Effect of vitamin K supplementation on insulin resistance in older men and women.
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ABSTRACT:
SUBMITTER: Yoshida M
PROVIDER: S-EPMC2571052 | biostudies-literature | 2008 Nov
REPOSITORIES: biostudies-literature
Publications
Effect of vitamin K supplementation on insulin resistance in older men and women.
Yoshida Makiko M Jacques Paul F PF Meigs James B JB Saltzman Edward E Shea M Kyla MK Gundberg Caren C Dawson-Hughes Bess B Dallal Gerard G Booth Sarah L SL
Diabetes care 20080812 11
<h4>Objective</h4>Vitamin K has a potentially beneficial role in insulin resistance, but evidence is limited in humans. We tested the hypothesis that vitamin K supplementation for 36 months will improve insulin resistance in older men and women.<h4>Research design and methods</h4>This was an ancillary study of a 36-month, randomized, double-blind, controlled trial designed to assess the impact of supplementation with 500 microg/day phylloquinone on bone loss. Study participants were older nondia ...[more]
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Project description:BackgroundCoronary artery calcification (CAC) is an independent predictor of cardiovascular disease. A preventive role for vitamin K in CAC progression has been proposed on the basis of the properties of matrix Gla protein (MGP) as a vitamin K-dependent calcification inhibitor.ObjectiveThe objective was to determine the effect of phylloquinone (vitamin K1) supplementation on CAC progression in older men and women.DesignCAC was measured at baseline and after 3 y of follow-up in 388 healthy men and postmenopausal women; 200 received a multivitamin with 500 microg phylloquinone/d (treatment), and 188 received a multivitamin alone (control).ResultsIn an intention-to-treat analysis, there was no difference in CAC progression between the phylloquinone group and the control group; the mean (+/-SEM) changes in Agatston scores were 27 +/- 6 and 37 +/- 7, respectively. In a subgroup analysis of participants who were > or =85% adherent to supplementation (n = 367), there was less CAC progression in the phylloquinone group than in the control group (P = 0.03). Of those with preexisting CAC (Agatston score > 10), those who received phylloquinone supplements had 6% less progression than did those who received the multivitamin alone (P = 0.04). Phylloquinone-associated decreases in CAC progression were independent of changes in serum MGP. MGP carboxylation status was not determined.ConclusionsPhylloquinone supplementation slows the progression of CAC in healthy older adults with preexisting CAC, independent of its effect on total MGP concentrations. Because our data are hypothesis-generating, further studies are warranted to clarify this mechanism. This trial was registered at clinicaltrials.gov as NCT00183001.
| S-EPMC2682995 | biostudies-literature
Project description:ContextVitamin K has been implicated in bone health, primarily in observational studies. However, little is known about the role of phylloquinone supplementation on prevention of bone loss in men and women.ObjectiveThe objective of this study was to determine the effect of 3-yr phylloquinone supplementation on change in bone mineral density (BMD) of the femoral neck bone in older men and women who were calcium and vitamin D replete.Design, participants, and interventionIn this 3-yr, double-blind, controlled trial, 452 men and women (60-80 yr) were randomized equally to receive a multivitamin that contained either 500 mug/d or no phylloquinone plus a daily calcium (600 mg elemental calcium) and vitamin D (400 IU) supplement.Main outcome measuresMeasurements of the femoral neck, spine (L2-L4), and total-body BMD, bone turnover, and vitamins K and D status were measured every 6-12 months. Intent-to-treat analysis was used to compare change in measures in 401 participants who completed the trial.ResultsThere were no differences in changes in BMD measurements at any of the anatomical sites measured between the two groups. The group that received the phylloquinone supplement had significantly higher phylloquinone and significantly lower percent undercarboxylated osteocalcin concentrations compared with the group that did not receive phylloquinone. No other biochemical measures differed between the two groups.ConclusionsPhylloquinone supplementation in a dose attainable in the diet does not confer any additional benefit for bone health at the spine or hip when taken with recommended amounts of calcium and vitamin D.
| S-EPMC2291488 | biostudies-literature
Project description:BackgroundThe skeletal protein osteocalcin is gamma-carboxylated by vitamin K. High serum uncarboxylated osteocalcin reflects low vitamin K status. In vitro and animal studies indicate that high uncarboxylated osteocalcin is associated with reduced insulin resistance. However, associations between osteocalcin and measures of insulin resistance in humans are less clear.ObjectiveOur aim was to examine cross-sectional and longitudinal associations between circulating forms of osteocalcin (total, uncarboxylated, and carboxylated) and insulin resistance in older men and women.DesignCross-sectional associations between serum measures of total osteocalcin, carboxylated osteocalcin, and uncarboxylated osteocalcin and insulin resistance were examined in 348 nondiabetic men and women (mean age: 68 y; 58% female) by using the homeostasis model assessment of insulin resistance (HOMA-IR). Associations between each form of osteocalcin at baseline and 3-y change in HOMA-IR were examined in 162 adults (mean age: 69 y; 63% female) who did not receive vitamin K supplementation.ResultsLower circulating uncarboxylated osteocalcin was not associated with higher HOMA-IR at baseline or at 3-y follow-up. Those in the lowest tertiles of total osteocalcin and carboxylated osteocalcin at baseline had higher baseline HOMA-IR (P = 0.006 and P = 0.02, respectively). The concentration of carboxylated osteocalcin at baseline was inversely associated with a 3-y change in HOMA-IR (P = 0.002).ConclusionsIn older adults, circulating uncarboxylated osteocalcin was not associated with insulin resistance. In contrast, elevated carboxylated osteocalcin and total osteocalcin were associated with lower insulin resistance, which supports a potential link between skeletal physiology and insulin resistance in humans. The role of vitamin K status in this association remains unclear and merits further investigation. This trial is registered at clinicaltrials.gov as NCT00183001.
| S-EPMC2762158 | biostudies-literature
Project description:ContextSerum 25-hydroxyvitamin D (25OHD) is lower in women with darker skin color. Is it due to lower skin production, lower absorption, or different metabolism of vitamin D?ObjectivesThe objective of the study was to measure the effect of vitamin D3 on serum 25OHD and serum PTH in older African American women with vitamin D insufficiency and the serum 25OHD 20 ng/mL or less (<50 nmol/L). The results can be used to estimate the Recommended Dietary Allowance (RDA).Design and settingThis was a randomized, double-blind placebo trial at Creighton University Medical Center and Indiana University Medical Center.ParticipantsParticipants were 110 healthy older African American women.InterventionsThe intervention consisted of participants randomly assigned to placebo, vitamin D3 400, 800, 1600, 2400, 3200, 4000, or 4800 IU daily; calcium supplements were given to maintain total calcium intake of 1200-1400 mg/d.Main outcome measurementsChange in serum 25OHD and serum PTH levels at 12 months was measured.ResultsMean baseline serum 25OHD was 13 ng/mL (33 nmol/L). On 4800 IU, serum 25OHD averaged 50 ng/mL (125 nmol/L) compared with 47 ng/mL (117 nmol/L) in Caucasian women. Serum PTH at 12 months decreased significantly (P = .008) when related to serum 25OHD but not dose. Hypercalcemia occurred in 7% and hypercalciuria in 15%. Events were unrelated to vitamin D dose.ConclusionVitamin D3 800 IU increased serum 25OHD greater than 20 ng/mL (>50 nmol/L) in 97.5% of the African American women just as it did in the Caucasian women, and therefore, the RDA is the same for both groups. Because absorption and metabolism of oral vitamin D absorption is similar in both groups, lower levels of serum 25OHD in African Americans must be due to lower production of vitamin D in skin.
| S-EPMC3590472 | biostudies-literature
Project description:BackgroundObservational studies among older women have associated vitamin D insufficiency with a greater prevalence and incidence of urinary incontinence. However, little is known about the effect of vitamin D supplementation in reducing urinary incontinence.ObjectiveThis study aimed to evaluate the effects of vitamin D supplementation in reducing the frequency of urinary incontinence in older women.Study designWe conducted an ancillary study of women aged ≥55 years in the Vitamin D and Omega-3 Trial, a randomized trial with a 2×2 factorial design. Recruitment of participants started from 2011 to 2014 across 50 US states, and the follow-up of participants ended in January 2018. Randomized treatments in the parent study included (1) vitamin D3 (cholecalciferol) at a dosage of 2000 IU/d, (2) marine omega-3 fatty acids at a dosage of 1 g/d, and (3) matching placebo. Here, we analyzed women according to their randomization to vitamin D supplementation or placebo, regardless of treatment with omega-3 fatty acid supplementation. Validated frequency of urinary incontinence questions were added in year 2 of the study and were used again in year 5 at the end of trial. Prespecified ancillary outcomes included the prevalence of urinary incontinence at years 2 and 5, along with incident incontinence and progression of incontinence (from lower to higher frequency) from year 2 to year 5. Preplanned subgroup analyses examined the following outcomes: prerandomization of low serum levels of vitamin D (serum 25-hydroxyvitamin D<20 ng/mL), incontinence types, weight categories, and African American race.ResultsAmong the randomized women who provided urinary incontinence data, 11,646 women at year 2 and 10,527 women at year 5, the mean age was 70 years at year 2, with 29% racial and ethnic minorities. The prevalence of urinary incontinence that occurred at least weekly was 29% at year 2 and increased to 37% at year 5. Vitamin D supplementation compared to with placebo was not associated with lower odds of urinary incontinence occurring at least weekly at year 2 (odds ratio, 1.08; 95% confidence interval, 0.99-1.19) or year 5 (odds ratio, 1.04; 95% confidence interval, 0.94-1.15). Vitamin D supplementation compared to placebo was not associated with lower incidence or progression of urinary incontinence from year 2 to year 5: incidence (odds ratio, 1.06; 95% confidence interval, 0.83-1.35) or progression (odds ratio, 0.94; 95% confidence interval, 0.82-1.08). Women with prerandomization of low serum levels of vitamin D (n=836) did not have lower odds of the prevalence, incidence, or progression of urinary incontinence. The findings were null in subgroups according to incontinence type, women with obesity, and African American women. Only women with healthy weight randomized to vitamin D had lower odds of progression of urinary incontinence (odds ratio, 0.78; 95% confidence interval, 0.63-0.95; P=.01).ConclusionVitamin D supplementation compared to placebo for 2 to 5 years was not associated with differences in the prevalence, incidence, or progression of urinary incontinence in older women with and without adequate serum vitamin D levels, with inconsistent differences among subgroups. The findings showed that the broad use of moderate doses of vitamin D supplementation did not reduce urinary incontinence in older women.
| S-EPMC8983596 | biostudies-literature
Project description:OBJECTIVE:The aim was to investigate whether vitamin D supplementation, combined with a hypocaloric diet, could have an independent effect on insulin sensitivity in subjects with both overweight and hypovitaminosis D. Changes from baseline in anthropometric parameters, body composition, glucose tolerance, and insulin secretion were considered as secondary outcomes. METHODS:Eighteen volunteers who were nondiabetic and vitamin D deficient and had BMI > 25 kg/m2 were randomized (1:1) in a double-blind manner to a hypocaloric diet + either oral cholecalciferol at 25,000 IU/wk or placebo for 3 months. Hyperinsulinemic-euglycemic clamp to measure insulin sensitivity was performed at baseline and after intervention. RESULTS:Body weight in both groups decreased significantly (-7.5% in the vitamin D group and -10% in the placebo group; P < 0.05 for both), with no between-group differences. Serum 25-hydroxyvitamin D levels in the vitamin D group increased considerably (from 36.7 ± 13.2 nmol/L to 74.8 ± 18.7 nmol/L; P < 0.001). Insulin sensitivity in the vitamin D group improved (from 4.6 ± 2.0 to 6.9 ± 3.3 mg·kg-1 ·min-1 ; P < 0.001), whereas no changes were observed in the placebo group (from 4.9 ± 1.1 to 5.1 ± 0.3 mg·kg-1 ·min-1 ; P = 0.84). CONCLUSIONS:Cholecalciferol supplementation, combined with a weight loss program, significantly improves insulin sensitivity in healthy subjects with obesity and might represent a personalized approach for insulin-resistant subjects with obesity.
| S-EPMC6175391 | biostudies-literature
Project description:IntroductionSarcopenia is a progressive loss in muscle mass, strength and function, the adverse consequences of which are severe, affecting quality of life and placing an increasing burden on social and healthcare systems. Vitamin D status is known to be associated with markers of sarcopenia, namely muscle mass, strength and function. Also, resistance exercise training (RET) is currently the only proven intervention to treat sarcopenia. However, very little data exist on the influence of combining the two interventions of vitamin D supplementation and resistance exercise training, although a recent systematic review provides tentative support for the current study's hypothesis that the combined intervention may further improve musculoskeletal function above exercise training alone. The aim of the present study is to determine whether vitamin D3 supplementation is any more effective in improving musculoskeletal function when combined with RET compared with exercise training alone in older adults.Methods and analysisThis double-blinded randomised placebo-controlled trial will recruit a target of 127 eligible men and women aged ≥65 years living independently or in sheltered housing within the Birmingham area to two groups: (1) 6 months RET and placebo or (2) 6 months RET and 800 IU/d vitamin D3. Measures of muscle power (Nottingham Power Rig), body composition (dual energy X-ray absorptiometry), muscle function (short physical performance battery, timed up and go), falls and fractures as events will be assessed. Assessments will take place at baseline and postintervention, with intermittent monitoring of bone turnover, calcium and vitamin D. The primary outcome will be lower limb extensor power output. Analyses of within-group changes and between-group differences in outcome measures are planned.Ethics and disseminationThe EXVITD study has ethical approval granted by the Black Country National Health Service Research Ethics Committee (14/WM/1220). Results of this trial will be submitted for publication in peer-reviewed journals and presented at conferences. The study is being conducted according to the principles of the Declaration of Helsinki.Trial registration numberNCT02467153; Post-results.
| S-EPMC7202733 | biostudies-literature
Project description:Vitamin D deficiency is common among older adults and has been linked to muscle weakness. Vitamin D supplementation has been proposed as a strategy to improve muscle function in older adults. The aim of this study was to investigate the effect of calcifediol (25-hydroxycholecalciferol) on whole genome gene expression in skeletal muscle of vitamin D deficient frail older adults. A double-blind placebo controlled trial was conducted in vitamin D deficient frail older adults (aged above 65), characterized by blood 25-hydroxycholecalciferol concentrations between 20 and 50 nmol/L. Subjects were randomized across the placebo group (n=12) and the calcifediol group (n=10, 10 µg per day). Muscle biopsies were obtained before and after six months of calcifediol or placebo supplementation and subjected to whole genome gene expression profiling using Affymetrix HuGene 2.1ST arrays. Expression of the vitamin D receptor gene was virtually undetectable in human skeletal muscle biopsies. Calcifediol supplementation led to a significant increase in blood 25-hydroxycholecalciferol levels compared to the placebo group. No difference between treatment groups was observed on strength outcomes. The whole transcriptome effects of calcifediol and placebo were very weak. Correcting for multiple testing using false discovery rate did not yield any differentially expressed genes using any sensible cut-offs. P-values were uniformly distributed across all genes, suggesting that low p-values are likely to be false positives. Partial least squares-discriminant analysis and principle component analysis was unable to separate treatment groups. Calcifediol supplementation did not affect the skeletal muscle transcriptome in frail older adults. Our findings indicate that vitamin D supplementation has no effects on skeletal muscle gene expression, suggesting that skeletal muscle may not be a direct target of vitamin D in older adults.
2019-06-10 | GSE123993 | GEO
Project description:CONTEXT:Vitamin D supplementation trials with diabetes-related outcomes have been conducted almost exclusively in adults and provide equivocal findings. OBJECTIVE:The objective of this study was to determine the dose-response of vitamin D supplementation on fasting glucose, insulin, and a surrogate measure of insulin resistance in white and black children aged 9–13 years, who participated in the Georgia, Purdue, and Indiana University (or GAPI) trial: a 12-week multisite, randomized, triple-masked, dose-response, placebo-controlled vitamin D trial. DESIGN:Black and white children in the early stages of puberty (N = 323, 50% male, 51% black) were equally randomized to receive vitamin D3 (0, 400, 1000, 2000, or 4000 IU/day) for 12 weeks. Fasting serum 25-hydroxyvitamin D (25(OH)D), glucose and insulin were assessed at baseline and weeks 6 and 12. Homeostasis model assessment of insulin resistance was used as a surrogate measure of insulin resistance. Statistical analyses were conducted as intent-to-treat using a mixed effects model. RESULTS:Baseline serum 25(OH)D was inversely associated with insulin (r = ?0.140, P = 0.017) and homeostasis model assessment of insulin resistance (r = ?0.146, P = 0.012) after adjusting for race, sex, age, pubertal maturation, fat mass, and body mass index. Glucose, insulin, and insulin resistance increased (F > 5.79, P < .003) over the 12 weeks, despite vitamin D dose-dependent increases in serum 25(OH)D. CONCLUSIONS:Despite significant baseline inverse relationships between serum 25(OH)D and measures of insulin resistance, vitamin D supplementation had no impact on fasting glucose, insulin, or a surrogate measure of insulin resistance over 12 weeks in apparently healthy children.
| S-EPMC4880166 | biostudies-literature
Project description:Diabetes prevention is a public health priority. Vitamin D supplementation may help prevent the development of diabetes in persons at increased risk. We performed a meta-analysis of controlled clinical trials that assessed glycemic outcome measures among adults at risk for type 2 diabetes, including prediabetes, overweight, or obesity. We searched PUBMED/ MEDLINE, CINAHL, and Google Scholar databases for trials published prior to April 2017. Placebo-controlled clinical trials with random allocation to vitamin D with or without calcium supplementation were selected. Data collection included country, study design, inclusion criteria, sample size, form, and dose of vitamin D, supplementation interval, control group, duration, participant characteristics, comorbidities, baseline and follow-up serum 25-hydroxyvitamin D [25(OH)D] concentration, and available outcome measures [glycosylated hemoglobin (HbA1c), fasting plasma glucose, plasma glucose after 2-hour oral glucose tolerance test, and homeostatic model assessment of insulin resistance (HOMA-IR)]. Data synthesis was conducted using random-effect models (PROSPERO registration no. CRD42017055326). Twenty-eight trials, representing 3848 participants, met the eligibility criteria. Compared with the control group, vitamin D supplementation significantly reduced HbA1c level by -0.48% (95% CI, -0.79 to -0.18), fasting plasma glucose level by -0.46 mmol/L (95% CI, -0.74 to -0.19), and HOMA-IR level by -0.39 (95% CI, -0.68 to -0.11). Subgroup analysis revealed that the effects of vitamin D supplementation on different glycemic measures were influenced by age, calcium coadministration, vitamin D deficiency, serum 25(OH)D level after supplementation, and duration of supplementation. Vitamin D supplementation and improved vitamin D status improved glycemic measures and insulin sensitivity and may be useful as part of a preventive strategy for type 2 diabetes.
| S-EPMC6016617 | biostudies-literature