Effects of phylloquinone supplementation on lipid profile in women with rheumatoid arthritis: a double blind placebo controlled study

Phylloquinone improves endothelial function, inhibits cellular senescence, and vascular inflammation

Phylloquinon (PK) and menaquinones (MK) are both naturally occurring compounds belonging to vitamin K group. Present study aimed to comprehensively analyze the influence of PK in several models of vascular dysfunction to determine whether PK has vasoprotective properties, similar to those previously described for MK. Effects of PK and MK on endothelial dysfunction were studied in ApoE/LDLR-/- mice in vivo, in the isolated aorta incubated with TNF, and in vascular cells as regard inflammation and cell senescence (including replicative and stress-induced models of senescence). Moreover, the vascular conversion of exogenous vitamins to endogenous MK-4 was analyzed. PK, as well as MK, given for 8 weeks in diet (10 mg/kg) resulted in comparable improvement in endothelial function in the ApoE/LDLR-/- mice. Similarly, PK and MK prevented TNF-induced impairment of endothelium-dependent vasorelaxation in the isolated aorta. In in vitro studies in endothelial and vascular smooth muscle cells, we identified that both PK and MK displayed anti-senescence effects via decreasing DNA damage while in endothelial cells anti-inflammatory activity was ascribed to the modulation of NFκB activation. The activity of PK and MK was comparable in terms of their effect on senescence and inflammation. Presence of endogenous synthesis of MK-4 from PK in aorta and endothelial and smooth muscle cells suggests a possible involvement of MK in vascular effects of PK. In conclusion, PK and MK display comparable vasoprotective effects, which may be ascribed, at least in part, to the inhibition of cell senescence and inflammation. The vasoprotective effect of PK in the vessel wall can be related to the direct effects of PK, as well as to the action of MK formed from PK in the vascular wall.

The association between vitamin K intake and dyslipidemia in US adults: the mediating effect of insulin resistance

Background: Dyslipidemia is one of the most common chronic diseases, and is associated with insulin resistance (IR) and inadequate vitamin K intake. We aimed to explore the association between IR, vitamin K intake, and dyslipidemia, and further to explore the mediating role of IR. Materials and methods: 12 860 participants from the National Health and Nutrition Examination Survey (NHANES) from 2001 to 2018 were included in this study. Insulin resistance was determined by using the homeostatic model assessment for insulin resistance (HOMA-IR). Weighted multiple logistic regression and mediation analyses were conducted to analyze the associations between IR, vitamin K intake, and dyslipidemia. Results: We found that both vitamin K intake-met Dietary Reference Intake (DRI) and non-IR were protective factors of high triglycerides (with ORs (95% CI) of 0.71 (0.57, 0.87) and 0.36 (0.29, 0.45), respectively) and low high-density lipoprotein cholesterol (with ORs (95% CI) of 0.72 (0.62, 0.82) and 0.39 (0.34, 0.41), respectively). IR-related indicators (HOMA-IR and insulin) partly mediated these effects, and the proportion ranged from 16.36% to 18.52%. Conclusion: Vitamin K intake-met DRI and non-IR were associated with lower risk of dyslipidemia including high TG and low HDL-C. IR partly mediated the association of vitamin K intake with high TG and low HDL-C.

The effect of vitamin K supplementation on cardiovascular risk factors: a systematic review and meta-analysis

Cardiovascular disease (CVD) is one of the most important diseases which controlling its related risk factors, such as metabolic and inflammatory biomarkers, is necessary because of the increased mortality risk of that. The aim of our meta-analysis is to reveal the general effect of vitamin K supplementation on its related risk factors. Original databases were searched using standard keywords to identify all randomized clinical trials (RCTs) investigating the effects of vitamin K on CVD. Pooled weighted mean difference (WMD) and 95 % confidence intervals (95 % CI) were achieved by random-model effect analysis for the best estimation of outcomes. The statistical heterogeneity was determined using the Cochran's Q test and I2 statistics. Seventeen studies were included in this systematic review and meta-analysis. The pooled findings showed that vitamin K supplementation can reduce homeostatic model assessment insulin resistance (HOMA-IR) (WMD: -0⋅24, 95 % CI: -0⋅49, -0⋅02, P = 0⋅047) significantly compared to the placebo group. However, no significant effect was observed on other outcomes. Subgroup analysis showed a significant effect of vitamin K2 supplementation compared to vitamin K1 supplementation on HOMA-IR. However, no significant effect was observed on other variables. Also, subgroup analysis showed no potential effect of vitamin K supplementation on any outcome and omitting any articles did not affect the final results. We demonstrated that supplementation with vitamin K has no effect on anthropometrics indexes, CRP, glucose metabolism, and lipid profile factors except HOMA-IR.

Revisiting the interconnection between lipids and vitamin K metabolism: insights from recent research and potential therapeutic implications: a review

Vitamin K is a lipophilic vitamin, whose absorption, transportation, and distribution are influenced by lipids. The plasma vitamin K level after supplementation is predominantly a lipid-driven effect and independent of existing vitamin K status. However, previous studies examining the efficacy of vitamin K supplementation often overlooked the influence of lipid levels on vitamin K absorption, resulting in inconsistent outcomes. Recent research discovered that impaired transportation of vitamin K2 within uremic high-density lipoproteins (HDL) in individuals with uremia might elucidate the lack of beneficial effects in preventing calcification observed in multiple trials involving menaquinone-7 (MK-7) supplementation among patients with chronic kidney disease. Clinical findings have shown that drugs used to regulate hyperlipidemia interact with the vitamin K antagonist warfarin, because cholesterol and vitamin K share common transport receptors, such as Niemann-Pick C1-like 1 (NPC1L1) and ATP-binding cassette protein G5/G8 (ABCG5/ABCG8), in enterocytes and hepatocytes. Additionally, cholesterol and vitamin K share a common biosynthetic intermediate called geranylgeranyl pyrophosphate (GGPP). It is important to note that statins, which hinder cholesterol synthesis, can also impede vitamin K conversion, ultimately impacting the functionality of vitamin K-dependent proteins. Furthermore, certain studies have indicated that vitamin K supplementation holds potential in managing hyperlipidemia, potentially opening a novel avenue for controlling hyperlipidemia using dietary vitamin K supplements. Therefore, attaining a more comprehensive understanding of the intricate interplay between vitamin K and lipids will yield valuable insights concerning the utilization of vitamin K and lipid regulation.

The effect of vitamin K4 supplementation on insulin resistance in individuals with type 2 diabetes: a double-blind randomised placebo-controlled clinical trial

PURPOSE

The purpose of this study was to assess the possible clinical effects of vitamin K4 supplementation in individuals with type 2 diabetes namely insulin resistance, glycaemic control, and lipid profile.

METHODS

This was a prospective randomised double-blind placebo-controlled clinical trial. A total of 106 patients were randomised to receive either 1 mg of vitamin K4 (menadiol diacetate) or placebo for 24 weeks.

RESULTS

Ninety patients (n = 45 in each study group) were included in the final analysis. After 24 weeks, homeostatic model assessment of insulin resistance (HOMA-IR) (16.54 ± 7.81 vs. 29.09 ± 36.56, P = 0.027) and fasting serum insulin (FSI) (6.86 ± 3.45 vs. 11.13 ± 12.66 µU/ml, P = 0.032) were significantly lower in the vitamin K group compared to placebo. Additionally, triglycerides (TG) (144.94 ± 50.7 vs. 172.8 ± 101.5 mg/dl, P = 0.031) and very low-density lipoproteins (VLDL) levels (28.9 ± 9.88 vs. 34.6 ± 20.30 mg/dl, P = 0.027) decreased significantly in the vitamin K group after 24 weeks compared to baseline. Moreover, more patients in the vitamin K group (35.6%) had their antidiabetic medication doses reduced after 24 weeks compared to placebo (13.3%, P = 0.029).

CONCLUSION

Vitamin K4 supplementation for 24 weeks is capable of improving insulin resistance and TG levels in individuals with type 2 diabetes. In addition, the improvement in insulin resistance was reflected in the decrease in antidiabetic medication doses. However, it did not affect fasting plasma glucose (FPG) or glycated haemoglobin (HbA1c).

TRIAL REGISTRATION

The study was registered on clinicaltrials.gov with ID: NCT04285450.

The Associations of Dietary Vitamin K Intake and Circulating Vitamin 25(OH)D with Serum Lipoprotein Levels: The Vitamin Deficiency Matters

A synergistic interplay between vitamins K and D appears to exist. We aimed to investigate for the first time whether the associations of dietary vitamin K intake and circulating 25(OH)D with serum lipoprotein levels are influenced by the existence of deficiency of either or both vitamins K and D. Sixty individuals [24 males, 36(18-79) years old] were examined. Vitamin deficiency of K1 and D were defined as vitamin K1 intake/body weight (BW)<1.00 μg/kg/day and circulating 25(OH)D<20 ng/ml, respectively. In individuals with vitamin K1 deficiency, the vitamin K1 intake/BW correlated positively with high density lipoprotein-cholesterol (HDL-C) (r=0.509, p=0.008) and negatively with serum triglycerides (TG) (r=-0.638, p=0.001), whereas circulating 25(OH)D correlated negatively with TG (r=-0.609, p=0.001). In individuals with vitamin D deficiency, the vitamin K1 intake/BW correlated positively with HDL-C (r=0.533, p=0.001) and negatively with TG (r=-0.421, p=0.009), while circulating 25(OH)D correlated negatively with TG (r=-0.458, p=0.004). The above-mentioned associations of vitamin K1 intake/BW and circulating 25(OH)D with serum lipoproteins were not detected in individuals without vitamin K1 deficiency or the ones without vitamin D deficiency. The vitamin K2 intake/BW correlated negatively with low density lipoprotein-cholesterol (LDL-C) (r=-0.404, p=0.001). In conclusion, the associations of vitamin K1 intake with TG and HDL-C and of circulating 25(OH)D with TG were more pronounced in individuals with deficiency of either or both vitamins K1 and D. Increased dietary vitamin K2 intake was associated with decreased LDL-C.

A critical review of the effects of vitamin K on glucose and lipid homeostasis: its potential role in the prevention and management of type 2 diabetes

In recent years, our knowledge regarding the physiological role of vitamin K has expanded beyond regulation of coagulation to include many other aspects of human health. In the present review, we aimed to evaluate the existing evidence for beneficial effects of vitamin K on type 2 diabetes and components of the metabolic syndrome as risk factors for cardiovascular disease. Increased dietary intake of vitamin K has been linked to lower incidence of type 2 diabetes mellitus (T2DM), possibly through its enhancement of insulin production and sensitivity. Additionally, higher plasma levels of vitamin K1 have been associated with lower T2DM risk and decreased insulin resistance, and supplementation trials also suggest a positive influence of vitamin K on glucose regulation. Vitamin K might also beneficially affect serum lipids and lipid metabolism. However, the available data remain controversial. Additionally, different studies use different approaches to assess vitamin K status owing to the absence of a generally accepted marker, which further complicates data evaluation. In conclusion, vitamin K possibly improves glucose and lipid metabolism and could be an emerging target in the context of prevention and control of T2DM, insulin resistance, and dyslipidemia.

Beneficial health effects of Menaquinone-7 on body composition, glycemic indices, lipid profile, and endocrine markers in polycystic ovary syndrome patients

OBJECTIVE

The aim of this study was to investigate the effect of oral vitamin K2 (Menaquinone-7 [MK-7]) on clinical and biochemical parameters in polycystic ovary syndrome (PCOS) patients.

METHODS

In this randomized, double-blind, placebo-controlled clinical trial, 84 PCOS patients were randomly assigned into the treatment (90 µg Menaquinone-7 daily for 8 weeks) and placebo groups. Insulin resistance, lipid profile, endocrine biomarkers, and body composition of the participants were measured before and after the intervention. This study was performed in Ghadir Mother & Child Hospital affiliated to Shiraz University of Medical Sciences, Shiraz, Iran.

RESULTS

Menaquinone-7 supplementation, when compared to placebo, significantly decreased serum fasting insulin (p = .002), homeostasis model of assessment insulin resistance (p = .002), and homeostasis model of assessment β-cell function (p = .02) in addition to a significant increase in quantitative insulin sensitivity check index (p = .001). Also, MK-7 administration led to significant declines in serum triglyceride (p = .003) and dihydrotestosterone (DHT; p = .03) levels, free androgen index (p < .001), waist circumference (p = .03), and body fat mass (p < .001) as well as significant increases in skeletal muscle (p < .001) and sex hormone binding globulin (SHBG, p < .001).

CONCLUSIONS

This study highlights the beneficial effects of MK-7 on insulin resistance, fat mass, skeletal muscle, and serum levels of triglyceride, DHT, and SHBG in PCOS patients. Therefore, it seems that MK-7 supplementation might be an appropriate additive treatment for PCOS patients.

Correlations among vitamin K intake, body fat, lipid profile and glucose homeostasis in adults and the elderly

Objective Recent research has investigated the possible inverse relationship between vitamin K intake and body fat. In addition, an increasing number of studies are supporting a key role for this vitamin in improving lipid profile and insulin sensitivity and reducing the risk of type 2 diabetes mellitus, but little is known about what mechanisms would be involved. Thus, the objective of this study was to investigate the relationship between vitamin K intake (in the form of phylloquinone - PK), body fat, lipid profile and markers of glucose homeostasis in adults and the elderly. Subjects and methods A cross-sectional study with 298 participants (46% men) in the São Paulo Health Survey 2014-2015. Spearman correlations were performed to evaluate the associations between vitamin K intake and the biochemical and body composition measures. Results Among normal-weight male adults (n = 15), PK intake presented a positive correlation with the quantitative insulin sensitivity check index (QUICKI) (r = 0.525; p = 0.045). Among men with high fat mass index (FMI) (n = 101), PK intake had a negative correlation with homeostasis model assessment estimate for β-cell function (HOMA-β) (r = -0.227; p = 0.022). In women with high FMI (n = 122), PK intake had a negative correlation with HOMA-β (r = -0.199, p = 0.032) and insulin (r = -0.207, p = 0.026). No correlations were found between PK intake and lipid profile. Conclusions Our findings support a potential relationship among PK intake, body fat and markers of glucose homeostasis in adults and the elderly.

Effect of Vitamin K Supplementation on Cardiometabolic Risk Factors: A Systematic Review and Meta-Analysis

BACKGROUND

Multiple cross sectional and longitudinal studies reported the benefits of vitamin K intake for management of cardiometabolic risk factors so as to minimize the risk of cardiovascular diseases.

OBJECTIVE

In present systematic review and meta-analysis, we aimed to evaluate the effect of vitamin K supplementation on cardiometabolic risk factors.

METHODOLOGY

A systematic literature search of PubMed, Cochrane central, Clinicaltrials.gov, Google Scholar, Web of Science, EBSCO and Scopus databases was done from inception to November, 2017. A total of 13 trials were selected for inclusion into the present systematic review to evaluate the effect of vitamin K supplementation on cardiometabolic risk factors in healthy or in population at high risk of cardiovascular diseases.

RESULTS

Significant beneficial effects of vitamin K supplementation were found only in case of Creactive protein (p = 0.01) and insulin sensitivity index (p <0.001), while no significant effects of vitamin K supplementation were found in case of total cholesterol (p=0.857), low density lipoprotein - cholesterol (p=0.964), high density lipoprotein - cholesterol (p=0.998), interleukin - 6 (p=0.766), systolic blood pressure (p=0.660), diastolic blood pressure (p=0.818), fasting plasma glucose (p=0.362), fasting plasma insulin (p=0.928) and homeostasis model assessment for insulin resistance (p=0.672).

CONCLUSION

Presently available evidence are insufficient to ascertain the beneficial effects of vitamin K supplementation for the management of cardiometabolic risk factors. In order to explore the true potential of vitamin K supplementation for management of cardiometabolic diseases, large randomized placebo controlled trials are required in population with disturbed cardiometabolic profile. Present systematic review and meta-analysis is registered with PROSPERO (Registration number: CRD42018084608).

Vitamin K1 Supplementation Did Not Alter Inflammatory Markers and Clinical Status in Patients with Rheumatoid Arthritis

Background: Rheumatoid arthritis (RA) is an inflammatory disorder in which the disease severity might be decreased by anti-inflammatory agents. There are several lines of evidence which support anti-inflammatory effects of vitamin K. The aim of this study was to examine whether vitamin K is a useful strategy for reducing inflammation in RA subjects. Materials and methods: In this double-blind placebo controlled trial, 58 patients with definitive RA were randomly allocated into two groups to receive vitamin K₁ as phylloquinone [10 mg/day] or placebo pills for 8 weeks. Clinical status using disease activity score-28 (DAS-28) and serum concentrations of some inflammatory markers (IL-6, hs-CRP, TNFα) were assessed at baseline and at the end of intervention. Results: There were no significant differences between the two groups regarding any of the baseline characteristics. In the vitamin K₁ group, a 27 % decrease in serum levels of IL-6 (P = 0.006) and a 13 % decrease in DAS-28 (P = 0.041) were observed. However, after adjusting for relevant confounders, i. e.; duration of RA, intake of folic acid supplements, energy intake, weight and baseline values of each variable, by comparing the two groups, we found no significant reduction in these markers. Conclusion: Vitamin K₁ supplementation at 10 mg/day for 8 weeks had no significant effects on blood biomarkers of inflammation and disease severity of patients with rheumatoid arthritis compared with the placebo group.

Lipoprotein redox status evaluation as a marker of cardiovascular disease risk in patients with inflammatory disease

Patients with chronic inflammatory disorders (ID) have an increased risk of developing cardiovascular disease, and routinely determined parameters do not reveal the real metabolic status of specific subgroups, such as patients with rheumatoid arthritis (RA). In this study, in order to evaluate state of the art markers for the assessment of cardiometabolic risk, abnormalities in lipoprotein levels in patients with a low-grade inflammatory status [diabetes mellitus (DM) subgroup] and in patients with a high systemic inflammatory burden (RA subgroup) was determined. The study group comprised patients with ID [DM (n=20) and RA (n=20)], with an aged-matched control group (n=17). Patient serum was used to determine routine biochemical parameters and to isolate low-density lipoprotein (LDL) and high-density lipoprotein (HDL). The heparin-citrate method was used for LDL precipitation and the phosphotungstic acid-MgCl₂ technique for the isolation of HDL. Further, Amplex Red and advanced oxidation protein product (AOPP) assays were applied to determine lipid peroxides and protein oxidation, respectively, while the levels of serum advanced glycation end products (AGEs) were also determined. Although the differences in the routinely determined lipidemic profile were notable between the DM and RA subgroups, markers of lipid peroxidation and of advanced protein oxidation/glycation did not differ significantly, indicating possible similar oxidative damage of serum lipoproteins. On the whole, as alterations in lipoprotein functionality can occur long before any changes in routinely measured biochemical parameters are observed, more sensitive markers for the assessment of cardiovascular risk are required. As AOPPs, AGEs, oxidized LDL (oxLDL) and especially oxidized HDL (oxHDL) are affected during the early stages of inflammatory disease, and due to their known link to coronary artery disease, it would be wise to include these markers in the routine cardiovascular evaluation of patients with chronic inflammatory disease, such as those with RA.

Beneficial role of vitamin K supplementation on insulin sensitivity, glucose metabolism, and the reduced risk of type 2 diabetes: A review

Micronutrients are gaining acceptance as an important nutritional therapy for the prevention and/or management of diabetes and its associated health risks. Although a very small quantity of micronutrients are required for specific functions in our bodies, moderate deficiencies can lead to serious health issues. Impaired insulin sensitivity and glucose intolerance play a major role in the development of diabetic pathophysiology. Vitamin K is well known for its function in blood coagulation. Moreover, several human studies reported the beneficial role of vitamin K supplementation in improving insulin sensitivity and glucose tolerance, preventing insulin resistance, and reducing the risk of type 2 diabetes (T2 D). Both animal and human studies have suggested that vitamin K-dependent protein (osteocalcin [OC]), regulation of adipokine levels, antiinflammatory properties, and lipid-lowering effects may mediate the beneficial function of vitamin K in insulin sensitivity and glucose tolerance. This review for the first time provides an overview of the currently available preclinical and clinical evidences on the effect of vitamin K supplementation in the management of insulin sensitivity and glucose tolerance. The outcome of this review will increase understanding for the development of a novel adjuvant therapy to achieve better control of glycemia and improve the lives of diabetic patients.