Real-life use of vitamin D3-fortified bread and milk during a winter season: the effects of CYP2R1 and GC genes on 25-hydroxyvitamin D concentrations in Danish families, the VitmaD study

Association of Single Nucleotide Polymorphism in VDR, GC Globulin and CYP2R1 with the Risk of Esophageal Cancer

BACKGROUND

The proactive role of vitamin D has been well determined in different cancers. The protein that encodes the components of the vitamin D metabolism could appear to play a pivotal role in vitamin D stability and its maintenance. A polymorphism in vitamin-D-receptor (VDR), carrier globulin/binding protein (GC) and cytochrome P-450 family 2, subfamily R, polypeptide 1 (CYP2R1) genes has been predicted to be associated with the development of cancer. This study was designed to detect the association of VDR, GC Globulin and CYP2R1 gene polymorphism with the risk of esophageal cancer in the North-east Indian population.

METHODS

To carry out the study, a total of 100 patients diagnosed with esophageal cancer and 101 healthy controls were enrolled. In a case-control manner, all samples were subjected to do genotype testing for known SNPs on the VDR (rs1544410), GC (rs4588), and CYP2R1 (rs10741657) genes using Restriction-fragment length polymorphism (RFLP) followed by Sanger sequencing. The collected demographic and clinical data were analysed using the statistical software package SPSS v22.0.

RESULTS

The VDR haplotype heterozygous TC was found strongly associated with the carcinoma group (OR:1.09, 95%CI:0.67-1.75). The risk factors analysis using the GC globulin rs4588 phenotype, found a positive correlation in terms of mutant AA's harmful influence on the cancer cohort (OR = 1.125, OR=1.125, 95% CI, 0.573-2.206). The influence of the CYP2R1 rs10741657 polymorphism on the malignant cohort revealed that the GG mutant had a significant negative influence on the carcinoma, has an influential role in disease severity ( OR:1.736, at 95% CI; 0.368-8.180).

CONCLUSION

In conclusion, this study revealed the potential association of VDR gene polymorphism in the progression and development of esophageal cancer in north east Indian population cohort.

Fortification of Staple Foods for Household Use with Vitamin D: An Overview of Systematic Reviews

Vitamin D deficiency is a global public health concern with significant implications for bone health and chronic disease prevention. Our aim was to summarize the evidence from Cochrane and other systematic reviews evaluating the benefits or harms of vitamin D fortification of staple foods for household use. In April 2023, we systematically searched Ovid MEDLINE, Embase, Epistemonikos and the Cochrane Database of Systematic Reviews for systematic reviews investigating the effects of vitamin D fortification of food in general populations of any age. We used Cochrane methodology and assessed the methodological quality of included studies using AMSTAR (A MeaSurement Tool to Assess Systematic Reviews). We assessed the degree of overlap among reviews. All outcomes included in systematic reviews were assessed. The protocol is registered in PROSPERO (registration number: CRD42023420991). We included 27 systematic reviews out of 5028 records for analysis. Overall, 11 out of 12 systematic reviews calculating pooled estimates reported a significant increase in serum 25(OH)D concentrations. The mean change in serum 25(OH)D concentrations per additional 100 units of vitamin D ranged from 0.7 to 10.8 nmol/L. Fortification of food with vitamin D showed a reduction in the prevalence of vitamin D deficiency based on high-certainty evidence. Parathormone (PTH) levels were described to decrease, bone mineral density to increase, while the effects on other bone turnover markers were inconsistent. Fortification did not significantly impact most anthropometric parameters, but it seemed to positively influence lipid profiles. In summary, fortification of food with vitamin D results in a reduction of vitamin D deficiency and might increase serum 25(OH)D concentrations, to varying extents depending on the fortified vehicle and population characteristics. Additionally, fortification may have a positive impact on bone turnover and lipid metabolism but may only have a limited effect on anthropometric parameters.

Genetic Determinants of 25-Hydroxyvitamin D Concentrations and Their Relevance to Public Health

Twin studies suggest a considerable genetic contribution to the variability in 25-hydroxyvitamin D (25(OH)D) concentrations, reporting heritability estimates up to 80% in some studies. While genome-wide association studies (GWAS) suggest notably lower rates (13−16%), they have identified many independent variants that associate with serum 25(OH)D concentrations. These discoveries have provided some novel insight into the metabolic pathway, and in this review we outline findings from GWAS studies to date with a particular focus on 35 variants which have provided replicating evidence for an association with 25(OH)D across independent large-scale analyses. Some of the 25(OH)D associating variants are linked directly to the vitamin D metabolic pathway, while others may reflect differences in storage capacity, lipid metabolism, and pathways reflecting skin properties. By constructing a genetic score including these 25(OH)D associated variants we show that genetic differences in 25(OH)D concentrations persist across the seasons, and the odds of having low concentrations (<50 nmol/L) are about halved for individuals in the highest 20% of vitamin D genetic score compared to the lowest quintile, an impact which may have notable influences on retaining adequate levels. We also discuss recent studies on personalized approaches to vitamin D supplementation and show how Mendelian randomization studies can help inform public health strategies to reduce adverse health impacts of vitamin D deficiency.

Vitamin d-fortified bread: Systematic review of fortification approaches and clinical studies

Vitamin d-fortified bread has been proposed as a strategy to increase the average daily intake and serum status of this nutrient. This review aimed to bring together the different types of scientific articles on vitamin d-fortified bread. The databases used for the research were PUBMED, WEB of SCIENCE and SCOPUS; all original indexed studies written in English, published between January 2000 and March 2021, were considered. Three important points were identified: i) theoretical models of fortification; ii) stability, bioaccessibility, and bioavailability studies of vitamin d-fortified breads; and iii) clinical effects of vitamin d-fortified breads. This review showed that vitamin d-fortified bread is a promising vehicle for fortification strategy effects, leading to increased serum concentrations of 25(OH)D and decreased parathyroid hormone. However, further studies are needed to elucidate the effects and effectiveness of this fortification strategy in the prevention/treatment of vitamin D deficiency.

Genetic Risk Score for Serum 25-Hydroxyvitamin D Concentration Helps to Guide Personalized Vitamin D Supplementation in Healthy Finnish Adults

BACKGROUND

Genetic factors modify serum 25-hydroxyvitamin D [25(OH)D] concentration and can affect the optimal intake of vitamin D.

OBJECTIVES

We aimed to personalize vitamin D supplementation by applying knowledge of genetic factors affecting serum 25(OH)D concentration.

METHODS

We performed a genome-wide association study of serum 25(OH)D concentration in the Finnish Health 2011 cohort (n = 3339) using linear regression and applied the results to develop a population-matched genetic risk score (GRS) for serum 25(OH)D. This GRS was used to tailor vitamin D supplementation for 96 participants of a longitudinal Digital Health Revolution (DHR) Study. The GRS, serum 25(OH)D concentrations, and personalized supplementation and dietary advice were electronically returned to participants. Serum 25(OH)D concentrations were assessed using immunoassays and vitamin D intake using FFQs. In data analyses, cross-sectional and repeated-measures statistical tests and models were applied as described in detail elsewhere.

RESULTS

GC vitamin D-binding protein and cytochrome P450 family 2 subfamily R polypeptide 1 genes showed genome-wide significant associations with serum 25(OH)D concentration. One single nucleotide polymorphism from each locus (rs4588 and rs10741657) was used to develop the GRS. After returning data to the DHR Study participants, daily vitamin D supplement users increased from 32.6% to 60.2% (P = 6.5 × 10-6) and serum 25(OH)D concentration from 64.4 ± 20.9 nmol/L to 68.5 ± 19.2 nmol/L (P = 0.006) between August and November. Notably, the difference in serum 25(OH)D concentrations between participants with no risk alleles and those with 3 or 4 risk alleles decreased from 20.7 nmol/L to 8.0 nmol/L (P = 0.0063).

CONCLUSIONS

We developed and applied a population-matched GRS to identify individuals genetically predisposed to low serum 25(OH)D concentration. We show how the electronic return of individual genetic risk, serum 25(OH)D concentrations, and factors affecting vitamin D status can be used to tailor vitamin D supplementation. This model could be applied to other populations and countries.

Associations between common polymorphisms in CYP2R1 and GC, Vitamin D intake and risk of colorectal cancer in a prospective case-cohort study in Danes

Background

The association between vitamin D and incidence of colorectal cancer has been thoroughly investigated, but the results are conflicting. The objectives in this study were to investigate whether two functional polymorphisms in GC and CYP2R1, respectively, previously shown to predict vitamin D concentrations, were associated with risk of colorectal cancer; and further, to assess gene-environment interaction between the polymorphisms and intake of vitamin D through diet and supplementation in relation to risk of colorectal cancer.

Methods

A nested case-cohort study of 920 colorectal cancer cases and 1743 randomly selected participants from the Danish prospective “Diet, Cancer and Health” study was performed. Genotypes CYP2R1/rs10741657 and GC/rs4588 were determined by PCR-based KASP^™ genotyping assay. Vitamin D intake from supplements and diet was assessed from a validated food frequency questionnaire. Incidence rate ratios were estimated by the Cox proportional hazards model, and interactions between polymorphisms in GC and CYP2R1 and vitamin D intake in relation to risk of colorectal cancer were assessed.

Results

Neither of the two polymorphisms was associated with risk of colorectal cancer per se. Heterozygote carriage of CYP2R1/rs10741657 and GC/rs4588, and carriage of two risk alleles (estimated by a genetic risk score) were weakly associated with 9–12% decreased risk of colorectal cancer per 3 μg intake of vitamin D per day (IRR_{CYP2R1/rs10741657} = 0.88, 95% CI: 0.79–0.97; IRR_GC/rs4588 = 0.91, 95% CI: 0.82–1.01, IRR_GRS2 = 0.90, 95% CI: 0.81–0.99).

Conclusions

The results suggest that genetic variation in vitamin D metabolising genes may influence the association between vitamin D intake, through food and supplementation, and risk of colorectal cancer.

Clinical trial registry

NCT03370432. Registered 12 December 2017 (retrospectively registered).

A preliminary transcriptome analysis suggests a transitory effect of vitamin D on mitochondrial function in obese young Finnish subjects

OBJECTIVE

The effect of vitamin D at the transcriptome level is poorly understood, and furthermore, it is unclear if it differs between obese and normal-weight subjects. The objective of the study was to explore the transcriptome effects of vitamin D supplementation.

DESIGN AND METHODS

We analysed peripheral blood gene expression using GlobinLock oligonucleotides followed by RNA sequencing in individuals participating in a 12-week randomised double-blinded placebo-controlled vitamin D intervention study. The study involved 18 obese and 18 normal-weight subjects (of which 20 males) with mean (±s.d.) age 20.4 (±2.5) years and BMIs 36 (±10) and 23 (±4) kg/m2, respectively. The supplemental daily vitamin D dose was 50 µg (2000 IU). Data were available at baseline, 6- and 12-week time points and comparisons were performed between the vitamin D and placebo groups separately in obese and normal-weight subjects.

RESULTS

Significant transcriptomic changes were observed at 6 weeks, and only in the obese subjects: 1724 genes were significantly upregulated and 186 genes were downregulated in the vitamin D group compared with placebo. Further analyses showed several enriched gene categories connected to mitochondrial function and metabolism, and the most significantly enriched pathway was related to oxidative phosphorylation (adjusted P value 3.08 × 10-14). Taken together, our data suggest an effect of vitamin D supplementation on mitochondrial function in obese subjects.

CONCLUSIONS

Vitamin D supplementation affects gene expression in obese, but not in normal-weight subjects. The altered genes are enriched in pathways related to mitochondrial function. The present study increases the understanding of the effects of vitamin D at the transcriptome level.

Effects of CYP2R1 gene variants on vitamin D levels and status: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

CYP2R1 is a key gene in the vitamin D metabolic pathway. It has been suggested that CYP2R1 gene variants in European populations are associated with concentrations of 25(OH)D, a biomarker of vitamin D levels and status in peripheral blood. However, a comprehensive meta-analysis of this effect including different ethnicities has never been conducted. The objective of this meta-analysis was to evaluate the association between CYP2R1 gene variants and 25(OH)D levels and vitamin D status.

METHODS

PubMed, EMBASE, Web of Science, CNKI and Wanfang databases were systematically searched up to May 2018. Reporting followed PRISMA guidelines. The quality of the evidence was assessed using the STREGA system. Random or fixed effects model combined estimates and sub-group tested for ethnic differences. The I² statistic quantified between-study variation due to heterogeneity.

RESULTS

Sixteen articles with a total of 52,417 participants met the inclusion criteria and were included in the meta-analysis. For rs10741657, GG genotype was associated with a clear descending trend of 25(OH)D levels when compared with the AA genotype [SMD = -2.32, 95% CI (-4.42, -0.20); SMD = -3.46, 95% CI (-6.60, -0.33) and SMD = -0.24, 95% CI (-0.51, -0.03) for total, Caucasian and Asian groups, respectively] with the following heterogeneities I² = 37.9%, 69.2% and 24.5%, respectively. However, under the AG/AA genetic model, significant changes in 25(OH)D levels [SMD and 95% CI: -1.27(-2.32, -0.23)] were only evident in the Caucasian population. The meta-analysis on vitamin D deficiency showed that the risk-allele G was associated with an increased risk of vitamin D deficiency (OR = 1.09; 95% CI = 1.03-1.15, P = 0.002). The association between rs10741657 and increased risk of vitamin D deficiency was significant (OR = 1.42; 95% CI = 1.11-1.83, P = 0.006) under the dominant model (GG + AG/AA), but not under the recessive model (GG/AG + AA), (OR = 1.28; 95% CI = 0.89-1.84, P = 0.181). There was no evidence of publication bias.

CONCLUSION

Published articles provide evidence supporting a major role for the rs10741657 polymorphism of the CYP2R1 gene in determining 25(OH)D levels and the presence of vitamin D deficiency.

Genetic polymorphisms of CYP2S1, CYP2J2 and CYP2R1 genes in three Chinese populations: Han, Tibetan and Uighur

AIM

Cytochrome P450 enzymes CYP2S1, CYP2J2 and CYP2R1 are of interest due to their unknown enzymatic function and disease-specific expression property. The aim of this study was to investigate the genetic variations of CYP2S1, CYP2J2 and CYP2R1 genes, and their polymorphic distribution in different Chinese populations.

MATERIALS & METHODS

All of the exons, exon-intron boundaries and 1 kb 5'-flanking region of the three genes were sequenced in 150 Chinese subjects.

RESULTS

There were 21, 15 and nine genetic variants identified in CYP2S1, CYP2J2 and CYP2R1 genes, respectively. The genetic polymorphisms of CYP2S1 and CYP2J2 showed significant difference. Thr353Ala variant in CYP2S1 protein was predicted to be consistently damaged. The hydrogen bond interactions were decreased in two mutants: Thr353Ala and Cys372Ser. -177C >T in CYP2S1 affected transcription factor EGR1 binding site.

CONCLUSION

This study highlights the importance of genetic polymorphism information on the CYP2S1, CYP2J2  and CYP2R1 genes in Chinese populations.

Common genetic variants are associated with lower serum 25-hydroxyvitamin D concentrations across the year among children at northern latitudes

In a longitudinal study including 642 healthy 8–11-year-old Danish children, we investigated associations between vitamin D dependent SNP and serum 25-hydroxyvitamin D (25(OH)D) concentrations across a school year (August–June). Serum 25(OH)D was measured three times for every child, which approximated measurements in three seasons (autumn, winter, spring). Dietary and supplement intake, physical activity, BMI and parathyroid hormone were likewise measured at each time point. In all, eleven SNP in four vitamin D-related genes: Cytochrome P450 subfamily IIR1 (CYP2R1); 7-dehydrocholesterol reductase/nicotinamide adenine dinucleotide synthetase-1(DHCR7/NADSYN1); group-specific complement (GC); and vitamin D receptor were genotyped. We found minor alleles of CYP2R1 rs10500804, and of GC rs4588 and rs7041 to be associated with lower serum 25(OH)D concentrations across the three seasons (all P<0·01), with estimated 25(OH)D differences of −5·8 to −10·6 nmol/l from major to minor alleles homozygosity. In contrast, minor alleles homozygosity of rs10741657 and rs1562902 in CYP2R1 was associated with higher serum 25(OH)D concentrations compared with major alleles homozygosity (all P<0·001). Interestingly, the association between season and serum 25(OH)D concentrations was modified by GC rs7041 (Pinteraction=0·044), observed as absence of increase in serum 25(OH)D from winter to spring among children with minor alleles homozygous genotypes compared with the two other genotypes of rs7041 (P<0·001). Our results suggest that common genetic variants are associated with lower serum 25(OH)D concentrations across a school year. Potentially due to modified serum 25(OH)D response to UVB sunlight exposure. Further confirmation and paediatric studies investigating vitamin D-related health outcomes of these genotypic differences are needed.

PTH and Vitamin D

PTH and Vitamin D are two major regulators of mineral metabolism. They play critical roles in the maintenance of calcium and phosphate homeostasis as well as the development and maintenance of bone health. PTH and Vitamin D form a tightly controlled feedback cycle, PTH being a major stimulator of vitamin D synthesis in the kidney while vitamin D exerts negative feedback on PTH secretion. The major function of PTH and major physiologic regulator is circulating ionized calcium. The effects of PTH on gut, kidney, and bone serve to maintain serum calcium within a tight range. PTH has a reciprocal effect on phosphate metabolism. In contrast, vitamin D has a stimulatory effect on both calcium and phosphate homeostasis, playing a key role in providing adequate mineral for normal bone formation. Both hormones act in concert with the more recently discovered FGF23 and klotho, hormones involved predominantly in phosphate metabolism, which also participate in this closely knit feedback circuit. Of great interest are recent studies demonstrating effects of both PTH and vitamin D on the cardiovascular system. Hyperparathyroidism and vitamin D deficiency have been implicated in a variety of cardiovascular disorders including hypertension, atherosclerosis, vascular calcification, and kidney failure. Both hormones have direct effects on the endothelium, heart, and other vascular structures. How these effects of PTH and vitamin D interface with the regulation of bone formation are the subject of intense investigation.

Economic evaluation of vitamin D and calcium food fortification for fracture prevention in Germany

OBJECTIVE

The study evaluates the economic benefit of population-wide vitamin D and Ca food fortification in Germany.

DESIGN

Based on a spreadsheet model, we compared the cost of a population-wide vitamin D and Ca food-fortification programme with the potential cost savings from prevented fractures in the German female population aged 65 years and older.

SETTING

The annual burden of disease and the intervention cost were assessed for two scenarios: (i) no food fortification; and (ii) voluntary food fortification with 20 µg (800 IU) of cholecalciferol (vitamin D3) and 200 mg of Ca. The analysis considered six types of fractures: hip, clinical vertebral, humerus, wrist, other femur and pelvis.

SUBJECTS

Subgroups of the German population defined by age and sex.

RESULTS

The implementation of a vitamin D and Ca food-fortification programme in Germany would lead to annual net cost savings of €315 million and prevention of 36 705 fractures in the target population.

CONCLUSIONS

Vitamin D and Ca food fortification is an economically beneficial preventive health strategy that has the potential to reduce the future health burden of osteoporotic fractures in Germany. The implementation of a vitamin D and Ca food-fortification programme should be a high priority for German health policy makers because it offers substantial cost-saving potential for the German health and social care systems.

Investigation of multiple factors which may contribute to vitamin D levels of bedridden pregnant women and their preterm neonates

OBJECTIVE

25-Hydroxyvitamin D (25-OH-D) is the marker, which indicates vitamin D levels. The aim of this study was to investigate the possible factors, which contribute to serum 25-OH-D levels in bedridden mothers and their preterm neonates.

METHODS

Twenty-six preterm neonates born during the period of 24-33 weeks of gestational age and 20 mothers (who experienced pregnancy complications) were recruited to the study.

RESULTS

Five major results were obtained. (i) The 25-OH-D serum levels for preterm neonates and their mothers were found to possess strong correlation (ii) and both differed significantly in comparison with the optimal levels. (iii) An increase of mothers' 25-OH-D serum levels was associated with an increased possibility that the neonates would be measured to have normal 25-OH-D levels. (iv) Sex was not a key factor to neonates' 25-OH-D levels. (v) No correlation was found between mothers' 25-OH-D levels and their vitamin D3 supplement (400 IU/d during pregnancy).

CONCLUSIONS

Due to insufficient exposure to sunlight and a diet not enriched with vitamin D, bedridden pregnant women suffer from vitamin D deficiency and pregnancy complications lead often to birth of preterm neonates with the same deficiency. Mothers should increase the total amount of vitamin D intake (food and supplement).

Common variants in CYP2R1 and GC genes are both determinants of serum 25-hydroxyvitamin D concentrations after UVB irradiation and after consumption of vitamin D₃-fortified bread and milk during winter in Denmark

BACKGROUND

Little is known about how the genetic variation in vitamin D modulating genes influences ultraviolet (UV)B-induced 25-hydroxyvitamin D [25(OH)D] concentrations. In the Food with vitamin D (VitmaD) study, we showed that common genetic variants rs10741657 and rs10766197 in 25-hydroxylase (CYP2R1) and rs842999 and rs4588 in vitamin D binding protein (GC) predict 25(OH)D concentrations at late summer and after 6-mo consumption of cholecalciferol (vitamin D₃)-fortified bread and milk.

OBJECTIVES

In the current study, called the Vitamin D in genes (VitDgen) study, we analyzed associations between the increase in 25(OH)D concentrations after a given dose of artificial UVB irradiation and 25 single nucleotide polymorphisms located in or near genes involved in vitamin D synthesis, transport, activation, or degradation as previously described for the VitmaD study. Second, we aimed to determine whether the genetic variations in CYP2R1 and GC have similar effects on 25(OH)D concentrations after artificial UVB irradiation and supplementation by vitamin D₃-fortified bread and milk.

DESIGN

The VitDgen study includes 92 healthy Danes who received 4 whole-body UVB treatments with a total dose of 6 or 7.5 standard erythema doses during a 10-d period in winter. The VitmaD study included 201 healthy Danish families who were given vitamin D₃-fortified bread and milk or placebo for 6 mo during the winter.

RESULTS

After UVB treatments, rs10741657 in CYP2R1 and rs4588 in GC predicted UVB-induced 25(OH)D concentrations as previously shown in the VitmaD study. Compared with noncarriers, carriers of 4 risk alleles of rs10741657 and rs4588 had lowest concentrations and smallest increases in 25(OH)D concentrations after 4 UVB treatments and largest decreases in 25(OH)D concentrations after 6-mo consumption of vitamin D₃-fortified bread and milk.

CONCLUSION

Common genetic variants in the CYP2R1 and GC genes modify 25(OH)D concentrations in the same manner after artificial UVB-induced vitamin D and consumption of vitamin D₃-fortified bread and milk.