daily for 12 months had no significant effect (P>0·1) on bone turnover markers or on the bone mass of the lumbar spine or femur, but modestly increased (P< 0·05) the bone mass of the total radius. Despite near maximal suppression of serum %ucOC, supplementation with 1000 μg of phylloquinone daily (with Ca and vitamin D3) had no effect on the indices of bone health in adult CD patients with likely vitamin K insufficiency.

Vitamin K has been related to cardiovascular disease and cancer risk. However, data on total mortality are scarce. The aim of the present study was to assess the association between the dietary intake of different types of vitamin K and mortality in a Mediterranean population at high cardiovascular disease risk. A prospective cohort analysis was conducted in 7216 participants from the PREDIMED (Prevención con Dieta Mediterránea) study (median follow-up of 4.8 y). Energy and nutrient intakes were evaluated using a validated 137-item food frequency questionnaire. Dietary vitamin K intake was calculated annually using the USDA food composition database and other published sources. Deaths were ascertained by an end-point adjudication committee unaware of the dietary habits of participants after they had reviewed medical records and linked up to the National Death Index. Cox proportional hazard models were fitted to assess the RR of mortality. Energy-adjusted baseline dietary phylloquinone intake was inversely associated with a significantly reduced risk of cancer and all-cause mortality after controlling for potential confounders (HR: 0.54; 95% CI: 0.30, 0.96; and HR: 0.64; 95% CI: 0.45, 0.90, respectively). In longitudinal assessments, individuals who increased their intake of phylloquinone or menaquinone during follow-up had a lower risk of cancer (HR: 0.64; 95% CI: 0.43, 0.95; and HR: 0.41; 95% CI: 0.26, 0.64, respectively) and all-cause mortality (HR: 0.57; 95% CI: 0.44, 0.73; and HR: 0.55; 95% CI: 0.42, 0.73, respectively) than individuals who decreased or did not change their intake. Also, individuals who increased their intake of dietary phylloquinone had a lower risk of cardiovascular mortality risk (HR: 0.52; 95% CI: 0.31, 0.86). However, no association between changes in menaquinone intake and cardiovascular mortality was observed (HR: 0.76; 95% CI: 0.44, 1.29). An increase in dietary intake of vitamin K is associated with a reduced risk of cardiovascular, cancer, or all-cause mortality in a Mediterranean population at high cardiovascular disease risk. This trial was registered at http://www.controlled-trials.com as ISRCTN35739639.

Vascular calcification occurs when calcium accumulates in the intima (associated with atherosclerosis) and/or media layers of the vessel wall. Coronary artery calcification (CAC) reflects the calcium burden within the intima and media of the coronary arteries. In population-based studies, CAC independently predicts cardiovascular disease (CVD) and mortality. A preventive role for vitamin K in vascular calcification has been proposed based on its role in activating matrix Gla protein (MGP), a calcification inhibitor that is expressed in vascular tissue. Although animal and in vitro data support this role of vitamin K, overall data from human studies are inconsistent. The majority of population-based studies have relied on vitamin K intake to measure status. Phylloquinone is the primary dietary form of vitamin K and available supplementation trials, albeit limited, suggest phylloquinone supplementation is relevant to CAC. Yet observational studies have found higher dietary menaquinone, but not phylloquinone, to be associated with less calcification. Vascular calcification is highly prevalent in certain patient populations, especially in those with chronic kidney disease (CKD), and it is plausible vitamin K may contribute to reducing vascular calcification in patients at higher risk. Subclinical vitamin K deficiency has been reported in CKD patients, but studies linking vitamin K status to calcification outcomes in CKD are needed to clarify whether or not improving vitamin K status is associated with improved vascular health in CKD. This review summarizes the available evidence of vitamin K and vascular calcification in population-based studies and clinic-based studies, with a specific focus on CKD patients.

Low vitamin K status is associated with low BMD and increased fracture risk. Additionally, a specific menaquinone, menatetrenone (MK4), may reduce fracture risk. However, whether vitamin K plays a role in the skeletal health of North American women remains unclear. Moreover, various K vitamers (e.g., phylloquinone and MK4) may have differing skeletal effects. The objective of this study was to evaluate the impact of phylloquinone or MK4 treatment on markers of skeletal turnover and BMD in nonosteoporotic, postmenopausal, North American women. In this double-blind, placebo-controlled study, 381 postmenopausal women received phylloquinone (1 mg daily), MK4 (45 mg daily), or placebo for 12 mo. All participants received daily calcium and vitamin D(3) supplementation. Serum bone-specific alkaline phosphatase (BSALP) and n-telopeptide of type 1 collagen (NTX) were measured at baseline and 1, 3, 6, and 12 mo. Lumbar spine and proximal femur BMD and proximal femur geometry were measured by DXA at baseline and 6 and 12 mo. At baseline, the three treatment groups did not differ in demographics or study endpoints. Compliance with calcium, phylloquinone, and MK4 treatment was 93%, 93%, and 87%, respectively. Phylloquinone and MK4 treatment reduced serum undercarboxylated osteocalcin but did not alter BSALP or NTX. No effect of phylloquinone or MK4 on lumbar spine or proximal femur BMD or proximal femur geometric parameters was observed. This study does not support a role for vitamin K supplementation in osteoporosis prevention among healthy, postmenopausal, North American women receiving calcium and vitamin D supplementation.

Vitamin K acts as a cofactor during the gamma-carboxylation of vitamin K-dependent proteins. Undercarboxylated osteocalcin (ucOC) is a suggested biomarker of vitamin K status. The +2255 polymorphism of the vitamin K epoxide reductase gene (VKORC1) was shown to be associated with the recycling rate of the active form of vitamin K. We investigated the association between dietary vitamin K intake and serum ucOC and hypothesized that this association might vary by VKORC1 genotype. ucOC and total intact osteocalcin (iOC) concentrations were quantified using specific ELISA tests in serum samples of 548 male and female participants (aged 18-81 years) of the Bavarian Food Consumption Survey II. ucOC was expressed relative to iOC (ucOC/iOC ratio). Dietary intake of vitamin K (phylloquinone and menaquinones) was estimated from three 24 h dietary recalls using previously published food composition data. The association between dietary vitamin K intake and ucOC/iOC ratio was analysed using linear and non-linear regression models. Median intakes of phylloquinone/menaquinones were 83.4/37.6 microg/d in men and 79.6/29.8 microg/d in women, respectively. As expected, vitamin K intake was significantly inversely associated with the ucOC/iOC ratio. The ucOC/iOC ratio differed significantly across variants of the +2255 polymorphism in the VKORC1 gene. Stratification by VKORC1+2255 genotype revealed that only in carriers of the GG genotype (39 % of all participants) did the ucOC/iOC ratio significantly decrease with increasing intake of vitamin K. Thus, the results show that the inverse association between dietary vitamin K intake and serum ucOC depends on a functionally relevant allelic variant of the VKORC1 gene.

Introduction: This review summarizes current knowledge on vitamin K for the paediatrician. Vitamin K is a fat-soluble vitamin, present in plants as phylloquinone and produced by bacteria as menaquinone. It is acting as a co-factor for gamma-glutamyl carboxylase. This enzyme is responsible for post-translational modification of some glutamate side chains to gamma-carboxyglutamate. The majority of gamma-carboxylated proteins function in blood coagulation; others play a role in calcium homeostasis., Data: Newborn babies are at particular risk of vitamin K deficiency, as placental transfer is limited and human milk is a poor source. Vitamin K prophylaxis at birth effectively prevents vitamin K deficiency bleeding (VKDB), formerly known as "haemorrhagic disease of the newborn". Recent epidemiological studies provide data on the effectiveness of different administration routes and dosing schemes. Infants of mothers taking drugs that inhibit vitamin K are at risk of early VKDB and should receive 1 mg intramuscular (i.m.) as soon as possible after birth. Classic VKDB is prevented by intramuscular as well as by oral administration of 1 mg vitamin K. In exclusively breast-fed infants, single i.m. administration at birth is also effectively preventing (rare) late VKDB but single oral administration is not. If given orally, prophylaxis should be continued by either weekly administration of 1 mg till 12 weeks or repeating 2 mg at weeks 1 and 4. Daily administration of 25 microg offers insufficient protection. The only infants not fully protected in this way are those with yet unrecognised liver disease., Conclusions: Further work is needed before firm recommendations can be made regarding dose in preterm infants and in patients with fat malabsorption/cholestasis or regarding the role of vitamin K in the prevention of osteoporosis.

Background: Vitamin K has been widely promoted as a supplement for decreasing bone loss in postmenopausal women, but the long-term benefits and potential harms are unknown. This study was conducted to determine whether daily high-dose vitamin K1 supplementation safely reduces bone loss, bone turnover, and fractures., Methods and Findings: This single-center study was designed as a 2-y randomized, placebo-controlled, double-blind trial, extended for earlier participants for up to an additional 2 y because of interest in long-term safety and fractures. A total of 440 postmenopausal women with osteopenia were randomized to either 5 mg of vitamin K1 or placebo daily. Primary outcomes were changes in BMD at the lumbar spine and total hip at 2 y. Secondary outcomes included changes in BMD at other sites and other time points, bone turnover markers, height, fractures, adverse effects, and health-related quality of life. This study has a power of 90% to detect 3% differences in BMD between the two groups. The women in this study were vitamin D replete, with a mean serum 25-hydroxyvitamin D level of 77 nmol/l at baseline. Over 2 y, BMD decreased by -1.28% and -1.22% (p = 0.84) (difference of -0.06%; 95% confidence interval [CI] -0.67% to 0.54%) at the lumbar spine and -0.69% and -0.88% (p = 0.51) (difference of 0.19%; 95% CI -0.37% to 0.75%) at the total hip in the vitamin K and placebo groups, respectively. There were no significant differences in changes in BMD at any site between the two groups over the 2- to 4-y period. Daily vitamin K1 supplementation increased serum vitamin K1 levels by 10-fold, and decreased the percentage of undercarboxylated osteocalcin and total osteocalcin levels (bone formation marker). However, C-telopeptide levels (bone resorption marker) were not significantly different between the two groups. Fewer women in the vitamin K group had clinical fractures (nine versus 20, p = 0.04) and fewer had cancers (three versus 12, p = 0.02). Vitamin K supplements were well-tolerated over the 4-y period. There were no significant differences in adverse effects or health-related quality of life between the two groups. The study was not powered to examine fractures or cancers, and their numbers were small., Conclusions: Daily 5 mg of vitamin K1 supplementation for 2 to 4 y does not protect against age-related decline in BMD, but may protect against fractures and cancers in postmenopausal women with osteopenia. More studies are needed to further examine the effect of vitamin K on fractures and cancers., Trial Registration: ClinicalTrials.gov (#NCT00150969) and Current Controlled Trials (#ISRCTN61708241).

A protective role for vitamin K in bone health has been suggested based on its role as an enzymatic cofactor. In observational studies, vitamin K insufficiency is generally associated with lower bone mass and increased hip fracture risk. However, these findings are not supported in randomized controlled trials (RCT) of phylloquinone (vitamin K(1)) supplementation and bone loss at the hip in the elderly. This suggests that increased vegetable and legume intakes may simultaneously improve measures of vitamin K status and skeletal health, even though the mechanisms underlying these improvements may be independent of each other. Menaquinone-4 (vitamin K(2)), when given at pharmacological doses, appears to protect against fracture risk and bone loss at the spine. However, there are emerging data that suggest the efficacy of vitamin K supplementation on bone loss is inconclusive.

Because of its role in osteoblastic metabolism, vitamin K has been studied with respect to bone. However, there has been limited research examining the influence of long-term vitamin K supplementation on bone mineral density (BMD). Therefore, the purpose of this study was to assess the impact of 6 months of vitamin K supplementation on BMD and biomarkers of bone in pre- and perimenopausal women. Based on previous work, we hypothesized that vitamin K would improve BMD and biochemical markers of bone formation. A double-blind, placebo-controlled, randomized trial is an effective way to study the impact of long-term supplementation. Thus, 14 pre- and perimenopausal women, 25 to 50 years of age, were randomly assigned to an experimental group (E) that received 600 microg/d of vitamin K in the form of phylloquinone (K(1)) or a control group (C) that received identical-looking placebo tablets. Regional BMD and percent body fat, measured by dual-energy x-ray absorptiometry, and serum osteocalcin and urinary N-telopeptide levels were all assessed at 0, 3, and 6 months. When BMD was measured across time, C had a significant increase (P = .011) in greater trochanter BMD compared to E. The E group had a nonsignificant increase (P = .067) in shaft BMD compared to the C group. There was no significant difference between E and C in serum osteocalcin concentrations over time. Urinary N-telopeptide levels increased significantly over time in E compared to C (P = .008). Six months of 600 microg/d vitamin K(1) supplementation did not improve regional BMD in this group of pre- and perimenopausal women.

Background: Vitamin K modulates cytokines involved in bone turnover, including interleukin-6 (IL-6) and osteoprotegerin in vitro., Objective: The objective of this study was to assess 1) associations between measures of vitamin K status [plasma phylloquinone and serum percentage of undercarboxylated osteocalcin (%ucOC)] and IL-6, osteoprotegerin, and C-reactive protein (CRP) concentrations and 2) the effect of daily 500 mug phylloquinone supplementation for 3 y on cytokine concentrations., Design: Concentrations of IL-6, osteoprotegerin, and CRP and bone mineral density (BMD) were measured at baseline and after 3 y of follow-up in 379 healthy men and women (60-81 y; 58.5% women) participating in a randomized trial that studied the effect of vitamin K supplementation on bone loss., Results: Cross-sectionally, plasma phylloquinone was inversely associated with IL-6 and CRP, whereas serum %ucOC was inversely associated with IL-6. Osteoprotegerin was associated positively with plasma phylloquinone and inversely with %ucOC. No differences were observed in the 3-y change in IL-6, osteoprotegerin, and CRP concentrations between participants who received phylloquinone supplementation and those who did not. Overall, no association was observed between the 3-y changes in circulating cytokines and BMD., Conclusions: Poor vitamin K status was associated with high concentrations of cytokines involved in bone turnover, but vitamin K supplementation did not confer a decrease in cytokine concentrations. The healthy status of this cohort may explain a lack of effect of vitamin K supplementation on cytokine concentrations. This trial was registered with www.clinicaltrials.gov as NCT00183001.

The physiological function and putative health roles of vitamin K-dependent proteins now extend beyond their classical role in hemostasis and include bone mineralization, arterial calcification, apoptosis, phagocytosis, growth control, chemotaxis, and signal transduction. Current assessments of vitamin K status do not reflect the variety of molecular forms of vitamin K. We assessed whether urinary excretion of 2-methyl-3-(5'-carboxy-3'-methyl-2'-pentenyl)-1,4-naphthoquinone (7C-aglycone) and 2-methyl-3-(3'-3'-carboxymethylpropyl)-1,4-naphthoquinone (5C-aglycone), vitamin K metabolites common to both phylloquinone and the menaquinone series, reflect dietary vitamin K intake. In a randomized crossover study, 9 adults resided in a metabolic unit for two 30-d periods separated by a free-living period of > or = 4 wk. During each residency, subjects consumed 3 sequential diets: a control diet (93 microg phylloquinone/d) for 5 d, a phylloquinone-restricted diet (11 microg/d) for 15 d, followed by a randomly assigned repletion diet for 10 d with either phylloquinone (206 microg/d) or dihydrophylloquinone (240 microg/d). During the second residency, the alternative repletion diet was assigned. Urinary excretion of the 5C- and 7C-aglycones was measured in sequential 24-h collections. The 5C-aglycone accounted for approximately 75% of total excretion and declined in response to phylloquinone restriction (P = 0.001) to approximately 30% of that during the control diet period. Repletion with phylloquinone and dihydrophylloquinone doubled the excretion rate of the major 5C-aglycone by 24 h (P < 0.001), and tripled excretion by 4 d. There was a linear relationship between the logarithm of total urinary excretion and dietary vitamin K intake (r = 0.699, P < 0.001). We conclude that the urinary excretion of vitamin K metabolites reflects dietary phylloquinone intake and offers the first candidate marker of global vitamin K status.

Phylloquinone is converted into menaquinone-4 and accumulates in extrahepatic tissues. Neither the route nor the function of the conversion is known. One possible metabolic route might be the release of menadione from phylloquinone by catabolic activity. In the present study we explored the presence of menadione in urine and the effect of vitamin K intake on its excretion. Menadione in urine was analysed by HPLC assay with fluorescence detection. Urine from healthy male volunteers was collected before and after administration of a single dose of K vitamins. Basal menadione excretion in non-supplemented subjects (n 6) was 5.4 (sd 3.2) microg/d. Urinary menadione excretion increased greatly after oral intake of the K vitamins, phylloquinone and menaquinone-4 and -7. This effect was apparent within 1-2 h and peaked at about 3 h after intake. Amounts of menadione excreted in 24 h after vitamin K intake ranged, on a molar basis, from 1 to 5 % of the administered dose, indicating that about 5-25 % of the ingested K vitamins had been catabolized to menadione. Menadione excretion was not enhanced by phylloquinone administered subcutaneously or by 2',3'-dihydrophylloquinone administered orally. In archived samples from a depletion/repletion study (Booth et al. (2001) Am J Clin Nutr 74, 783-790), urinary menadione excretion mirrored dietary phylloquinone intake. The present study shows that menadione is a catabolic product of K vitamins formed after oral intake. The rapid appearance in urine after oral but not subcutaneous administration suggests that catabolism occurs during intestinal absorption. The observations make it likely that part of the menaquinone-4 in tissues results from uptake and prenylation of circulating menadione.

Purpose: The role of vitamin K in the prevention and treatment of osteoporosis and arterial calcification is examined., Summary: Vitamin K is essential for the activation of vitamin K-dependent proteins, which are involved not only in blood coagulation but in bone metabolism and the inhibition of arterial calcification. In humans, vitamin K is primarily a cofactor in the enzymatic reaction that converts glutamate residues into gamma-carboxyglutamate residues in vitamin K-dependent proteins. Numerous studies have demonstrated the importance of vitamin K in bone health. The results of recent studies have suggested that concurrent use of menaquinone and vitamin D may substantially reduce bone loss. Menaquinone was also found to have a synergistic effect when administered with hormone therapy. Several epidemiologic and intervention studies have found that vitamin K deficiency causes reductions in bone mineral density and increases the risk of fractures. Arterial calcification is an active, cell-controlled process that shares many similarities with bone metabolism. Concurrent arterial calcification and osteoporosis have been called the "calcification paradox" and occur frequently in postmenopausal women. The results of two dose-response studies have indicated that the amount of vitamin K needed for optimal gamma-carboxylation of osteocalcin is significantly higher than what is provided through diet alone and that current dosage recommendations should be increased to optimize bone mineralization. Few adverse effects have been reported from oral vitamin K., Conclusion: Phytonadione and menaquinone may be effective for the prevention and treatment of osteoporosis and arterial calcification.

Background: Vitamin K has been suggested to have a role in bone metabolism, and low vitamin K intake has been related to low bone density and increased risk of osteoporotic fracture., Objective: The objective of this study was to determine whether phylloquinone (vitamin K(1)) intake and biochemical indicators of vitamin K status are related to bone mineral content (BMC) and markers of bone formation and bone resorption in girls., Design: Vitamin K status [plasma phylloquinone concentration and percentage of undercarboxylated osteocalcin (%ucOC)] was measured at baseline in a study of 245 healthy girls aged 3-16 y. Cross-linked N-telopeptide of type 1 collagen (NTx) breakdown, osteocalcin, and bone-specific alkaline phosphatase were measured to reflect bone resorption and formation. BMC of the total body, lumbar spine, and hip and dietary phylloquinone intake were measured annually for 4 y., Results: Phylloquinone intake (median: 45 microg/d) was not consistently associated with bone turnover markers or BMC. Better vitamin K status (high plasma phylloquinone and low %ucOC) was associated with lower bone resorption and formation. Plasma phylloquinone was inversely associated with NTx and osteocalcin concentrations (P < 0.05), and %ucOC was positively associated with NTx and bone-specific alkaline phosphatase concentrations (P < 0.05). Indicators of vitamin K status were not consistently associated with current BMC or gain in BMC over the 4-y study period., Conclusions: Better vitamin K status was associated with decreased bone turnover in healthy girls consuming a typical US diet. Randomized phylloquinone supplementation trials are needed to further understand the potential benefits of phylloquinone on bone acquisition in growing children.

Assessment of vitamin K dietary intakes has been limited by incomplete vitamin K food composition data for the US food supply. The phylloquinone (vitamin K(1)) concentrations of nuts (n=76) and fruits (n=215) were determined by high-performance liquid chromatography. Each sample represented a composite of units obtained from 12 to 24 outlets, which provided geographic representation of the US food supply. With the exception of pine nuts and cashews, which contain 53.9 and 34.8 microg of phylloquinone per 100 g of nut, respectively, nuts are not important dietary sources of vitamin K. Similarly, most fruits are not important sources of vitamin K, with the exception of some berries, green fruits, and prunes. Menu planning for patients on warfarin can include a healthy diet including fruits and nuts without compromising the stability of their oral anticoagulation therapy.

Aim: To evaluate oral vitamin K prophylaxis at birth by giving 2 mg phytomenadione, followed by weekly oral vitamin K prophylaxis; 1 mg was administered by the parents until 3 mo of age., Methods: A total of 507850 live babies were born in Denmark during the study period, November 1992 to June 2000. Of these infants, 78% and 22% received oral and intra-muscular prophylaxis, respectively; i.e. about 396000 neonates received oral prophylaxis at birth. Weekly oral prophylaxis was recommended for all infants as long as they were mainly breastfed. A survey of possible cases of vitamin K deficiency bleeding (VKDB) was carried out by repeated questionnaires to all Danish paediatric departments and by checking the National Patient Register., Results: No cases of VKDB were revealed, i.e. the incidence was 0-0.9:100000 (95% CI). The questionnaires were used to evaluate compliance with the regimen. Parents of 274 infants participated. A dose of vitamin K was regarded as having been given if the infant received a drop of vitamin K or was mostly formula-fed that week, and the prophylaxis was regarded as completed if the infant had received at least 9 doses. Compliance was good, with 94% of the infants completing the course of prophylaxis., Conclusion: Weekly oral vitamin K supplementation during the first 3 mo of life was an efficient prophylaxis against VKBD. Parental compliance with the regimen was good.

Few epidemiological studies that rely on the food frequency questionnaire (FFQ) for dietary assessment have measured biomarkers of vitamin K intake to independently confirm associations between self-reported dietary vitamin K intake and disease risk. Associations were examined between two sensitive biomarkers of vitamin K status, plasma phylloquinone and serum percent undercarboxylated osteocalcin (%ucOC), and self-reported usual phylloquinone intake as estimated from a FFQ. The influence of other dietary and nondietary factors on plasma phylloquinone concentrations was also examined. Dietary phylloquinone intake was estimated using a FFQ in 369 men and 468 women of the Framingham Offspring Study. The prevalence of high %ucOC concentrations (>/= 20%), suggestive of a low vitamin K status, was 44% in men and 54% in women, respectively. After multivariate adjustment, the odds of a high %ucOC was 2.5 greater for women (odds ratio: 2.5; 95% confidence interval [CI]: 1.2-5.1) and almost three times greater for men (odds ratio: 2.8; 95% CI: 1.3-5.9) in the lowest dietary phylloquinone intake quintile category compared to the highest quintile category. Fasting triglyceride concentrations, smoking status and season were associated with plasma phylloquinone concentrations, independent of dietary phylloquinone intake. Phylloquinone and green vegetable intake was linearly associated with plasma phylloquinone, after adjustment for potential confounding factors. There were limitations in the use of the FFQ to predict plasma phylloquinone, evident in an observed plateau effect and required nondietary adjustment factors. Despite these caveats, these findings support the use of a FFQ for a relative assessment of vitamin K status in population-based studies.

In a preliminary experiment, the inclusion of vitamin K1 (K1) at a dietary level of 0.1 mg/kg was as effective as 1 or 2 mg/kg in reducing plasma prothrombin time (PT). To obtain an estimate of the dietary K1 requirement and to compare the biopotency of different vitamin K sources for poults, three additional experiments were conducted. In Experiment 1, an incomplete factorial arrangement of treatments was used in which five dietary concentrations of K1 (0, 0.1, 0.25, 0.5, or 2.0 mg/kg) were tested and two concentrations of neomycin (0 or 75 mg/L) in drinking water were used in conjunction with 0, 0.1, and 0.5 mg of K1/kg of diet. Thus, we used a total of eight treatments. Each treatment was given to two pens of poults, with eight poults per pen. Prothrombin time and prothrombin concentration (PC) in plasma were not influenced by inclusion of neomycin in drinking water. The K1 requirement was estimated, on the basis of PT and PC, to be 0.099 and 0.13 mg/kg, respectively, in Experiment 1. Dietary K1 concentrations tested in Experiment 2 were 0, 0.08, 0.31, or 0.44 mg/kg. A similar protocol to that of Experiment 1 was used in this experiment. The results of Experiment 2 indicated that the dietary K1 requirement was 0.079 mg, based on the influence of dietary K1 on PT. In Experiment 3, dietary treatments consisted of the equivalent of 0.22, 0.55, or 1.11 microM of menadione equivalent/kg from vitamin K1, menadione dimethypyrimidinol bisulfite (MPB) or menadione nicotinamide bisulfite (MNB), respectively, and a control without supplementation of any vitamin K source. The results of Experiment 3 showed that the biopotency of K1 was greater than that of MPB or MNB. The biopotencies of MPB and MNB were similar, although MNB was more potent in reducing plasma PT when supplemented at the level of 0.1 mg of menadione/kg. A nadir of PT and a plateau of PC were evident with a dietary supplementation of MPB or MNB at a level of 0.25 mg of menadione/kg. Results of this research show that the dietary K1 requirement of young turkeys is in the range of 0.079 to 0.13 mg/kg, and ingestion of neomycin did not affect estimates of the requirement. The biopotency of vitamin K1 in reducing plasma PT and increasing plasma PC was greater than that of MPB or MNB. The biopotency of MNB was greater than that of MPB when menadione supplementation was equivalent to 0.10 mg of K1/kg.

With the aim of overcoming the delivery problems (water-solubility and bioreductive activation problems) of phyllohydroquinone (PKH), an active form of phylloquinone (PK, vitamin K1), the N,N-dimethylglycine esters of phyllohydroquinone (1-mono, 1; 4-mono, 2; and 1,4-bis, 3) have been synthesized and assessed in vitro as a prodrug for the systemic bioreductive activation-independent delivery of PKH. The hydrochloride salts of the esters were found to be quite soluble in water. Hydrolysis of the esters in rat liver S9 fraction, rat plasma and phosphate buffer, pH 7.4, at 37 degrees C, was kinetically studied in the presence and absence of an esterase inhibitor. The hydrolysis was catalyzed by esterases located in rat liver and rat plasma and quantitatively yielded PKH. The enzymatic cleavage and the vitamin K-dependent carboxylation activity of the esters in the rat liver microsome preparation at pH 7.2 and 25 degrees C were studied. The regeneration of PKH from the esters was catalyzed by carboxylesterases located in the rat liver microsome, and the order was as follows: 1 > 3 > 2. The carboxylation was stimulated by selected ester 1 in the absence of dithiothreitol, an activator of the vitamin K cycle. The carboxylation activity of 1 was strongly inhibited in the presence of eserine, a carboxylesterase inhibitor. Compound 1 could also stimulate carboxylase under warfarin-poisoning conditions, where the vitamin K cycle was strongly inhibited. These results indicated that these highly water-soluble and liver-esterase hydrolyzable ester derivatives of PKH are potential candidates for parenteral prodrugs which can thus achieve the systemic bioreductive activation-independent delivery of PKH.

Background: Phylloquinone, found in dark-green vegetables and certain plant oils, is the primary dietary source of the fat-soluble vitamin K. Limited data suggest that the relative bioavailability of phylloquinone from vegetables is lower than that from a supplement. This finding is relevant to the maintenance of optimal vitamin K status., Objective: The objective of this study was to compare, in younger and older adults, the relative bioavailability of phylloquinone from a vegetable with that of a fortified oil., Design: In a crossover design with three 15-d residency periods in a metabolic unit, younger and older men and women (n = 36) consumed a mixed diet containing 100 microg phylloquinone/d. During 2 residency periods, the mixed diet was supplemented for 5 d with either broccoli (377 microg phylloquinone/d; broccoli diet) or phylloquinone-fortified oil (417 microg/d; oil diet). The relative bioavailability of phylloquinone was defined by the difference in plasma phylloquinone, percentage serum undercarboxylated osteocalcin (%ucOC), and urinary gamma-carboxyglutamic acid in response to 5 d of supplementation., Results: For both younger and older adults, plasma phylloquinone concentrations were higher (P < 0.001) and %ucOC values were lower (P = 0.001) after the broccoli and oil diets than after the mixed diet only. Overall, the response to broccoli supplementation was not significantly different from the response to the fortified oil in either age group. Urinary gamma-carboxyglutamic acid did not change in response to supplementation., Conclusions: There was no significant difference in the relative bioavailability of phylloquinone, as evidenced by the lack of a significant difference in plasma phylloquinone and %ucOC between the 2 groups after either the broccoli or oil diets for younger and older adults.

Subjects taking a hydrogen pump blocking agent (omeprazole) develop bacterial overgrowth of the small intestine. We tested the hypothesis that this bacterial overgrowth produces menaquinones, which would meet the vitamin requirement in situations of vitamin K deficiency. In a crossover-type design, 13 healthy volunteers eating a phylloquinone-restricted diet for 35 d were randomly assigned to take omeprazole during the first period of study or starting on day 15 until the end of the study. Coagulation times, serum osteocalcin [total osteocalcin and undercarboxylated osteocalcin (ucOC)], plasma phylloquinone, urinary gamma-carboxyglutamic acid, and plasma undercarboxylated prothrombin (PIVKA-II) were measured. Plasma phylloquinone concentrations declined 82% with dietary phylloquinone restriction (P < 0.05) and were not significantly different in the period when the diet was combined with omeprazole treatment (P > 0.05). The mean value for PIVKA-II during the phylloquinone-restricted diet significantly increased 5.7-fold from baseline (P < 0.05); however, the combination of omeprazole treatment and the phylloquinone-restricted diet significantly reduced PIVKA-II values by 21% (P < 0.05) compared with the diet period alone. There were no alterations in total or percentage ucOC concentrations during the phylloquinone-restricted diet or during the period of diet plus omeprazole treatment. Our data support the hypothesis that bacterial overgrowth results in the synthesis and absorption of menaquinones. These menaquinones contribute to vitamin K nutriture during dietary phylloquinone restriction, but not enough to restore normal vitamin K status.

The ability of male rats to accumulate menaquinone-4 (MK-4) in tissues when fed a vitamin K-deficient diet supplemented with intraperitoneal phylloquinone (K) as the sole source of vitamin K for 14 d was assessed. In both conventionally housed controls and gnotobiotic rats, supplementation with the equivalent of 1500 microg vitamin K/kg diet increased (P < 0.001) tissue MK-4 concentrations above those of controls fed a vitamin K-deficient diet. MK-4 concentrations were approximately 5 ng/g (11 pmol/g) in liver, 14 ng/g in heart, 17 ng/g in kidney, 50 ng/g in brain and 250 ng/g in mandibular salivary glands of gnotobiotic rats. MK-4 concentrations in conventionally housed rats were higher than in gnotobiotic rats in heart (P < 0.01), brain (P < 0.01) and kidney (P < 0.05) but lower in salivary gland (P < 0.05). Cultures of a kidney-derived cell line (293) converted K to the expoxide of MK-4 in a manner that was dependent on both time of incubation and concentration of vitamin K in the media. A liver-derived cell line (H-35) was less active in carrying out this conversion. These data offer conclusive proof that the tissue-specific formation of MK-4 from K is a metabolic transformation that does not require bacterial transformation to menadione as an intermediate in the process.

Atrophic gastritis patients have intestinal bacterial overgrowth which could produce menaquinones. The aim of this study was to evaluate the interaction between a diet low in phylloquinone and minidoses of warfarin in subjects with and without bacterial overgrowth. Subjects with atrophic gastritis (indicated by serum pepsinogen ratio) and healthy volunteers were studied while fed a restrictive phylloquinone diet and while receiving a minidose of warfarin. Coagulation times, serum osteocalcin, serum undercarboxylated osteocalcin, plasma phylloquinone, plasma K-epoxide, plasma undercarboxylated prothrombin (PIVKA)-II and urinary gamma-carboxyglutamic acid (Gla) were measured. At baseline, there were no differences between groups for any variable measured. Comparisons between baseline and post intervention in both groups, showed significant increases in circulating levels of K-epoxide, PIVKA II and undercarboxylated osteocalcin. However, no differences were observed when comparisons were made between groups. Our data do not support the hypothesis that bacterial synthesis of menaquinones in patients with bacterial overgrowth due to atrophic gastritis confers considerable resistance to the effect of warfarin.

Patients with burn injuries exhibit multiple risk factors for the development of vitamin K deficiency, including malabsorption, limited enteral intake, antibiotic therapy, and multiple surgical procedures. A prospective evaluation of 48 children was conducted to evaluate serum vitamin K values during the first 4 postburn weeks. Serum levels were analyzed in relation to clinical course. Days of antibiotic (p < 0.02) and albumin therapy (p < 0.003), percentage body surface area excised (p < 0.006), and the administration of blood products (p < 0.05) were significantly correlated with serum vitamin K levels, and days of diarrhea approached statistical significance (p < 0.06). No relationship was found between serum values and prothrombin time, activated partial thromboplastin time, or serum albumin. Ninety-one percent of the children demonstrated serum values below expected norms. These data suggest a relationship between coagulopathy and an intact functioning gastrointestinal tract. However, the relative importance of dietary versus endogenous vitamin K produced by intestinal bacteria remains to be elucidated.

The response of osteocalcin and other biochemical markers of vitamin K status to diets formulated to contain different amounts of phylloquinone was assessed in nine healthy subjects aged 20-33 y. Subjects resided in a metabolic ward for two 15-d cycles with a minimum of 6 wk between cycles. A mixed diet containing 100 micrograms phylloquinone/d was fed throughout both cycles; however, the phylloquinone content of one of the cycles was increased to a total of 420 micrograms/d on days 6 through 10 by fortifying corn oil in the diet with phylloquinone (supplemented diet). Total serum osteocalcin concentrations were not affected by either of the dietary treatments. The percentage of undercarboxylated osteocalcin increased an average of 28% over the 15-d cycle with the mixed diet (P < 0.05) and declined significantly an average of 41% with 5 d of the supplemented diet (day 6: 21.9 +/- 1.3%, day 11: 12.8 +/- 1.1%; P = 0.0001) with a rise after the return to the mixed diet (16.7 +/- 1.3%, P < 0.001). Plasma phylloquinone concentrations increased significantly with supplementation (day 6: 0.95 +/- 0.16 nmol/L, day 11: 1.40 +/- 0.29 nmol/L; P < 0.001) and then rapidly returned to presupplementation concentrations on returning to the mixed diet. Twenty-four-hour ratios of urinary gamma-carboxyglutamic acid to creatinine were unchanged with the supplemented diet; however, excretion declined to 91 +/- 2% of baseline after 10 d on the mixed diet (P = 0.01). These results show that undercarboxylated osteocalcin, plasma phylloquinone, and urinary gamma-carboxyglutamic acid excretion appear to be sensitive measures of vitamin K nutritional status because all of these variables were responsive to changes in dietary intake.

The distributions of phylloquinone (PK) and menaquinone-4 (MK-4) in various tissues were assessed after the oral administration of phylloquinone. Wistar rats were fed a vitamin-K-deficient diet for nine days, fasted for 24 h and then given phylloquinone orally at 4 mg/kg body weight. Rats were sacrificed 0, 6, 12 and 24 h after the administration, and an analysis was made of the vitamin K analogues in the plasma, liver, brain, testis, kidney and spleen. The phylloquinone concentration in plasma and the tissues reached a peak 6 h after the oral administration of phylloquinone. By contrast, the concentration of MK-4 peaked in the liver, plasma, kidney and spleen at 12 h, and in brain and testis at 24 h. This data suggests that the ingested phylloquinone was probably converted into MK-4 within the tissues themselves, rather than via hepatic metabolism. The evidence for this is that, after phylloquinone administration, (i) in each of the tissues, the MK-4 concentration increased much more slowly than that of phylloquinone, and (ii) the MK-4 concentration in the plasma and liver reached only much lower levels than those seen in other tissues.

To determine the influence of vitamin E on phylloquinone activity, one day-old chicks were raised on a masch diet supplemented with different amounts of vitamin E for 31 days. In chicks fed a diet high in vitamin E (4000 mg allrac-alpha-tocopheryl acetate/kg) but adequate in vitamin K (0.14 mg phylloquinone/kg) a threefold increase in prothrombin time and an increase in mortality rate (five out of twelve animals died from increased bleeding tendency) was observed. The inhibiting effect of high dietary vitamin E on procoagulant factors could be prevented by increasing dietary phylloquinone supplementation. Weight development, and feed utilization were insignificantly different in chicks fed different amounts and ratios of vitamins E and K1. Plasma and liver alpha-tocopherol levels correlated with dietary amounts of vitamin E. Increased phylloquinone levels in the diet did not significantly influence alpha-tocopherol concentrations in plasma and liver, but coagulopathy caused by high vitamin E intake could be reversed.

The human vitamin K requirement is not known precisely, but the minimal requirement is often assumed to be between 0.5 and 1 x 10(-6) g/kg body weight. In the present study we addressed the question to what extent circulating vitamin K concentrations are influenced by the form in which the vitamer is consumed. The experimental group consisted of five healthy volunteers who received phylloquinone after an overnight fast. On the first day of three successive weeks the participants consumed 1 mg (2.2 mumol) phylloquinone, either in the form of a pharmaceutical preparation (Konakion), or in the form of spinach + butter, or as spinach without added fat. Circulating phylloquinone levels after spinach with and without butter were substantially lower (7.5- and 24.3-fold respectively) than those after taking the pharmaceutical concentrate. Moreover, the absorption of phylloquinone from the vegetables was 1.5 times slower than from Konakion. In a second experiment in the same five volunteers it was shown that relatively high amounts of menaquinone-4 enter the circulation after the consumption of butter enriched with this vitamer. It is concluded that the bioavailability of membrane-bound phylloquinone is extremely poor and may depend on other food components, notably fat. The bioavailability of dietary vitamin K (phylloquinone + menaquinones) is lower than generally assumed, and depends on the form in which the vitamin is ingested. These new insights may lead to a revision of the recommended daily intake for vitamin K.

Dihydro-vitamin K1 was recently identified as a dietary form of vitamin K produced during the hydrogenation of vitamin K1-rich vegetable oils. Dihydro-vitamin K1 is absorbed, with measurable levels in human plasma following dietary intake. To determine the primary food sources of dihydro-vitamin K1 in the American diet, 261 foods from the U.S. Food and Drug Administration's (FDA) Total Diet Study (TDS) were analyzed by high-performance liquid chromatography. Of these foods, 36 contained dihydro-vitamin K1. Fast-food items that were otherwise poor sources of vitamin K1, such as french fries and fried chicken, contained appreciable amounts of dihydro-vitamin K1 (36 and 18 micrograms/100 g, respectively). These nutrient values were then applied to the FDA TDS consumption model to determine average dietary intake of dihydro-vitamin K1 in 14 age-gender groups. With the exception of infants, all age-gender groups had estimated mean daily dihydro-vitamin K1 intakes of 12-24 micrograms, compared to mean daily vitamin K1 intakes of 24-86 micrograms. The vitamin K1 and dihydro-vitamin K1 intakes were summed, and the dietary contribution of dihydro-vitamin K1 was expressed as a percentage of total vitamin K intake. Children reported the highest intakes of dihydro-vitamin K1 (30% of total vitamin K intake), followed by a progressive decrease in percentage contribution with age. There are currently no data on the relative bioavailability of dihydro-vitamin K1 but given its abundance in the American diet, this hydrogenated form of vitamin K warrants further investigation.

To clarify the origin of organ menaquinone-4 (MK-4), the distributions of phylloquinone and MK-4 were investigated in rats fed diets containing phylloquinone, MK-4 or menadione (1.1, 2.2 and 31 mumol/kg diet, respectively, 6 rats per group). Warfarin (2 x 1 mg/kg subcutaneously) was given (3 rats per group) to study the effect of vitamin K cycle blockage. In rats fed phylloquinone the vitamin accumulated mainly in liver and heart. Additionally, the diet resulted in significantly higher organ MK-4 concentrations compared with the vitamin K-deficient controls. The epoxide of MK-4 also was significantly higher in some organs. The MK-4 diet increased MK-4 concentration primarily in the heart, liver and lung. Rats fed menadione had significantly higher MK-4 and MK-4 epoxide concentrations in all organs examined. The greatest accumulations were in nonhepatic organs, particularly the pancreas, salivary gland and brain. Generally, liver and plasma had low MK-4 concentrations. Warfarin treatment lowered significantly the MK-4 concentrations, whereas MK-4 epoxide accumulated. The study shows the following: 1) dietary phylloquinone is accumulated mainly in the heart and liver, 2) the MK-4 accumulation in nonhepatic organs is due to synthesis rather than uptake and 3) MK-4 rather than phylloquinone may be the functional vitamin in nonhepatic organs.

To study the metabolism of K Vitamins (VK) in the liver, two types of natural VK, phylloquinone (K1) and menaquinone-4 (MK-4), were administered to male Wistar rats orally (P.O.), intravenously (I.V.) and intraperitoneally (I.P.). Blood and a small portion of the liver (and ascites by I.P.) were collected 8 times up to 72 h (P.O.) or 24 h (I.V. and I.P.). A modified assay procedure followed by high performance liquid chromatography (HPLC) was developed to detect VK from small amounts of liver tissue. After oral administration of both K1 and MK-4 (10 mumol/kg-P.O.), their concentrations in the liver increased from 1 h then reached a maximum at 6 h (10 nmol/g v.s. 0.35 nmol/g). After intravenous or intraperitoneal administration of K1 and MK-4 (0.5 mumol/kg-I.V. and I.P.), MK-4 concentrations in the liver reached a maximum faster than those of K1 (1.2 nmol/g -3 h vs. 1.3 nmol/g -0.5 h I.V. and 0.97 nmol/g -6 h vs. 0.47 nmol/g -1 h I.P.). MK-4 also increased in the liver from 6 h to 12 h (0.11 nmol/g -12 h) after oral administration of K1 (P.O.). These results indicate that K1 stays in plasma and liver longer than MK-4 and orally administered K1 might be transformed partially into MK-4 in the liver.

Rats were made vitamin K-deficient by feeding them a diet devoid of vitamin K and by rigorously preventing coprophagy. After one week, circulating prothrombin concentrations were between 5 and 10% of initial values, and various amounts of phylloquinone, menaquinone-4, and menaquinone-9 were given in a single dose either subcutaneously, orally, or colorectally. The relative 'vitamin K activities' of these compounds were assessed by comparing their ability to support prothrombin synthesis after subcutaneous injection. Intestinal and colonic absorption were deduced from the difference between subcutaneous and either oral or colorectal administration of the vitamers. It is concluded that the colonic absorption of all three forms of vitamin K is extremely poor, suggesting that physiological menaquinones in the colon do not contribute substantially to vitamin K status in rats. Furthermore, the stimulation of prothrombin synthesis by menaquinone-9 lasted much longer than that by the two other K-vitamers, resulting in a substantially higher 'vitamin K activity' of menaquinone-9.

Background: Oral administration of vitamin K to neonates is quite satisfactory for preventing hemorrhagic disease of the newborn. The aim of this study is to test efficacy of a micellar solution of vitamin K at birth., Population and Methods: Thirty full term infants, exclusively breast-fed during the first month of life, were included in this study. Seven of them (control group Cos) were given oral supplementation with 5 mg vitamin K1, cremophor; 15 other infants were given oral supplementation with 3 mg micellar solution of vitamin K1 (group MMos) and 7 were given an intramuscular injection of 1.5 mg micellar solution of vitamin K1 (group MMim). Prothrombin time activity and plasma vitamin K concentration were measured in the cord blood, 24 +/- 12 hours and 1 month after supplementation., Results: No hemorrhage was seen and tolerance to vitamin K was good in the 3 groups. Mean prothrombin time activity was 54% in the cord blood, around 55% and 75%, 24 hrs and 1 month after supplementation, respectively; only one infant had low value (41%) by 1 month despite normal plasma vitamin K concentration. Two infants had low plasma vitamin K1 concentration by the second control despite normal prothrombin time activity; one belonged to the MMos group and the other to the Cos group. Mean values of plasma vitamin K1 concentration were higher by 1 month in the MMos group., Conclusion: A unique dose of micellar solution of vitamin K given orally at birth seems effective to prevent hemorrhagic disease.

To clarify the mechanism of absorption and metabolism of K vitamins (VK), we administered phylloquinone (K1) and menaquinone-4 (MK-4) orally to male Wistar rats whose portal and femoral veins were cannulated. Blood was collected 9 times up to 120 min later, and 50 microliters plasma was used for VK analysis by high performance liquid chromatography (HPLC) using a modification of our previous method. There were no significant differences between portal and femoral venous VK concentrations throughout all the experiments. When K1 and MK-4 were administered simultaneously, K1 appeared in plasma at 15 min, and MK-4 at 10 min. The concentration of MK-4 was significantly higher than that of K1 up to 60 min. In contrast to the single administration, the MK-4 concentration was reduced after 60 min. After K1 single administration, the MK-4 was not detected in either portal or femoral venous plasma up to 120 min. These results suggested that (1) the main absorption route of both VK may be the extra-portal pathway, (2) MK-4 is absorbed faster than K1 (3) some interactions may exist between K1 and MK-4 and (4) the intestinal cells might not be the major site to transform K1 into MK-4.

Rats were made vitamin K-deficient by feeding them a 1:1 (w/w) mixture of a commercial vitamin K-depleted diet and boiled white rice. After one week of treatment the rats had developed severe vitamin K deficiency, resulting in Thrombotest values of 5-10% of the initial values. In this experimental system the efficacy of phylloquinone (K1) was compared with that of menaquinone-4 (MK-4) by measuring the extent to which the Thrombotest was normalized after the administration of varying doses of the respective vitamins. Oral administration of the vitamins showed that the efficacy of K1 was at least two-fold higher than that of MK-4. As comparable results were obtained after subcutaneous administration of the vitamins, we conclude that after oral administration the intestinal absorption had been quick and nearly complete. A less pronounced effect of K1 and MK-4 was found after colorectal administration. For both forms of vitamin K relatively high amounts (well above the physiological concentration) were required before significant effects on the Thrombotest could be observed. Therefore these data demonstrate the importance of sufficient dietary vitamin K consumption in rats. The efficacy of other menaquinones may be investigated in the same experimental animal model system.

There is limited information available on the vitamin K intake of lactating mothers, concentration of vitamin K1 in breast milk, and the effect of long-term vitamin K1 supplementation of lactating mothers on the vitamin K1 concentration in breast milk. In a randomized study, we followed 20 mothers who received a daily oral vitamin K1 supplement (average 88 micrograms, supplemented group) and 16 mothers receiving no supplement (control group) from 4 throughout 91 days postpartum. Maternal vitamin K intakes (weighed dietary intake) at 4-6, 25-29 and 87-91 days postpartum ranged between 73 and 1735 micrograms/day. Differences between the groups were statistically not significant. Average intake exceeded the recommended dietary intake for lactating women of 55 micrograms/day by 670%. In the supplemented group, mean breast-milk vitamin K1 concentrations (HPLC) at 5, 26 and 88 days postpartum were 1.73 (SD 0.74), 1.36 (SD 0.81) and 1.67 (SD 2.01) ng/ml, respectively. Corresponding values in the control group were 1.44 (SD 0.57), 1.68 (SD 0.70) and 1.78 (SD 1.05) ng/ml. The latter were not statistically different from values in the supplemented group. Mean daily vitamin K1 intakes of infants breast-fed by supplemented mothers were 0.69 (SD 0.42), 0.93 (SD 0.51) and 1.25 (1.53) micrograms, respectively on days 5, 26 and 88. Corresponding values in the control group were 0.69 (SD 0.30), 1.07 (SD 0.58) and 1.31 (SD 0.95) micrograms and were statistically not different from values in the supplemented group. Average vitamin K1 intakes corresponded to 7-13% of the recommended dietary intake of 10 micrograms/d for infants.(ABSTRACT TRUNCATED AT 250 WORDS)

The metabolic basis for the high vitamin K requirement of chicks compared with rats was investigated. When chicks and rats were fed the same diet, containing 500 micrograms phylloquinone/kg, the total amounts of phylloquinone and its epoxide metabolite found in the liver and plasma were similar in both species. However, phylloquinone 2,3-epoxide was present in high concentrations in chick liver and serum but not in rat liver and serum. This metabolite of the vitamin is normally reduced by a hepatic vitamin K epoxide reductase. The activity of this enzyme in chicks was approximately 10% of that in rats, and the inability of chicks to effectively recycle the epoxide of vitamin K seems to be the major factor in its high requirement. Other species differences in vitamin K metabolism were observed. Much higher concentrations of bacterial menaquinones were present in rat feces compared with chick feces, but neither species had appreciable hepatic concentrations of menaquinones. Chicks, but not rats, were found to have a liver concentration of menaquinone-4 that exceeded that of phylloquinone. This vitamer was present even when its recognized precursor, menadione, was not present in the diet, and the data indicate that chicks convert phylloquinone to menaquinone-4 under the conditions of these experiments. The mechanism of this conversion was not established.

Vitamin K is an essential cofactor necessary for the production of clotting factors II, VII, IX, and X in humans and has recently been found to be an essential factor for many other proteins in the body. There are two sources of this essential vitamin, including vitamin K1, or phylloquinone which is primarily found in green leafy vegetables and vitamin K2 or menaquinone which is synthesized by certain intestinal bacteria. The precise contribution of the bacterially synthesized menaquinone to overall vitamin K requirements in man is unknown. This paper reviews the available literature regarding the production and liberation of menaquinones from bacteria, the animal experiments which have been done to examine the absorption of menaquinones and the indirect and direct evidence in humans regarding utilization of menaquinones. The preponderance of the evidence suggests that bacterially synthesized menaquinones, particularly in the ileum can and do play a significant role in contributing to vitamin K requirements in humans to prevent clinically significant coagulopathy, especially during periods of episodic dietary lack of the vitamin.

The hepatic turnover of phylloquinone and menaquinone-9 (MK-9) and their relative efficacy in satisfying the dietary requirement for vitamin K were compared in male rats. Rats fed 1.1 mumol phylloquinone/kg diet had higher initial liver and serum vitamin K concentrations than rats fed an equimolar amount of MK-9. The initial rate of hepatic turnover of phylloquinone was two to three times as rapid as that of MK-9. After about 48 h of vitamin K restriction there were no significant differences in hepatic vitamin K concentration of rats fed phylloquinone or MK-9. Phylloquinone was much more effective than MK-9 in maintaining normal vitamin K status at low dietary concentrations (0.2 mumol/kg diet), whereas at high dietary concentrations (5.6 mumol/kg diet) they were equally effective.

Liver and serum concentrations of vitamin K active compounds were measured in two groups of (deficient and normal) broilers after administration of phylloquinone 1 mg/kg. Assays were performed by HPLC after extraction and purification of these compounds. The only menaquinone found in the chicken was menaquinone-4. In the deficient group, the chickens exhibited hepatic concentrations of vitamin K1, vitamin K1 epoxide and menaquinone-4 markedly lower than those of the control group. After administration of phylloquinone, vitamin K and vitamin K epoxide levels fell sharply. There is no hepatic storage of vitamin K comparable to that of vitamin A. However, while menaquinone levels were found to be stable in the control group, they rose significantly in the deficient group after vitamin K injection. The question is: is there a transformation of vitamin K into menaquinone and/or is there a preferential utilization of one of the vitamin K active compounds?

The potential for 20 g olestra/d to affect vitamin K status was assessed in a 6-wk study involving 202 free-living subjects. Functional prothrombin [Simplastin (S)-Ecarin (E) assay] concentrations and classical clotting times were unaffected by olestra. Initial S:E values were 0.80 and 0.79 for the olestra and placebo groups, respectively, compared with a value of 0.92 for normal reference plasma. At week 6 the value was 0.81 for both groups. Mean phylloquinone serum concentrations, expressed as differences from baseline, were not significantly different between groups. Weekly food diaries indicated that the average phylloquinone intake of the subjects was low, approximately 60 micrograms/d. Sensitive measures of vitamin K status were unaffected in a population where any significant decrease in phylloquinone bioavailability should have been reflected in those measures, indicating that 20 g olestra/d in the diet did not affect vitamin K status.