The serum 25-hydroxyvitamin D response to vitamin D supplementation is related to genetic factors, BMI, and baseline levels

A Prospective Open-Label Dose-Response Study to Correct Vitamin D Deficiency in Cirrhosis

BACKGROUND

Patients with advanced liver disease often have vitamin D deficiency, but the daily dosages of vitamin D3 needed to raise their serum 25-hydrodroxyvitamin D [25(OH)D] concentrations are unknown.

OBJECTIVE

We aimed to establish the dose-response relationship between vitamin D3 and 25(OH)D in patients with liver cirrhosis.

DESIGN

An open-label study of orally-administered vitamin D3 (gelcaps) was conducted in patients with liver cirrhosis using a tiered-dosing regimen: 4,000 IU/d for baseline 25(OH)D ≤ 15 ng/mL and 2,000 IU/d for baseline 25(OH)D > 15 to ≤ 25 ng/mL (NCT01575717). Supplementation continued for 6 months, or until liver transplantation. Changes in 25(OH)D were measured after ≥ 3 months. Dose-response data on 48 patients (21 receiving 4000 IU/d and 27 receiving 2,000 IU/d) reporting ≥ 80% adherence were analyzed using generalized estimating equations (GEE).

RESULTS

Among the 48 patients, 39 (81%) had 25(OH)D > 20 ng/mL while on supplements, and none experienced hypercalcemia. The magnitude of the increase in 25(OH)D was approximately twofold greater in patients receiving the higher dose. The mean incremental increase was 5.1 ng/ml ± 3.9 of 25(OH)D per 1000 IU/d of vitamin D3. Multivariable models demonstrated a significant positive relationship between baseline 25(OH)D and serum albumin (p < 0.01) and hemoglobin (p = 0.01), and a negative relationship with the MELD score (p < 0.01) and total bilirubin (p < 0.01).

CONCLUSIONS

A two-tiered dosing regimen of daily oral vitamin D3 supplementation safely raised 25(OH)D concentrations in the majority of adults with liver cirrhosis who were adherent to supplement use.

Clarifying the Heterogeneity in Response to Vitamin D in the Development, Prevention, and Treatment of Type 2 Diabetes Mellitus: A Narrative Review

In this review, we explore the potential drivers of heterogeneity in response to Vitamin D (VitD) therapy, such as bioavailability, sex-specific response, and autoimmune pathology, in those at risk for and diagnosed with T2DM. In addition, we propose distinct populations for future interventions with VitD. The literature concerning VitD supplementation in the prevention, treatment, and remission of type 2 diabetes mellitus (T2DM) spans decades, is complex, and is often contradictory with mixed findings upon intervention. By association, VitD status is powerfully predictive with deficient subjects reporting greater risk for T2DM, conversion to T2DM from prediabetes, and enhanced response to VitD therapy. Preclinical models strongly favor intervention with VitD owing to the pleiotropic influence of VitD on multiple systems. Additional research is crucial as there remain many questions unanswered that are related to VitD status and conditions such as T2DM. Future research must be conducted to better understand the potentially spurious relationships between VitD status, supplementation, sun exposure, health behaviors, and the diagnosis and management of T2DM. Public health practice can greatly benefit from a better understanding of the mechanisms by which we can reliably increase VitD status and how this can be used to develop education and improve health behaviors.

REsCue trial: Randomized controlled clinical trial with extended-release calcifediol in symptomatic COVID-19 outpatients

OBJECTIVES

This double-blind randomized controlled trial investigated raising serum 25-hydroxyvitamin D (25D) with extended-release calcifediol (ERC) on time to symptom resolution in patients with mild to moderate COVID-19.

METHODS

COVID-19 outpatients received oral ERC (300 mcg on days 1-3 and 60 mcg on days 4-27) or placebo (NCT04551911). Symptoms were self-reported daily. Primary end points were raising 25D to ≥50 ng/mL and decreasing resolution time for five aggregated symptoms (three respiratory).

RESULTS

In all, 171 patients were randomized, 160 treated and 134 (65 ERC, 69 placebo) retained. The average age was 43 y (range 18-71), 59% were women. The mean baseline 25D was 37 ± 1 (SE) ng/mL. In the full analysis set (FAS), 81% of patients in the ERC group achieved 25D levels of ≥50 ng/mL versus 15% in the placebo group (P < 0.0001). In the per-protocol (PP) population, mean 25D increased with ERC to 82 ± 4 (SE) ng/mL (P < 0.0001) by day 7; the placebo group trended lower. Symptom resolution time was unchanged in the FAS by ERC (hazard ratio [HR], 0.983; 95% confidence interval [CI], 0.695-1.390; P = 0.922). In the PP population, respiratory symptoms resolved 4 d faster when 25D was elevated above baseline level at both days 7 and 14 (median 6.5 versus 10.5 d; HR, 1.372; 95% CI, 0.945-1.991; P = 0.0962; Wilcoxon P = 0.0386). Symptoms resolved in both treatment groups to a similar extent by study end. Safety concerns including hypercalcemia were absent with ERC treatment.

CONCLUSION

ERC safely raised serum 25D to ≥50 ng/mL in outpatients with COVID-19, possibly accelerating resolution of respiratory symptoms and mitigating the risk for pneumonia. These findings warrant further study.

Determinants and Effects of Vitamin D Supplementation in Postmenopausal Women: A Systematic Review

Hormonal fluctuations, excessive clothing covering, sunscreen use, changes in body fat composition, a vitamin D-deficient diet, and a sedentary lifestyle can all predispose postmenopausal women to vitamin D deficiency. An effective supplementation plan requires a thorough understanding of underlying factors to achieve the desired therapeutic concentrations. The objective of this study was to conduct a systematic review of the predictors that affect vitamin D status in postmenopausal women. From inception to October 2022, we searched MEDLINE, Embase, Web of Science, Scopus, and clinical trial registries. Randomized clinical trials of postmenopausal women taking supplements of vitamin D with serum 25-hydroxyvitamin D (25(OH)D) measurement as the trial outcome were included. Two independent reviewers screened selected studies for full-text review. The final assessment covered 19 trials within 13 nations with participants aged 51 to 78. Vitamin D supplementation from dietary and pharmaceutical sources significantly increased serum 25(OH)D to optimal levels. Lower baseline serum 25(OH)D, lighter skin color, longer treatment duration, and prolonged skin exposure were all associated with a better response to vitamin D supplementation in postmenopausal women.

Effect of Vitamin D Supplementation on Serum 25-Hydroxyvitamin D and Homeostatic Model of Insulin Resistance Levels in Healthy Pregnancy: A Systematic Review and Meta-Analysis

Background

Progressive insulin resistance is a physiological condition during pregnancy that can lead to gestational diabetes. Given the association between low blood vitamin D levels and insulin resistance, the present meta-analysis evaluated the effect of vitamin D supplementation on serum 25-hydroxyvitamin D (25[OH]D) and the homeostatic model of insulin resistance (HOMA-IR) levels in non-diabetic pregnant women.

Methods

A comprehensive literature search was conducted using electronic databases and gateways such as Cochrane Library, Medline, Google Scholar, Science Direct, Web of Sciences, Embase, and Scopus. Articles up to 2020 in both English and Persian were included in the study. The effect of vitamin D supplementation on 25(OH)D and HOMA-IR was determined based on the differences in mean changes from baseline to post-intervention. Weighted mean and 95% confidence intervals (CI) were pooled using a random-effects model. Data were analyzed using STATA software.

Results

Four studies, including six trials with 380 participants, reported that vitamin D supplementation increased 25(OH)D (mean change: 13.72, 95% CI: 7.28-20.17) and decreased HOMA-IR (mean change: 1.46, 95% CI: 0.56-2.37) levels compared with the placebo group. A high weekly dose of vitamin D further reduced HOMA-IR levels (adjusted R²=77.99, I² residuals=80.49%, P=0.047). There was no significant association between the dose of vitamin D and 25(OH)D (P=0.974). Intervention duration was not associated with an increase in 25(OH)D (P=0.102), nor with a decrease in HOMA-IR (P=0.623).

Conclusion

Vitamin D supplementation increased 25(OH)D and decreased HOMA-IR levels in non-diabetic pregnant women. Vitamin D in high doses further reduced HOMA-IR, but did not affect 25(OH)D concentrations.

Impact of daily vitamin D3 supplementation on the risk of vitamin D deficiency with the interaction of rs2282679 in vitamin D binding protein gene (GC) among overweight and obese children and adolescents: A one-year randomized controlled trial

Background

The rs2282679 polymorphism in the vitamin D binding protein (DBP) gene may influence the response to vitamin D supplementation. Therefore, we examine the effect of 1-year vitamin D supplementation on vitamin D deficiency (VDD) with the interaction of rs2282679 polymorphism in overweight and obese children and adolescents.

Materials and methods

The participants (n = 300) were part of a randomized controlled trial who received a daily supplement of either 1,000 or 2,000 IU or four supplements of 1,000 IU weekly (equal to 600 IU daily) of vitamin D₃ for 12 months. Genotyping was performed using amplification refractory mutation system polymerase chain reaction (ARMS-PCR).

Results

The mean of 25(OH)D values at baseline for participants with the TT, TG, and GG genotypes were 15.4, 14.4, and 10.8 ng/mL, respectively, and were not different between the three genotype groups (P = 0.062). A significant reduction in VDD was observed after vitamin D supplementation with dosages of 1,000 or 2,000 IU compared to 600 IU. No significant association of genotypes with risk of VDD was observed in each intervention group after vitamin D supplementation, except, that individuals with TG genotype showed a higher risk of VDD compared to those with TT genotype in the 2,000 IU group after 6 months of supplementation [odds ratio (95% CI): 6.94; 1.30-37.02]. We observed no interaction between time duration, three genotypes, and dosages with serum 25(OH)D, calcium, phosphorus, alkaline phosphatase, and parathyroid hormone levels.

Conclusion

Response to vitamin D supplementation by three doses of 600, 1,000, and 2,000 IU could not be affected by rs2282679 polymorphism during 12 months in overweight and obese children and adolescents.

Definition, Assessment, and Management of Vitamin D Inadequacy: Suggestions, Recommendations, and Warnings from the Italian Society for Osteoporosis, Mineral Metabolism and Bone Diseases (SIOMMMS)

In the recent years, both the prescriptions of serum 25(OH)D levels assay, and vitamin D supplementation are constantly increasing, as well as the costs to be incurred relating to these specific aspects. As in many other countries, the risk of vitamin D deficiency is particularly high in Italy, as recently confirmed by cohort studies in the general population as well as in patients with metabolic bone disorder. Results confirmed the North-South gradient of vitamin D levels described among European countries, despite the wide use of supplements. Although vitamin D supplementation is also recommended by the Italian Medicine Agency for patients at risk for fragility fracture or for initiating osteoporotic medication, the therapeutic gap for osteoporosis in Italy is very high. There is a consistent proportion of osteoporotic patients not receiving specific therapy for osteoporosis following a fragility fracture, with a poor adherence to the recommendations provided by national guidelines and position paper documents. The failure or inadequate supplementation with vitamin D in patients on antiresorptive or anabolic treatment for osteoporosis is thought to further amplify the problem and exposes patients to a high risk of re-fracture and mortality. Therefore, it is important that attention to its possible clinical consequences must be given. Thus, in light of new evidence from the literature, the SIOMMMS board felt the need to revise and update, by a GRADE/PICO system approach, its previous original recommendations about the definition, prevention, and treatment of vitamin D deficiency in adults, released in 2011. Several key points have been here addressed, such as the definition of the vitamin D status: normality values and optimal values; who are the subjects considered at risk of hypovitaminosis D; opportunity or not of performing the biochemical assessment of serum 25(OH)D levels in general population and in subjects at risk of hypovitaminosis D; the need or not to evaluate baseline serum 25(OH)D in candidate subjects for pharmacological treatment for osteoporosis; how and whether to supplement vitamin D subjects with hypovitaminosis D or candidates for pharmacological treatment with bone active agents, and the general population; how and whether to supplement vitamin D in chronic kidney disease and/or chronic liver diseases or under treatment with drugs interfering with hepatic metabolism; and finally, if vitamin D may have toxic effects in the subject in need of supplementation.

Raloxifene/Vitamin D Combination Therapy vs. Raloxifene Monotherapy on Serum 25-Hydroxy-Vitamin D Level among Postmenopausal Women with Osteoporosis or Osteopenia: A Randomized Controlled Trial

Background

We compared the efficacy of a fixed dose combination of raloxifene 60 mg/vitamin D 800 IU to raloxifene 60 mg alone on vitamin D status, as indicated by change in serum 25-hydroxy-vitamin D (25[OH]D) levels.

Methods

In this 16-week, open-label, randomized, active controlled, multicenter clinical trial conducted in 4 university-affiliated hospitals in Korea, postmenopausal women aged 55 to 70 years with osteoporosis or osteopenia were randomly assigned in a 1:1 ratio to receive raloxifene 60 mg/cholecalciferol 800 IU combination therapy or raloxifene 60 mg monotherapy. Primary endpoint was change in serum 25(OH)D level from baseline to 16 weeks after the intervention.

Results

A total of 96 participants were randomly assigned to raloxifene/vitamin D combination therapy (N=49) and raloxifene monotherapy (N=47) groups. At week 16, serum 25(OH)D level increased from baseline, only in the raloxifene/vitamin D combination therapy group. Change in serum 25(OH)D level from baseline to week 16 was higher in the raloxifene/vitamin D combination therapy group (2.7±6.5 ng/mL) than in the raloxifene monotherapy (−1.7±6.2 ng/mL; P=0.0034) group. Proportions and number of adverse events (AEs) categorized by the System-Organ Class were not different between the groups. There was only one severe AE case (spondylolisthesis; raloxifene/vitamin D group), unlikely to be related to trial intervention.

Conclusions

Among postmenopausal women with osteoporosis or osteopenia, a fixed dose combination of raloxifene 60 mg/vitamin D 800 IU showed superior efficacy in elevating serum 25(OH)D levels compared with raloxifene 60 mg alone during 16 weeks of follow-up. The safety of raloxifene/vitamin D combination was comparable to raloxifene alone.

Vitamin D supplementation in chronic obstructive pulmonary disease patients with low serum vitamin D: a randomized controlled trial

BACKGROUND

Vitamin D deficiency is frequently found in patients with chronic obstructive pulmonary disease (COPD). Vitamin D has antimicrobial, anti-inflammatory, and immunomodulatory effects. Therefore, supplementation may prevent COPD exacerbations, particularly in deficient patients.

OBJECTIVES

We aimed to assess the effect of vitamin D supplementation on exacerbation rate in vitamin D-deficient patients with COPD.

METHODS

We performed a multicenter, double-blind, randomized controlled trial. COPD patients with ≥1 exacerbations in the preceding year and a vitamin D deficiency (15-50 nmol/L) were randomly allocated in a 1:1 ratio to receive either 16,800 International Units (IU) vitamin D3 or placebo once a week during 1 y. Primary outcome of the study was exacerbation rate. Secondary outcomes included time to first and second exacerbations, time to first and second hospitalizations, use of antibiotics and corticosteroids, pulmonary function, maximal respiratory mouth pressure, physical performance, skeletal muscle strength, systemic inflammatory markers, nasal microbiota composition, and quality of life.

RESULTS

The intention-to-treat population consisted of 155 participants. Mean ± SD serum 25-hydroxyvitamin D [25(OH)D] concentration after 1 y was 112 ± 34 nmol/L in the vitamin D group, compared with 42 ± 17 nmol/L in the placebo group. Vitamin D supplementation did not affect exacerbation rate [incidence rate ratio (IRR): 0.90; 95% CI: 0.67, 1.21]. In a prespecified subgroup analysis in participants with 25(OH)D concentrations of 15-25 nmol/L (n = 31), no effect of vitamin D supplementation was found (IRR: 0.91; 95% CI: 0.43, 1.93). No relevant differences were found between the intervention and placebo groups in terms of secondary outcomes.

CONCLUSIONS

Vitamin D supplementation did not reduce exacerbation rate in COPD patients with a vitamin D deficiency.This trial was registered at clinicaltrials.gov as NCT02122627.

Effect of vitamin D supplementation on glycose homeostasis and islet function in vitamin D deficient or insufficient diabetes and prediabetes: a systematic review and meta-analysis

Objective of the present study was to evaluate the effect of vitamin D supplementation on glycose homeostasis, islet function, and diabetes progress. Literatures were searched via electronic databases, websites, and previous reviews from the earliest available time to the end of May 2020. Randomized controlled trials initially designed for diabetes and prediabetes with 25-dihydroxyvitamin D [25(OH)D]<30 ng/ml were included. All data were analyzed and presented based on the Cochrane guidelines and PRISMA guidelines. In total, 27 articles (n = 1,932) were enrolled in this study. Vitamin D supplementation significantly improved fasting blood glucose, postprandial blood glucose, and quantitative insulin sensitivity check index in diabetes and prediabetes with baseline 25(OH)D<30 ng/ml. Higher percentages regressing from prediabetes to normal glucose status [1.60 (1.19, 2.17), p = 0.002, n = 564] and lower percentage progressing from prediabetes to diabetes [0.68 (0.36, 1.27), p = 0.23, n = 569] were found in the supplementation group. The positive effects of vitamin D supplementation on body mass index, waist, HDL-C, LDL-C, and CRP were also demonstrated. In conclusion, modest improvements in vitamin D supplementation on short-term glycose homeostasis, insulin sensitivity, and disease development in diabetes and prediabetes with 25(OH)D<30 ng/ml were demonstrated, but more research needs to be conducted in the future to support the clinical application. (Register ID: CRD42020186004)

The use of finite mixture models to examine the serum 25(OH)D levels among Saudis

BACKGROUND

Recorded serum 25(OH)D in survey data varies with observed and unobserved respondent characteristics. The aim of this study was to expose latent population sub-groups and examine variation across groups regarding relationships between serum 25(OH)D and observable characteristics.

METHODS

This study explored the role of unobserved heterogeneity on associations between surveyed 25(OH)D and various factors using a sample (n = 2,641) extracted from the Saudi Health Interview Survey (2013). Linear regression and finite mixture models (FMM) were estimated and compared. The number of latent classes in the FMM was chosen based on BIC score.

RESULT

Three latent classes were identified. Class I (39.82%), class II (41.03%), and class III (19.15%) with mean 25(OH)D levels of 22.79, 34.88, and 57.45 ng/ml respectively. Distinct patterns of associations with nutrition, behaviour and socio-demographic variables were recorded across classes that were not revealed in pooled linear regression.

CONCLUSION

FMM has the potential to provide additional insights on the relationship between 25(OH)D levels and observable characteristics. It should be more widely considered as a method of investigation in this area.

Association between Polymorphisms in Vitamin D Pathway-Related Genes, Vitamin D Status, Muscle Mass and Function: A Systematic Review

An association between vitamin D level and muscle-related traits has been frequently reported. Vitamin D level is dependent on various factors such as sunlight exposure and nutrition. But also on genetic factors. We, therefore, hypothesize that single nucleotide polymorphisms (SNPs) within the vitamin D pathway-related genes could contribute to muscle mass and function via an impact on vitamin D level. However, the integration of studies investigating these issues is still missing. Therefore, this review aimed to systematically identify and summarize the available evidence on the association between SNPs within vitamin D pathway-related genes and vitamin D status as well as various muscle traits in healthy adults. The review has been registered on PROSPERO and was conducted following PRISMA guidelines. In total, 77 studies investigating 497 SNPs in 13 different genes were included, with significant associations being reported for 59 different SNPs. Variations in GC, CYP2R1, VDR, and CYP24A1 genes were reported most frequently, whereby especially SNPs in the GC (rs2282679, rs4588, rs1155563, rs7041) and CYP2R1 genes (rs10741657, rs10766197, rs2060793) were confirmed to be associated with vitamin D level in more than 50% of the respective studies. Various muscle traits have been investigated only in relation to four different vitamin D receptor (VDR) polymorphisms (rs7975232, rs2228570, rs1544410, and rs731236). Interestingly, all of them showed only very low confirmation rates (6-17% of the studies). In conclusion, this systematic review presents one of the most comprehensive updates of the association of SNPs in vitamin D pathway-related genes with vitamin D status and muscle traits in healthy adults. It might be used for selecting candidate SNPs for further studies, but also for personalized strategies in identifying individuals at risk for vitamin D deficiency and eventually for determining a potential response to vitamin D supplementation.

Relationship between BsmI polymorphism and VDR gene methylation profile, gender, metabolic profile, oxidative stress, and inflammation in adolescents

BACKGROUND

the biological activity of vitamin D depends on the activity of its receptor or VDR. On the other hand, the activity of this receptor is influenced by its state of methylation. The objective of this study was to verify if the BsmI polymorphism of the VDR gene influences its methylation profile in adolescents. Secondly, it was to verify if the status of some metabolic factors (oxidative stress, inflammation, lipid profile, and glycemia) in the serum, and gender-adjusted vitamin D levels are independent factors with an influence on the VDR methylation profile.

METHODS AND RESULTS

the study included 198 adolescents of both sexes, aged 15-19 years, who underwent testing for VDR gene methylation polymorphisms, serum vitamin D levels, and metabolic, oxidative stress, and systemic inflammation markers. It was observed that the BB genotype was less methylated than the other groups (26.1 % versus 30.3 %, and 29.3 % for Bb and bb, respectively), although without statistical differences between them. The odds ratio indicated a protection of 13 % (partially methylated) for vitamin D status, while alpha glycols increased the risk ratio (of being partially methylated) by 3 %. MDA was protective at a 28 % chance of risk that adolescents with higher levels of lipid peroxidation would be hypomethylated.

CONCLUSION

we conclude that the methylation profile of the VDR gene is not influenced by the different BsmI polymorphism genotypes, and that serum vitamin D and serum markers of oxidative stress and inflammation can modulate this profile.

Effectiveness of eight-week zinc supplementation on vitamin D3 status and leptin levels in a population of postmenopausal women: a double-blind randomized trial

BACKGROUND

The menopausal period is characterized by hormonal imbalance related to the alteration of parameters involved in lipid metabolism. In addition, menopause increases the risk of deficiencies of key vitamins and minerals such as vitamin D and zinc in such women. The present study investigates the influence of zinc supplementation on the status of vitamin D₃ and other lipid parameters in postmenopausal women.

METHODS

Fifty-one healthy postmenopausal women aged 44-76 years from the province of Granada (Spain) were divided into two groups (placebo and zinc) of 25 and 26 women, respectively. The zinc group was supplemented with 50 mg/day of zinc for 8 weeks. Nutrient intake assessment was performed by means of a 24 -h reminder. Zinc was determined by flame atomic absorption spectrophotometry. Vitamin D was analyzed by liquid chromatography - tandem mass spectrometry. Leptin was determined by enzyme immunoassay.

RESULTS

Zinc supplementation improved the initial vitamin D₃ status of the postmenopausal population (p = 0.049). Plasma levels of 25-OH-D₃ increased significantly after Zn supplementation in women with lower age at menopause (p = 0.045). Both intake and plasma zinc levels were inversely correlated to serum leptin levels (p = 0.044 and p = 0.033, respectively), being significantly lower in lower age at menopause (p < 0.001).

CONCLUSION

Zinc supplementation improved vitamin D₃ status and was associated to low leptin levels in the postmenopausal women of the study.

Cholecalciferol Supplementation Does Not Prevent the Development of Metabolic Syndrome or Enhance the Beneficial Effects of Omega-3 Fatty Acids in Obese Mice

BACKGROUND

Cholecalciferol (D3) may improve inflammation, and thus provide protection from cardiometabolic diseases (CMD), although controversy remains. Omega-3 fatty acids (ω-3FA) may also prevent the development of CMD, but the combined effects of ω-3FA and D3 are not fully understood.

OBJECTIVES

We determined the chronic independent and combined effects of D3 and ω-3FA on body weight, glucose homeostasis, and markers of inflammation in obese mice.

METHODS

We gave 8-week-old male C57BL/6J mice, which had been fed a high-fat, high-sucrose (HF) diet (65.5% kcal fat, 19.8% kcal carbohydrate, and 14% kcal protein) for 12 weeks, either a standard D3 dose (+SD3; 1400 IU D3/kg diet) or a high D3 dose (+HD3; 15,000 IU D3/kg diet). We fed 1 +SD3 group and 1 +HD3 group with 4.36% (w/w) fish oil (+ω-3FA; 44% eicosapentaenoic acid, 25% docosahexaenoic acid), and fed the other 2 groups with corn oil [+omega-6 fatty acids (ω-6FA)]. A fifth group was fed a low-fat (LF; 15.5% kcal) diet. LF and HF+ω-6+SD3 differences were tested by a Student's t-test and HF treatment differences were tested by a 2-way ANOVA.

RESULTS

D3 supplementation in the +HD3 groups did not significantly increase plasma total 25-hydroxyvitamin D and 25-hydroxyvitamin D3 [25(OH)D3] versus the +SD3 groups, but it increased 3-epi-25-hydroxyvitamin D3 levels by 3.4 ng/mL in the HF+ω-6+HD3 group and 4.0 ng/mL in the HF+ω-3+HD3 group, representing 30% and 70%, respectively, of the total 25(OH)D3 increase. Energy expenditure increased in those mice fed diets +ω-3FA, by 3.9% in the HF+ω-3+SD3 group and 7.4% in the HF+ω-3+HD3 group, but it did not translate into lower body weight. The glucose tolerance curves of the HF+ω-3+SD3 and HF+ω-3+HD3 groups were improved by 11% and 17%, respectively, as compared to the respective +ω-6FA groups. D3 supplementation, within the ω-3FA groups, altered the gut microbiota by increasing the abundance of S24-7 and Lachnospiraceae taxa compared to the standard dose, while within the ω-6FA groups, D3 supplementation did not modulate specific taxa.

CONCLUSIONS

Overall, D3 supplementation does not prevent CMD or enhance the beneficial effects of ω-3FA in vitamin D-sufficient obese mice.

Genotype-guided dietary supplementation in precision nutrition

Achieving adequate micronutrient status, while avoiding deficiencies, represents a challenge for people globally. Consequently, many individuals resort to oral nutrient supplementation (ONS) in order to correct suboptimal dietary intakes. Advances in the fields of nutrigenetics and nutritional genomics have identified differences in response to micronutrient supplementation according to genetic makeup, adding dietary supplement use to the clinician's toolkit in the precision nutrition era. This review focuses on published evidence linking genetic variants to the responses associated with some of the most popular dietary supplements. With an increasing number of health professionals becoming involved in the prescription of ONS, identifying and matching individuals to the appropriate dietary supplement according to their genotype is important for achieving optimal health benefits and micronutrient equilibrium, while reducing the adverse events and financial costs often associated with excessive ONS.

Genetic Variation and Hot Flashes: A Systematic Review

CONTEXT

Approximately 70% of women report experiencing vasomotor symptoms (VMS, hot flashes and/or night sweats). The etiology of VMS is not clearly understood but may include genetic factors.

EVIDENCE ACQUISITION

We searched PubMed and Embase in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidance. We included studies on associations between genetic variation and VMS. We excluded studies focused on medication interventions or prevention or treatment of breast cancer.

EVIDENCE SYNTHESIS

Of 202 unique citations, 18 citations met the inclusion criteria. Study sample sizes ranged from 51 to 17 695. Eleven of the 18 studies had fewer than 500 participants; 2 studies had 1000 or more. Overall, statistically significant associations with VMS were found for variants in 14 of the 26 genes assessed in candidate gene studies. The cytochrome P450 family 1 subfamily A member 1 (CYP1B1) gene was the focus of the largest number (n = 7) of studies, but strength and statistical significance of associations of CYP1B1 variants with VMS were inconsistent. A genome-wide association study reported statistically significant associations between 14 single-nucleotide variants in the tachykinin receptor 3 gene and VMS. Heterogeneity across trials regarding VMS measurement methods and effect measures precluded quantitative meta-analysis; there were few studies of each specific genetic variant.

CONCLUSIONS

Genetic variants are associated with VMS. The associations are not limited to variations in sex-steroid metabolism genes. However, studies were few and future studies are needed to confirm and extend these findings.

Comparisons of different vitamin D supplementation for prevention of osteoporotic fractures: a Bayesian network meta-analysis and meta-regression of randomised controlled trials

Previous randomised controlled trials have shown the controversial effectiveness of oral vitamin D supplementation in preventing osteoporotic fractures. PubMed, EMBASE and Cochrane Library electronic databases were searched. Pairwise meta-analysis, Bayesian network meta-analysis and meta-regression were applied. A total of 33 studies containing 83,083 participants were included. Oral vitamin D supplementation showed no statistically significant on reducing the risk of total fractures (RR = 0.96, 95%CI = 0.87-1.05 p = 0.389). Vitamin D₃ (700-800IU/d) plus calcium showed statistical significance in reducing the incidence of total, hip and non-vertebral fractures in the pairwise meta-analysis. Significant reductions were specifically identified in female in total and hip fractures. However, we did not observe any above significant results using Bayesian network meta-analyses. Strikingly, a meta-regression analysis identified an inverse association between the efficacy of fracture prevention and increased body mass index. Thus, we recommended that the vitamin D dose should be adjusted according to BMI based on further confirmation.

Marker changes of blood plasma proteinogram in rats with toxic hepatitis

In recent years, there has been a pronounced tendency to increase in the incidence of drug-induced liver damage due to the growing expansion of the pharmaceutical market, which is also observed in the case of incorrect administration of nonsteroidal anti-inflammatory drugs (NSAIDs). In this case, the violation of the functional state of the body has a negative effect on synthetic processes, which in combination with the protein system of tissues significantly affects the metabolic homeostasis of the body. Therefore, the aim of the study was to determine marker changes in the plasma protein spectrum in laboratory rats with diclofenac-induced hepatitis and the effectiveness of reparative therapy based on milk phospholipids. The drug form of toxic hepatitis in laboratory animals was induced according to the author’s model by oral administration of diclofenac sodium (NSAID group) at a dose of 12.5 mg/kg, once a day for 14 days. Thus, in rats with toxic hepatitis there was a probable decrease in plasma total protein content by 15.6% compared with control, indicating a violation of protein-synthesizing function of the liver. With the introduction into the body of clinically healthy and sick animals of the liposomal form of the bioadditive "FLP-MD" based on milk phospholipids, the level of total protein in blood plasma corresponded to control values. As a result of the study of the plasma protein spectrum of Wistar rats, the four most sensitive indicators, which undergo significant probable changes in absolute and relative units of measurement with the development of toxic diclofenac-induced hepatitis, are protein fractions with molecular weights of 180–190, 150–170, 60 and 54–58 kDa and four markers of the effectiveness of restoring the protein-synthesizing function of the liver with the use of corrective therapy, in particular, bioadditives "FLP-MD" – 900, 180–190, 68–70 kDa and the value of A/G ratio, which is important for implementation in applied veterinary medicine, especially in the diagnosis of NSAID hepatopathy, supplementing the picture of its pathogenesis at the molecular level and testing the effectiveness of newly created drugs of hepatoprotective profile.

Personalized Nutrition for Management of Micronutrient Deficiency-Literature Review in Non-bariatric Populations and Possible Utility in Bariatric Cohort

Background

Bariatric surgery can effectively treat morbid obesity; however, micronutrient deficiencies are common despite recommendations for high-dose supplements. Genetic predisposition to deficiencies underscores necessary identification of high-risk candidates. Personalized nutrition (PN) can be a tool to manage these deficiencies.

Methods

Medline, PubMed, and Google Scholar were searched. Articles involving genetic testing, micronutrient metabolism, and bariatric surgery were included.

Results

Studies show associations between genetic variants and micronutrient metabolism. Research demonstrates genetic testing to be a predictor for outcomes among obesity and bariatric surgery populations. There is limited research in bariatric surgery and micronutrient genetic variants.

Conclusion

Genotype-based PN is becoming feasible to provide an effective treatment of micronutrient deficiencies associated with bariatric surgery. The role of genomic technology in micronutrient recommendations needs further investigation.

Markers Indicating Body Vitamin D Stores and Responses of Liver and Adipose Tissues to Changes in Vitamin D Intake in Male Mice

Circulating 25-hydroxyvitamin D (25(OH)D) is regarded as the most reliable biomarker of vitamin D status. However, limited data exist concerning the suitability of 25(OH)D as an indicator of body vitamin D stores and the ability of adipose tissue to mobilize vitamin D. In the first study, in which male mice received different vitamin D₃ doses for three weeks, we found strong linear response relationships between vitamin D₃ intake and levels of vitamin D₃ in the plasma (p < 0.001), liver (p < 0.001) and adipose tissues (p < 0.001), and strong positive correlations between plasma and tissue stores of vitamin D₃ (p < 0.001). Plasma levels of 25(OH)D₃ and 24,25-dihydroxyvitamin D₃ (24,25(OH)₂D₃) showed weak or no correlations with tissue vitamin D₃ stores. Data from a second study demonstrate a strong and rapid response of plasma 25(OH)D₃ in vitamin D₃-treated mice with a low vitamin D status. Additionally, mice fed a vitamin D-free diet showed a strong and rapid decline in vitamin D₃ in the liver, whereas the decline in different adipose tissues was distinctly lower than that in the liver. To conclude, tissue stores of vitamin D₃ were best reflected by plasma vitamin D₃. In contrast to the liver, adipose tissues responded less sensitively to an absence of vitamin D intake.

Serum PTH is not a good marker for defining a threshold for vitamin D deficiency

OBJECTIVE

In addition to its skeletal effects, vitamin D may also be important for health in general. It is uncertain what level of serum 25-hydroxyvitamin D (25(OH)D), marker of vitamin D status, is sufficient for these effects. With decreasing serum 25(OH)D levels there is an increase in serum PTH. The point at which this occurs has been considered as a threshold for vitamin D sufficiency. The thresholds found have varied widely and have mainly been based on observational studies. However, to truly establish a threshold for vitamin D effects, this has to be based on randomized controlled trials (RCTs).

METHODS

The study included 2803 subjects from a general health survey, the Tromsø study, and pooled individual person data from five vitamin D intervention studies (n = 1544). Serum parathyroid hormone (PTH) and change in PTH after vitamin D supplementation were related to serum 25(OH)D levels in steps of 25 nmol/L (<24, 25-49, 50-74, 75-99, and >99 nmol/L).

RESULTS

In the Tromsø study, in the females there was a gradual decrease in serum PTH with increasing serum 25(OH)D with no apparent plateau, whereas in the males the decrease in PTH in subjects with serum 25(OH)D >74 nmol/l was marginal. In pooled RCTs, there was a significant reduction in serum PTH by vitamin D supplementation regardless of baseline serum 25(OH)D level.

CONCLUSIONS

The use of the serum PTH-25(OH)D relation from observational studies to determine a threshold for vitamin D sufficiency is highly questionable.

Free vitamin D correlate better with bone mineral density and thoracolumbar junction osteoporotic vertebral fractures than serum vitamin D

Background

Vitamin D deficiency has long been studied as a risk factor for osteoporosis. However, the association between serum vitamin D status, bone mineral density (BMD) and the incidence of vertebral fractures (OVFs) remain controversial. It is believed that free portion of the circulating vitamin D carries the metabolic activities of vitamin D. Therefore, the aim of the present study is to analyse if free vitamin D correlates with BMD and osteoporotic fragile vertebral fractures in the elderly population.

Methods

A total of 90 consecutive patients, including 81 female and 9 male patients, aged > 48 years, were included in this cross sectional study between March and July of 2018. Total vitamin D (total 25(OH)D), free vitamin D (free 25(OH)D), calcium and phosphorus were measured. BMD was measured using dual energy X-ray absorptiometry (DEXA) and osteoporotic vertebral fracture was assessed using plain radiograph. Multiple linear regression was performed to find out the association between total vitamin D, free vitamin D and BMD at various sites. To evaluate the association with osteoporotic vertebral multivariate logistic regression model was used.

Results

The mean total vitamin D and free vitamin D were 25.1 ± 10.2 and 6.1 ± 1.7 respectively. Free vitamin D had a linear correlation with total vitamin D (R² = 0.69). While free vitamin D had a positive correlation with lumbar BMD roles (p < 0.05), total vitamin D didn’t have any association with BMD at any site. Of the total patients, 62 patients (68.9%) had thoracolumbar junction OVFs. Free vitamin D level correlated with the prevalence of OVFs as well as lumbar osteoporosis (p < 0.05). However, there was no statistical correlation between serum vitamin D status and the OVFs.

Conclusions

Free vitamin D was significantly related to the occurrence of thoracolumbar junction OVFs and lumbar BMD, which assumed to be a positive predictor for fracture and osteoporosis prevention. However, total serum vitamin D levels did not have any association with BMD at different sites as well as fragile vertebral fracture.

Trial registration

The study is registered at clinicaltrials.gov NCT03605173.

Association between Body Fatness and Vitamin D3 Status in a Postmenopausal Population

Vitamin D is a micronutrient that plays a key role in phosphocalcic metabolism. The postmenopausal population presents a risk of deficiency in this vitamin due to hormonal alterations which, in the case of obesity, would be exacerbated. The objective was to assess the status of vitamin D in a postmenopausal population and determine the relationship of 25-hydroxivitamin D [25(OH)D] and its metabolites with anthropometric parameters. The study included 78 healthy postmenopausal women aged from 44 to 76. The nutrient intake assessment was carried out using the 24 h reminder (R24h). 25(OH)D was analyzed using ultra-high-performance liquid chromatography (UHPLC). A total of 80% and 68% of the women studied did not reach sufficient values of 25(OH)D and 25-hydroxivitamin D₃ [25(OH)D₃], respectively, which was inversely correlated with Body Mass Index (BMI) (r = −0.25, p = 0.04), hip perimeter (r = −0.26 and r = −0.24, all p < 0.05), arm circumference (r = −0.29, p = 0.01) and fat mass (r = −0.28 and r = −0.26, all p < 0.05). 25(OH)D₃ is the metabolite that contributed most to this association. In conclusion, 25(OH)D₃ levels are related to anthropometric parameters in the postmenopausal women in this study, confirming insufficient status in the majority of the population. Approach strategies are necessary to correct and avoid this risk in order to ensure future quality of life.

Genetic Components of 25-Hydroxyvitamin D Increase in Three Randomized Controlled Trials

The 25-Hydroxyvitamin D (25[OH)D) serum concentration depends on vitamin D intake, endogenous vitamin D production and genetic factors. The latter have been demonstrated in large genome-wide association studies indicating that single nucleotide polymorphisms (SNPs) in genes related to the vitamin D metabolism are as important for serum 25(OH)D levels as the influence of season. The mechanism on how these SNPs influence serum 25(OH)D levels are still unclear. The aim of the present study was to investigate the genetic effects of ten selected SNPs related to vitamin D metabolism on 25-hydroxyvitamin D increase (∆25(OH)D) after vitamin D supplementation in three randomized controlled trials. Genotypes of SNPs related to vitamin D metabolism were determined in 411 participants with 25(OH)D concentrations < 75 nmol/l receiving 20,000 IU cholecalciferol per week for 8 or 12 weeks after study inclusion. For the vitamin D receptor (VDR) rs10783219 polymorphism, the minor A-allele was associated with lower ∆25(OH)D values in the entire study population (p = 0.022), which was not consistent in all three cohorts when analysed separately. VDR rs10783219 might therefore be a genetic modulator of increasing 25-hydroxyvitamin D concentrations. Considering the wide-spread use of vitamin D supplementation, future large and well-designed randomized controlled trials (RCTs) should investigate the clinical impact of this polymorphism.

Effect of genetic factors on the response to vitamin D3 supplementation in the VIDARIS randomized controlled trial

OBJECTIVES

Supplementation provides the best means of improving vitamin D status; however, individual responses vary partly owing to genetics. The aim of this study was to determine whether 28 single nucleotide polymorphisms (SNPs) in six key vitamin D pathway genes (GC, DHCR7, CYP2 R1, CYP24 A1, CYP27 B1, VDR) were associated with differences in response to supplementation.

METHODS

Participants (N = 313; n = 160 vitamin D, n = 153 placebo) were part of VIDARIS (Vitamin D and Acute Respiratory Infections Study), a double-blind, randomized controlled trial involving oral monthly supplementation of either vitamin D₃ (200 000 IU each for the first 2 mo, thereafter 100 000 IU monthly) or placebo for 18 mo. Circulating 25-hydroxyvitamin D (25[OH]D) concentrations at baseline and 2, 6, 12, and 18 mo, and vitamin D binding protein (Gc-globulin) and calculated free 25(OH)D concentrations at baseline and 2 mo were obtained. Multiple regression was used to model associations between genetic variants and 25(OH)D, Gc-globulin, and free 25(OH)D concentrations.

RESULTS

SNPs within GC, CYP2 R1, and CYP27 B1 were associated with 25(OH)D concentrations following supplementation. However, only two GC gene SNPs (rs2282679, rs1155563) were significant after adjustment for multiple testing. This effect disappeared after more than 2 mo of supplementation. None of the SNPs were significantly associated with Gc-globulin concentrations; however, there was a significant interaction with one SNP in DHCR7 (rs12785878), which was associated with reduced free 25(OH)D concentrations in the supplemented arm.

CONCLUSION

Only variants of GC were associated with 25(OH)D concentrations after supplementation. This effect was modest and disappeared after >2 mo of supplementation, suggesting it may be time/dose-dependent and saturable.

Factors Predicting the Response to a Vitamin D-Fortified Milk in Healthy Postmenopausal Women

Background: Milk products fortified with vitamin D may constitute an alternative to pharmacological supplements for reaching the optimal levels of serum 25-hydroxyvitamin D [25(OH)D]. Our aim was to analyze the response of serum 25(OH)D and its predictive factors in postmenopausal healthy women after a dietary intervention with a milk fortified with vitamin D and calcium. Methods: We designed a prospective study including 305 healthy postmenopausal women who consumed a fortified milk with calcium (900 mg/500 mL) and vitamin D3 (600 IU/500 mL) daily for 24 months. Results: The 25(OH)D concentrations at 24 months were correlated to weight, to body mass index, to the percentage of fat, triglycerides and to baseline 25(OH)D levels. We found significant differences in the levels of 25(OH)D at 24 months according to baseline 25(OH)D levels (p < 0.001) and body mass index (p = 0.019) expressed at quartiles. Multivariate analysis showed an association between levels of 25(OH)D after the intervention and at baseline 25(OH)D (Beta = 0.47, p < 0.001) and percentage of body fat (Beta = −0.227, p = 0.049), regardless of the body mass index. Conclusions: In healthy postmenopausal women, the improvement in 25(OH)D after an intervention with a fortified milk for 24 months depends mainly on the baseline levels of serum 25(OH)D and on the percentage of body fat.

Intake of ergosterol increases the vitamin D concentrations in serum and liver of mice

Factors that can modify the bioavailability of orally administered vitamin D are not yet widely known. Ergosterol is a common fungal sterol found in food which has a chemical structure comparable to that of vitamin D. This study aimed to investigate the effect of ergosterol on vitamin D metabolism. Therefore, 36 male wild type-mice were randomly subdivided into three groups (n = 12) and received a diet containing 25 μg vitamin D₃ and either 0 mg (control), 2 mg or 7 mg ergosterol per kg diet for 6 weeks. To elucidate the impact of ergosterol on hepatic hydroxylation of vitamin D, human hepatoma cells (HepG2) were treated with different concentrations of ergosterol. Concentrations of vitamin D₃ and 25-hydroxyvitamin D₃ (25(OH)D₃) in cells, livers and kidneys of mice and additionally 24,25-dihydroxyvitamin D₃ (24,25(OH)₂D₃) in serum were quantified by LC-MS/MS. The concentration of 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) in serum was analyzed by commercially-available enzyme immuno assay. The concentrations of cholesterol and triglycerides were analyzed in livers of mice by photometric assays. Analyses revealed that mice receiving 7 mg/kg ergosterol with their diet had 1.3-, 1.7- and 1.5-times higher concentrations of vitamin D₃ in serum, liver and kidney, respectively, than control mice (P < 0.05), whereas no significant effects were observed in mice fed 2 mg/kg ergosterol. The hydroxylation of vitamin D remained unaffected by dietary ergosterol, since the concentration of 25-hydroxyvitamin D₃ in serum and tissues and the concentrations of 1,25(OH)₂D₃ and 24,25(OH)₂D₃ in serum were not different between the three groups of mice. The lipid concentrations in liver were also not affected by dietary ergosterol. Data from the cell culture studies showed that ergosterol did not influence the conversion of vitamin D₃ to 25(OH)D₃. To conclude, ergosterol appears to be a modulator of vitamin D₃ concentrations in the body of mice, without modulating the hydroxylation of vitamin D₃ in liver.

Genetic Variation of the Vitamin D Binding Protein Affects Vitamin D Status and Response to Supplementation in Infants

CONTEXT

Single nucleotide polymorphisms (SNPs) of the vitamin D binding protein encoding the GC (group component) gene affect 25-hydroxyvitamin D (25OHD) concentrations, but their influence on vitamin D status and response to vitamin D supplementation in infants is unknown.

OBJECTIVE

To study GC genotype-related differences in 25OHD concentrations and the response to supplementation during a vitamin D intervention study in infants.

DESIGN

In this randomized controlled trial, healthy term infants received vitamin D3 (10 or 30 μg/d) from 2 weeks to 24 months of age. GC SNPs rs2282679, rs4588, rs7041, and rs1155563 were genotyped. rs4588/7041 diplotype and haplotypes of rs2282679, rs4588, and rs7041 (Haplo3SNP) and of all four SNPs (Haplo4SNP) were determined.

MAIN OUTCOME MEASURES

25OHD measured in cord blood at birth and at 12 and 24 months during intervention.

RESULTS

A total of 913 infants were included. Minor allele homozygosity of all studied GC SNPs, their combined haplotypes, and rs4588/rs7041 diplotype 2/2 were associated with lower 25OHD concentrations at all time points in one or both intervention groups [analysis of covariance (ANCOVA) P < 0.043], with the exception of rs7041, which did not affect 25OHD at birth. In the high-dose supplementation group receiving 30 μg/d vitamin D3, but not in those receiving 10 µg/d, genotype of rs2282679, rs4588, and rs7041; diplotype; and Haplo3SNP significantly affected intervention response (repeated measurement ANCOVA Pinteraction < 0.019). Minor allele homozygotes had lower 25OHD concentrations and smaller increases in 25OHD throughout the intervention.

CONCLUSIONS

In infants, vitamin D binding protein genotype affects 25OHD concentration and efficiency of high-dose vitamin D3 supplementation.

Ancestry-specific polygenic scores and SNP heritability of 25(OH)D in African- and European-ancestry populations

Vitamin D inadequacy, assessed by 25-hydroxyvitamin D [25(OH)D], affects around 50% of adults in the United States and is associated with numerous adverse health outcomes. Blood 25(OH)D concentrations are influenced by genetic factors that may determine how much vitamin D intake is required to reach optimal 25(OH)D. Despite large genome-wide association studies (GWASs), only a small portion of the genetic factors contributing to differences in 25(OH)D has been discovered. Therefore, knowledge of a fuller set of genetic factors could be useful for risk prediction of 25(OH)D inadequacy, personalized vitamin D supplementation, and prevention of downstream morbidity and mortality. Using PRSice and weights from published African- and European-ancestry GWAS summary statistics, ancestry-specific polygenic scores (PGSs) were created to capture a more complete set of genetic factors in those of European (n = 9569) or African ancestry (n = 2761) from three cohort studies. The PGS for African ancestry was derived using all input SNPs (a p value cutoff of 1.0) and had an R2 of 0.3%; for European ancestry, the optimal PGS used a p value cutoff of 3.5 × 10-4 in the target/tuning dataset and had an R2 of 1.0% in the validation cohort. Those with highest genetic risk had 25(OH)D that was 2.8-3.0 ng/mL lower than those with lowest genetic risk (p = 0.0463-3.2 × 10-13), requiring an additional 467-500 IU of vitamin D intake to maintain equivalent 25(OH)D. PGSs are a powerful predictive tool that could be leveraged for personalized vitamin D supplementation to prevent the negative downstream effects of 25(OH)D inadequacy.

Bioavailability of Fat-Soluble Vitamins and Phytochemicals in Humans: Effects of Genetic Variation

Recent data have shown that interindividual variability in the bioavailability of vitamins A (β-carotene), D, and E, and carotenoids (lutein and lycopene), as well as that of phytosterols, is modulated by single nucleotide polymorphisms (SNPs). The identified SNPs are in or near genes involved in intestinal uptake or efflux of these compounds, as well as in genes involved in their metabolism and transport. The phenotypic effect of each SNP is usually low, but combinations of SNPs can explain a significant part of the variability. Nevertheless, results from these studies should be considered preliminary since they have not been validated in other cohorts. Guidelines for future studies are provided to ensure that sound associations are elucidated that can be used to build consolidated genetic scores that may allow recommended dietary allowances to be tailored to individuals or groups by taking into account the multiloci genotypic signature of people of different ethnic origin or even of individuals.

Effect of vitamin D3 seasonal supplementation with 1500 IU/day in north Italian children (DINOS study)

Background

The appropriate dose of vitamin D supplementation in children is still debated. We calculated that the recommended dose of 600–1000 IU vitamin D3/day is not sufficient to reach a serum 25-hydroxyvitamin D (25-OH-D) level of at least 30 ng/ml (75 nmol/l) in north Italian children > 12 months. The aim of this study was to analyse the effect of seasonal supplementation with 1500 IU (=37.5 μg) vitamin D3/day.

Methods

DINOS (D-vitamIN Oral Supplementation) study was a pilot, monocentric, non-random case-control register study. It was conducted in a paediatric primary care setting near Padova (North Italy, 45°N latitude). The data of 203 children (girls:boys 1:1,33) aged 2–15 years, collected between November 2010 and January 2015, were analysed. Active group A (n = 82) were given 1500 IU vitamin D3/day from November to April; control Group B (n = 121) received no supplementation. The serum 25-OH-D test was part of a laboratory tests panel and performed using a chemiluminescence immunoassay method.

Results

Serum 25-OH-D mean level + standard deviation throughout the period was 32 + 13 ng/ml (80 + 32 nmol/l) in group A vs 22 + 10 ng/ml (55 + 25 nmol/l) in group B. In group A 12% had vitamin D deficiency 25-OH-D < 20 ng/ml (50 nmol/l) and 1.2% severe vitamin D deficiency 25-OH-D < 10 ng/ml (25 nmol/l). In group B 46% had vitamin D deficiency and 9% severe deficiency (P <  0.001). In group A mean levels were normal or near-normal all the year except in May. Group B reached mean 25-OH-D levels close to 30 ng/ml (75 nmol/l) only in late summer. The active group mean 25-OH-D level was normal in preschoolers and schoolers but not in adolescents. Non-white children had a three-times vitamin D deficiency probability despite supplementation.

Conclusions

Vitamin D supplementation with at least 1500 IU vitamin D3/day from November to April was found appropriate for children in North Italy. A prolongation until May could be useful. Higher doses and/or prolonged periods could be more appropriate especially in adolescents and in non-white children.

Study registration

DINOS gained the approval of Padova Ethics Committee (n. 3960/U16/2016).

Electronic supplementary material

The online version of this article (10.1186/s13052-018-0590-x) contains supplementary material, which is available to authorized users.

The Association between Polymorphisms of Vitamin D Metabolic-Related Genes and Vitamin D3 Supplementation in Type 2 Diabetic Patients

OBJECTIVE

To investigate the effect of single nucleotide polymorphisms (SNPs) of the key genes in vitamin D metabolic pathway on the serum 25(OH)D level after long-term vitamin D₃ supplementation and provide a theoretical basis for rational vitamin D₃ supplementation in diabetic patients with different genetic backgrounds.

METHODS

Patients with type 2 diabetes (T2DM) who met the inclusive criteria were given 800 IU of vitamin D₃ daily for 30 consecutive months. Serum 25(OH)D levels was measured at enrollment and every 6 months after enrollment. The average value of four-time measurements represented individual serum 25(OH)D level during vitamin D₃ supplementation. Multiplex TaqMan genotyping was used to determine the distribution of eight candidate SNPs in genes of DHCR7, CYP2R1, CYP27B1, CYP24A1, and VDR, which are key genes in the vitamin D metabolic pathway, in diabetic patients.

RESULTS

At baseline, the average serum 25(OH)D level was 22.71 ± 6.87 ng/mL, and 17.9% of patients had a ≥30 ng/mL level. During supplementation, the level of 25(OH)D increased significantly at each time point, and the average 25(OH)D level increased to 30.61 ± 5.04 ng/mL; however, there were 44.6% of patients whose serum 25(OH)D levels were still below 30 ng/mL. In the patients with CYP27B1 (rs10877012) G/T genotype, 71.79% achieved sufficient level of 25(OH)D, which was significantly higher than the other two genotypes (P < 0.05). Compared with those with T/T genotype, the RR of the patients with rs10877012 for <30 ng/mL level was 0.544 (95% CI: 0.291-0.917), and the RR after adjusting age and outdoor activity was 0.560 (95% CI: 0.292-0.970).

CONCLUSION

The serum 25(OH)D level in patients with diabetes mellitus after long-term vitamin D₃ supplementation is associated with CYP27B1 polymorphism. Patients with rs10877012 G/T allele have a better response to vitamin D₃ supplementation.

TRIAL REGISTRATION

This trial is registered with ChiCTR-IPC-17012657.

Linking the metabolic syndrome and obesity with vitamin D status: risks and opportunities for improving cardiometabolic health and well-being

The global death toll from noncommunicable diseases is exceptionally high, reported to cause 71% of global deaths worldwide. Metabolic syndrome risk factors, especially excessive adiposity and obesity, are at the heart of the problem resulting in increased co-morbidities such as cardiometabolic diseases and cancer, increased health costs, poorer quality of life, and shortened survival. Vitamin D₃ can positively reverse many of these adverse effects and outcomes through blocking signaling mechanisms that predispose to cardiometabolic and metastatic disease. As an affordable natural agent, vitamin D₃ can be used to counteract obesity-induced inflammation, block early adipogenesis, enhance glucose uptake, counteract hyperleptinemia, ameliorate insulin resistance, and reduce hypertension. This is supported by data from in vitro, in vivo and epidemiological studies and clinical trials. We propose that everyone in general and obese patients in particular consider raising 25-hydroxyvitamin D levels through UVB exposure and/or supplemental vitamin D₃ intake to reduce cardiometabolic and metastatic disease and increase longevity.

Blunted serum 25(OH)D response to vitamin D3 supplementation in children with autism

Introduction: Data suggest a potential role for vitamin D in autism spectrum disorder (ASD) prevention and treatment. It is likely that the serum response to vitamin D supplementation contributes to its effectiveness. Multiple factors affect serum vitamin D 25(OH)D response to supplementation. Methods: We conducted post-hoc analysis of two double-blind, randomized, placebo-controlled trials (RCT) of vitamin D₃ supplementation, one RCT involving children with ASD and another involving children with asthma. Both trials were conducted in the same geographic location (Dublin, Ireland, 53°N), conducted over Winter season and utilized the same vitamin D₃ dose (2000 IU/day). Results: We included 18 children with ASD and 17 children with asthma. There was no significant difference in 25(OH)D or age at baseline, however, BMI was significantly lower in ASD (P = 0.03). Compliance with vitamin D supplementation was high in both trials. Despite a significantly longer intervention period (20w vs. 15w; P < 0.0001), ASD children had a significantly lower absolute increase (+26 vs. +45 nmol/l) in 25(OH)D (P = 0.04). Conclusions: Despite similar demographics, children with ASD had a lower increase in 25(OH)D levels with supplementation. Potential mechanisms include altered absorption/metabolism as well as well genetic factors. Clinical and research work relating to vitamin D is ASD should measure 25(OHO)D response to supplementation to assess therapeutic doses.

Global prevalence and disease burden of vitamin D deficiency: a roadmap for action in low- and middle-income countries

Vitamin D is an essential nutrient for bone health and may influence the risks of respiratory illness, adverse pregnancy outcomes, and chronic diseases of adulthood. Because many countries have a relatively low supply of foods rich in vitamin D and inadequate exposure to natural ultraviolet B (UVB) radiation from sunlight, an important proportion of the global population is at risk of vitamin D deficiency. There is general agreement that the minimum serum/plasma 25-hydroxyvitamin D concentration (25(OH)D) that protects against vitamin D deficiency-related bone disease is approximately 30 nmol/L; therefore, this threshold is suitable to define vitamin D deficiency in population surveys. However, efforts to assess the vitamin D status of populations in low- and middle-income countries have been hampered by limited availability of population-representative 25(OH)D data, particularly among population subgroups most vulnerable to the skeletal and potential extraskeletal consequences of low vitamin D status, namely exclusively breastfed infants, children, adolescents, pregnant and lactating women, and the elderly. In the absence of 25(OH)D data, identification of communities that would benefit from public health interventions to improve vitamin D status may require proxy indicators of the population risk of vitamin D deficiency, such as the prevalence of rickets or metrics of usual UVB exposure. If a high prevalence of vitamin D deficiency is identified (>20% prevalence of 25(OH)D < 30 nmol/L) or the risk for vitamin D deficiency is determined to be high based on proxy indicators (e.g., prevalence of rickets >1%), food fortification and/or targeted vitamin D supplementation policies can be implemented to reduce the burden of vitamin D deficiency-related conditions in vulnerable populations.

Body Mass Index, Vitamin D, and Type 2 Diabetes: A Systematic Review and Meta-Analysis

The deficiency of vitamin D is prevalent all over the world. Studies have shown that vitamin D may play an important role in the development of obesity. The current study was conducted to quantitatively evaluate the association between serum 25-(OH) vitamin D levels and the risk of obesity in both diabetic and non-diabetic subjects. A systematic review and meta-analysis of observational studies was carried out for that purpose. We searched the Medline, PubMed, and Embase databases throughout all of March 2018. A total of fifty five observational studies for both diabetic and non-diabetic subjects were finally included in the meta-analysis. The data were analyzed by comprehensive meta-analysis software version 3 and the random effects model was used to analyze the data. The meta-analysis showed an overall inverse relationship between serum vitamin D status and body mass index (BMI) in studies of both diabetic (r = −0.173, 95% = −0.241 to −0.103, p = 0.000) and non-diabetic (r = −0.152, 95% = −0.187 to −0.116, p = 0.000) subjects. The evidence of publication bias was not found in this meta-analysis. In conclusion, the deficiency of vitamin D is associated with an increased level of BMI in the studies of both diabetic and non-diabetic subjects. Reliable evidence from well-designed future randomized controlled trials is required to confirm the findings from observational studies and to find out the potential regulatory effects of vitamin D supplementation to lower BMI.

Effects of vitamin D supplementation on markers for cardiovascular disease and type 2 diabetes: an individual participant data meta-analysis of randomized controlled trials

Background

Evidence from randomized controlled trials (RCTs) for the causal role of vitamin D on noncommunicable disease outcomes is inconclusive.

Objective

The aim of this study was to investigate whether there are beneficial or harmful effects of cholecalciferol (vitamin D3) supplementation according to subgroups of remeasured serum 25-hydroxyvitamin D [25(OH)D] on cardiovascular and glucometabolic surrogate markers with the use of individual participant data (IPD) meta-analysis of RCTs.

Design

Twelve RCTs (16 wk to 1 y of follow-up) were included. For standardization, 25(OH)D concentrations for all participants (n = 2994) at baseline and postintervention were re-measured in bio-banked serum samples with the use of a certified liquid chromatography-tandem mass spectrometry method traceable to a reference measurement procedure. IPD meta-analyses were performed according to subgroups of remeasured 25(OH)D. Main outcomes were blood pressure and glycated hemoglobin (HbA1c). Secondary outcomes were LDL, HDL, and total cholesterol and triglycerides; parathyroid hormone (PTH); fasting glucose, insulin, and C-peptide; and 2-h glucose. In secondary analyses, other potential effect modifiers were studied.

Results

Remeasurement of 25(OH)D resulted in a lower mean 25(OH)D concentration in 10 of 12 RCTs. Vitamin D supplementation had no effect on the main outcomes of blood pressure and HbA1c. Supplementation resulted in 10-20% lower PTH concentrations, irrespective of the 25(OH)D subgroups. The subgroup analyses according to achieved 25(OH)D concentrations showed a significant decrease in LDL-cholesterol concentrations after vitamin D supplementation in 25(OH)D subgroups with <75, <100, and <125 nmol of -0.10 mmol/L (95% CI: -0.20, -0.00 mmol/L), -0.10 mmol/L (95% CI: -0.18, -0.02 mmol/L), and -0.07 mmol/L (95% CI: -0.14, -0.00 mmol/L), respectively. Patient features that modified the treatment effect could not be identified.

Conclusions

For the main outcomes of blood pressure and HbA1c, the data support no benefit for vitamin D supplementation. For the secondary outcomes, in addition to its effect on PTH, we observed indications for a beneficial effect of vitamin D supplementation only on LDL cholesterol, which warrants further investigation. This trial was registered at www.clinicaltrials.gov as NCT02551835.

Emerging Evidence of Thresholds for Beneficial Effects from Vitamin D Supplementation

Publications from clinical trials of vitamin D supplementation have increased substantially over the last 15 years. Yet, despite the growing number of randomized controlled trials, meta-analyses of these studies have drawn inconsistent conclusions. Many meta-analyses assume that vitamin D is a pharmacological agent, and give scant consideration of it being a nutrient. This limits their potential to detect beneficial effects in participants with vitamin D deficiency. An increasing body of evidence from both observational studies and clinical trials supports the presence of thresholds in vitamin D status below which disease risk increases and vitamin supplementation has beneficial effects. Future supplementation trials which seek to replicate these findings should recruit sufficient numbers of participants with low vitamin D levels, and not give low-dose vitamin D to the placebo group. If the presence of vitamin D thresholds for beneficial effects is confirmed, this would strengthen the need for vitamin D fortification of foods.

Prevalence of vitamin D insufficiency and evidence for disease prevention in the older population

The prevalence of vitamin D insufficiency, usually assessed by the analysis of circulating 25-hydroxyvitamin D (25[OH])D), is very high in the aging German population. An important factor that reduces endogenous vitamin D synthesis in older persons is physical inactivity or care-dependency that limits the time spent outside. Additionally, it has been suggested that the age-dependent decline in the glomerular filtration rate is associated with a reduced production of bioactive calcitriol. As this phenomenon is not detectable by the assessment of 25(OH)D, it is necessary to analyze the level of parathyroid hormone as a marker of calcitriol function. Because 25(OH)D levels are highly correlated with an active and healthy life style, data from epidemiological studies are not necessarily suitable to elucidate the role of vitamin D in disease prevention. Recently published meta-analyses of randomized controlled trials (RCTs) showed moderate effects of vitamin D supplementation on fracture risk and found that vitamin D was more effective when administered in combination with calcium. The role of vitamin D in the prevention of falls and frailty remains unclear. Much evidence has demonstrated the beneficial effects of vitamin D on respiratory tract infections and asthma, which are very relevant health issues in the older population. To conclude, vitamin D, particularly combined with calcium, has moderately beneficial effects on the skeletal system and is useful for the prevention of respiratory tract infections.

Ancestry-Adjusted Vitamin D Metabolite Concentrations in Association With Cytochrome P450 3A Polymorphisms

We investigated the association between genetic polymorphisms in cytochrome P450 (CYP2R1, CYP24A1, and the CYP3A family) with nonsummer plasma concentrations of vitamin D metabolites (25-hydroxyvitamin D3 (25(OH)D3) and proportion 24,25-dihydroxyvitamin D3 (24,25(OH)2D3)) among healthy individuals of sub-Saharan African and European ancestry, matched on age (within 5 years; n = 188 in each ancestral group), in central suburban Pennsylvania (2006-2009). Vitamin D metabolites were measured using high-performance liquid chromatography with tandem mass spectrometry. Paired multiple regression and adjusted least-squares mean analyses were used to test for associations between genotype and log-transformed metabolite concentrations, adjusted for age, sex, proportion of West-African genetic ancestry, body mass index, oral contraceptive (OC) use, tanning bed use, vitamin D intake, days from summer solstice, time of day of blood draw, and isoforms of the vitamin D receptor (VDR) and vitamin D binding protein. Polymorphisms in CYP2R1, CYP3A43, vitamin D binding protein, and genetic ancestry proportion remained associated with plasma 25(OH)D3 after adjustment. Only CYP3A43 and VDR polymorphisms were associated with proportion 24,25(OH)2D3. Magnitudes of association with 25(OH)D3 were similar for CYP3A43, tanning bed use, and OC use. Significant least-squares mean interactions (CYP2R1/OC use (P = 0.030) and CYP3A43/VDR (P = 0.013)) were identified. A CYP3A43 genotype, previously implicated in cancer, is strongly associated with biomarkers of vitamin D metabolism. Interactive associations should be further investigated.

Oral vitamin D3 supplementation for chronic plaque psoriasis: a randomized, double-blind, placebo-controlled trial

PURPOSE

The management of psoriasis remains a challenge for dermatologist and patient. This study aimed to determine whether vitamin D₃ supplementation improves psoriasis compared to placebo.

MATERIALS AND METHODS

In a randomized, doubled-blind, placebo-controlled trial, 101 participants ≥18 years with psoriasis were grouped by severity and allocated to 100,000 International Units (IU) vitamin D₃/month for 12 months (200,000 IU at baseline; n = 67) or an identical placebo (n = 34). Psoriasis Area and Severity Index (PASI) and serum 25(OH)D concentrations were assessed at 3-monthly intervals. The primary outcome was the difference in PASI between groups over time. The relationship between 25(OH)D and PASI across the sample was also considered in a post hoc analysis.

RESULTS

PASI did not differ between groups at any time (group F(1, 104) = 0.48, p = .49; group*time F(4, 384) = 0.26, p = .90). However, 25(OH)D increased in both groups, rendering these findings inconclusive. A significant inverse relationship existed between PASI and 25(OH)D, with elevation of 25(OH)D by up to 125 nmol/L associated with mild decreases in PASI (estimated range of decrease 0-2.6; p = .002).

CONCLUSIONS

A direct benefit of vitamin D₃ supplementation for psoriasis could not be determined. However, these findings suggest a relationship between 25(OH)D and psoriasis severity, at least in some subgroups. Australian New Zealand Clinical Trials Registry #12611000648921.

Prevalence and determinants of vitamin D deficiency in the third trimester of pregnancy: a multicentre study in Switzerland

Vitamin D deficiency during pregnancy is associated with negative health consequences for mothers and their infants. Data on the vitamin D status of pregnant women in Switzerland are scarce. A three-centre study was conducted in the obstetric departments of Zurich, Bellinzona and Samedan (Switzerland) to investigate the prevalence and determinants of vitamin D deficiency (serum 25-hydroxyvitamin D (25(OH)D)<50 nmol/l) in 3rd-trimester pregnant women living in Switzerland (n 305), and the correlation between 25(OH)D in pregnant women and their offspring at birth (n 278). Demographic and questionnaire data were used to explore the determinants of vitamin D deficiency. Median concentration of serum 25(OH)D in the third trimester of pregnancy was 46·0 nmol/l (1st-3rd quartiles: 30·5-68·5), representing a 53·4 % prevalence of vitamin D deficiency. 25(OH)D levels in the umbilcal cord blood (median: 50·0 nmol/l; 1st-3rd quartiles: 31·0-76·6) strongly correlated with mothers' serum 25(OH)D (Spearman's correlation ρ=0·79, P<0·001). Multivariable logistic regression analysis showed that significant determinants of vitamin D deficiency in pregnant women were centre of study, country of origin, season of delivery and vitamin D supplement intake. Near-term BMI, skin colour, use of sunscreen and mothers' education, although each not individually significant, collectively improved the ability of the model to explain vitamin D status. Low vitamin D levels were common in this sample of pregnant women and their newborns' cord blood. Vitamin D supplement intake was the most actionable determinant of vitamin D status, suggesting that vitamin D supplementation during pregnancy should receive more attention in clinical practice.

Understanding Personalized Training Responses: Can Genetic Assessment Help?

Background:

Traditional exercise prescription is based on the assumption that exercise adaptation is predictable and standardised across individuals. However, evidence has emerged in the past two decades demonstrating that large inter-individual variation exists regarding the magnitude and direction of adaption following exercise.

Objective:

The aim of this paper was to discuss the key factors influencing this personalized response to exercise in a narrative review format.

Findings:

Genetic variation contributes significantly to the personalized training response, with specific polymorphisms associated with differences in exercise adaptation. These polymorphisms exist in a number of pathways controlling exercise adaptation. Environmental factors such as nutrition, psycho-emotional response, individual history and training programme design also modify the inter-individual adaptation following training. Within the emerging field of epigenetics, DNA methylation, histone modifications and non-coding RNA allow environmental and lifestyle factors to impact genetic expression. These epigenetic mechanisms are themselves modified by genetic and non-genetic factors, illustrating the complex interplay between variables in determining the adaptive response. Given that genetic factors are such a fundamental modulator of the inter-individual response to exercise, genetic testing may provide a useful and affordable addition to those looking to maximise exercise adaption, including elite athletes. However, there are ethical issues regarding the use of genetic tests, and further work is needed to provide evidence based guidelines for their use.

Conclusion:

There is considerable inter-individual variation in the adaptive response to exercise. Genetic assessments may provide an additional layer of information allowing personalization of training programmes to an individual’s unique biology.

Impact of a single oral dose of 100,000 IU vitamin D3 on profiles of serum 25(OH)D3 and its metabolites 24,25(OH)2D3, 3-epi-25(OH)D3, and 1,25(OH)2D3 in adults with vitamin D insufficiency

BACKGROUND

We investigate the effect of a high dose of vitamin D3 on circulating concentrations of 25(OH)D3 and its metabolites 24,25(OH)2D3, 3-epi-25(OH)D3, and 1,25(OH)2D3 in healthy individuals with self-perceived fatigue and vitamin D insufficiency [25(OH)D3<50 nmol/L].

METHODS

One hundred and seven study participants (age 20-50 years) were randomized to receive a single 100,000 IU dose of vitamin D3 (n=52) or placebo (n=55). Vitamin D metabolite concentrations in serum were measured before, and 4 weeks after, supplementation.

RESULTS

Overall, 52% of participants receiving vitamin D3 attained a serum 25(OH)D3 level >75 nmol/L. Among individuals who received vitamin D3, there were significant increases in serum concentrations of 25(OH)D3 and its metabolites 24,25(OH)2D3, 3-epi-25(OH)D3, and 1,25(OH)2D3 at 4 weeks; however, inter-individual variability in these changes was substantial. Positive correlations between serum 25(OH)D3 and 24,25(OH)2D3 and 3-epi-25(OH)D3, and a significant negative correlation between serum 1,25(OH)2D3 and 3-epi-25(OH)D3, were found 4 weeks after supplementation. The 24,25(OH)2D3/25(OH)D3 and 24,25(OH)2D3/1,25(OH)2D3 ratios were significantly increased, compared with baseline, in participants receiving vitamin D3. Baseline 25(OH)D3 concentration was the only factor predictive of the change in 25(OH)D3 after supplementation.

CONCLUSIONS

Administration of a single high dose of vitamin D3 leads to a significant increase in concentrations of 25(OH)D3, 24,25(OH)2D3, 3-epi-25(OH)D3 and 1,25(OH)2D3; induction of the catabolic pathway predominates over the production of 1,25(OH)2D3. Due to the high inter-individual variation in the 25(OH)D3 response to supplementation, any given dose of vitamin D is unlikely to achieve optimal vitamin D status in all treated individuals.